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Correlations of Postural Stability to Proprioception, Tactile Sensation, and Strength Among People With Chronic Ankle Instability

Yanhao Liu, Qipeng Song, Ziyin Liu, Shiyu Dong, Claire Hiller, Daniel T.P. Fong, and Peixin Shen

Objectives: The static and dynamic correlations of postural stability to its three potential contributors, namely, proprioception, tactile sensation, and strength remain unclear among people with chronic ankle instability (CAI). This study aimed to compare static and dynamic postural stability, along with proprioception, tactile sensation, and strength between people with and without CAI and explore their correlations. Methods: Sixty-seven participants with CAI and 67 participants without CAI were enrolled in this study. Ankle proprioception, plantar tactile sensation, and lower limb strength were measured by a proprioception test device, a set of monofilaments, and a strength testing system, respectively. Static and dynamic postural stability were measured during standing and jump landing on a force plate and indicated by the root mean square of center of pressure and time to stability. Results: Compared to people without CAI, people with CAI had poorer postural stability, proprioception, tactile sensation, and strength. Both groups demonstrated correlation between proprioception and static postural stability, but only people without CAI showed correlation between proprioception and dynamic postural stability. Both groups demonstrated a correlation between tactile sensation and static postural stability, but not with dynamic stability. Both groups demonstrated a correlation between strength and both static and dynamic postural stability. Conclusions: People with CAI had deficits in static and dynamic postural stability, proprioception, tactile sensation, and strength. Among people with CAI, proprioception, tactile sensation, and strength can help maintain static postural stability; strength can help maintain dynamic postural stability, whereas proprioception may not provide sufficient information for dynamic postural stability.

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Chronic Adaptions in Quadriceps Fascicle Mechanics Are Related to Altered Knee Biomechanics After Anterior Cruciate Ligament Reconstruction

McKenzie S. White, Lucia M. Mancini, Luke Stoneback, Riann M. Palmieri-Smith, and Lindsey K. Lepley

Following anterior cruciate ligament reconstruction (ACLR), patients exhibit abnormal walking mechanics and quadriceps dysfunction. Quadriceps dysfunction has been largely attributed to muscle atrophy and weakness. While important, these factors do not capture intrinsic properties of muscle that govern its ability to generate force and withstand load. While fascicle abnormalities after ACLR have been documented in early stages of recovery (<12 mo), long-term effects of ACLR on fascicle mechanics remain unexplored. We evaluated quadriceps fascicle mechanics during walking 3 years post-ACLR and examined the relationship with knee mechanics. Participants included 24 individuals with ACLR and 24 Controls. Linear mixed models compared the ACLR, Contralateral, and Controls limbs for (1) quadriceps strength, (2) fascicle architecture and mechanics, and (3) knee mechanics. No difference in strength or overall fascicle length excursions was found between limbs. The ACLR limb exhibited longer fascicles at heel strike and peak knee extension moment (P < .001–.004), and smaller fascicle angles at heel strike, peak knee extension moment, and overall suppressed fascicle angle excursions (P < .001–.049) relative to the Contralateral and/or Control limb. This indicates an abnormality in fascicle architecture and mechanics following ACLR and suggests abnormalities in contractile function that cannot be explained by muscle weakness and may contribute to long-term gait irregularities.

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Measurement Position Influences Sex Comparisons of Distal Femoral Cartilage Thickness With Ultrasound Imaging

Harry S. Battersby, Ryan J. Evans, Iwi J. Eghobamien, and Derek N. Pamukoff

The purpose was to examine (1) the effect of measurement position and sex on femoral cartilage outcomes, and (2) the association between gait biomechanics and cartilage outcomes. Fifty individuals participated (25 males and 25 females; age = 20.62 [1.80] y). Ultrasound measured femoral cartilage thickness and echo-intensity at 90°, 115°, and 140° of knee flexion. Gait outcomes included the external knee adduction and knee flexion moments. Cartilage outcomes were compared using 2 (sex) × 3 (position) repeated-measures analysis of variance. Gait and cartilage associations were assessed using stepwise regression. Medial cartilage was thicker when measured at 90° compared with 115° (P = .02) and 140° (P < .01), and 115° compared with 140°, (P < .01) in males but not in females. Cartilage was thicker at 90° compared with 140° across both sexes within all regions (P < .01). Males had thicker cartilage than females in all positions (P < .01). Echo-intensity was lower at 90° than 115° (P < .01) and 140° (P = .01) in the central and lower at 90° than at 115° (P < .01) and 140° (P = .03) in lateral regions. No association was found between gait and cartilage outcomes. Ultrasound imaging position effects cartilage features more in males compared with females. Imaging position and sex influence cartilage outcomes and should be considered in study designs and clinical evaluation.

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Do Motor–Cognitive and Motor–Motor Dual-Task Training Differently Affect Dual-Task Interference in Individuals With Intellectual Disability?

Rihab Borji, Rym Baccouch, Rabeb Laatar, Sirine Falhi, Sonia Sahli, and Haithem Rebai

This study explored the effect of different dual-task (DT) training programs on DT interference in adults with intellectual disability. Center-of-pressure (CoP) mean velocity in single-task (ST) and cognitive-DT conditions and the Timed Up-and-Go Test (TUGT) during ST, cognitive-DT, and motor-DT conditions were assessed before and after intervention in a cognitive–motor training group, a motor–motor training group, and a control group. Before training, CoP mean velocity and TUGT time increased (p < .001) in DT compared with the ST condition. After training, the CoP mean velocity values remained unchanged (p = .07) in DT compared with the ST condition among the cognitive–motor training group. Furthermore, compared with the ST condition, no increase (p = 1) was reported in the TUGT time during the cognitive-DT condition for the cognitive–motor training group and during the motor-DT for the motor–motor training group (p = .12). The effect of DT training on DT interference depends on the training modality.

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Evaluating the Validity of Tests to Predict Sprint and Change of Direction Speed in Para-Athletes With Brain Impairments

Raul Reina, Emma M. Beckman, Mark J. Connick, Jemima G. Spathis, and Sean M. Tweedy

Maximum running speed is a performance determinant in para-athletics and cerebral palsy football. Sixty international para-athletes with brain impairments completed five activity-limitation tests (standing broad jump, four bounds for distance, split jumps, 10-m speed skip, and running in place) and two criterion tests (40-m sprint and modified agility test). The same three tests (standing broad jump, four bounds for distance, and 10-m speed skip) that correlated with running performance in nondisabled runners (.67 < r < −.82; p < .05; 75% of variance) also correlated in para-athletes with brain impairments (.41 < r <  −.62; p < .01; 55% of variance). Standing broad jump, four bounds for distance, split jumps, and running in place also correlated with change-of-direction speed (.43 < r <  −.63; p < .01; 58% of variance). Results indicate that methods of classification for para-athletics with nondisabled runners are also valid with para-athletes with brain impairments, and new sport-specific relationships were found for assessing the performance of rapid and short sprints toward different directions, specific of a team para-sport like cerebral palsy football.

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Impact of Sport Engagement and Social Support on the Health-Related Quality of Life of Youth Athletes With Physical Disabilities

Myung Ha Sur, Deborah R. Shapiro, and Jeffrey Martin

Health-related quality of life (HRQOL) is a multidimensional concept focusing on the impact of health status on quality of life. The purpose of this study was to examine if sport engagement and sport-specific social support predicted HRQOL among adolescents with physical disabilities. Sixty-eight participants completed surveys assessing sport engagement, sport-specific social support, and HRQOL. Participants had moderate to high perceptions of sport engagement, social support, and HRQOL supporting the affirmation model of disability. Based on a canonical correlation, esteem, information, and tangible social support and sport engagement—confidence—were the strongest predictor variables of the sport engagement/social support variant, which was linked to the HRQOL variant predicted by emotional, social, and school functioning. The findings support the importance of social support and confidence in the sport context for the HRQOL of youth with physical disabilities.

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Volume 41 (2024): Issue 3 (Jul 2024)

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Volume 28 (2024): Issue 3 (Jul 2024)

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Entropy as a Window Into Behavioral Phase Transitions: Unveiling Contextual Dynamics in Affordance-Based Reaching

Dalton S. Cooper, Tarcisio S. Moreira, and Tehran J. Davis

Prior work has demonstrated the presence of hysteresis effects in the control of affordance-guided behavior, in that behavioral transitions around a critical action boundary vary with directions of change in said action boundary. To date, research on this topic has overlooked the influence of the global context on these phenomena. We employ an affordance-based reaching task, whereby participants were asked to move a target to a goal by passing through one of two apertures (size variable or size constant). It was found that the direction of change in the size of the variable aperture influenced the point of behavioral transitions, and this effect interacted with the location of a given goal. In addition, we considered fluctuations in the entropy of participants’ reach trajectories as a window into the nature of the behavioral phase transitions. Differences in the structure of entropy were found depending on the direction of change in the size variable aperture. These results are discussed in light of a dynamical systems approach, and recommendations for future work are made.

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Hierarchical Organization and Adjustment of Force Coordination in Response to Self-Triggered and External-Triggered Cues in Simulated Archery Performance

Kitae Kim, Junkyung Song, Dawon Park, and Jaebum Park

The purpose of this study was to investigate the hierarchical organization of digit force production and its effect on stability and performance during the simulated archery task. The simulated archery shooting task required the production of a prescribed level of force in virtual space with the left hand and an equivalent force with all 4 fingers of right hand. A single trial had 2 phases, including static force production as aiming in archery and quick force release to shoot the virtual arrow. The timing of the force release was determined by the participant’s choice or response to the external cue. The coordination indices, that is, the synergy index, of force stabilization were quantified in 2 hierarchies by decomposing the variance components. The accuracy and precision of the hit position of the virtual arrow were calculated as performance-related indices. The results confirmed that the precision, that is, reproducibility, of the performance was greater when the force release time was determined by the self-selected time, suggesting the beneficial effect of the anticipatory mechanism. There was a distinct synergistic organization of digit forces for the stabilization of net forces in both bimanual and multifinger levels, which was especially correlated with the precision of performance.