The goal of this clinical trial is to compare the effects of resistance training (RT) preconditioning vs no training on disuse-induced atrophy and post-disuse resistance training in young healthy individuals. The main questions it aims to answer are: * To determine if performing RT prior to a period of disuse enhances the regain of strength, skeletal muscle size, and skeletal muscle quality while performing RT after a period of disuse. * To determine if performing RT prior to a period of disuse dampens the maladaptive effects of disuse on muscle size, muscle quality, and strength. * To determine the anabolic and proteolytic mechanisms underpinning the observed outcomes. Participants will: 1. Perform either 6 weeks of resistance training or maintain an untrained lifestyle 2. Perform 2 weeks of limb immobilization induced disuse of a randomized leg 3. Perform 6 weeks of resistance training Researchers will compare the resistance training preconditioning condition vs the non-trained condition to see if resistance training prior to a period of disuse is beneficial during the disuse period and in the return to training period on skeletal muscle size, strength, and underpinning molecular markers.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
24
Resistance training prior to disuse-induced atrophy followed by another period of resistance training
Activities of daily living prior to disuse-induced atrophy followed by a period of resistance training
Change in vastus lateralis fiber cross-sectional area
Upon the procurement and analysis of muscle from the vastus lateralis of participants, histological techniques will be used to assess fiber cross-sectional area of muscle fibers
Time frame: Through completion of study, 16 weeks
Change in quadriceps strength via 3 repetition maximum testing
Strength of the quadriceps will be assessed via 3-repetition maximum testing of select exercises (leg press, leg extension, hex-bar deadlift)
Time frame: Through completion of study, 16 weeks
Change in quadriceps strength via isokinetic dynamometry
Strength of the quadriceps will be assessed via isokinetic dynamometry
Time frame: Through completion of study, 16 weeks
Change in protein expression of anabolic signaling proteins
Western blotting will be performed and quantified in relative fluorescence units for proteins involved in the mechanistic target of rapamycin signaling pathway.
Time frame: Through completion of study, 16 weeks
Change in protein expression of catabolic signaling proteins
Western blotting will be performed and quantified in relative fluorescence units for proteins involved in the catabolic signaling pathways (e.g. ubiquitin-proteasome system, calpain system, autophagy).
Time frame: Through completion of study, 16 weeks
Change in activity of catabolic systems
Activity assays will be performed and quantified in relative fluorescence units normalized to muscle soluble protein abundance in order to quantify the activity of the calpain system and the 20S proteasome core.
Time frame: Through completion of study, 16 weeks
Gene expression at the mRNA level of atrophy-associated genes (atrogenes)
Real time quantitative polymerase chain reactions (qPCR) will be used to quantify the expression of select genes associated with atrophy. These data will be reported as fold-change from baseline and will be normalized to one or more housekeeping genes whose value does not change throughout the duration of the study.
Time frame: Through completion of study, 16 weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.