Muscle Injury Prevention & Rehabilitation in Military Personnel

Six subjects will be enrolled in this group. MRI measures will be performed at baseline and 48 hours post-exercise, when the largest amount of muscle damage is typically observed. They will be tested for maximum strength of the dorsiflexors and then undergo an eccentric exercise protocol for both lower legs on the Biodex with varying loads. Approximately two days after the exercise protocol, the participants will have another MRI of the lower legs to assess any change in T2 relaxation time as a construct of muscle edema/damage.

"All subjects will be tested initially with an MRI, blood work for creatine kinase levels (CK), subjective report of pain, range of motion (ROM) of the lower leg/ankle, and maximum strength of the dorsiflexors. They will also receive the stretch-contract protocol on one leg consisting of the following: a 5 second passive stretch of the dorsiflexors, followed immediately by a 5 second active isometric contraction of the dorsiflexors, and a 5 second rest/relaxation period. This cycle will continue for a duration of \~5 minutes."

All subjects will be tested initially with an MRI, blood work for creatine kinase levels (CK), subjective report of pain, range of motion (ROM) of the lower leg/ankle, and maximum strength of the dorsiflexors.

These subjects will undergo MRI and strength testing at baseline and will also be assessed for CK levels, pain report, and ROM. They will then receive an eccentric loading paradigm for the dorsiflexor muscles of the involved leg using an isokinetic dynamometer with varying loads. Approximately two days after the exercise protocol, follow-up assessment of MRI, CK levels, pain report, ROM, and strength will be done.