Investigating Female Athletes’ Balance Using Center-of-Pressure (COP) Derived Displacement and Velocity Parameters

Abstract

A realization of how specific exercises relate to balance performance is important for a wide demographic of individuals. Maintaining active and healthy living is particularly important for balance-impaired individuals (e.g., otherwise healthy individuals recovering from injury, fall-prone elderly, and stroke survivors) whom are interested in improving their balance for function in daily life. However, balance performance is also important for persons that are unimpaired (e.g., athletes). How balance performance may be improved as a result of, and in relation to, various athletic activities and exercises is a common question. Further, how certain activities can be used to prevent injury is an ultimate goal. Our objective was to compare standing balance in 3 unimpaired groups (i.e., female track & female tennis collegiate athletes and female non-athletes). To assess static balance, participants performed stance variations increasing in difficulty-level, utilizing a wide or tandem stance (increasing or decreasing support base) and eyes-open or eyes-closed (limiting or providing visual cues), while standing on a forceplate walkway. Through the recorded ground reaction forceplate-based, center-of-pressure (COP) position time series, we extracted velocity and displacement parameters that aided in identifying differences between the above groups. Our general findings were that anterior-posterior (AP, or front-to-back) COP displacement and velocity measures for female track athletes were unchanged relative to the (baseline) female non-athletes. However, mediolateral (ML, or side-to-side) measures, which have previously been shown to be associated with fall-risk, showed observable differences in displacement and velocity parameters, particularly for the female track athletes. Specifically, the female track athletes were better able to control their ML COP velocity in eyes-closed, wide, and eyes-open tandem conditions compared to non-athletes. However, tennis athletes had difficulty balancing in situations where eyes were closed (vision eliminated) and feet were tandem (base-of-support decreased) which was made apparent by the increases in all AP and ML COP-derived parameters. We interpreted this finding as the female tennis athletes were trained to rely heavily on visual cues (e.g., hand-eye or eye-body coordination), and also their balance may be more focused on maintaining their center-of-mass stability and body orientation, as opposed to COP per se. Our study lends new insights as to how various types of athletic activities, and reliance on vision in athletes, impacts balance performance in un-impaired females.

A Statistical and AI Analysis of the Frequency Spectrum in the Measurement of the Center of Pressure Track in the Seated Position in Healthy Subjects and Subjects with Low Back Pain

“…Against the background of maintaining an active lifestyle and avoiding immobility, the quantification of postural control and the evaluation of the effect of certain exercises on the development of balance ability are of particular importance, especially for older people, stroke patients, patients with multiple sclerosis, and patients with chronic back pain [37,38]. Therefore, it is necessary to have a measurement method where the neuromuscular control of people with physical limitations can also be examined in a reliable, safe, and low-risk setting.…”

Moderate sensory balance training leads to improvements in elderly

“…Another standard method to quantify balance is measuring the center-of-pressure (COP) time series. Extracting parameters from the COP series leads to well-defined measures of balance performance [15][16][17][18][19][20][21][22]. Previously, Prieto et al [15] was the first to utilize displacement, velocity, and frequency measures extracted from participants' COP time series to quantify differences in postural steadiness between young adults and healthy elderly adults with eyes-open/closed conditions.…”

“…Shifts in COP position, or changes in the location (position) of resultant vertical ground reaction force vector, as a function of time were recorded. The measures extracted from the each of the ML and AP COP time-series were computed as shown in [15][16][17][18][19][20][21][22] and were: maximum displacement, root mean square displacement, mean velocity and root mean square velocity.…”

“…This finding was interpreted as the participants' increased ability to control their posture in both planes. In previous studies [15][16][17][18][19][20][21][22], the COP velocity and displacement parameters have been sensitive towards distinguishing between various populations; balance performance could be characterized via COP displacement and velocity response curves. From the COP position time series, displacement and velocity parameters were computed and plotted as a function of increasing test condition difficulty level.…”