Pain Reduction Following Massage After Induced Fatigue Is Not Mediated by Changes in Muscle Stiffness or Intramuscular Fluid Content: A Randomized Controlled Trial With Mediation Analysis.

CONTEXT: Massage therapy is a common intervention for athletic recovery. However, its effects on fatigue, muscle stiffness, and intramuscular fluid content or the mechanism for pain reduction remain uncertain.

OBJECTIVES

To evaluate the immediate and subacute effects (24-72 hours) of massage on pain, fatigue, muscle stiffness, and intramuscular fluid content in university athletes after an induced fatigue protocol. Additionally, we investigated whether changes in muscle stiffness and intramuscular fluid content mediate the effects of massage on pain and fatigue.

DESIGN

Randomized controlled clinical trial.

SETTING

Laboratory.

PATIENTS OR OTHER

PARTICIPANTS

Eighty-six university athletes, who completed a quadriceps fatigue protocol involving isokinetic concentric contractions.

INTERVENTIONS: Participants received either 10-minute massage therapy targeting the quadriceps or a sham control intervention. They were applied immediately after the fatigue protocol and repeated 48 hours later.

MAIN OUTCOME MEASURES: Pain and fatigue were assessed using numeric rating scales. Muscle stiffness and intramuscular fluid content were evaluated using ultrasound elastography and echo intensity, respectively.

RESULTS

Massage therapy reduced pain immediately after the intervention compared with the sham group by -1.4 points (95% confidence interval = -2.8, -0.1). No differences were observed for pain at subsequent time points or for fatigue, muscle stiffness, or intramuscular fluid content at any time. Mediation analysis did not reveal indirect effects of changes in muscle stiffness or intramuscular fluid content on changes in pain or fatigue.

CONCLUSIONS

Massage therapy provides immediate pain relief after induced fatigue but does not produce lasting effects on pain, fatigue, muscle stiffness, or intramuscular fluid content. The observed pain reduction was not mediated by changes in muscle stiffness or intramuscular fluid content.