Contributed by MK Brennan, MS, RN, LMBT; Derek Austin, PT, DPT, MS, BCTMB, CSCS and April V Neufeld, BS, LMP

Massage therapy is commonly used following physical exertion to manage soreness and promote healing. Physical exercise often results in microscopic muscle injury with its associated soreness, decreased range of motion, pain, and inflammation, particularly with high force or repetitive muscle contractions. This month’s research review by the Massage Therapy Foundation explores the findings of a randomized, blinded study examining the effects of Swedish massage on exertion-induced muscle injury. Dr. Nina Franklin and her team at the University of Illinois at Chicago published their research in the Archives of Physical Medicine and Rehabilitation in 2014.

Massage therapy may be an effective treatment for exercise-induced injury and is often recommended. Recent research studies have shown that massage may contribute to a reduction of post-exercise inflammation. Following exercise, especially eccentric exercise, there can be an acute increase in inflammatory cytokines in muscle. This cytokine reaction can lead to a systemic inflammatory response in which neutrophils may be activated and result in impaired endothelial function as they adhere to vascular endothelial cells. For that reason, the authors sought to investigate the effect of massage therapy on endothelial dysfunction.

The study included 36 sedentary adults aged 18 to 40 who were divided into three groups: the exertion-induced muscle injury and massage group, the control group of exertion-induced muscle injury without massage, and a control group of massage without exertion-induced muscle injury. Only sedentary adults were included in the study, as defined by "<150 minutes of moderate physical activity per week [and] no history of resistance or aerobic training within the past six months prior to enrollment." Subjects were excluded if they had a history of cardiovascular disease, suspected collagen vascular disease, or cancer and no use of vasoactive medications. Physical and physiological characteristics such as weight and blood pressure were similar among all groups.

Study subjects were initially screened prior to the study and assessed five times before and after the intervention. Total cholesterol, high-density lipoproteins, low-density lipoproteins, and glucose were all measured in the initial screening following a 12-hour fast. The researchers also assessed heart rate, blood pressure, height, weight, and waist circumference as well as dietary intake and nutritional content.

Following the initial assessment, subjects were then tested for their baseline endothelial function. This was done by testing the brachial artery flow-mediated dilation (FMD) using ultrasound technology and a blood pressure cuff. Brachial artery diameter was measured after the cuff was inflated 50mmHG above the person’s systolic blood pressure reading and again after release of the cuff. Dilation was determined with 30-second images taken during the first, second, and third minutes after the cuff was released. Each subject’s FMD was assessed at baseline and then again at 90 minutes, 24 hours, 48 hours, and 72 hours after the intervention. Sublingual nitroglycerin was given to the subjects to induce endothelium-independent dilation of blood vessels after each FMD measurement.

Perceived muscle soreness was also assessed. Using a ranking scale of 1 (normal) to 10 (very sore), the subjects were asked to rate their perceived muscle soreness by palpation of their relaxed quadriceps muscles by an exercise professional.

The subjects randomized to one of the exertion-induced muscle injury groups performed a single bout of bilateral eccentric exercise on a leg press machine. The subjects worked up to their 1 repetition maximum, or the maximum amount of weight that they could press one time, over the course of several familiarization sets. Then, in order to induce muscle injury, subjects performed 6 to 8 sets of 10 repetitions at approximately 70 percent to 80 percent of the maximum. To emphasize eccentric muscle contraction, the researchers instructed the subjects to lower the weight under control for 5 seconds per repetition.

The massage therapy treatment used in this study was a 30-minute protocol of Swedish techniques to the muscle groups of the bilateral lower extremities. Effleurage and petrissage were used according to a well-defined massage protocol. The treatments were provided within 30 minutes after exercise for those assigned to the exercise/massage group or after rest for those assigned to the massage only group. All of the sessions were provided by the same massage therapist.

Results indicate that massage has systemic effects. The subjects who received massage on the lower extremities had significantly higher FMD measurements in the upper extremity both after exertion and after rest. One thought is that this is due to the effect on circulation through massage. The authors write, "Increased local blood flow with massage may hasten the inflammatory response by reducing the time course of neutrophil infiltration and activation, thereby protecting against neutrophil-mediated tissue damage." Reducing inflammation with massage may improve endothelial function and thus may benefit many recipients of massage therapy, since this result was also true for those who received massage after rest.

In addition to circulatory responses, modulation of the autonomic nervous system may contribute to the results observed from massage therapy. Eliciting the parasympathetic nervous system with massage can result in a decreased heart rate and blood pressure. These effects may have an impact on the brachial artery FMD, even though no changes in heart rate and blood pressure were noted in this study. The lack of any blood pressure or heart rate response following massage was viewed by the authors as one of the limitations of their study.

Further limitations include the lack of a true control group, meaning a group with neither massage therapy nor exertion-induced muscle injury. Additionally, specific differences among different sexes, races, or ethnicities were not considered as possible influences on endothelial function. One further limitation is the potential impact body mass index (BMI) may have on the effect of massage, though the authors did note that subjects in each group had similar BMI measurements. Finally, endothelium independent dilation to the nitroglycerin was not able to be tested before the exertion-induced muscle injury and/or massage due to the vasodilatory effect of the medication on blood pressure.

The implications of this study are far-reaching since massage is being used more and more for health promotion and in hospital settings. Demonstrating that massage has a positive impact on brachial artery endothelium-dependent FMD may help support the use of massage as a way to reduce exertion-induced muscle injury and hypoperfusion in some individuals with heart disease or other at-risk populations in exercise training regimens. The conclusions of this study regarding massage’s effect on endothelial function may also be beneficial for those with other physiological stressors that have vascular responses such as hypertension, wound healing, and hypoxemia.

To help massage practitioners become more comfortable with scientific research, the Massage Therapy Foundation offers courses on research literacy. Online courses include Basics of Research Literacy (8 CE hours) and Finding and Evaluating Research (3 CE hours). The AMTA 2015 National Convention in Pittsburgh, Pa. this August also offers a research track developed in partnership with the Massage Therapy Foundation. This year the research track will consist of five high caliber researchers, including Dr. Nina Cherie Franklin. Any of these options offer an excellent way to bolster your skills in reading and evaluating massage research.

References

1. Franklin NC, Ali MM, Robinson AT, Norkeviciute E, Phillips SA. Massage therapy restores peripheral vascular function after exertion. Archives Physical Medicine and Rehabilitation, June 2014;95(6):1127-34.