Effects of Far-Infrared Radiation Lamp Therapy on Recovery from a Simulated Soccer-Match in Elite Female Soccer Players

We investigated the effects of far-infrared radiation (FIR) lamp therapy on changes in muscle damage and performance parameters following six sets of 15-min Loughborough intermittent shuttle test (LIST), a simulated soccer match. Twenty-four elite female soccer players (20-24 y) were assigned into FIR or sham treatment group (n = 12/group). The participants received a 60-min FIR or sham treatment (30 min per muscle) over knee extensors (KE) and flexors (KF) at 2, 25, 49, 73, and 97 h post-LIST. Maximal voluntary isometric contraction (MVC) torque and muscle soreness of the KE and KF, plasma creatine kinase (CK) activity as muscle damage markers, and several performance parameters including countermovement jump (CMJ) and Yo-Yo intermittent recovery test level 1 (YYIR1) were measured before and 1, 24, 48, 72, 96, and 120 h post-LIST. Changes in the measures were compared between groups by a mixed-design two-way ANOVA. The running distance covered during LIST and changes in the measures at 1-h post-LIST (before the treatment) were similar (p = 0.118-0.371) between groups. Changes in muscle damage markers at 24-120 h post-LIST were smaller (p < 0.05, eta(2) = 0.208-0.467) for the FIR (e.g., MVC-KE torque decrease at 48-h post-LIST: -1 +/- 2%, peak KE soreness: 16 +/- 10 mm, peak CK: 172 +/- 42 IU/L) than sham group (-11 +/- 9%, 33 +/- 7 mm, 466 +/- 220 IU/L, respectively). Performance parameters recovered faster (p < 0.05, eta(2) = 0.142-0.308) to baseline for the FIR (e.g., decreases at 48-h post-LIST; CMJ: 0 +/- 1%, YYIR1: 0 +/- 1%) than sham group (-6 +/- 2%, -9 +/- 6%, respectively). These results suggest that the FIR lamp therapy was effective for enhancing recovery from a soccer match.