Recent MASL research studies include:
- Effects of different proteins or L-leucine supplementation on resistance training variables
- Effects of graded whey protein supplementation on resistance training adaptations
- Physiology behind low versus high hypertrophic responders
- Effects of exercise training on LINE-1 “jumping gene” activity in skeletal muscle”
- Effects of dietary milk exosomes on skeletal muscle physiology
Effects of different proteins or L-leucine supplementation on resistance training variables
Data from Mobley et al. (Nutrients, 2017) demonstrating that whey protein concentrate supplementation, hydrolyzed whey protein concentrate supplementation, soy protein concentrate supplementation, and L-leucine with maltodextrinelicited similar increases in back squat strength and body composition in previously untrained college-aged males following a 12-week intervention.
Effects of graded whey protein supplementation on resistance training adaptations
Data from Haun et al. (Frontiers Nutr, 2018) demonstrating that weekly graded whey protein concentrate supplementation elicited superior improvements in body composition compared to a standard dosing strategy or a maltodextrinplacebo in previously trained college-aged males following a 6-week intervention.
Physiology behind low versus high hypertrophic responders
Data from Mobley et al. (PLOS One, 2018) demonstrating that the mid-thigh muscle clearly grows in some previously untrained college-aged males following 12 weeks of resistance training (delta = post-training values after subtracting out pre-training values; positive values indicate growth, and “HI” responders showed the most growth versus “MOD” or “LOW” responders). The right pictures are representative ultrasound images prior to and following training from a LOW and HI responder. Under these images shows that total muscle RNA (i.e., ribosome content) clearly increases in HI versus LOW responders supporting the hypothesis that muscle ribosomes are critical for muscle growth during resistance training.
Effects of exercise training on LINE-1 “jumping gene” activity in skeletal muscle”
Data from Romero et al. (AJP Cell Physiol, 2018) demonstrating that skeletal muscle mRNA expression of the LINE-1 “jumping gene” is decreased previously untrained college-aged males following 12 weeks of resistance training. Also shown are: 1) LINE-1 promoter methylation increasing with training (indicating the mechanism which down-regulates LINE-1 mRNA), and 2) a decrease in muscle reverse transcriptase (or RT) activity. Collectively, these are the first results to demonstrate that exercise can downregulate this putative “genetic parasite” in muscle. Implications of these data are that lifelong exercise may preserve muscle health through this mechanism, and current ongoing studies in Dr. Roberts’ laboratory are examining these markers in younger and older humans.
Effects of dietary milk exosomes on skeletal muscle physiology
Data from Parry, Mobley et al. (FrontiersPhysiol, under review) demonstrating in rats that feeding sonicated-modified milk exosomes to young rats for 4 weeks (ERD rats) increases muscle fiber cross-sectional area (fCSA) and muscle ribosome content. ERS rats consumed a similar milk-based diet which was not disrupted through sonication. These data imply that, not only is milk a muscle-building food due to its protein content, but that milk contains bioactives(e.g., exosomes) which may affect muscle physiology. This project is being performed in collaboration with Dr. Andreas Kavazis, Dr. Janos Zempleni (University of Nebraska-Lincoln), and Dr. John McCarthy (University of Kentucky).