The primary purposes of the proposed study is 1) To examine the changes of muscle fiber cross-sectional areas in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction and 2) To examine changes in motor unit size (a non-invasive measure of muscle fiber size) in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction.
Specific Aims and Hypotheses: Specific Aim 1: To examine the changes of type I and II (different types of muscle fibers) muscle fiber cross-sectional areas in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction. Hypothesis 1: Type I and II fiber cross-sectional area will increase following low-intensity resistance training with blood flow restriction, however, only cross-sectional area of type II fibers will increase post high-intensity resistance training. Specific Aim 2: To examine changes in the size of the motor units that are active during low and high intensity contractions in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction. Hypothesis 2: The motor units that are active during low and high intensity contractions will increase in size from low-intensity resistance training with blood flow restriction, but only the motor units that are active during high intensity contractions will increase in size from high-intensity resistance training. Specific Aim 3: To examine changes in whole muscle cross-sectional area as measured via ultrasound pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction. Hypothesis 3: Whole muscle cross-sectional area will increase to similar degrees from both high-intensity resistance training and low-intensity resistance training with blood flow restriction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
31
This intervention consists of inflatable cuffs that are designed to partially occlude veinous blood return from the lower extremities during resistance training.
This intervention consists of performing low-intensity bilateral (both legs at the same time) leg extensions using 30% of a participants 1 repetition maximum (the maximum weight an individual can complete 1 repetition with, but not 2) to volitional failure.
This intervention consists of performing high-intensity bilateral (both legs at the same time) leg extensions using 80% of a participants 1 repetition maximum (the maximum weight an individual can complete 1 repetition with, but not 2) to volitional failure.
Robinson Center
Lawrence, Kansas, United States
Determine changes in muscle fiber cross-sectional area
A primary purpose of the study is to examine the changes of muscle fiber cross-sectional areas in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction
Time frame: July 2021-May 2022
Determine changes in motor unit size
Another primary purpose of the study is to examine changes in motor unit size (a non-invasive measure of muscle fiber size) in the leg extensor muscles (vastus lateralis) pre- to post- 6 weeks of high-intensity resistance training and low-intensity resistance training with blood flow restriction
Time frame: July 2021- May 2022
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