Resistance Training and 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.

Inclusion criteria

-

Exclusion criteria

• Participants must not have participated in resistance training more than 5 times in the 6 months preceding the study.
• Participants must be healthy and free of any cardiovascular, metabolic or musculoskeletal conditions that may affect the results of the investigation.
• Participants must not have a history of severe hip, knee and/or ankle injuries, or any other pathological conditions that impair their motor control.
• Participants must not have any pre-existing cardiovascular conditions that involve blood flow/blood clotting.
• Participants who are currently taking blood thinners or any medications regulating blood pressures or heart rate will not be eligible to participate in the study.
• Female participants who are pregnant at the start of or who are planning to become pregnant during the resistance training intervention will not be eligible to participate in the study.