Atrophy, Disuse, Atrophy, Muscular
Conditions
Brief summary
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.
Interventions
OTHERResistance Training Preconditioning
Resistance training prior to disuse-induced atrophy followed by another period of resistance training
OTHERControl
Activities of daily living prior to disuse-induced atrophy followed by a period of resistance training
Sponsors
Auburn University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* Between the ages of 18-30 * Free from medical implants in lower extremity that would interfere with low-dose radiation * Are not allergic to ultrasound gel or Lidocaine * Have no or minimal experience with resistance training (less than 1 training session/week for a 1 year period)
Exclusion criteria
* Have been exposed to medically necessary radiation in the past 12 months other than dental x-rays * Have known overt cardiovascular or metabolic disease * Have a medical condition that would contraindicate participating in an exercise program or donating a skeletal muscle biopsy (e.g. blood clotting disorder, taking blood thinners, etc.) * Are undergoing medical treatment for a disease that would interfere physiologically or logistically with study outcomes and/or protocols (e.g. undergoing chemotherapy and/or radiation for cancer treatment) * Have consumed supplemental protein, creatine, and/or agents that affect hormone status (e.g. testosterone, growth hormone boosters, etc.) within the previous 2 months.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in vastus lateralis fiber cross-sectional area | Through completion of study, 16 weeks | 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 |
| Change in quadriceps strength via 3 repetition maximum testing | Through completion of study, 16 weeks | Strength of the quadriceps will be assessed via 3-repetition maximum testing of select exercises (leg press, leg extension, hex-bar deadlift) |
| Change in quadriceps strength via isokinetic dynamometry | Through completion of study, 16 weeks | Strength of the quadriceps will be assessed via isokinetic dynamometry |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in protein expression of anabolic signaling proteins | Through completion of study, 16 weeks | Western blotting will be performed and quantified in relative fluorescence units for proteins involved in the mechanistic target of rapamycin signaling pathway. |
| Gene expression at the mRNA level of atrophy-associated genes (atrogenes) | Through completion of study, 16 weeks | 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. |
| Change in protein expression of catabolic signaling proteins | Through completion of study, 16 weeks | 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). |
| Change in activity of catabolic systems | Through completion of study, 16 weeks | 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. |
Contacts
Primary ContactMichael D Roberts, PhD
Backup ContactJohn M Michel, MS
Outcome results
None listed