Muscle Damage and Disuse Atrophy

In Young Healthy Males and Females, What is the Effect of Prior Eccentric Exercise on Thigh Muscle Atrophy During One Week of Leg Disuse Compared to no Prior Exercise?

Limb injury generally requires a period of recovery during which time the limb is often immobilised (e.g. with a cast or brace) resulting in a rapid loss of skeletal muscle. Despite the importance of muscle loss during injury, our understanding of how it occurs is incomplete. Several factors are likely to contribute, including a lack of muscle contraction and injury induced inflammation. In this study, the investigators will recruit healthy volunteers who will spend 7 days in a knee brace to replicate leg immobilisation. Prior to immobilisation, half of the participants will perform a single session of strenuous resistance exercise which is known to cause muscle damage and initiate an inflammatory response. This is designed to replicate the muscle damage and inflammation that occurs with injury. The remaining half of participants will not perform this exercise, allowing us to look at the additive effect of muscle damage and inflammation on muscle loss with immobilisation.

Inclusion Criteria:

• Aged 18 - 40
• BMI between 18 and 27
• Healthy, recreationally active, non smoker

Exclusion Criteria:

• Non-removable metallic implants (including heart pacemaker, cochlear implants, medication pumps, surgical clips, plates or screws) or claustrophobia
• Use of nutritional supplements
• Chronic use of over the counter medication
• Any diagnosed metabolic disease (e.g. type 1 or 2 Diabetes).
• Any diagnosed cardiovascular disease or hypertension.
• Anyone with previous motor disorders. Anyone with a current musculoskeletal injury that may impair their use of crutches.