Muscle from Aged Rats Is Resistant to Mechanotherapy

Massage is a type of mechanotherapy on muscles that have been shown to improve protein turnover during disuse atrophy. It has also been shown to enhance muscle regrowth during recovery from disuse atrophy in adult muscle.

A new study investigated whether massage could cause beneficial adaptations in skeletal muscle from aged rats during normal weight-bearing conditions, hindlimb suspension, or reloading following hindlimb suspension. Aged (30 months) male Fischer 344/Brown Norway rats were divided into two experiments:

(1) Weight-bearing for 7 days (WB, n = 8), Weight-bearing with massage (WBM, n = 8), hindlimb suspended for 7 days (HS7, n = 8), or hindlimb suspended with massage (HSM, n = 8), and

(2) WB for 14 days (WB14, n = 8), HS for 14 days (HS14, n = 8), reloading (RE, n = 10), or reloading with massage (REM, n = 10) for 7 days following HS.

The study showed that massage did have an anabolic benefit during reloading or weight-bearing. In contrast, massage during hindlimb suspension enhanced myofibrillar protein turnover in both the massaged limb and contralateral non-massaged limb. However, massage did not prevent muscle loss.

In summary, the study demonstrates that massage may not be effective for the prevention of atrophy during muscle disuse or recovery of muscle mass during reloading in aged rats.