The knee and ankle joints were fixed at α = 90° and β = 90°, respectively. … The experimental session began with a standardized warm-up of 3 × 50 skipping and repetitive submaximal plantar flexions. The pretests consisted of three isometric plantar flexed MVCs with the

dominant leg separated by a 1-min rest. Right after the last MVC, NMES was started and lasted for 9 min. The posttest comprises three MVC separated by 3 min. To keep up the fatigue in GL, NMES was applied to the GL during the 3-min breaks. Thereafter, participants Inhibitors,research,lifescience,medical carried out three MVC at 10, 15, and 20 min during recovery. During MVC, force was recorded at 1000 Hz using a three-dimensional force plate (Kistler 9281C, Winterthur, Switzerland). Participants were advised to rise up force continuously until a plateau is reached and hold it for 3 sec. To make sure that participants performed a MVC, we considered the methodological recommendations of Gandevia (2001). Briefly, (1) all maximal efforts were accompanied by same instruction and practice; (2) visual feedback Inhibitors,research,lifescience,medical was given to the Inhibitors,research,lifescience,medical subjects; (3) the investigator gave appropriate and standardized verbal encouragement; (4) subjects were allowed to reject efforts that they did not regard as “maximal.” For data synchronization

purposes, an analog signal from the force platform was used as a trigger and sent to the EMG system. EMG activities of SOL, GL, and GM were recorded during Inhibitors,research,lifescience,medical MVC. We did not measure the antagonistic tibialis anterior, as the activation during MVC is negligible and did not change with fatigue (Patikas et al. 2002). Before the experiment started, the skin was prepared

and electrode placements were localized according to the recommendations of SENIAM (Hermens and Roessingh Research and Development BV 1999). Briefly: the skin was dry shaved, abraded, and cleaned with alcohol. Surface EMG activity was detected by two NVP-BKM120 self-adhesive Ag/AgCl− electrodes with a 20 mm interelectrode Inhibitors,research,lifescience,medical distance. The signals were preamplified (bandwidth 10–500 Hz) and recorded at 1000 Hz using the Biovision system (Wehrheim, Germany). EMG data were full wave rectified and digitally filtered using a 10 Hz lowpass filter (butterworth, second order) (Arampatzis et al. 2003). The maximal amplitude of the EMG signal was calculated in a time frame of 500 msec around Adenosine MVC force. Maximal force and maximal EMG amplitude of SOL, GM, and GL were calculated for nine MVC (three pretest, three posttest, and three recovery). Hence, the three MVC of each condition were averaged. The GL was fatigued with a portable muscle stimulator (Compex Sport-P, Medicompex SA, Ecublens, Switzerland). Two self-adhesive electrodes (5 × 5 cm) were placed 2 cm proximal to the upper EMG electrode (negative) and 2 cm distal to the lower EMG electrode (positive). Rectangular wave pulse currents (80 Hz) lasting 400 μsec were delivered to the GL.