The goal of this study was to analyze and compare the superficial temperature, dorsiflexion force and electromyographic (EMG) signal of tibialis anterior muscle before and after superficial cooling application. Seventeen healthy untrained volunteers were divided into two groups. Subjects were submitted to seven procedures of maximal voluntary isometric contractions of dorsiflexion, once before and six times after thirty minutes of either superficial cooling of the anterolateral side of the leg with an ice pack (LC group) or rest (control group). Superficial temperature, dorsiflexion force and EMG of the tibialis anterior muscle were evaluated immediately, 5, 15, 30, 45 and 60 minutes after cooling intervention. The results showed that the superficial temperature reduced significantly for 60 minutes post cooling, dorsiflexion force and amplitude of EMG signal was reduced only immediately after cooling application, whereas median frequency of EMG signal was significantly reduced up to 60 minutes post cooling application. The study concludes that superficial cooling with ice pack for thirty minutes can decrease the dorsiflexion force and EMG activity only immediately after the cooling application, while it causes a prolonged decrement on the superficial local temperature and on the median frequency of the EMG signal. These findings suggest that clinicians should be aware of the immediately alterations in motor output performance that result from muscle local cooling interventions which are followed by rapid recovery.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.