November 2021


By Amanda Laxganger, Debbie Espy, and Ann Reinthal

Poor balance and falls remain a large concern for older adults and individuals with physical disability. Clinicians use adapted commercial video gaming as one intervention technique to address balance impairments. However, a lack of standardized balance intensity measures poses a significant challenge in prescribing appropriate dosage for balance rehabilitation interventions such as gaming. Movement kinematics provide one method for quantifying functional demands of a therapeutic intervention. This study’s objective was to use kinematics to investigate how varied balance training game demands and gaming surface increase the intensity of balance challenge, specifically movement of the center of mass (COM) relative to base of support (BOS).


Twenty-seven self-reported community ambulators, ages 50-79, played 4 randomly selected videogaming conditions. Each condition consisted of a specific game (Microsoft Kinect) and play surface combination. Game conditions were grouped into those requiring kicking (4 conditions), stepping (5 conditions), or no stepping (6 conditions). Participants played about 5 minutes per condition. They rated their self-perceived balance challenge of each condition using the visual Rate of Perceived Stability (RPS) Scale. Three-dimensional motion capture was collected using the Helen Hayes marker set, an 8-camera system and Cortex software (Motion Analysis Corp., Rohnert Park, CA). Capture data were processed through Cortex and custom MATLAB code to determine the fraction of game play time that the COM moved outside of the BOS (FX) as well as the maximum excursion range of the COM (EX). Descriptive statistics were calculated for these measures in each condition.


Tables 1-3 display the mean and ranges for RPS scores (maximum challenge 10 on 1 to 10 scale), the fraction of time the COM was outside of the BOS (FX: %), and the maximum excursion of the COM (EX: mm).

During the kicking games (Table 1), EX and FX increased on the mat while decreasing on the slider and rocker surfaces. EX especially decreased on the slider while having the highest RPS score. Since there were 3 conditions using the same game (Hard Target Kick) with 3 different surfaces, RPS scores ranked these surfaces from easiest to hardest as floor, rocker, and slider, respectively. During stepping games, FX was highest on the mats and the 2 harder floor games, while RPS and EX increased on the mat surface in the 1 game played on both floor and mats (Cruiser Reflex Ridge). In the non-stepping games, EX was highest on the floor/mat surfaces and lowest on the slider. FX was lowest in the slider and highest on the rocker surface while RPS was highest on the rocker.


Overall, FX and EX were highest in the stepping games, where the games demanded more movement, and lowest in the non-stepping games where the games demanded stability. They also decreased on the 2 mobile surfaces, especially on the slider. Thus, kinematic analysis of balance intensity in terms of EX and FX must be coupled with an understanding of the game condition.


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