Michael D Roberts

Michael D Roberts
Auburn University | AU · Department of Kinesiology

PhD

About

338
Publications
110,843
Reads
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4,770
Citations
Introduction
Michael D Roberts is a Professor in the School of Kinesiology at Auburn University. He serves as the Director of the Molecular and Applied Sciences Laboratory (MASL) as well as the Applied Physiology Laboratory (APL). His laboratories examine how exercise and nutrition affect variables related to molecular outcomes (muscle and blood markers), body composition outcomes, and functional outcomes of performance.
Additional affiliations
February 2017 - present
Auburn University
Position
  • Professor (Associate)
August 2013 - February 2017
Auburn University
Position
  • Professor (Assistant)
May 2010 - August 2013
University of Missouri
Position
  • PostDoc Position

Publications

Publications (338)
Article
Full-text available
We sought to determine the effects of L-leucine (LEU) or different protein supplements standardized to LEU (~3.0 g/serving) on changes in body composition, strength, and histological attributes in skeletal muscle and adipose tissue. Seventy-five untrained, college-aged males (mean ± standard error of the mean (SE); age = 21 ± 1 years, body mass = 7...
Article
We sought to examine potential amino acid independent mechanisms whereby hydrolyzed whey protein (WP) affects muscle protein synthesis (MPS) and anabolism in vitro. Specifically, we tested (1) whether 3-h and 6-h treatments of WP, essential amino acids, or l-leucine (Leu) affected MPS, and whether 6-h treatments with low-, medium-, or high doses of...
Article
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Objective: The objective of this study was to compare the chronic effects of different whey protein forms on body composition and performance when supplemented with resistance training. Methods: Resistance-trained men (N = 56, 21.4 ± 0.4 years, 79.5 ± 1.0 kg) participated in an 8-week resistance training regimen (2 upper-body sessions and 2 lowe...
Article
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We compared immediate post-exercise whey protein (WP, 500 mg) versus L-leucine (LEU, 54 mg) feedings on skeletal muscle protein synthesis (MPS) mechanisms and ribosome biogenesis markers 3 h following unilateral plantarflexor resistance exercise in male, Wistar rats (~250 g). Additionally, in vitro experiments were performed on differentiated C2C12...
Article
Full-text available
Objective Long INterspersed Element-1 (L1) is an autonomous transposable element in the genome. L1 transcripts that are not reverse transcribed back into the genome can accumulate in the cytoplasm and activate an inflammatory response via the cyclic GMP-AMP (cGAS)-STING pathway. We examined skeletal muscle L1 markers as well as STING protein levels...
Article
New findings: In pennate muscle, changes in myofiber cross-sectional area (fCSA), fascicle length (Lf ), and pennation angle (PA) with exercise training likely interact to alter whole-muscle cross-sectional area (mCSA). Herein, we are the first to use multiple regression to show that changes in vastus lateralis (VL) mean fCSA, Lf and PA following...
Article
We sought to determine the effects of long-term voluntary wheel running on markers of Long Interspersed Nuclear Element-1 (L1) in skeletal muscle, liver, and the hippocampus of female rats. Additionally, markers of the cGAS-STING DNA sensing pathway that results in inflammation were interrogated. Female Lewis rats (n=34) were separated into one of...
Article
This study had two aims. AIM1 was to determine the agreement between mid-thigh vastus lateralis (VL) cross-sectional area measured by ultrasound (mCSA US ) versus magnetic resonance imaging (mCSA MRI ) at a single time point, and the ability of each to detect hypertrophic changes. AIM2 was to assess the relationships between pre-to-post training ch...
Article
Retrotransposons are gene segments that proliferate in the genome, and the Long INterspersed Element 1 (LINE-1, or L1) retrotransposon is active in humans. Although older mammals show enhanced skeletal muscle L1 expression, exercise generally reverses this trend. We hypothesize skeletal muscle L1 expression affects muscle physiology, and additional...
Article
Full-text available
Naked mole-rats (NMR) and Damaraland mole-rats (DMR) exhibit extraordinary longevity for their body size, high tolerance to hypoxia and oxidative stress and high reproductive output; these collectively defy the concept that life-history traits should be negatively correlated. However, when life-history traits share similar underlying physiological...
Preprint
Background: In the endothelium, tumor necrosis factor (TNF) binding to TNF receptor-I (TNFR-I) facilitates monocyte recruitment and consequently the development of atherosclerosis. The prevalence of inflammation, endothelial dysfunction, and subclinical atherosclerosis is higher in the African American (AA) population. This is supported by in vitro...
Article
Hypothesis: We hypothesize that MRI-determined vastus lateralis (VL) cross-sectional area (CSA) will increase following resistance training and that changes in VL size determined by ultrasonography and histology methods will agree with and/or be related to MRI-determined changes in VL size. Methods: Twelve healthy, untrained, college-aged males...
Article
Objective: We sought to determine how one bout of resistance training to failure with either higher repetitions (30FAIL) or lower repetitions (80FAIL) affected the promoter methylation statuses of genes that drive skeletal muscle hypertrophy. Hypotheses: We hypothesized that a bout of 80FAIL training would lead to a more robust hypomethylation o...
Article
Objective: We sought to determine the effects of chronic, voluntary wheel running on Long Interspersed Nuclear Element-1 (LINE-1) mRNA expression and promoter methylation, as well as markers of the cGAS-STING inflammatory pathway, in skeletal muscle. Hypotheses: LINE-1 mRNA expression will increase with age, and exercise will mitigate this incre...
Article
Objective: Our objective was to determine how global DNA methylation status of skeletal muscle differs with resistance training (RT) to failure in trained participants using either 80% of their estimated one-repetition maximum (Est. 1-RM) (80FAIL) or 30% of their Est. 1-RM (30FAIL). Hypotheses: We hypothesize there will be a significant decrease...
Article
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Objective: To determine if markers of skeletal muscle extracellular matrix (ECM) content and ECM remodeling are indicators of hypertrophy in previously untrained collage aged males. Hypotheses: Higher-responders (HR) to resistance training would demonstrate more malleable changes in assayed ECM markers than lower-responders (LR). Methods: Untr...
Article
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It is well-established that creatine supplementation augments the gains in muscle mass and performance during periods of resistance training. However, whether the timing of creatine ingestion influences these physical and physiological adaptations is unclear. Muscle contractions increase blood flow and possibly creatine transport kinetics which has...
Article
Full-text available
The bacteria inhabiting the gastrointestinal tract contribute to numerous host functions and can be altered by lifestyle factors. We aimed to determine whether a 6-week training intervention altered fecal microbiome diversity and/or function in older males. Fecal samples were collected prior to and following a 6-week twice-weekly supervised resista...
Article
Limited pre-clinical and clinical data suggest theacrine or theacrine-based supplements modulate biological processes associated with lipid metabolism and aging. Herein, we sought to examine if 12 weeks of daily supplementation with a theacrine-based supplement (termed NAD3®; 312 mg of combined Wasabia japonica freeze-dried rhizome standardized for...
Article
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This study assesses if a lower dose of whey protein can provide similar benefits to those shown in previous work supplementing Army Initial Entry Training (IET) Soldiers with two servings of whey protein (WP) per day. Eighty-one soldiers consumed one WP or a calorie matched carbohydrate (CHO) serving/day during IET (WP: n = 39, height = 173 ± 8 cm,...
Article
Full-text available
We evaluated the effects of higher-load (HL) versus (lower-load) higher-volume (HV) resistance training on skeletal muscle hypertrophy, strength, and muscle-level molecular adaptations. Trained men (n = 15, age: 23 ± 3 years; training experience: 7 ± 3 years) performed unilateral lower-body training for 6 weeks (3× weekly), where single legs were r...
Article
Background: Skeletal muscle adaptations are affected by resistance training (RT)-induced acute and chronic transcriptional responses. An under-explored gene target involved in mechanotransduction is the expression of the G protein-coupled receptor 56 (GPR56). However, studies investigating the acute and chronic effects of RT manipulations on GPR56...
Article
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We sought to determine if manipulating resistance training (RT) variables differentially altered the expression of select sarcoplasmic and myofibril proteins as well as myofibrillar spacing in myofibers. Resistance-trained men ( n = 20; 26 ± 3 years old) trained for 8 weeks where a randomized leg performed either a standard (CON) or variable RT pro...
Article
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Protein supplementation is a commonly employed strategy to enhance resistance training adaptations. However, little research to date has examined if peanut protein supplementation is effective in this regard. Thus, we sought to determine if peanut protein supplementation (PP; 75 total g/d of powder providing 30 g/d protein, >9.2 g/d essential amino...
Article
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Muscle protein synthesis and proteolysis are tightly coupled processes. Given that muscle growth is promoted by increases in net protein balance, it stands to reason that bolstering protein synthesis through amino acids while reducing or inhibiting proteolysis could be a synergistic strategy in enhancing anabolism. However, there is contradictory e...
Article
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Human muscle fibers are generally classified by myosin heavy chain (MHC) isoforms characterized by slow to fast contractile speeds. Type I, or slow-twitch fibers, are seen in high abundance in elite endurance athletes, such as long-distance runners and cyclists. Alternatively, fast-twitch IIa and IIx fibers are abundant in elite power athletes, suc...
Article
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Skeletal muscle adaptations to resistance and endurance training include increased ribosome and mitochondrial biogenesis, respectively. Such adaptations are believed to contribute to the notable increases in hypertrophy and aerobic capacity observed with each exercise mode. Data from multiple studies suggest the existence of a competition between r...
Article
Resistance training (RT) dynamically alters the skeletal muscle nuclear DNA methylome. However, no study has examined if RT affects the mitochondrial DNA (mtDNA) methylome. Herein, ten older, Caucasian untrained males (65 ± 7 y.o.) performed six weeks of full‐body RT (twice weekly). Body composition and knee extensor torque were assessed prior to a...
Article
Full-text available
Resistance training increases muscle fiber hypertrophy, but the morphological adaptations that occur within muscle fibers remain largely unresolved. Fifteen males with minimal training experience (24±4years, 23.9±3.1kg/m2 body mass index) performed 10weeks of conventional, full-body resistance training (2× weekly). Body composition, the radiologica...
Article
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Mild cognitive impairment (MCI) designates the boundary area between cognitive function in natural aging and dementia, and this is viewed as a therapeutic window to prevent the occurrence of dementia. The current study investigated the neurocognitive effects of oral creatine (Cr) supplementation in young female Wistar rats that received intracerebr...
Preprint
Full-text available
Naked mole-rats (NMR) and Damaraland mole-rats (DMR) are the only two eusocial mammals known. Both species exhibit extraordinary longevity for their body size, high tolerance to hypoxia and oxidative stress and high reproductive output; these collectively defy the concept that all life-history traits should be negatively correlated. However, when l...
Article
Full-text available
Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given they serve as rapid and localized support of energy- and mechanical-dependent processes. This evolutionary advantage is based on the action of creatine kinase (CK) isozymes that connect places of ATP synthesis with sites of ATP consumption (the CK/PCr sy...
Article
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The purpose of this study was to validate the efficacy of a customized vitamin-mineral supplement on blood biomarkers in pre-menopausal females. Women (21–40 years old) who were apparently healthy were recruited from the local community (ClinicalTrials.gov trial registration NCT03828097). Pretesting (PRE) occurred in the morning 5 ± 2 days followin...
Preprint
Full-text available
Aim We evaluated the effects of higher-load (HL) versus (lower-load) higher-volume (HV) resistance training on skeletal muscle hypertrophy, strength, and muscle-level molecular markers. Methods Trained men (n=15, age: 23±3 y; training experience: 7±3 y) performed unilateral lower body training for 6 weeks (3x weekly), where single legs were assign...
Article
Vann, CG, Haun, CT, Osburn, SC, Romero, MA, Roberson, PA, Mumford, PW, Mobley, CB, Holmes, HM, Fox, CD, Young, KC, and Roberts, MD. Molecular differences in skeletal muscle after 1 week of active vs. passive recovery from high-volume resistance training. J Strength Cond Res 35(8): 2102-2113, 2021-Numerous studies have evaluated how deloading after...
Preprint
Full-text available
Resistance training increases myofiber hypertrophy, but the morphological adaptations that occur within myofibers remain largely unresolved. Fifteen males with minimal training experience (24±4 years, 17.9±1.4 kg/m2 lean body mass index) performed 10 weeks of conventional, full-body resistance training (2x weekly). Body composition, the radiologica...
Article
Full-text available
Creatine supplementation in conjunction with resistance training (RT) augments gains in lean tissue mass and strength in aging adults; however, there is a large amount of heterogeneity between individual studies that may be related to creatine ingestion strategies. Therefore, the purpose of this review was to (1) perform updated meta-analyses compa...
Preprint
Full-text available
Resistance training (RT) alters skeletal muscle nuclear DNA methylation patterns (or the methylome). However, no study has examined if RT affects the mitochondrial DNA (mtDNA) methylome. Herein, ten older untrained males (65+/-7 years old) performed six weeks of full-body RT (twice weekly). Body composition and knee extensor torque were assessed pr...
Article
Full-text available
Creatine (Cr) is a ubiquitous molecule that is synthesized mainly in the liver, kidneys, and pancreas. Most of the Cr pool is found in tissues with high-energy demands. Cr enters target cells through a specific symporter called Na+/Cl−-dependent Cr transporter (CRT). Once within cells, creatine kinase (CK) catalyzes the reversible transphosphorylat...
Article
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We examined the association between genotype and resistance training‐induced changes (12 wk) in dual x‐ray energy absorptiometry (DXA)‐derived lean soft tissue mass (LSTM) as well as muscle fiber cross‐sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m2). Over 315 000 genetic polymorphisms were interrogated from...
Article
Physical inactivity is positively associated with anxiety and depression. Considering physical inactivity, anxiety, and depression each have a genetic basis for inheritance, our lab used artificial selectively bred low-voluntary running (LVR) and wild type (WT) female Wistar rats to test if physical inactivity genes selected over multiple generatio...
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The aim of this study was to investigate the effects of resistance training (RT) on the redox status of skeletal muscle in older adults. Thirteen males aged 64 ± 9 years performed full-body RT 2x/week for 6 weeks. Muscle biopsies were obtained from the vastus lateralis prior to and following RT. The mRNA, protein, and enzymatic activity levels of v...
Article
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Introduction: Amino acid transporters are essential for cellular amino acid transport and promoting protein synthesis. While previous literature has demonstrated the association of amino acid transporters and protein synthesis following acute resistance exercise and amino acid supplementation, the chronic effect of resistance exercise and supplemen...
Article
Full-text available
There is evidence in rodents to suggest that theacrine-based supplements modulate tissue sirtuin activity as well as other biological processes associated with aging. Herein, we examined if a theacrine-based supplement (termed NAD3) altered sirtuin activity in vitro while also affecting markers of mitochondrial biogenesis. The murine C2C12 myoblast...
Article
Full-text available
Background: There are animal data suggesting green tea can enhance blood flow. However, human data are lacking. Thus, the purpose of this study was to examine the acute effects of low and high doses of a green tea-based supplement (GBS) on brachial artery blood flow before and following a resistance exercise bout. Methods: In this, double-blinde...
Article
Full-text available
Several studies suggest resistance training (RT) while supplementing with various protein supplements can enhance strength and muscle mass in older individuals. However, to date, no study has examined the effects of RT with a peanut protein powder (PP) supplement on these outcomes. Herein, 39 older, untrained individuals ( n = 17 female, n = 22 mal...
Article
Full-text available
We investigated the acute and chronic effects of resistance training (RT) on skeletal muscle markers of mitochondrial content and remodeling in older, untrained adults. Sixteen participants (n = 6 males, n = 10 females; age = 59 ± 4 years) completed 10 weeks of full‐body RT (2 day/week). Muscle biopsies from the vastus lateralis were obtained prior...
Preprint
Full-text available
There is evidence in rodents to suggest theacrine-based supplements modulate tissue sirtuin activity as well as other biological processes associated with aging. Herein, we examined if a theacrine-based supplement (NAD3) altered sirtuin activity in vitro while also affecting markers of mitochondrial biogenesis and the mRNA expression of genes relat...
Preprint
Full-text available
Several studies suggest resistance training (RT) with protein supplementation has positive effects on strength and muscle mass in older individuals. However, to date, no study has examined the effects of RT with a high-protein, defatted peanut powder (PP) supplement on these markers. Herein, 39 older, untrained individuals (n=17 female, n=22 male;...
Preprint
Full-text available
Several studies suggest resistance training (RT) while supplementing with various protein supplements can enhance strength and muscle mass in older individuals. However, to date, no study has examined the effects of RT with a peanut protein powder (PP) supplement on these outcomes. Herein, 39 older, untrained individuals (n=17 female, n=22 male; ag...
Article
Full-text available
Training civilians to be soldiers is a challenging task often resulting in musculoskeletal injuries, especially bone stress injuries. This study evaluated bone health biomarkers (P1NP/CTX) and whey protein or carbohydrate supplementations before and after Army initial entry training (IET). Ninety male IET soldiers participated in this placebo-contr...
Article
Full-text available
The 2018 CrossFit Open (CFO) was the initial stage of an annual competition that consisted of five weekly workouts. Current evidence suggests that a variety of fitness parameters are important for progressing beyond this stage, but little is known about which are the most important. To examine relationships between CFO performance, experience, and...
Article
Full-text available
Skeletal muscle fibers are multinucleated cells that contain mostly myofibrils suspended in an aqueous media termed the sarcoplasm. Select evidence suggests sarcoplasmic hypertrophy, or a disproportionate expansion of the sarcoplasm relative to myofibril protein accretion, coincides with muscle fiber or tissue growth during resistance training. The...
Article
Full-text available
Objectives We determined if multivitamin supplementation (MV) affected serum folate levels in women during a 12-week intervention, and if genotypes affected these outcomes. Methods Women (21–40 years old) were recruited from the local community. PRE testing occurred between 0600–0900 AM 5 ± 2 days following each participants’ last menstrual cycle,...