The effect of custom carbon ankle-foot orthosis alignment on roll-over shape and center of pressure velocity

Background: Maintaining an optimal rolling of the foot over the ground is thought to increase the stability and efficiency of pathologic gait. Ankle-foot orthoses are often prescribed to improve gait mechanics in individuals with lower extremity injuries; however, their design may compromise how the foot rolls over the ground. Objectives: The aim of this study was to investigate the effects of the sagittal plane ankle-foot orthosis alignment on roll-over shape and center of pressure velocity in individuals with lower limb reconstructions. Study design: Randomized cross-over study with a control group comparison. Methods: In total, 12 individuals with lower limb reconstruction who used a custom carbon ankle-foot orthosis and 12 uninjured controls underwent gait analysis. Ankle-foot orthosis users were tested in their clinically-provided ankle-foot orthosis alignment, with an alignment that was 3° more plantarflexed, and with an alignment that was 3° more dorsiflexed. Components of roll-over shape and center of pressure velocity were calculated from heel strike on the ankle-foot orthosis limb to contralateral heel strike. Results: Roll-over shape radius was not affected by 3° changes to alignment and was not significantly different from controls. Aligning the ankle-foot orthosis in more dorsiflexion than clinically provided resulted in a smaller peak center of pressure velocity that occurred later in stance. Conclusion: Individuals using custom carbon ankle-foot orthoses can accommodate 3° alterations in the dorsiflexion or plantarflexion alignment.

Effect of Visual Condition on Performance of Balance-Related Tasks in Elite Dance Students

The purpose of this study was to investigate the effects of visual condition (low light, full light, and full light with mirror) on balance control and technical form during two technical dance movements in a group of elite collegiate dance students. Dancers demonstrated higher center of pressure velocity indicating lower control while performing a static dance task (parallel relevé retiré) and a dynamic dance task (fondu relevé en croix) under low light conditions than either lighted condition. Measures of Western ballet technique (pelvic obliquity, knee extension, and ankle plantar flexion) showed no decrement under low light conditions. No effect of concurrent mirror feedback was found on either center of pressure velocity or technical requirements of the dance tasks.

Effects of altering heel wedge properties on gait with the Intrepid Dynamic Exoskeletal Orthosis

Background: The Intrepid Dynamic Exoskeletal Orthosis is a custom-made dynamic response carbon fiber device. A heel wedge, which sits in the shoe, is an integral part of the orthosis-heel wedge-shoe system. Because the device restricts ankle movement, the system must compensate to simulate plantarflexion and allow smooth forward progression during gait. Objectives: To determine the influence of wedge height and durometer on the walking gait of individuals using the Intrepid Dynamic Exoskeletal Orthosis. Study design: Repeated measures. Methods: Twelve individuals walked over level ground with their Intrepid Dynamic Exoskeletal Orthosis and six different heel wedges of soft or firm durometer and 1, 2, or 3 cm height. Center of pressure velocity, joint moments, and roll-over shape were calculated for each wedge. Results: Height and durometer significantly affected time to peak center of pressure velocity, time to peak internal dorsiflexion and knee extension moments, time to ankle moment zero crossing, and roll-over shape center of curvature anterior-posterior position. Wedge height had a significant influence on peak center of pressure velocity, peak dorsiflexion moment, time to peak knee extension moment, and roll-over shape radius and vertical center of curvature. Conclusion: Changes in wedge height and durometer systematically affected foot loading. Participants preferred wedges which produced ankle moment zero crossing timing, peak internal knee extension moment timing, and roll-over shape center of curvature anterior-posterior position close to that of able-bodied individuals. Clinical relevance Adjusting the heel wedge is a simple, straightforward way to adjust the orthosis-heel wedge-shoe system. Changing wedge height and durometer significantly alters loading of the foot and has great potential to improve an individual’s gait.

The Effect of Holographic Wristbands on Proprioception

Context: Wearing wristbands embedded with holograms at certain frequencies are believed to increase proprioception. There has been very little research to determine if holographic wristbands have any physiological effect on the body. Objective: To determine if the holograms embedded in the wristbands will improve proprioception during a single leg stance test on the dominant foot. Design and Setting: Controlled Athletic Training laboratory study. Participants: Twenty-four healthy college students of different activity levels (7 men, 17 women; age = 22.6 ± 1.2 years, height = 170.18 ± 12.10 cm, mass = 69.51 ± 15.63 kg) without any lower extremity injuries in the past three months participated. The subjects were also excluded if they have worn a holographic wristband in the past three months. Intervention(s): Each subject completed two trials under three protocols (holographic wristband, placebo wristband, no wristband) in a counter-balanced order for a total of six different tests with each test lasting 30 seconds. Subjects tested under each protocol using a single leg stance test on their dominant leg, hands on their hips, and looking forward at a fixed point on the wall. Main Outcome Measure(s): Balance analysis of the subjects was performed using an AMTI AccuSway Force Platform measuring Center of Pressure velocity and Center of Pressure Area 95. A statistical analysis of the data was done using repeated measures to test for differences between each condition. Results: The results showed no significant differences between protocols for Center of Pressure velocity (F = 1.130, P = .332). We also found no significant differences between protocols for Center of Pressure Area 95 (F = 1.271, P = .290). Conclusions: The results showed that the use of the holographic wristbands or a placebo wristband did not appear to have an impact on static balance. Overall, the results show that the use of the wristbands did not appear to have an impact on proprioception.