Upper Versus Lower Limb Responses to Higher Versus Lower Load Resistance Training in Young Men
Condition: Muscle Hypertrophy; Muscle Strength
MeSH terms: Hypertrophy
Study type: Interventional

Summary: 
      Recent research suggests that performing resistance exercise training with relatively light
      loads is equally as effective at increasing muscle mass and muscle strength as performing
      resistance exercise training with relatively heavy loads. Whether or not performing
      resistance exercise with relatively heavy loads or light loads is equally as effective
      between the upper- and lower-body within the same individual has never been investigated.
      Given the substantial individual variance in resistance exercise training-induced changes in
      muscle mass and strength, this study is designed to quantify the relative influence that
      extrinsic training variables (e.g., load), as opposed to intrinsic muscle-based
      predisposition, has on resistance training-induced changes in muscle mass and muscle
      strength.
    

Detailed description: 
      Each participant will come to the Exercise Metabolism Research Laboratory gym three times per
      week for 10 weeks to perform lower- and upper-body resistance exercise training with both
      relatively heavy- (~80% one repetition maximum [1RM]) and light- (~40 %1RM) loads. One arm
      and one leg will be randomized to lift with relatively heavy loads such that the other arm
      and leg will be randomized to lift with relatively light loads. Each workout will be
      supervised by a study investigator.

      The time commitment of this study is 12 weeks (including pre- and post-study testing). Each
      workout to take 30 minutes and, with testing days included, the investigators foresee a total
      time commitment of 41 hours, or just under three and half hours per week.

      The pre- and post-study measurements include muscle biopsies, dual x-ray absorptiometry
      scans, ultrasonography scans, 1RM assessment, and maximum voluntary contraction assessment.
      The muscle biopsies will be taken from each of the participant's vastus lateralis to assess
      muscle fibre cross sectional area in both legs during the beginning (four biopsies) and end
      (four biopsies) of the intervention. The dual x-ray absorptiometry scans are used to assess
      body composition and will be done pre- and post-intervention. The ultrasonography scans will
      be used to assess biceps brachii and vastus laterals thickness and cross sectional area. The
      ultrasound scans will be assessed during the beginning (four scans) and end (four scans) of
      the intervention. The 1RM assessment will include 1RM testing on a knee extension machine and
      biceps curl machine and will be done at the beginning and end of the intervention. The
      maximum voluntary contraction assessment will be performed on a System 3 Biodex Dynamometer
      (Shirley, NY, USA), which is an immovable machine that the participants contract against to
      measure their peak force. The maximum voluntary contractions will be recorded three times:
      twice at the beginning of the intervention and once at the end of the intervention.
    

Intervention name(s): Unilateral resistance exercise
Intervention type(s): Behavioral
Intervention description(s): The participants performed three sets of their unilateral resistance exercise (biceps curls and knee extensions) three times per week for 10 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: One arm and one leg of each participant were randomized to lift with heavier loads while the other arm and leg of each participant were randomized to lift with lighter loads for 10 weeks.
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science