Abstract

This study investigated whether pulsed electromagnetic field (PEMF) therapy enhanced recovery after fatiguing exercise. Thirty recreationally-trained participants were randomly allocated to PEMF (22:32 min:s of PEMF therapy), PLAC (placebo; held device that was not on), or CONT (control) groups. Fatigue was induced by a Yo-Yo running protocol. Recovery interventions were provided after the fatigue protocol (0 hours), and at 24, 48, and 72 hours. Recovery was measured quantitatively by a cycle ergometer peak power (PP) and cadence test, vertical jump, and leg/back dynamometer. These were measured at baseline, and after the interventions from 0-72 hours. Qualitative recovery was measured by visual analogue and Likert scales pre and post intervention. A 3 (group) x 5 (time) repeated measures ANCOVA, with sex as a covariate, derived between-group differences. Change scores relative to baseline were calculated, and analyzed by a 3x4 (0-baseline, 24-baseline, 48-baseline, 72-baseline) repeated measures ANCOVA. Paired samples t-tests compared the qualitative measures pre and post recovery intervention. A 3x8 and 3x4 repeated measures ANCOVA calculated differences in perceived recovery and change scores. There were no significant time by group ANCOVAs for any variable. The PEMF group did have 11-385% greater PP change scores at each time point. There was a significant decrease (p=0.015; d=0.949) in the PEMF group Likert scale score at 72 hours with the qualitative data indicating recovery for this group. Large standard deviations suggested variation in individual responses. Although significant differences were lacking, PEMF therapy may be beneficial for recovery from fatiguing exercise among some individuals.

Keywords: electromagnetic fields, fatigue, Likert scale, muscle soreness, peak power