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Immobilization & Rehabilitation

Cast immobilization is a common treatment following a bone or joint injury, such as a fracture. After being in a cast for a period of weeks, the muscles around the immobilized area get smaller and weaker because they are not active. This phenomenon is called “disuse muscle atrophy” and can have a big impact on a person’s ability to do daily activities. For example, after lower leg immobilization, it becomes difficult for a person to walk, run and climb stairs.

The Muscle Physiology Lab has two ongoing projects examining cast immobilization. The first study is an animal model of hindlimb cast immobilization in which mice are injected with a virus prior to casting to promote muscle growth. The second is a clinical study in which people who have lower leg injuries requiring them to wear a cast and/or boot, such as a fracture to the fibula or small bones in the foot, for at least 4 weeks are asked to participate. The subjects undergo MRI at the Advanced Magnetic Resonance Imaging and Spectroscopy Facility, strength and functional testing and muscle biopsies of the calf muscle after coming out of their cast and after 6 weeks of physical therapy. Physical therapy is provided at the University of Florida Orthopaedics and Sports Medicine Institute. This study is being conducted in collaboration with Dr. Mark Scarborough and Dr. Parker Gibbs

The data from this study provide information on how muscle size and function decline during immobilization and how they improve with rehabilitation exercise. Muscle biopsies are used to examine which genes are expressed in the muscle during the phases of immobilization and rehabilitation and how these genes are related changes in muscle size and strength.

Study Participation

If you have sustained a lower leg fracture, have to wear a cast for at least 4 weeks and do not require surgery, you may be eligible to participate in this study. For further information, contact:

Dr. Chris Gregory,, 352-273-6111

Click on the thumbnails to enlarge the following photos regarding research within the Muscle Physiology Laboratory (below):

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Study Participation

This page was last updated Sep. 23, 2009.