The Study Question
Exertion-induced muscle injury (EMI) can result from engaging in physical activities that involve high-force and/or repetitive eccentric muscle contractions. This type of injury typically results in muscle pain, soreness and swelling related to the body’s normal inflammatory response. The inflammatory response can also cause impaired endothelial function, an early indicator of cardiovascular disease.
Massage therapy is often recommended for reducing symptoms of EMI and can reduce post-injury inflammation. This study investigated whether massage performed on the lower limbs following EMI could reduce or attenuate impaired endothelial function in the brachial artery in sedentary, but otherwise healthy, adults.
The Study Methods
36 adult participants (28 women and 8 men) aged 18 to 40 years were studied. To be considered sedentary, they must have performed less than 150 minutes of moderate physical activity per week, had no history of resistance or aerobic training within the past six months, no history of cardiovascular disease or suspected collagen vascular disease such as systemic vasculitis, diabetes mellitus, thyroid dysfunction or orthopedic injuries, no history of smoking (for at least six months prior to participation), and no use of vasoactive medications. Participants were randomly assigned to one of three groups: (1) massage therapy treatment following exposure to EMI (EMI + MT), (2) a control intervention consisting of EMI with no massage (EMI only), or (3) a control intervention of massage therapy treatment without EMI (MT only).
Following baseline measures, participants underwent a single bout of bilateral eccentric exercise on an isotonic variable resistance leg press machine. Starting from a seated position, each repetition began with the hips and knees flexed (approximately 90 degrees) performing single repetitions to exhaustion. The 10-point Borg rating of perceived exertion (RPE) scale was used as an index of intensity, and weight was increased with each successive set as tolerated.
Subjects assigned to group 1 (EMI + MT) received massage therapy within 30 minutes after eccentric exercise while subjects assigned to group 3 (MT only) underwent treatment after 30 minutes of rest. Massage therapy targeted the bilateral lower-extremity muscle groups using a specific and timed protocol of Swedish techniques, primarily effleurage and petrissage, and varying in depth from superficial to deep. All treatments were performed by a single licensed and certified massage therapist.
Measures were taken again at 90 minutes, 24 hours, 48 hours and 72 hours after the intervention. Brachial artery flow-mediated dilation (FMD) was used as a measure of endothelial function and was determined by ultrasound at each time point.
Groups were similar in terms of baseline demographics and dietary patterns. Brachial FMD increased from baseline in both the EMI + MT group and the MT only group (7.38±0.18 to 9.02±0.28%, p<0.05 and 7.77±0.25 to 10.20±0.22%, p < 0.05, respectively) at 90 minutes, remaining elevated until 72 hours. In the EMI only group, FMD was reduced from baseline at 24 and 48 hours (7.78±0.14 to 6.75±0.11%, p<0.05 and 6.53±0.11, p<0.05, respectively) and returned to baseline level after 72 hours.
Limitations of the Study
This was a thoughtfully designed and carefully conducted study. However, the potential influence of massage on autonomic nervous system function may have played a role in endothelial responses.
Implications for Evidence-Informed Practice
These results show that local massage has systemic effects on endothelial function. Massage therapy applied to the lower extremities may have a protective effect on impairment of brachial artery FMD following EMI in sedentary adults and appears to enhance brachial artery FMD even without exercise-induced injury.