Acute and chronic skeletal muscle pain and weakness are among the most common ailments treated by physicians. Minimizing this pain and weakness is of critical importance considering high exercise attrition rate in patients with muscle dysfunction, as well as the direct economic burden of physical inactivity, in excess of 76 billion dollars annually in the United States. Although the effectiveness of massage for overcoming muscle pain and weakness following exercise is limited to a few high quality studies, Americans make more than 160 million visits annually to seek relief of musculoskeletal weakness and pain by manipulative, body-based practices. However, neither the mechanisms of actions nor the effectiveness or optimal strategies for massage therapies have been conclusively demonstrated.

In order to achieve an optimal efficacy for any therapy, it is essential to understand the molecular basis of its actions. In this dissertation, in vivo mechanisms of massage-mediated biomechanical signals that may limit muscle inflammation, weakness, and damage were explored. We determined a combined magnitude, frequency, and duration of massage (via a customized pneumatic device) that optimized functional recovery following eccentric exercise through quantification of active (peak isometric torque) and passive (stress relaxation) muscle mechanical properties. In particular by:​ (A) identifying the most effective combination of massage parameters (0.25 or 0.5 Hz, 5 or 10N, 15 or 30 min), (B) quantifying muscle membrane disruption and myofiber damage, and (C) using the quasi-linear viscoelasticity (QLV) model to study passive time-dependent responses of skeletal muscle to repeated massage-like compressive loading (MLL) following damaging eccentric exercise.

Mechanical properties of the tibialis anterior of New Zealand White rabbits were tested prior to one bout of eccentric exercise, post exercise, and pre and post four consecutive days of massage. The contralateral hind limb served as the non-exercised control. The 0.5Hz, 10N, 15min protocol produced greatest peak torque recovery, values approximately equal to pre-eccentric exercise (EEX). There were no significant interactions between or among the parameters. This is the first evidence of a dose-response effect for magnitude and frequency of massage on recovery of in vivo active muscle properties following EEX. This relationship was also seen for the passive properties, with the 0.5Hz, 10N, 15 min protocol showing the an accelerated recovery of muscle viscoelastic properties. With no significant differences in either instantaneous elastic or reduced relaxation response of the muscle between the 0.5Hz, 10N, 15 and 30 min protocols.

The previous work was extended by comparing the effect of immediate vs. delayed application of massage on peak torque recovery following intense EEX. While there is clinical significance of both immediate and delayed massage producing enhanced recovery compared to non-massaged control animals, massage beginning 48 hours post EEX had a significantly diminished effect in restoring function of EEX muscle compared to immediate massage. These data provide a starting point for linking the mechanical properties of skeletal muscle with physical therapies, and may shed light on the design and optimization of therapeutic massage based therapies for recovery from EEX in humans.