Effects of real-time gait biofeedback on paretic propulsion and gait biomechanics in individuals post-stroke.

Objectives Gait training interventions that target paretic propulsion induce improvements in walking speed and function in individuals post-stroke. Previously, we demonstrated that able-bodied individuals increase propulsion unilaterally when provided real-time biofeedback targeting anterior ground reaction forces (AGRF). The purpose of this study was to, for the first time, investigate short-term effects of real-time AGRF gait biofeedback training on post-stroke gait. Methods Nine individuals with post-stroke hemiparesis (6 females, age = 54 ± 12.4 years 39.2 ± 24.4 months post-stroke) completed three 6-minute training bouts on an instrumented treadmill. During training, visual and auditory biofeedback were provided to increase paretic AGRF during terminal stance. Gait biomechanics were evaluated before training, and during retention tests conducted 2, 15, and 30 minutes post-training. Primary dependent variables were paretic and non-paretic peak AGRF; secondary variables included paretic and non-paretic peak trailing limb angle, plantarflexor moment, and step length. In addition to evaluating the effects of biofeedback training on these dependent variables, we compared effects of a 6-minute biofeedback training bout to a non-biofeedback control condition. Results Compared to pre-training, significantly greater paretic peak AGRFs were generated during the 2, 15, and 30-minute retention tests conducted after the 18-minute biofeedback training session. Biofeedback training induced no significant effects on the non-paretic leg. Comparison of a 6-minute biofeedback training bout with a speed-matched control bout without biofeedback demonstrated a main effect for training type, with greater peak AGRF generation during biofeedback. Discussion Our results suggest that AGRF biofeedback may be a feasible and promising gait training strategy to target propulsive deficits in individuals post-stroke.

Relationship between hip strength and trunk motion in college cross-country runners.

PURPOSE: Hip strength may directly relate to abnormal running mechanics and contribute to the high incidence of overuse injuries in distance runners. The purpose of this study was to determine the relationship between hip isokinetic strength and thorax and pelvic motion during treadmill running. METHODS: Isokinetic hip strength and treadmill running kinematics were collected on 24 collegiate cross-country runners (14 males and 10 females). Each subject completed a running protocol on a treadmill at a self-selected speed (3.58 ± 0.26 m·s) and prescribed speed (3.58 ± 0.0 m·s). Kinematic data were collected with retroreflective markers attached to the thorax, pelvis, and each lower extremity segment (thigh, shank, and foot). Thorax and pelvis range of motion (ROM) were calculated from initial ground contact to toe-off. Pearson correlation coefficients were used to determine the relationship between strength and ROM (P < 0.05). Differences between male and female athletes were tested with mixed-design ANOVAs (P < 0.05). RESULTS: Isokinetic hip extension and abduction torque had significant inverse correlations to thorax axial rotation ROM during stance phase of running (r = -0.60 and r = -0.53) at self-selected speed. Frontal plane pelvic obliquity ROM was also significantly correlated to hip strength (extension r = -0.49; abduction r = -0.44). Similar correlations were found during the prescribed speed condition. Female runners had significantly decreased normalized strength (hip extension 1.8 ± 0.4 N·m·kg, P < 0.05; hip abduction 1.0 ± 0.2 N·m·kg, P < 0.05), increased pelvic obliquity (13.1° ± 2.6°, P < 0.05), and thorax axial rotation (34.5° ± 7.0°, P < 0.05) ROM compared to males (hip extension 2.5 ± 0.5 N·m·kg; hip abduction 1.3 ± 0.2 N·m·kg; pelvic obliquity 8.9° ± 1.9°; thorax axial rotation 22.6° ± 3.5°). CONCLUSIONS: Moderate correlations were found in hip extensor and hip abductor strength and pelvic and thorax motion during running in collegiate runners.