A comprehensive method for assessing postural control during dynamic balance testing

Postural control, despite its complexity, has been investigated based on single or multiple domain parameters, mainly under static conditions. The purpose of this study was to investigate whether semi-squatting in one leg, in contrast to simply standing in one leg, can challenge the postural control in a more dynamic manner similar to those encountered during sporting activities, using posturographic-based parameters coupled with EMG data of the ankle musculature. Our findings revealed that the decreased stability induced with single-leg semi-squatting (SLSQ) required primarily the contribution of the tibialis anterior and the peroneus brevis, as opposed to the medial gastrocnemius and lateral gastrocnemius who were the main controllers of body posture during single-leg standing (SLST) with open eyes. The lower variability found in the CoP-based parameters and the EMG activity of the muscle under investigation suggests that postural control can be more accurately assessed under dynamic conditions such as with SLSQ compared to the more static SLST test. Multi-factorial analysis of postural control combining posturographic and EMG data, particularly under dynamic conditions, can provide useful information in the diagnosis and rehabilitation of clinical cases where the assessment of muscle dysfunction is required to design a rehabilitation program and monitor patient progress. • Simultaneous recordings of posturographic-based parameters and the EMG activity of the ankle/foot musculature suggest that postural control is challenged more during SLSQ. • Postural control with SLSQ is mainly controlled by the tibialis anterior and peroneus brevis in response to a greater anteroposterior- compared to mediolateral-directed sway of the body. • The limited body sway elicited with the traditional SLST test is mainly controlled by the gastrocnemius muscle. • Postural control may be assessed more accurately under dynamic conditions such as with SLSQ as opposed to the standard SLST test.