Issue link: https://www.massageandbodyworkdigital.com/i/992435
A B M P m e m b e r s e a r n F R E E C E a t w w w. a b m p . c o m / c e b y r e a d i n g M a s s a g e & B o d y w o r k m a g a z i n e 47 Law of Symmetry or, as described in the article, the crossover effect. The clinically meaningful issue examined in this bench research is muscle atrophy and the potential for massage to enhance muscle regrowth. "Enhanced Skeletal Muscle Regrowth and Remodelling in Massaged and Contralateral Non-Massaged Hindlimb" was published in the January 2018 issue of The Journal of Physiology. 3 Given the journal's discipline and nature of the research, the article may not be one massage therapists will generally access or learn about. Due to this work's potential impact on the massage therapy field, I want to be sure therapists and educators learn of and understand this work's results and value. Here, I provide a brief review of the study's methodology and results followed by massage education and practice implications and suggestions. STUDY OVERVIEW AND RESULTS Cyclic compressive loading (CCL) applied via a computer-driven device is the massage mimetic used in the study. Essentially, the CCL device supports an anesthetized animal while its limb with the muscle of focus is secured and rhythmically "massaged" by a pneumatically driven wheel, which controls determined shear and compressive forces. 4 The CCL delivery device was used so treatment application could be standardized—a feat challenging for human-administered massage. The study examined the gastrocnemius muscles of rats and used a randomized controlled experimental design. At the start of the experiment, 32 10-month-old rats were randomized to one of four groups (eight in each group). 1. Weight bearing: rats were allowed to move and exercise freely. This was essentially the experiment's control group, with no induced atrophy. 2. Hindlimb suspension: muscle atrophy was induced by suspending rats' hindquarters for 14 days, becoming the experiment's atrophy-only control. 3. Reambulation: after 14 days of hindlimb suspension, rats were allowed to reambulate/move and exercise freely for seven days. 4. Reambulation plus massage: same as reambulation group, with 30 minutes of standardized (load and frequency) CCL applied over the gastrocnemius muscle every other day starting on reambulation day 1 (four total bouts). The experiment ended after 14 days for rats in groups 1 and 2 (weight-bearing and hindlimb-suspended control groups) and after 21 days for rats in groups 3 and 4 (reambulation and reambulation plus massage groups). At the end of the experiment, rats were euthanized and measured aspects (intracardiac blood, gastrocnemius muscles, and femur bone marrow) were harvested for testing. The outcomes and measures used in the research were at cellular and cellular component (e.g., DNA, RNA, and specific proteins) levels and are different from those I usually discuss and work with (e.g., those measured at the system or person level). Muscle size measures, along with muscle cell signaling components and aspects involved with protein synthesis, were measured in the study and compared at the end of the experiment. Study Analysis The first step of this study's analysis was to confirm that muscle atrophy did occur for rats in groups 2–4. Comparisons of the gastrocnemius muscles of rats in the control (weight bearing) and atrophy-only (hindlimb suspension) groups confirmed atrophy occurred, with average muscle fiber cross-sectional area decreasing by 38 percent. Because the rats in groups 3 and 4 experienced hindlimb suspension the same as those in the atrophy-only group, we can assume atrophy occurred for these rats similarly even though they were not measured immediately after atrophy inducement (that is what the rats in the atrophy-only group were for). Here's where it gets exciting: rats in the reambulation group did not experience a significant regrowth response in the gastrocnemius muscle compared to the atrophy-only group. However, those in the reambulation plus massage group had significantly larger muscle fibers compared to the atrophy-only and rehabilitation groups. In addition, muscle size also increased significantly in the nonmassaged gastrocnemius muscle in the reambulation plus massage rats compared to the reambulation rats, indicating a crossover effect occurred. Let this information sink in a little bit. This research indicates that cyclic compression load, an animal mimetic for massage therapy, can enhance muscle regrowth directly (on the immediate muscle addressed) and contralaterally (the same muscle on the other side of the body). While the exact cell-signaling mechanisms through which these outcomes occur are still unknown, this research points to increased muscle size due to increased protein synthesis at both the myofibrillar (the actual muscle fibers making up the sarcomeric lattice) and cytosolic (fluid cell component) levels. Protein degradation, the targeting and elimination of damaged or faulty proteins within a cell, was also elevated in the reambulation plus massage rats, which the authors point to as contributing to enhanced protein synthesis. IMPLICATIONS FOR THE MASSAGE THERAPY FIELD We do not yet know what force is ideal or at what "dose" massage administration is necessary for human muscle, or at which level of atrophy. However, the principle that rhythmic sheer and compression administered to muscle through massage has the potential to enhance muscle regrowth on not just the applied but opposite limb is huge and can be applied to a large variety of general and trademarked massage