Yong Tai Wang

Effect of the Ankle Stabilizing Orthosis on Foot and Ankle Kinematics During Cutting Maneuvers

This study was to examine the stability and functionality of the Ankle Stabilizing Orthosis (ASO) in normal ankle kinematics during sideward and forward lateral cutting. Fifteen college students with normal ankles were randomly assigned to each of the following four conditions: sideward and forward lateral cutting, with and without the ASO. Ankle inversion–eversion and dorsiflexion–plantarflexion angular displacements and velocities during movement were recorded by a 3-D Qualisys system and analyzed with repeated measures ANOVA and Bonferroni test. In forward lateral cutting, the ASO decreased inversion angle at touchdown. On both lateral cutting conditions, the ASO decreased inversion angle at footflat and push-off, and decreased plantarflexion angle at touchdown. Furthermore, the ASO did not change inversion–eversion and dorsiflexion–plantarflexion angular velocities or stance phase duration. The ASO is likely to prevent ankle sprains during activities that involve lateral cutting while not hindering athletic performance. Information presented may help clinicians in brace prescription. Acknowledgment: To Medical Specialties, Inc., for donating the Ankle Stabilizing Orthosis

Custom-molded foot-orthosis intervention and multisegment medial foot kinematics during walking

CONTEXT Foot-orthosis (FO) intervention to prevent and treat numerous lower extremity injuries is widely accepted clinically. However, the results of quantitative gait analyses have been equivocal. The foot models used, participants receiving intervention, and orthoses used might contribute to the variability. OBJECTIVE To investigate the effect of a custom-molded FO intervention on multisegment medial foot kinematics during walking in participants with low-mobile foot posture. DESIGN Crossover study. SETTING University biomechanics and ergonomics laboratory. PATIENTS OR OTHER PARTICIPANTS Sixteen participants with low-mobile foot posture (7 men, 9 women) were assigned randomly to 1 of 2 FO groups. INTERVENTION(S) After a 2-week period to break in the FOs, individuals participated in a gait analysis that consisted of 5 successful walking trials (1.3 to 1.4 m/s) during no-FO and FO conditions. MAIN OUTCOME MEASURE(S) Three-dimensional displacements during 4 subphases of stance (loading response, midstance, terminal stance, preswing) were computed for each multisegment foot model articulation. RESULTS Repeated-measures analyses of variance (ANOVAs) revealed that rearfoot complex dorsiflexion displacement during midstance was greater in the FO than the no-FO condition (F(1,14) = 5.24, P = .04, partial η(2) = 0.27). Terminal stance repeated-measures ANOVA results revealed insert-by-insert condition interactions for the first metatarsophalangeal joint complex (F(1,14) = 7.87, P = .01, partial η(2) = 0.36). However, additional follow-up analysis did not reveal differences between the no-FO and FO conditions for the balanced traditional orthosis (F(1,14) = 4.32, P = .08, partial η(2) = 0.38) or full-contact orthosis (F(1,14) = 4.10, P = .08, partial η(2) = 0.37). CONCLUSIONS Greater rearfoot complex dorsiflexion during midstance associated with FO intervention may represent improved foot kinematics in people with low-mobile foot postures. Furthermore, FO intervention might partially correct dysfunctional kinematic patterns associated with low-mobile foot postures.

An Instrumented Wheel System for Measuring 3-D Pushrim Kinetics During Racing Wheelchair Propulsion

The purpose of this study was to design and validate an instrumented wheel system (IWS) that can measure 3-dimensional (3-D) pushrim forces during racing wheelchair propulsion. Linearity, precision, and percent error were determined for both static and dynamic conditions. For the static condition, the IWS demonstrated a high linearity (0.91 ≤ slope ≤ 1.41) with less than 2.72% error rate. Under dynamic loading, the IWS provided the well-matched measurement forces with the predicted values from the inverse dynamics method (0.96 ≤ slope ≤ 1.07) with less than 4.32% error rate. The results revealed that the IWS developed in the study can be used to measure 3-D pushrim reaction forces with acceptable accuracy. This was the first instrumented wheel device that can register 3-D pushrim forces during racing wheelchair propulsion. With the available kinetic information of the 3-D pushrim forces, the upper extremity joint reaction forces could be determined.

Effect of an Ankle Stabilizing Orthosis on Selected Ankle Kinematics During Walking

This study evaluated the stability effects of an ankle stabilizing orthosis on unstable ankles on selected three-dimensional ankle kinematics during two speeds (2.5 and 4.5 mph) of treadmill walking. Eleven subjects with one unstable ankle walked at these two treadmill speeds with and without the ankle stabilizing orthosis. The angular excursions and velocities of the ankle in the sagittal and frontal planes were recorded with a three-dimensional ProReflex Imaging System and analyzed with two-way repeated-measure ANOVA and paired t test. It was found that the ankle stabilizing orthosis provided significant stability control in the angular excursions of plantarflexion, and it did not affect the maximum velocity of plantarflexion and the walking speed during the treadmill walking. As the speed increased, the angular excursions and the maximum angular velocities in the sagittal and frontal planes increased significantly.

A Pilot Investigation of the Effect of Postural Control Strategies and Balance in Children with Unilateral Lower-Limb Amputation

Introduction Previous research has addressed the effects of backpack loads on balance in adults and children, but there is a gap in the literature concerning children with lower-limb amputation. The purpose of this study was to assess the effect of backpack loads on postural sway in children with lower-limb amputation. Materials and Methods Four children with unilateral Syme amputation and five controls were assessed in quiet standing with backpacks loaded with 0%, 10%, 20%, and 25% of body weight. Kinetic data were collected using force platforms, and the path of the center of pressure was calculated. Results Considering the sway parameters, the control group showed the expected increase with each successive weight level, whereas the group of children with amputation showed an unexpected nonlinear response as weight increased. Conclusions Postural control mechanisms used by the children with amputation may be different from their able-bodied counterparts.

Fundamental Locomotive Activity Time Efficiency with Differently Positioning Drive-Axis Wheelchairs Among Elderly: 2388

This study examined time efficiency in wheelchair locomotive activities among four different wheelchairs propelled by elders with arms and/or legs. Sixteen elder manual wheelchair users propelled her/his own wheelchair and three wheelchairs (the main drive-axis wheels positioning in front, middle, and rear, respectively) in the test of seven wheelchair locomotive activities of daily living. A Mixed-Model ANOVA and Bonferroni post hoc test (p < .05) were employed to determine the time efficiency among four wheelchairs and three groups. The results demonstrated better time efficiency resulted from propelling the mid drive-axis and/or rear drive-axis wheelchairs; using arms and legs simultaneously propelling wheelchairs was more time efficient than using the arms or legs only in the selected locomotive activities.