Tai Chi intervention has been shown to be beneficial for balance improvement. The current study examined the effectiveness of Tai Chi to improve the dynamic postural control among older adults with mobility disability. Six sedentary older adults with mobility disability participated in a 16-week Tai Chi intervention consisting of one hour sessions three times a week. Dynamic postural control was assessed pre- and post intervention as participants initiated gait in four stepping conditions: forward; 45° medially, with the stepping leg crossing over the other leg; 45° and 90° laterally. The center of pressure (CoP) displacement, velocity, and its maximum separation distance from the center of mass in the anteroposterior, mediolateral, and resultant directions were analyzed. Results showed that in the postural phase, Tai Chi increased the CoP mediolateral excursions in the medial (13%) and forward (28%) conditions, and resultant CoP center of mass distance in the medial (9%) and forward (19%) conditions. In the locomotion phase, the CoP mediolateral displacement and velocity significantly increased after the Tai Chi intervention (both by > 100% in the two lateral conditions). These results suggest that through alteration in CoP movement characteristics, Tai Chi intervention might improve the dynamic postural control during gait initiation among older adults.
Srikant Vallabhajosula, Beverly L. Roberts and Chris J. Hass
Lauren A. Brown, Eric E. Hall, Caroline J. Ketcham, Kirtida Patel, Thomas A. Buckley, David R. Howell and Srikant Vallabhajosula
Context: Sports often involve complex movement patterns, such as turning. Although cognitive load effects on gait patterns are well known, little is known on how it affects biomechanics of turning gait among athletes. Such information could help evaluate how concussion affects turning gait required for daily living and sports. Objective: To determine the effect of a dual task on biomechanics of turning while walking among college athletes. Design: Cross-sectional study. Setting: University laboratory. Participants: Fifty-three participants performed 5 trials of a 20-m walk under single- and dual-task conditions at self-selected speed with a 180° turn at 10-m mark. The cognitive load included subtraction, spelling words backward, or reciting the months backward. Interventions: Not applicable. Main Outcome Measures: Turn duration, turning velocity, number of steps, SD of turn duration and velocity, and coefficient of variation of turn duration and velocity. Results: Participants turned significantly slower (155.99 [3.71] cm/s vs 183.52 [4.17] cm/s; P < .001) and took longer time to complete the turn (2.63 [0.05] s vs 2.33 [0.04] s; P < .001) while dual tasking, albeit taking similar number of steps to complete the turn. Participants also showed more variability in turning time under the dual-task condition (SD of turn duration = 0.39 vs 0.31 s; P = .004). Conclusions: Overall, college athletes turned slower and showed more variability during turning gait while performing a concurrent cognitive dual-task turning compared with single-task turning. The slower velocity increased variability may be representative of specific strategy of turning gait while dual tasking, which may be a result of the split attention to perform the cognitive task. The current study provides descriptive values of absolute and variability turning gait parameters for sports medicine personnel to use while they perform their concussion assessments on their college athletes.
David R. Howell, Jessie R. Oldham, Melissa DiFabio, Srikant Vallabhajosula, Eric E. Hall, Caroline J. Ketcham, William P. Meehan III and Thomas A. Buckley
Gait impairments have been documented following sport-related concussion. Whether preexisting gait pattern differences exist among athletes who participate in different sport classifications, however, remains unclear. Dual-task gait examinations probe the simultaneous performance of everyday tasks (ie, walking and thinking), and can quantify gait performance using inertial sensors. The purpose of this study was to compare the single-task and dual-task gait performance of collision/contact and noncontact athletes. A group of collegiate athletes (n = 265) were tested before their season at 3 institutions (mean age= 19.1 ± 1.1 years). All participants stood still (single-task standing) and walked while simultaneously completing a cognitive test (dual-task gait), and completed walking trials without the cognitive test (single-task gait). Spatial-temporal gait parameters were compared between collision/contact and noncontact athletes using MANCOVAs; cognitive task performance was compared using ANCOVAs. No significant single-task or dual-task gait differences were found between collision/contact and noncontact athletes. Noncontact athletes demonstrated higher cognitive task accuracy during single-task standing (P = .001) and dual-task gait conditions (P = .02) than collision/contact athletes. These data demonstrate the utility of a dual-task gait assessment outside of a laboratory and suggest that preinjury cognitive task performance during dual-tasks may differ between athletes of different sport classifications.