One Week of Immobilization

We don’t lose strength gradually as we age.  Instead, we generally get injured, get sick, or undergo a medical procedure that causes a period of inactivity and a subsequent rapid decline in strength (and lean muscle tissue).  Over decades, a stepwise reduction in muscle occurs as opposed to a gradual, linear reduction.  To be clear, inactivity drives both muscle loss and strength loss, but we lose strength at a five times greater rate than we do muscle. 

Perhaps the most significant cause of rapid strength loss is limb immobilization.  Authors of a brand-new study published in the journal Medicine and Science in Sport and Exercise sought to understand the outcomes of one week of leg immobilization on muscle strength.  The study design was simple: test muscle size and strength and “muscle connective protein synthesis”; immobilize one limb for seven days, and then measure muscle size, strength, and muscle connective protein synthesis rates when the cast is removed. 

The results?  Seven days of immobilization substantially reduces muscle connective protein synthesis rates and key glycoproteins that drive muscle strength.  We get weaker very fast.

Take home message: If we stop moving and become more sedentary, we lose muscle and strength incredibly rapidly. When you are injured or ill, train the healthy limbs and return to training the injured limb/area as soon as possible. This might be one of the top two or three core tenets of healthy aging.