Source: UNIVERSITY OF NEBRASKA submitted to NRP
INTERACTIONS AMONG EXERCISE, NUTRITION, AND MUSCULOSKELETAL HEALTH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1009500
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
May 6, 2016
Project End Date
Sep 30, 2020
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF NEBRASKA
(N/A)
LINCOLN,NE 68583
Performing Department
Nutritional & Health Sciences
Non Technical Summary
A variety of conditions, including ageing, or energy deficiency, which occurs during weight loss or disordered eating, are associated with a loss of skeletal muscle and bone mass, which can lead to suboptimal health outcomes across the life span. However, diet and exercise strategies may be effective in counteracting the effects of ageing or energy deficiency on muscle and bone health.As part of our proposed five-year research plan, we will assess how muscle function decreases in ageing by comparing the effects of resistance exercise in college-aged adults and elderly adults. We will further assess whether increasing the protein content of the diet during weight loss is beneficial for bone and skeletal muscle health.Our goal is to improve diet and exercise strategies for the prevention of the age-related loss of muscle mass and function as well as for healthy weight loss. This research may improve the knowledge, behavior, and quality of life, particularly for older adults and for individuals who are overweight or obese or are at risk of unhealthy weight gain.
Animal Health Component
75%
Research Effort Categories
Basic
25%
Applied
75%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7246010101075%
7026010101025%
Knowledge Area
724 - Healthy Lifestyle; 702 - Requirements and Function of Nutrients and Other Food Components;

Subject Of Investigation
6010 - Individuals;

Field Of Science
1010 - Nutrition and metabolism;
Goals / Objectives
This proposed five-year research plan will integrate two primary objectives: 1) Assessment of age-related declines in muscle function by comparing the responses of college-aged and elderly adults during short-term resistance exercise; and 2) Assessment of the effectiveness of a dietary strategies aimed at increasing dietary protein intake in order to minimize the detrimental effects of weight loss on bone and skeletal muscle.Objective 1 will compare the responses of college-aged and elderly adults during short-term resistance exercise. Objective 1 is a blend of applied and basic research that will determine the physiological (neural versus hypertrophic) mechanisms underlying early phase adaptations to resistance exercise in young and older adults. Second, with the information gathered during the first objective, we will assess the effectiveness of short-term resistance training programs for improving neuromuscular function, strength, functionality, and muscle mass. Because Medicare often only covers the expenses of the first few physical therapy sessions and the compliance and adherence to resistance training programs can be relatively short-lived, the research question that we wish to answer is "What are the age-related differences in short-term resistance exercise adaptations in young versus older adults?" Answering this research question will improve how rehabilitative resistance exercise programs are designed. Compared to the plethora of literature showing that chronic resistance training (≥ 8 weeks) can prevent and treat sarcopenia (Fiatarone, O'Neill et al. 1994, Verdijk, Jonkers et al. 2009), limited evidence is available on the health-related benefits of short-term resistance training (1 - 4 weeks) (Cramer, Stout et al. 2007). Previous studies have demonstrated that only 2 or 3 resistance training sessions (about 1 week) have elicited small improvements in strength (Prevost, Nelson et al. 1999, Cramer, Stout et al. 2007) and acceleration (Brown and Whitehurst 2003). However, no previous studies have examined these short-term resistance protocols in older adults, which may be a common practice in physical therapy and rehabilitation. Therefore, this study may provide a better understanding of the early adaptations to resistance training and potentially identify factors that improve the compliance and adherence to longer-term lifestyle modifications.We hypothesize approximately 5% improvements in strength in the older adults compared to approximately 10% improvements in strength for the younger adults. Furthermore, we expect the majority of these improvements to be a result of neural factors, as opposed to increases in muscle size.Objective 2 will determine whether a dietary intervention of increased protein intake can preserve anabolic responsiveness of bone and skeletal muscle during energy deficiency and whether these effects translate in the long-term into improved bone mineral density and skeletal muscle mass in individuals undergoing weight loss. By addressing the following research questions: "Are strategies that preserve lean mass during energy-restricted weight loss effective in maintaining the anabolic sensitivity of the musculoskeletal system?" and "Are these strategies effective in preserving musculoskeletal health in individuals undergoing long-term weight loss?", objective 2 addresses both basic and applied research objective. To this end, we will chose a dietary strategy of increased dietary protein intake, which has previously been shown to attenuate the loss of lean mass and improve protein balance during energy deficiency (Pikosky, Smith et al. 2008, Pasiakos, Margolis et al. 2014). It is further known that a high protein intake, particularly when coupled with exercise, is associated with improved bone strength (Chevalley, Bonjour et al. 2008), an effect that is likely modulated by the stimulating effects of dietary protein on the secretion of IGF-1 (Rizzoli, Bianchi et al. 2010). Taken together, these findings lend to the idea that increased dietary protein during calorie restriction may preserve the anabolic sensitivity of bone and skeletal muscle, that this effect is modulated by increased secretion of anabolic hormones, and that increased protein intake, particularly when coupled with exercise, could result in improved bone health in individuals undergoing weight loss. For this purpose, we will conduct a short-term randomized controlled study (objective 2a) as well as a long-term clinical trial (objective 2b) involving diet and exercise interventions.Our short-term approach involves three experimental conditions lasting 5 days each: a) calorie restriction and exercise with normal protein intake (0.8 g/kg; CR-NP); b) calorie restriction and exercise with high protein intake (1.7 g/kg; CR-HP); and c) a control period of balanced caloric intake with exercise and matched protein intake (1.7 g/kg; CON). We will determine whether increased protein intake can preserve metabolic function and maintain anabolic sensitivity during calorie restriction (Aim 1) and whether increased protein intake can attenuate the increase in bone turnover, and particularly the increase in bone resorption, during calorie restriction (Aim 2). We hypothesize that weight loss will be similar following CR-HP and CR-LP, but that the loss of lean mass and the suppression of resting metabolic rate will be reduced in CR-HP when compared to CR-NP (H1A). We further hypothesize that the reduction in circulating concentrations of the anabolic hormones IGF-1, insulin, and testosterone will be attenuated in CR-HP when compared to CR-NP (H1B) and that likewise, the increase in markers of bone resorption (NTx, CTx) will be attenuated in CR-HP when compared to CR-NP (H2A).Our long-term approach involves a clinical trial over 18 months, the minimum duration required to detect measurable changes in bone health, with the following study arms: 1) calorie restriction with exercise and high protein intake (CR+EX+HP), 2) calorie restriction with exercise and normal protein intake (CR+EX+NP), and 3) a control group which exercises while maintaining their body weight (EX-CON). We will determine the effects of increased protein intake in conjunction with exercise on long-term weight loss and body composition (Aim 3) and bone mineral content and measures of bone geometry and strength (Aim 4). We hypothesize that short-term weight loss during the first 3 months of the intervention will be similar between CR+EX+HP and CR+EX+NP, but that long-term weight loss, assessed after the end of the 18-month study, will be greater in CR+EX+HP when compared to CR+EX+NP and EX-CON (H3A). We further hypothesize that increased protein intake will attenuate the loss of lean mass, such that lean mass loss will be greater in CR+EX+NP when compared to CR+EX+HP and EX-CON (H3B). We also hypothesize that increased protein intake will attenuate the reduction in bone mineral density such that bone mineral density at the end of the 18-month study will be reduced only in CR+EX+NP when compared to EX-CON, whereas at the end of the study bone mineral density in CR+EX+HP will be similar to that in EXCON (H4A).
Project Methods
Objective 1. Twenty college-aged (19-29 years, 10 women and 10 men) and 20 elderly (≥65 years; 10 women and 10) participants will be recruited from the university and local communities for this objective. Muscle strength testing will occur during pretest 1, pretest 2, and posttest for the determination of isometric peak torque (PT), rate of torque development (RTD), and concentric isokinetic PT of the non-dominant (based on throwing preference) forearm flexors on a calibrated Biodex System 3 isokinetic dynamometer (Biodex Medical Systems, Inc., Shirley, NY, USA).For the strength training protocol, the subjects will perform three separate concentric isokinetic training sessions. Forty-eight to seventy-two hours of rest will be allowed between all testing and training sessions. Electromyographic signals will be amplified (gain: x1000) using differential amplifiers (EMG 100, Biopac Systems, Inc., Santa Barbara, CA). Mechanomyographic signals from the biceps brachii will be detected with an accelerometer (Model; EGAS-FT-10/V05, bandwidth 0-200 Hz, deminsions: 1.0 x 1.0 x 0.5 cm, mass 1.0g, Entran Devices, Inc., Fairfield, NJ).The dependent variables will include peak torque (PT), rate of torque development (RTD), the electromechanical delay (EMD), EMG amplitude, and MMG amplitude during the voluntary and evoked muscle contractions. Voluntary peak torque (PTV) will be calculated as the highest consecutive 500 ms average torque value (Nm) obtained during the MVIC. The evoked peak twitch torque (PTE) will be defined as the highest torque value (Nm) obtained after the onset of the evoked twitch. Voluntary rate of torque development (RTDV) and evoked rate of torque development (RTDE) will be calculated from the first derivative of the torque signal (Nm·s-1) occurring between the onset of torque and peak torque. Muscle mass will be assessed with portable ultrasound technology (LOGIQ e BT12, GE Healthcare Ultrasound OTR, Wauwatosa, WI).Means, standard deviations, and 95% confidence intervals (CI) using the studentized t-distribution will be calculated across the sample and reported for each dependent variable. The sample sizes for this objective will be determined using the reliability coefficients determined in previous studies (Buckthorpe, Hannah et al. 2012, Jenkins, Palmer et al. 2014). Repeated-measures analyses of variance (ANOVA) will be used to statistically analyze the results. When necessary, follow-up analyses will include dependent-samples t-tests. All data analyses will be performed using SPSS v. 22.0 (SPSS Inc., Chicago, IL.). The type I error rate used to determine statistical significance will be ≤ 5%.Objective 2a. We will use a repeated-measures, randomized cross-over design with 3 experimental conditions lasting 5 days. Each participant will complete two conditions of caloric restriction (30 kcal/kg FFM), once with a protein intake of 0.8 g/kg (CR-NP) and once with a protein intake of 1.7 g/kg (CR-HP), and one control condition in energy balance (55 kcal/kg FFM). During all conditions, participants will conduct supervised aerobic exercise to expend 15 kcal/kg FFM per day.Participants: Inclusion criteria are 1) male, 2) age: 18-30, 3) ≥4 hours/week of purposeful aerobic exercise, 4) body mass index: 19-25 kg/m2, 5) ≤15% body fat, 6) weight stability (±2.5 kg) in the past 6 months. Exclusion criteria are: 1) smoking, 2) past or present diagnosis of a clinical eating disorder, 3) metabolic or cardiovascular disease, or use of medication that would interfere with study outcomes.Diet: For each condition, participants will be provided with all food consisting of a clinical product (Ensure Therapeutic Nutrition, Abbot) and maltodextrin (Tate & Lyle). Total caloric intake and protein intake will match prescriptions. Participants will supplement calcium and vitamin D to maintain intakes at levels recommended for optimal bone health (Ross, Manson et al. 2011).Exercise: During all conditions, participants will conduct supervised exercise on a bicycle ergometer (Monark LC6) at 60% VO2max to expend 15 kcal/kg FFM.Assessments: Assessments before and after completion of each condition include: fasting body weight, body composition using Bioimpedance (Quadscan 4000), resting metabolic rate (COSMED QUARK CPET), and a blood draw for the assessment of serum IGF-1, testosterone, insulin, NTx, CTx, Osteocalcin, AP, and P1NP.Statistical Analysis: A sample size of n=10 participants completing all three interventions are required to detect a 50% reduction in the loss of lean mass and a 25-50% attenuation in the suppression of insulin, IGF-1, and testosterone during CR-HP when compared to CR-LP with a power of 80% and p<0.05. Linear mixed model analysis will be used to identify differences in study outcomes across time between conditions, followed by post-hoc analyses.Objective 2b. We will use a randomized controlled design with three treatment arms. In the intervention groups, caloric intake will be restricted by 15% and caloric expenditure will be increased by 15% through exercise. In one group, we will maintain a normal dietary protein intake of 0.8 g/kg (CR+EX-NP), whereas we will increase dietary protein intake in the other group to 1.7 g/kg (CR+EX-HP). A control group will also conduct exercise but remain weight stable (CON+EX). Regular lab visits will occur over 18 months. Participants will be randomized to one of three treatment arms (CR+EX-HP; CR+EX-NP; CON+EX). Primary outcome variables will include measures of body weight, body composition, and bone mineral density (BMD).Participants: Inclusion criteria are 1) age: 19-40, 2) <1 hours/week of purposeful exercise, 3) body mass index: 25-30 kg/m2, 4) no excessive weight loss or gain in the recent past (±10% weight change within the past year). Exclusion criteria are: 1) smoking, 2) past or present diagnosis of a clinical eating disorder, 3) menopause (female participants only), and 4) metabolic or cardiovascular disease, or use of medication that would interfere with study outcomes.Diet: Participants will be trained by clinical dieticians to adjust their diet such that dietary intake goals for total daily caloric and protein intake are in agreement with the study requirements. To maintain the calcium and Vitamin D intake at levels recommended for optimal bone health, participants will be supplemented with calcium and Vitamin D (Ross, Manson et al. 2011).Exercise: Participants will undergo regular exercise training to increase daily caloric expenditure by 15%, which corresponds to approximately 180-240 min of moderate-intensity aerobic exercise per week. Exercise prescriptions will be adjusted individually based on individual progression of fitness.Body Composition and Bone Density: Dual X-ray absorptiometry (DXA) will be utilized throughout the study for the assessment of body composition and bone strength and quality via a GE Lunar iDXA (GE Healthcare, Madison, WI).Statistical Analysis: Data generated will be longitudinal (18 months) with three treatment arms. For longitudinal data collected at multiple time points (baseline, within intervention, post-intervention), we will utilize longitudinal general linear mixed effects models with the treatment difference at post-intervention as the primary contrast of interest. Possible missing data will be resorted using multiple imputation methods, if data is missing at. As such, we data analysis will include all data collected on participants irrespective of whether they completed all visits. We require a minimum sample size of n=27 per study condition (n=81 total) to detect the expected differences in body weight, body composition, and bone mineral density with a power of 80% and p<0.05.

Progress 05/06/16 to 09/30/20

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Dr. Cramer has separated from UNL.

Publications


    Progress 10/01/18 to 09/30/19

    Outputs
    Target Audience:The primary target audience of our efforts are scientists, allied health professionals, extension educators, student in sports and performance nutrition, and coaches and parents of youth athletes. Anyone with interest in youth physical activity and sports performance may wish to understand the roles of growth and development, neuromuscular development, dietary iron intake, and the risk-benefit ratio of depth jumps in children. In addition, companies such as Abbott Nutrition will be interested in the outcomes of our clinical trial study (NCT03701867) exploring muscle energy metabolism and metabolic flexibility in sarcopenic older adults. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?For Training Activities, the project involved training 3 graduate students and 2 undergraduate students during 2019. Students were trained in laboratory techniques, human subject compliance, research study design, and dissemination through scientific writing in a positive, team mentorship environment under the direction of principle investigator, Joel Cramer. In addition to the lab mentorship, each student also engaged in the following specific training activities: Registered Dietician Continuing Education: How do we Feed the Future without Eating the Planet? Examining the Human and Environmental Impacts of Beef Production. Beef Checkoff. March, 2019. Registered Dietician Continuing Education: Optimize Athletic Performance from Mid- to Ultra-distance Events. Nebraska Academy of Nutrition and Dietetics (NAND). March, 2019. Registered Dietician Continuing Education: Performance Nutrition: More than Bars and Hydration. Nebraska Academy of Nutrition and Dietetics (NAND). November, 2019. Certified by USA Weightlifting as USA Weightlifting Local Referee. January, 2019. Attended the Children's Hospital & Medical Center Pediatric Pain Conference (Omaha, NE). May, 2019. For Professional Development, five students (3 graduate students, 2 undergraduate students) and the principle investigator attended and presented at national conferences, including annual meetings of the Sports, Cardiovascular, and Wellness Nutrition (SCAN) Symposium in Phoenix, AZ, in April 2019; American College of Sports Medicine (ACSM) in Orlando, FL, in May 2019; International Society of Sport Nutrition (ISSN) in Las Vegas, NV in June 2019; and National Strength and Conditioning Association (NSCA) in Washington DC in July 2019. How have the results been disseminated to communities of interest?Results from this project and the knowledge acquired have been shared publically through educational television programs and interactive lectures within the local Lincoln and Nebraska state communities of interest. Cramer, J.T., Renaud, J. Exercise and Nutrition for Healthy Aging. Live and Learn, Public Access Television Program, Lincoln, NE: April 26, 2019. Airing in May, 2019. Cramer, J.T. What is Sarcopenia? Exercise and Nutrition for Healthy Aging. Oral/slide Presentation at Aging Partners Outreach Breakfast, Lincoln, NE: Feb 13, 2019. What do you plan to do during the next reporting period to accomplish the goals?Our laboratory team will continue to conduct research, teach, and disseminate the knowledge gained by the objectives of this project.

    Impacts
    What was accomplished under these goals? IMPACT Statement Skeletal muscle and bone health status are altered in a variety of circumstances that include age-related physical decline, organized physical activity participation, and inadequate dietary habits. Declines in muscle and bone mass and function can lead to suboptimal health outcomes across the lifespan, especially with advanced age. Understanding musculoskeletal changes during periods of significant growth and development becomes necessary as youth participate in organized physical activities earlier in life. Likewise, understanding age-related decreases in metabolic flexibility, through carbohydrate metabolism in older adults, justifies the necessity of practical diet and exercise strategies needed for the preservation and improvement of musculoskeletal health in these vulnerable populations. OBJECTIVE #1: Compare musculoskeletal responses of college-aged and elderly adults during exercise Major activities completed / experiments conducted Experiment #1: Reliability of Noninvasive Measurements of Muscle Tissue Oxygenation During Exercise. Experiment #2: Comparisons of muscle strength, size, and neuromuscular function in pre- and post-pubescent males and females. Data collected Experiment #1: Twenty-three subjects were enrolled and n=22 subjects (12 males, 10 females) completed two experimental lab visits to examine a non-invasive measurement system for skeletal muscle blood flow called continuous-wave near-infrared spectroscopy (NIRS). Blood flow (perfusion and diffusion) and muscle activation via electromyography were measured at rest and during resistance exercise performance at high and low intensities. Experiment #2: Forty-six participants consented to be in this study. Three pre-pubertal females did not finish the study, 1 pre-pubertal male did not finish the study, and 2 post-pubertal males did not meet the inclusion criteria for analyses. Therefore, n = 10 pre-pubertal males, n = 10 pre-pubertal females, n = 10 post-pubertal males, and n = 10 post-pubertal females were included in all analyses. Measurements of muscle strength, size, and neuromuscular function were compared between all groups. Summary statistics and discussion of results Experiment #1: Test-retest reliability was calculated from the two visits, which provides quantitative information about repeatability of the NIRS device for skeletal muscle blood flow and the sensitivity of measurement. Overall, the NIRS device showed excellent reliability with intra-class correlation coefficients ranging from 0.79-0.99. The NIRS device was reasonably sensitive, within 10-20% of average measurements, which is very good for noninvasive human subject measurement tools. Another key finding was that skeletal muscle blood flow systematically decreased while muscle force production increased, yet muscle tissue oxygen saturation remained constant until 60% exercise intensity, at which point oxygenation began to decline. Experiment #2: As expected, the post-pubertal males and females were stronger than the pre-pubertal males and females. There were greater differences in muscle size between the pre- and post-pubertal males, whereas there were greater differences in neuromuscular function between the pre- and post-pubertal females. Increases in muscle strength in young males likely originates from hypertrophy, or the increases in muscle size. In contrast, muscle strength increases during growth and development in females is driven more by neural adaptations, such as increases in motoneuron activation. Key outcomes Experiment #1: Preliminary findings indicate that the NIRS device will be useful for non-invasively examining skeletal muscle blood flow in athletic and clinical populations. Furthermore, the intensity of exercise at which skeletal muscle oxygen availability declines is much higher than orginally thought. These findings will lead to a change in action, whereby resistance training at or below 60% of maximal intensity can be used for short durations (~5 seconds) without declines in muscle oxygen availability. Prior to these findings, resistance training at 25% and above were thought to deminish oxygen availability. Experiment #2: These results provide evidence that skeletal muscle grows and develops differently in males and females, which provides a greater understanding on the healthy, normal growth and development of skeletal muscle among youth. The results of this study will lead to changes in knowledge of how young males and females get stronger during growth. Furthermore, these findings will lead to changes in how exercise is performed in males versus females for the development of muscle strength. OBJECTIVE #2: Nutrient intake to preserve anabolic responsiveness of bone and skeletal muscle Major activities completed / experiments conducted A pilot study to explore muscle energy metabolism and metabolic flexibility in older men and women (clinicaltrials.gov, NCT03701867). Data collected Twenty-two (n=22) older adults were studied over two separate laboratory visits. Subjects were screened for the presence of sarcopenia, defined as low handgrip strength and low skeletal muscle mass. Eleven subjects (n=11) were classified as sarcopenic, while n=11 were classified as non-sarcopenic. Skeletal muscle metabolism was measured by open-circuit spirometry and indirect calorimetry, which quantified calories, carbohydrates, and fats used for fuel. Measurements were taken during a 3-hour post-prandial period after eating a standardized, high-glycemic meal. Measurements were then taken while exercising on a treadmill at 50-60% of maximum intensity for 10 minutes. Finally, metabolic measurements were taken during leg extension resistance exercise to exhaustion with low resistance. Summary statistics and discussion of results Sarcopenic subjects showed a much higher use of carbohydrates than fats during all aspects of this experiment. Sarcopenic subjects also showed greater tendancies toward diabetes, although diabetes had not been diagnosed in any subjects. The high-sugar meal given induced greater blood sugar spikes and higher carbohydrate metabolism in sarcopenic individuals, which ultimately led to lower fat utilization. This trend over longer periods of time likely leads to greater intravascular and intramuscular fat stores in sarcopenic older adults. Furthermore, noninvasive measurements of skeletal muscle blood flow indicated less muscle blood flow in sarcopenic than non-sarcopenic older adults. Key outcomes Preliminary analyses indicated that sarcopenic older adutls had higher body weights and body fat mass, but similar leg muscle strength and whole-body skeletal muscle mass as non-sarcopenic older adults. The higher respiratory quotient in sarcopenic older adults at rest indicated a greater reliance on carbohydrate metabolism, and lower fat metabolism than non-sarcopenic subjects. This difference was amplified during exercise. Perhaps most disturbing was the inability of sarcopenic subjects to transition efficiently between carbohydrate and fat metabolism, indicating metabolic inflexibility - a condition common in diabetes. Furthermore, those who were sarcopenic had lower muscle tissue oxygenation, indicating less blood flow to the working muscles. Thus, if there is limited blood flow to the working muscles, nutrition interventions to improve muscle metabolic health may also be limited if nutrients cannot get to the targeted organ. Not only do these findings change our knowledge that sarcopenia is at least partly defined by metabolic inflexibility, but also change our actions in how nutrients are designed for older adults to maximize delivery to skeletal muscles.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gillen ZM, Shoemaker ME, McKay BD, Cramer JT. State Population Influences Athletic Performance Combine Test Scores in High School-Aged American Football Players. Int J Exerc Sci. 2019 Jan 1;12(6):256-262. eCollection 2019. PubMed PMID: 30761209; PubMed Central PMCID: PMC6355118.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gillen ZM, Shoemaker ME, McKay BD, Cramer JT. Performance Differences between National Football League and High School American Football Combine Participants. Res Q Exerc Sport. 2019 Jun;90(2):227-233. doi: 10.1080/02701367.2019.1571679. Epub 2019 Feb 22. PubMed PMID: 30794113.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Muscle strength, size, and neuromuscular function before and during adolescence. Eur J Appl Physiol. 2019 Jul;119(7):1619-1632. doi: 10.1007/s00421-019-04151-4. Epub 2019 May 13. PubMed PMID: 31087141.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Shoemaker ME, Gillen ZM, McKay BD, Koehler K, Cramer JT. High Prevalence of Poor Iron Status Among 8- to 16-Year-Old Youth Athletes: Interactions Among Biomarkers of Iron, Dietary Intakes, and Biological Maturity. J Am Coll Nutr. 2019 Jul 24:1-8. doi: 10.1080/07315724.2019.1621229. [Epub ahead of print] PubMed PMID: 31339828.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Jenkins NDM, Miramonti AA, Hill EC, Smith CM, Cochrane-Snyman KC, Housh TJ, Cramer JT. Mechanomyographic Amplitude Is Sensitive to Load-Dependent Neuromuscular Adaptations in Response to Resistance Training. J Strength Cond Res. 2019 Aug 23. doi: 10.1519/JSC.0000000000003276. [Epub ahead of print] PubMed PMID: 31453941.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Shoemaker ME, Gillen ZM, Mckay BD, Bohannon NA, Gibson SM, Koehler K, Cramer JT. Sex-specific relationships among iron status biomarkers, athletic performance, maturity, and dietary intakes in pre-adolescent and adolescent athletes. J Int Soc Sports Nutr. 2019 Sep 18;16(1):42. doi: 10.1186/s12970-019-0306-7. PubMed PMID: 31533743; PubMed Central PMCID: PMC6751686.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gillen ZM, Jahn LE, Shoemaker ME, McKay BD, Mendez AI, Bohannon NA, Cramer JT. Effects of Eccentric Preloading on Concentric Vertical Jump Performance in Youth Athletes. J Appl Biomech. 2019 Oct 1;35(5):327-335. doi: 10.1123/jab.2018-0340. PubMed PMID: 31541066.
    • Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: McKay, B.D. Oxygenation and activation of the vastus lateralis during dynamic constant external resistance leg extension muscle actions in older women with and without sarcopenia. Thesis Committee members: Cramer, J.T. (Chair), Housh, T.J., Schmidt, R.J.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Peak torque, but not rate of torque development, explains unique variability in growth measurements in boys and girls. Presented at the National Strength & Conditioning Association National Conference in Washington D.C., as a Poster presentation. July 2019.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Shoemaker ME, Gillen ZM, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Vertical jump power differences in male and female high school athletes can be accounted for by height and muscle-mass related variables. Presented at the National Strength & Conditioning Association National Conference in Washington D.C., as a Poster presentation. July 2019.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shoemaker ME, Gillen ZM, McKay BD, Bohannon NA, Mendez AI, Cramer JT. Effects of an online sports nutrition curriculum on biomarkers of iron status in youth athletes. Presented at the Annual Meeting of the American College of Sports Medicine in Orlando, FL, as a Thematic Poster presentation. June 2019. Medicine and Science in Sports and Exercise, 49(5): S702, 2019.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gillen ZM, Shoemaker ME, McKay BD, Bohannon NA, Mendez AI, Jahn LE, Cramer JT. Effects of arm swing and overhead target on vertical jump performance in children and adolescents. Presented at the Annual Meeting of the American College of Sports Medicine in Orlando, FL, as a Thematic Poster presentation. May 2019. Medicine and Science in Sports and Exercise, 49(5): S482, 2019.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Shoemaker ME, Gillen ZM, McKay BD, Bohannon NA, Gibson SM, Cramer JT. Does online sports nutrition education improve athletic performance in high school athletes? Presented at the Annual Symposium of Sports, Cardiovascular, and Wellness Nutrition (SCAN) in Phoenix, AZ, as a Poster presentation. April 2019.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Bohannon NA, Gibson SM, Gillen ZM, Shoemaker ME, McKay BD, Cramer JT. Test-retest reliability of static and counter-movement power push-ups in young male athletes. Presented at the University of Nebraska-Lincoln Spring Research Fair in Lincoln, NE, as a poster presentation. April 2019.


    Progress 10/01/17 to 09/30/18

    Outputs
    Target Audience:The primary target audience of our efforts are scientist, health professionals, and extension personnel and other educators working with parents of youth athletes and older adults (>65 years), of whom 45% are estimated to be affected by sarcopenia, as well as individuals who would benefit from healthy weight loss, such as the two-third of adults in the United States who are overweight or obese, as well as up to 6% of the normal-weight population who chronically diet. In addition, parents of youth athletes with interest in their child's physical performance and dietary intake may be interested in understanding the value of protein and iron intake, especially in pre-adolescent, adolescent, and post-adolescent athletic females. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project involved training of 5 graduate and 4 undergraduate students. Students were trained in laboratory techniques, human subject compliance, and research study design. Further, for their professional development, students were provided with opportunities to attend national conferences, including annual meetings of the American College of Sports Medicine (ACSM), the American Society for Nutrition (ASN), the National Strength and Conditioning Association (NSCA), and the International Society of Sport Nutrition (ISSN). How have the results been disseminated to communities of interest?In addition to publication in research articles, results have been disseminated through presentations for continuing education efforts for extension educators and professional organizations What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Skeletal muscle and bone health is impaired in a variety of conditions, including ageing, weight loss and disordered eating. Because declines in muscle and bone mass and function lead to suboptimal health outcomes across the life span, diet and exercise strategies are needed to preserve musculoskeletal health during these conditions. Objective 1: Compare the responses of college-aged and elderly adults during short-term resistance exercise Major activities completed/experiments conducted: dissemination of research results to better understand how sports participation influences athletic performance and health outcomes in youth athletes completion of a two-year study examining the associations among beef intake, iron status, and athletic performance in youth athletes completion of a clinical trial on carbohydrates and children Initiation of a clinical trial comparing the muscle energy metabolism of sarcopenic versus non-sarcopenic older adults. Data collected: Will Beef Make you Child a Better Athlete? Year 1: Male (n=179) and female (n=70) adolescent athletes participated in the combine testing and 128 adolescents participated in the blood collection to analyze hemoglobin (n=128), ferritin (n=118), and sTfR (n=105). Dietary intake was collected with a Food Frequency Questionnaire (FFQ) (n=128) and a 24-hour recall (n=97). Additional measurements included height, weight, predicted peak height velocity, percent body fat and thigh and arm estimated muscle cross-sectional area. Year 2: Three schools (n=184 students) piloted a sports nutrition curriculum and 139 high school athletes (male, n=66; female, n=73) participated in both the curriculum and combine testing sessions. 120 students participated in the blood collection to analyze hemoglobin (n=103), ferritin (n=105), and sTfR (n=92). Dietary intake was collected with a Food Frequency Questionnaire (n=119) and a 24-hour recall (n=110). Carbohydrates and Children (NCT03185884): Twenty-one pre-pubescent males (9 -13 years of age) or females (9- 10 years of age) were enrolled; n=19 completed the study. Metabolic Flexibility in Older Men and Women (NCT03701867): This study is actively enrolling subjects. To date, n=24 older adults have been screened, and n=9 have been enrolled in this study. Summary statistics & discussion of results: Will Beef Make you Child a Better Athlete? Year 1: Protein intake was greater in males than females and increased maturity in boys only. Approximately 50% of the sample was anemic as determined by low Hb and 75 % by low ferritin (boys: 65%, girls: 91%). For sTfR, 50-70% of the boys and girls, respectively, showed abnormal values. Athletic performance was significantly correlated with hemoglobin for all tests (VJ, BJ, PA, LC, 20yd, and pushup), while ferritin was only related to the 20yd dash performance. Year 2: Over half of the enrolled students were active in the curriculum. After removal of outliers, average beef intake was 155.1 g·week-1 and was significantly lower in iron depleted females than those with normal ferritin levels. At baseline, approximately 22% of the students were anemic, 26% iron deficient, and 61% iron depleted. Athletic performance was significantly correlated with Hb for all tests (VJ, BJ, PA, LC, and 20YD), except the PPU, for all students together, as well as for males. Hb was only correlated PPU in female, which was the only relationship observed in females between athletic performance and iron biomarkers. NCT03185884: Results indicate that consuming different carbohydrate blends has a significant and immediate impact on the contribution of substrates used for energy in prepubescent children.Specifically, the carbohydrates in the rapidly-digested Control blend were preferentially oxidized across the 180-minute study, and this was associated with a reduced energy utilized from endogenous energy sources (glycogen and fat). NCT03701867: There are no results compiled yet. This study is actively enrolling participants. Key outcomes or other accomplishments realized: Will Beef Make you Child a Better Athlete? Year 1: Impact Finding #1: Significant prevalence of poor iron status in young athletes. Given the importance of hemoglobin for muscle performance, there is clearly a need to improve the iron status of our young athletes in Nebraska. Impact Finding #2: Significant relationships between hemoglobin status, athletic performance tests, and dietary intakes indicated that beef intake is related to athletic performance for our youth athletes in Nebraska. Year 2: Impact Finding #1: The online sports nutrition education curriculum showed promise. Impact Finding #2: After curriculum participation, power push up (PPU) and peak power of the vertical jump (VJ) increased. Impact Finding #3: There was a significant prevalence of depleted iron stores, low iron levels for transport to tissues, and anemia. NCT03185884: The shift in energy substrates after consuming the Experimental vs Control blend would be important to promote insulin sensitivity, reduced lipogenesis and fat storage. Objective 2: Determine whether a dietary intervention of increased protein intake can preserve anabolic responsiveness of bone and skeletal muscle during energy deficiency and whether these effects translate in the long-term into improved bone mineral density and skeletal muscle mass in individuals undergoing weight loss. Major activities completed/experiments conducted: Completed data collection for a randomized, controlled cross-over study determining the effects of increased protein during weight loss on muscle and bone metabolism (Study A). Begun data collection for a randomized, controlled cross-over study determining the effect weight loss and protein on the anabolic response to resistance exercise (Study B). Data collected: Study A: A total of 7 young, healthy, and physically fit men completed this randomized, controlled cross-over study. In one CR condition, dietary protein intake was set at the current RDA (0.8 g/kg; CR-LP), in the other at 1.7 g/kg (CR-HP). Throughout all 5-day conditions, participants conducted aerobic exercise (60%VO2max). Body composition and metabolic hormones were measured before and after each condition. Study B: To date, 7 young, healthy, resistance-trained men and women have participated in this study. Weight loss is achieved through calorie restriction (CR). After two days of CR or CON, participants conducted supervised resistance exercise (back squat, 5x5 repetitions at 90% of 1 RM), followed by a protein (CR-P) or maltodextrin (CR-CHO, CON) ingestion. Serial blood collections are conducted for 24h. Summary statistics & discussion of results: Study A: Body weight decreased equally during CR-LP (p<0.001) and CR-HP (p<0.001) but FFM decreased only during CR-LP (p<0.05). Loss of fat mass was significant only during CR-HP (p<0.05). Insulin-like growth factor 1 (IGF-1) decreased (p<0.01) during CR-LP. CR-HP (p<0.05), but not CR-LP and CON resulted in reductions in insulin. Sclerostin was elevated only in CRLP (p < 0.05). CTX was reduced in CON (p < 0.05) but did not change in CRHP or CRLP. P1NP, a marker of bone formation, did not change significantly in any group. Study B: Data collection is ongoing, there is no data to report yet. Key outcomes or other accomplishments realized: Despite similar weight loss, increased dietary protein intake preserved FFM and shifted weight loss almost towards fat loss. High protein CR further attenuated declines in IGF-1, resulted in a greater reduction in insulin, and produced more favorable changes in bone turnover markers, suggesting suggest that a protein intake of 1.7 g/kg preserves lean mass and bone during weight loss.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2018 Citation: CR Gustafson, N Rakhmatullaeva, SE Beckford, A Ammachathram, A Cristobal, K Koehler (2018). Exercise and the Timing of Snack Choice: Healthy Snack Choice is Reduced in the Post-Exercise State. Nutrients 2018, 10 (12), 1941
    • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: CA Murphy, S Takahashi, J Bovaird, JA Fischer, M ?ernjul, D Cooney, Koehler K (2018). Relationship between Body Composition and Health Behaviors in High and Low Fit College Women. Medicine & Science in Sports & Exercise 50 (5S), 74-75
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ R Fan, K Koehler, S Chung (2018). Adaptive thermogenesis by dietary n-3 polyunsaturated fatty acids: emerging evidence and mechanisms. Biochimica et Biophysica Acta (BBA)-Molecular and Cell Biology of Lipids
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: D Dinkel, C Hanson, K Koehler, AA Berry, A Kyvelidou, M Bice, J Wallen, D Bagenda, L Jana, J Pressler (2018). An overview of assessment methodology for obesity-related variables in infants at risk. Nutrition and health 24 (1), 47-59
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: K Koehler, C Drenowatz. (2017) Monitoring Energy Expenditure Using a Multi-Sensor Device⿿Applications and Limitations of the SenseWear Armband in Athletic Populations. Frontiers in physiology 8, 983
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ McKay BD, Miramonti AA, Gillen ZM, Leutzinger TJ, Mendez AI, Jenkins NDM, Cramer JT. Normative Reference Values for High School-Aged American Football Players: Proagility Drill and 40-Yard Dash Split Times. J Strength Cond Res. 2018 Nov 8. [Epub ahead of print] PubMed PMID: 30418328.
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: McKay BD, Miramonti AA, Gillen ZM, Leutzinger TJ, Mendez AI, Jenkins NDM, Cramer JT. Normative reference values for high school-aged American football players. J Strength Cond Res. 2018 Feb 27. [Epub ahead of print] PubMed PMID: 29489728.
    • Type: Book Chapters Status: Published Year Published: 2019 Citation: K Koehler, B Geesmann (2019). Nutrition for Ultraendurance Exercise, Nutrition and Enhanced Sports Performance, 521-531
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ Gillen ZM, Miramonti AA, McKay BD, Leutzinger TJ, Cramer JT. Test-Retest Reliability and Concurrent Validity of Athletic Performance Combine Tests in 6-15-Year-Old Male Athletes. J Strength Cond Res. 2018 Oct;32(10):2783-2794. PubMed PMID: 29465606.
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ Leutzinger TJ, Gillen ZM, Miramonti AM, McKay BD, Mendez AI, Cramer JT. Anthropometric and Athletic Performance Combine Test Results Among Positions Within Grade Levels of High School-Aged American Football Players. J Strength Cond Res. 2018 May;32(5):1288-1296. PubMed PMID: 29389695.
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ Gillen ZM, Miramonti AA, McKay BD, Jenkins NDM, Leutzinger TJ, Cramer JT. Reliability and Sensitivity of the Power Push-up Test for Upper-Body Strength and Power in 6-15-Year-Old Male Athletes. J Strength Cond Res. 2018 Jan;32(1):83-96. PubMed PMID: 29084096.


    Progress 10/01/16 to 09/30/17

    Outputs
    Target Audience:The primary target audience of our efforts are scientist, health professionals, and extension personnel and other educators working with older adults (>65 years), of whom 45% are estimated to be affected by sarcopenia, as well as individuals who would benefit from healthy weight loss, such as the two-third of adults in the United States who are overweight or obese, as well as up to 6% of the normal-weight population who chronically diet. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project involved training of 2 graduate and 2 undergraduate students. Students were trained in laboratory techniques, human subject compliance, and research study design. Further, for their professional development, students were provided with opportunities to attend national conferences, including annual meetings of the American College of Sports Medicine (ACSM), the National Strength and Conditioning Association (NSCA), and the International Society of Sport Nutrition (ISSN). How have the results been disseminated to communities of interest?In addition to publication in research articles, results have been disseminated through presentations for continuing education efforts for extension educators and professional organizations What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Skeletal muscle and bone health is impaired in a variety of conditions, including ageing, weight loss and disordered eating. Because declines in muscle and bone mass and function lead to suboptimal health outcomes across the life span, diet and exercise strategies are needed to preserve musculoskeletal health during these conditions. In this project, we have assessed the differences in the response to short-term resistance exercise between elderly and college-aged adults. We have further determined the effects of weight loss on measures of muscle strength and performance and have initiated an experiment determining whether increased protein intake can prevent the loss of bone and muscle function during weight loss. Objective 1: Compare the responses of college-aged and elderly adults during short-term resistance exercise Major activities completed/experiments conducted: Two major activities were completed: (a) established reliability and sensitivity of physical function tests in frail and malnourished elderly men and women and (b) dissemination of short-term resistance training exercise experimental results for college-aged men. Determined the test-retest reliability and minimum detectable change scores for seven common clinical measurements of muscle strength and physical function in a multiethnic sample of sarcopenic, malnourished men and women. Reported neuromuscular adaptations following 3 and 6 weeks of 80 vs. 30% one repetition maximum (1RM) resistance training to failure in the leg extensors. Data collected: Data were collected during a clinical trial at 23 sites in the United States and Europe. Subjects included sarcopenic, malnourished, older adults (N = 257; n = 98 men aged 76.8 ± 6.3, n = 159 women aged 75.9 ± 6.6). Each participant visited the laboratory seven times over 25 to 26 weeks. Reliability was assessed for each measurement from Familiarization 1 to Familiarization 2 (R1), Familiarization 2 to baseline testing (R2), Familiarization 3 to 12-week testing (R3), and Familiarization 4 to 24-week testing (R4). During each visit, participants completed the Short Physical Performance Battery (SPBB) and isometric handgrip and isokinetic leg extensor and flexor strength testing at a slow (1.05 rad/s) and fast (3.15 rad/s) velocity. Twenty-six men (age = 23.1 ± 4.7 years) were randomly assigned to a high- (80% 1RM;n= 13) or low-load (30% 1RM;n= 13) resistance training group and completed leg extension resistance training to failure 3 times per week for 6 weeks. Testing was completed at baseline, 3, and 6 weeks of training. During each testing session, ultrasound muscle thickness and echo intensity, 1RM strength, maximal voluntary isometric contraction (MVIC) strength, and contractile properties of the quadriceps femoris were measured. Percent voluntary activation (VA) and electromyographic (EMG) amplitude were measured during MVIC, and during randomly ordered isometric step muscle actions at 10-100% of baseline MVIC. Summary statistics & discussion of results: Handgrip strength, gait speed, SPPB score, and isokinetic leg extension and flexion peak torque (PT) had intraclass correlation coefficients (ICCs) that were significantly greater than 0 (all ≥0.59) at R1, R2, R3, and R4, although most of these variables demonstrated systematic increases at R1, and several exhibited systematic variability beyond the baseline testing session. There were similar increases in muscle thickness from Baseline to Week 3 and 6 in the 80 and 30% 1RM groups. However, both 1RM and MVIC strength increased from Baseline to Week 3 and 6 to a greater degree in the 80% than 30% 1RM group. VA during MVIC was also greater in the 80 vs. 30% 1RM group at Week 6, and only training at 80% 1RM elicited a significant increase in EMG amplitude during MVIC. The peak twitch torque to MVIC ratio was also significantly reduced in the 80%, but not 30% 1RM group, at Week 3 and 6. Finally, VA and EMG amplitude were reduced during submaximal torque production as a result of training at 80% 1RM, but not 30% 1RM. Despite eliciting similar hypertrophy, 80% 1RM improved muscle strength more than 30% 1RM, and was accompanied by increases in VA and EMG amplitude during maximal force production. Key outcomes or other accomplishments realized: A three tier-approach to interpreting the clinical importance of statistically significant results that includes null hypothesis testing, examination and interpretation of the effect magnitude, and comparison of individual changes with the SEM and minimum detectable change of the measurements used is recommended. Our data suggest that high-load training results in greater neural adaptations that may explain the disparate increases in muscle strength despite similar hypertrophy following high- and low-load training programs. Objective 2: Determine whether a dietary intervention of increased protein intake can preserve anabolic responsiveness of bone and skeletal muscle during energy deficiency and whether these effects translate in the long-term into improved bone mineral density and skeletal muscle mass in individuals undergoing weight loss. Major activities completed/experiments conducted: a. Data collection for a study determining whether increased protein intake can attenuate the effects of weight loss on muscle and bone metabolism. b. Literature review on the singular and combined effects of exercise and high protein intake during weight loss (Murphy et al. 2017) Data collected: Twenty young, healthy, and physically fit men were recruited to participate in Study II. Calorie restriction (CR) was induced by reducing energy availability (EA) to 15 kcal/kg fat free mass (FFM). In one CR condition, dietary protein intake was set at the current RDX (0.8 g/kg; CR-LP). In the second CR condition, dietary protein intake was increased to 1.7 g/kg (CR-HP). During an energy-balanced control condition, EA was set at 40 kcal/kg FFM. Throughout all conditions, participants conducted aerobic exercise (60%VO2max) to expend 15 kcal/kg FFM. Conditions lasted 5 days. Body composition, resting, metabolic rate, substrate metabolism, and metabolic hormones, were measured before and after each condition. Summary statistics & discussion of results: Body weight decreased equally during CR-LP (-2.4±0.2 kg, p<0.001) and CR-HP (-2.3±0.5 kg, p<0.001) and stayed constant during CON (-0.1±0.4 kg, n.s.). However, FFM decreased only significantly during CR-LP (-1.8±0.6 kg; p<0.05) but not during CR-HP (-0.4±1.0 kg; n.s.) and CON (-0.2±1.0 kg; n.s.). Changes in fat mass were significant only during CR-HP (-1.8±1.1 kg; p<0.05), whereas changes in fat mass during CR-LP (-0.6±0.6 kg, n.s.) failed to reach statistical significance. Insulin-like growth factor 1 (IGF-1) decreased by 27±7% (p<0.01) during CR-LP. Changes in IGF-1 during CR-HP (-13±9%) were non-significant. CR-HP (-36±6%, p<0.05), but not CR-LP (-13±12%, n.s.) and CON (+2±26%, n.s.) resulted in significant reductions in insulin. Peak fat oxidation rates increased during CR-LP from 0.39±0.16 g/min to 0.59±0.04 g/min (p<0.001) and during CR-HP from 0.35±0.01 g/min to 0.68±0.08 g/min (p<0.001) and stayed almost identical during CON (0.57±0.12 g/min vs. 0.59±0.03 g/min, n.s.). Key outcomes or other accomplishments realized: Despite similar weight loss, an increased dietary protein intake almost completely preserved FFM and shifted weight loss almost exclusively towards fat loss. High protein CR further attenuated declines in IGF-1 and resulted in a greater reduction in insulin. Our findings suggest that a protein intake of 1.7 g/kg during favorably modulates weight loss such that lean tissues are preserved and fat loss is accelerated.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Murphy C, Koehler K. (2017). Modulating Weight Loss and Regain through Exercise and Dietary Protein. Diabesity, 3, 13-17.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Geesmann, B., Gibbs, J. C., Mester, J. & Koehler, K. (2017). Association Between Energy Balance and Metabolic Hormone Suppression During Ultra-Endurance Exercise. International Journal of Sports Physiology and Performance, 12, 984-989.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: H�lsemann, F., Koehler, K., Wittsiepe, J., Wilhelm, M., Hilbig, A., Kersting, M., Braun, H., Flenker, U. & Sch�nzer, W. (2017). Prediction of human dietary ?15N intake from standardised food records: validity and precision of single meal and 24-h diet data. Isotopes in Environmental & Health Studies, 53, 356-367.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Okla, M., Kim, J., Koehler, K. & Chung, S. (2017). Dietary Factors Promoting Brown and Beige Fat Development and Thermogenesis. Advances in Nutrition, 8, 473-483
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Koehler, K., De Souza, M. J. & Williams, N. I. (2017). Less-than-expected weight loss in normal-weight women undergoing caloric restriction and exercise is accompanied by preservation of fat-free mass and metabolic adaptations. European Journal of Clinical Nutrition, 71, 365-371.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Gillen ZM, Miramonti AA, McKay BD, Jenkins NDM, Leutzinger TJ, Cramer JT. Reliability and Sensitivity of the Power Push-up Test for Upper-body Strength and Power in 6-15-year old Male Athletes. J Strength Cond Res. 2017 Oct 27.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Palmer TB, Jenkins NDM, Thompson BJ, Cramer JT. Influence of stretching velocity on musculotendinous stiffness of the hamstrings during passive straight-leg raise assessments. Musculoskelet Sci Pract. 2017 Aug;30:80-85. Epub 2017 Jan 5. PubMed PMID: 28715304.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Jenkins NDM, Miramonti AA, Hill EC, Smith CM, Cochrane-Snyman KC, Housh TJ, Cramer JT. Greater Neural Adaptations following High- vs. Low-Load Resistance Training. Front Physiol. 2017 May 29;8:331. eCollection 2017. PubMed PMID: 28611677; PubMed Central PMCID: PMC5447067.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Jenkins NDM, Cramer JT. Reliability and Minimum Detectable Change for Common Clinical Physical Function Tests in Sarcopenic Men and Women. J Am Geriatr Soc. 2017 Apr;65(4):839-846. doi: 10.1111/jgs.14769. Epub 2017 Mar 15. PubMed PMID: 28295148.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: McKay BD, Yeo NM, Jenkins NDM, Miramonti AA, Cramer JT. Exertional Rhabdomyolysis in a 21-Year-Old Healthy Woman: A Case Report. J Strength Cond Res. 2017 May;31(5):1403-1410. PubMed PMID: 28146033.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Miramonti AA, Jenkins NDM, Oza PD, Weir JP, Cramer JT. Mechanomyographic responses during recruitment curves in the soleus muscle. Muscle Nerve. 2017 Jul;56(1):107-116. Epub 2017 Feb 6. PubMed PMID: 27718510.


    Progress 05/06/16 to 09/30/16

    Outputs
    Target Audience:The primary target audience of our efforts are scientist, health professionals, and extension personnel and other educators working with older adults (>65 years), of whom 45% are estimated to be affected by sarcopenia, as well as individuals who would benefit from healthy weight loss, such as the two-third of adults in the United States who are overweight or obese, as well as up to 6% of the normal-weight population who chronically diet. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project involved training of 2 graduate and 2 undergraduate students. Students were trained in laboratory techniques, human subject compliance, and research study design. Further, for their professional development, students were provided with opportunities to attend national conferences, including annual meetings of the American College of Sports Medicine (ACSM), the National Strength and Conditioning Association (NSCA), and the International Society of Sport Nutrition (ISSN). How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Skeletal muscle and bone health is impaired in a variety of conditions, including ageing, weight loss and disordered eating. Because declines in muscle and bone mass and function lead to suboptimal health outcomes across the life span, diet and exercise strategies are needed to preserve musculoskeletal health during these conditions. In this project, we have assessed the differences in the response to short-term resistance exercise between elderly and college-aged adults. We have further determined the effects of weight loss on measures of muscle strength and performance and have initiated an experiment determining whether increased protein intake can prevent the loss of bone and muscle function during weight loss. Objective 1: Compare the responses of college-aged and elderly adults during short-term resistance exercise Major activities completed/experiments conducted: Two major activities were completed: (a) dissemination of research results for elderly adults and (b) dissemination of short-term resistance training exercise experimental results for college-aged men. The results of two clinical trials studying the effects of dietary supplements in elderly adults were disseminated. One study investigated 8 weeks of rumenic acid rich (RAR) conjugated linoleic acid (CLA) supplementation on handgrip strength and cognitive function in older men and women. The other study evaluated the effects of two oral nutritional supplements (ONS) differing in amount and type of key nutrients in older adult men and women. Muscle strength and size adaptations were studied after 2 and 4 weeks of high- versus low-load resistance training to failure in college-aged men. Data collected: Sixty-five (43 women, 22 men) participants (mean±SD; age=72.4±5.9yrs; BMI=26.6±4.2kg·m-2) were randomly assigned to a RAR CLA (n=30: 10 men, 20 women) or placebo (PLA; high oleic sunflower oil; n=35: 12 men, 23 women) group. Cognitive function, handgrip strength, and hand joint discomfort were measured before and after the 8-week supplementation. A multicenter, randomized, double-blinded, controlled clinical trial assessed health outcomes in malnourished and sarcopenic men and women, 65years and older (n=330). A 24-week intervention period with 2 energy-rich oral nutritional supplements (ONS) treatment groups: Control ONS (CONS, 14g protein; 147 IU vitamin D3) versus Experimental ONS (EONS, 20g protein; 499 IU vitamin D3; 1.5g CaHMB) taken twice daily. Leg strength, grip strength, gait speed, muscle mass, and muscle quality were assessed at baseline and 12 and 24weeks. Subgroup analyses were performed: severe sarcopenia(lowskeletal mass index, low grip strength [<30kg men; <20kg women], low gait speed [<0.8m·s-1]) and mild-moderate sarcopenia (low skeletal mass index, normal gait speed, or normal grip strength). Fifteen men were randomly assigned to either a high- (80% 1RM; n=7) or low-load (30% 1RM; n=8) resistance training group and completed the exercises to failure 3 times per week for 4 weeks. The participants were tested at baseline, 2-, and 4-weeks of training. Muscle size, quality, strength, activation, rate of force development, and electromechanical delay were measured. Summary statistics & discussion of results: There were no treatment differences for handgrip strength. However, RAR CLA supplementation improved cognitive function and hand joint discomfort.Both ONS groups (EONSand CONS) improved muscle strength, muscle quality, and gait speed from baseline with no treatment differences. Those with severe sarcopenia (44%) exhibited lower baselinemuscle strength and quality, with no differences in strength improvements between treatments. However, participants with mild-moderate sarcopenia exhibited higher baseline strength and quality, with differences instrength improvements at 12weeks (EONS>CONS, P=.032) in those with normal grip strength. There were no treatment differences based on sarcopenic severity for either grip strength or gait speed. Muscle size increased from baseline to week 2 and to week 4 for both resistance training groups. Strength increased from baseline to weeks 2 and 4 in the high-load, 80% 1RM group only. Muscle activation was increased in some, but not all, levels of force production, particularly for the high-load group. Rate of force development improved after the high-load, 80% 1RM training only. Key outcomes or other accomplishments realized: RAR CLA supplementation was associated with a small improvement in cognitive function and joint discomfort, but not handgrip strength, in older men and women. Without exercise, 6-months of ONS improved strength and function in malnourished older adults with sarcopenia. In those with mild-moderate sarcopenia, but not severe sarcopenia, consumption of the experimental ONS (increased protein, vitamin D, and HMB)improved leg muscle strength and quality more than the standard ONS. Therefore, RAR CLA supplementation may improve cognition and joint discomfort, but not strength; while high-protein ONS may improve strength and function without including exercise in elderly adults. Resistance training exercise to failure at high-load (80% 1RM) vs. low-load (30% 1RM) elicited similar in muscle size, but only high-load (80% 1RM) exercise increased muscle strength and rate of force development. Objective 2: Determine whether a dietary intervention of increased protein intake can preserve anabolic responsiveness of bone and skeletal muscle during energy deficiency and whether these effects translate in the long-term into improved bone mineral density and skeletal muscle mass in individuals undergoing weight loss. Major activities completed/experiments conducted: Two major activities were completed: a) retrospective analysis of data collected during a controlled weight loss trial. The goal of this study was to determine the effects of a short-term energy deficit on human performance and metabolism and to compare if exercise can offset these effects (Study I). b) Obtained research compliance approval for a study determining whether increased protein intake can attenuate the effects of weight loss on muscle and bone metabolism (Study II). Data collected: Young, healthy, and physically fit men (25.2±2.4 y; 79.7±7.7 kg; 9.6±1.5% body fat) participated in this study. Calorie restriction was induced by reducing energy availability to 15 kcal/kg fat free mass (FFM), once accomplished via caloric and exercise (CR+EX) and once via caloric restriction alone (CR-EX). Control conditions were characterized by an EA of 40 kcal/kg FFM, accomplished both with (CON+EX) and without EX (CON-EX). Conditions lasted 4 days. Body composition, substrate metabolism, aerobic and anaerobic performance, strength, and indices of well-being were measured before and after each condition. We are currently in the process of data collection. There is not sufficient data to conduct preliminary data analyses. Summary statistics & discussion of results: Body weight decreased in CR+EX (-1.8±0.4 kg, p=0.004) and CR-EX (-2.4±0.3 kg, p<0.001); whereas FFM decreased only in CR-EX (p=0.06). No significant changes were found in anaerobic performance, leg curl, and leg extension. Bench press performance decreased only in CR+EX (p=0.04). Fasting glucose decreased in CR+EX (-11.9±2.3% p=0.008), but not in CR-EX. In CR-EX, but not in CR+EX, there was a decrease in positive mood (p=0.04), self-confidence (p=0.02), sense of fitness (p=0.08), physical energy (p=0.06), and recovery (p=0.07). Nothing to report. Key outcomes or other accomplishments realized: Despite similar changes in body weight and substrate metabolism during both CR conditions, reductions in fat-free mass and indices of well-being were only observed in CR-EX. Our findings suggest that exercise seems to be an effective means to maintain performance, fat-free mass, and well-being during short-term weight loss.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jenkins ND, Housh TJ, Miramonti AA, McKay BD, Yeo NM, Smith CM, Hill EC, Cochrane KC, Cramer JT. Effects of rumenic acid rich conjugated linoleic acid supplementation on cognitive function and handgrip performance in older men and women. Exp Gerontol. 2016 Nov;84:1-11. doi: 10.1016/j.exger.2016.08.004. PubMed PMID: 27521997.
    • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Cramer JT, Cruz-Jentoft AJ, Landi F, Hickson M, Zamboni M, Pereira SL, Hustead DS, Mustad VA. Impacts of High-Protein Oral Nutritional Supplements Among Malnourished Men and Women with Sarcopenia: A Multicenter, Randomized, Double-Blinded, Controlled Trial. J Am Med Dir Assoc. 2016 Nov 1;17(11):1044-1055. doi: 10.1016/j.jamda.2016.08.009. PubMed PMID: 27780567.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jenkins ND, Housh TJ, Buckner SL, Bergstrom HC, Cochrane KC, Hill EC, Smith CM, Schmidt RJ, Johnson GO, Cramer JT. Neuromuscular Adaptations After 2 and 4 Weeks of 80% Versus 30% 1 Repetition Maximum Resistance Training to Failure. J Strength Cond Res. 2016 Aug;30(8):2174-85. doi: 10.1519/JSC.0000000000001308. PubMed PMID: 26848545.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jenkins ND, Housh TJ, Buckner SL, Bergstrom HC, Smith CM, Cochrane KC, Hill EC, Miramonti AA, Schmidt RJ, Johnson GO, Cramer JT. Four weeks of high- versus low-load resistance training to failure on the rate of torque development, electromechanical delay, and contractile twitch properties. J Musculoskelet Neuronal Interact. 2016 Jun 1;16(2):135-44. PubMed PMID: 27282457.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Petersen J, Braun H, Zinner C, Koehler K. Exercise Preserves Fat-free Mass, Submaximal Performance, And Well-being During Short-term Energy Deficiency: 3686 Board #125 June 4, 9: 30 AM - 11: 00 AM. Med Sci Sports Exerc. 2016 May;48(5 Suppl 1):1027. doi: 10.1249/01.mss.0000488089.17600.2b.