Context: Deep friction massage (DFM) is often used in the treatment of tendinopathies; however, the pressure applied may vary and interfere with the obtained results.
Objective: To assess whether the immediate effects of DFM on pain (pain intensity and time to onset of analgesia) and muscle strength are dependent on the pressure applied during the DFM application in athletes with patellar tendinopathy.
Design: Randomized, controlled, cross-over trial.
Setting: University research laboratory (institutional).
Participants: Ten athletes with diagnosis of unilateral patellar tendinopathy (age 27.90 [5.24] y).
Interventions: All participants attended 4 sessions, 3 treatment sessions with DFM applied with different pressures (the mean pressure-previously determined for each participant-and the mean pressure ± 25%) and a control session, each of which was separated by 48 hours.
Main outcome measures: Pain (intensity upon palpation and time to onset of analgesia), and muscle strength of knee extensors were assessed before and immediately after each session.
Results: Pain intensity changed significantly over time (F1,9 = 52.364; P < .001; ηp2=.853) and among sessions (F3,27 = 82.588; P < .001; ηp2=.902), with a significant interaction for group × time (F3,27 = 19.841; P < .001; ηp2=.688). The knee extensors strength did not change significantly over time (F1,9 = 2.240; P = .17; ηp2=.199), nor a significant interaction for session × time was observed (F3,27 = 3.276; P = .07; ηp2=.267). Regardless of the pressure applied, the time to onset of analgesia was not significantly different (F2,18 = 1.026; P > .05; ηp2=.102).
Conclusion: It was shown that DFM induces an immediate reduction in pain intensity upon palpation, regardless of the pressure performed. Notwithstanding, the reader should take into account the small sample size and the caution needed in the results' interpretation.
Keywords: Cyriax; manual therapy; muscle strength; pain.