Physioacoustic therapy: placebo effect on recovery from exercise-induced muscle damage

Abstract

We evaluated claims that physioacoustic therapy can enhance muscle healing following damaging exercise. Untrained subjects were randomly assigned to control (C), placebo (P) or treatment (T) groups. All groups performed 70 eccentric triceps contractions followed by; no treatment (C), sham physioacoustic treatment (P), or actual physioacoustic therapy (T) on days 1–4 post-exercise. Muscle soreness and isometric and concentric triceps peak torque were determined pre-exerciseand on days 1–4 and 7 post-exercise. The T group received physioacoustic therapy for 30 min/day on the treatment days. The P group believed they received physioacoustic therapy, although the chairs were turned off. Peak torques were depressed (P < 0.05) on days 1–3 in all groups and returned to pre-exercise values by days 4–7 in both P and T groups. C group peak torques remained depressed (P < 0.05) through day 7. Soreness was elevated (P < 0.05) in all groups on days 1–2 post-exercise. P and T groups reported no soreness by day 3 while the C group remained sore (P < 0.05) through days 3–4. The T group recovered soreness and force faster than C but at a similar rate to the P group. The effectiveness of physioacoustic therapy in enhancing post-exercise muscle healing may be attributable to a placebo effect.