The Short and Long Term Effects of Tibialis Anterior Local Cooling on Dorsiflexion Force

The goal of this study was to analyze and compare the superficial temperature, dorsiflexion force and electromy-ographic (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 volun-tary 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, dor-siflexion force and EMG of the tibialis anterior muscle were evaluated immediately, 5, 15, 30, 45 and 60 minutes af-ter 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 applica-tion, 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 superfi-cial 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 interven-tions which are followed by rapid recovery.