Muscle Injury Prevention & Rehabilitation in Military Personnel

Study Summary

The overall goal of this study is to establish a new pre-rehabilitation program in the prevention of muscle injury in the legs of healthy people serving in the military and injured individuals with muscle wasting following leg injuries. The specific goals include: 1) the amount of exercise that causes injury to healthy muscle in the lower leg of healthy people; 2) what is the effect of an intervention (pre-rehabilitation program) on decreasing how easily the muscle of the lower leg can be injured in healthy people; 3a) what amount of exercise causes injury to muscle that has recently been injured and is recovering and 3b) the effect of the new pre-rehabilitation program on the muscles of the lower leg when the muscle has recently been injured and is still recovering. For the first goal, the investigators will determine how easily the muscle can get injured from a specific exercise in 6 healthy, conditioned men and women. Participants will perform different amounts of exercise with the lower leg muscles to see how easily the muscle can be damaged. Magnetic resonance imaging (MRI) will be used to estimate how much damage occurs with the different levels of exercise. For the second goal, the investigators will examine the effect of a new pre-rehabilitation program on decreasing how easily muscle gets damaged from the exercise we did in the first goal. The investigators will invite healthy people to participate in this goal. The investigators will use MRI, blood markers, and pain as ways of assessing muscle damage in 10 people who do the pre-rehabilitation program before exercising and 10 who do not do the new program. The third goal will focus on a) determining how easily muscle gets injured that has recently recovered from some trauma (5 people will participate in this part of the third goal), and b) determining how a pre-rehabilitation program decreases how easily a muscle that has just recovered from trauma gets injured from exercise (10 people will participate in

Primary Outcome

T2 weighted spin-echo magnetic resonance imaging (MRI) will be acquired with a fixed bandwidth, a TR=3s, optimized field of view (FOV\_, 7mm slice thickness, and TEs of 20, 40, 60, 80, and 100 msec. A pixel-by-pixel T2 map will be created for each slice by fitting the decay in image signal intensity (SI) to a single exponential (SI=Aexp-TE/T2+B; A=proton density) with respect to echo time (TE).

Interventions

• PROCEDURE Healthy Muscle Group
• PROCEDURE Stretch-Contract Pre-rehabilitation Group
• PROCEDURE Stretch-Contract Control Group
• PROCEDURE Muscle Atrophy