The EMG data were time synchronized with a force plate (Bertec
force plate) which indicated IC of the foot. Raw EMG data were
processed by creating a linear envelope using full-wave rectification
and low-pass filtered at 50 Hz with a 2nd order Butterworth filter was
applied. A computer algorithm was created to identify the onset
timing of gluteus medius EMG activity, in which it identified the point
where EMG signal deviated by more than 2 standard deviations above
the baseline level for at least 25 ms. Baseline EMG activity was
calculated in the 198 ms window prior to foot initial contact. This
starting time (198 ms) was stipulated by estimating the time for each
subject to contact the floor after the 31 cm drop off, ensuring that
onset threshold was referred to baseline means calculated exclusively
during the airborne period. This procedure (adapted from Dedrick et
al. [13]) was performed to avoid the incidence of erroneous onsets
referred to gluteus medius muscle activation during the step-off phase
of the single leg drop landing. Onset threshold search was initiated at