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Context: Thirty percent of athletes go on to sustain a secondary anterior cruciate ligament (ACL) injury after return to sport. Those that went on to suffer a secondary injury had greater kinesiophobia levels at time of return to sport; however, these relationships have primarily been observed in patients after primary ACL reconstruction (ACLR). The purpose of this study is to compare differences in kinesiophobia 4 to 8 months after an individual’s primary versus secondary ACLR. Methods: This is a secondary analysis of an ongoing point of care study. To create our analytic sample, we identified participants between the ages of 14 and 35 years in the study protocol who provided data after primary and secondary ACLR, were 4 to 8 months status post-ACLR, and reported no concomitant surgical procedures at the time of primary or secondary ACLR that significantly delayed their rehabilitation protocol (e.g., meniscal repair). Demographic and participant characteristics and the Tampa Scale of Kinesiophobia-17 scores were collected after both primary and secondary ACLR. This study is a within-subjects design. Paired t tests were used to compare Tampa Scale of Kinesiophobia-17 scores between the primary and secondary ACLR. Results: Sixteen participants (male = 10, female = 6; height = 172.2 [11.5] cm, weight = 72.2 [20.9] kg) met inclusion criteria for the present study. Participants were 18.2 (3.0) years old and 5.6 (1.0) months since surgery after primary ACLR and 19.0 (1.0) years old and 5.9 (1.0) months since surgery after secondary ACLR. The average score for Tampa Scale of Kinesiophobia-17 was not different (P = .77) after the primary (32.7 [5.0]) and secondary ACLR (33.1 [5.2]). Conclusion: There were no significant differences in kinesiophobia levels in individuals after their primary and secondary ACLR. Although nonsignificant, there is lack of resolution of kinesiophobia between primary and secondary ACLR.

This study investigated the influence of playing experience on muscle synergy and the vertical (VV) and horizontal release velocities of the basketball during mid- to long-distance jump shots (4.8 and 6.75 m). A total of 28 participants performed jump shot tasks at these two distances, completing three valid attempts at each. The shooting movements were captured using a 3D motion capture system, and surface electromyographic data were recorded from five key muscles. Velocity data were used to calculate VV and horizontal release velocity, while electromyographic data were analyzed using nonnegative matrix factorization to extract muscle synergies. A two-factor mixed-effects model was applied to assess significant differences. The results showed that playing experience significantly enhanced VV (p < .001), which was potentially associated with higher contribution weights from the anterior deltoid, triceps brachii, flexor carpi radialis, and gastrocnemius lateralis within the extracted muscle synergies. As shooting distance increased, both VV and horizontal release velocity significantly increased (p < .05) in both groups. Synergy analysis further revealed that experienced athletes demonstrated higher contribution weights of triceps brachii and exhibited synergy activation profiles with later peak timings, greater activation magnitudes, and shorter activation durations. These synergy-based patterns suggest more efficient and stable motor control in experienced athletes. Based on these findings, it is recommended that novice athletes incorporate strength and timing control training targeting anterior deltoid, triceps brachii, flexor carpi radialis, and gastrocnemius lateralis to improve shooting consistency and stability.

Introduction: Chronic ankle instability (CAI) is a common sequela of lateral ankle sprains that impairs postural stability during functional tasks. External biofeedback may be an appropriate rehabilitation tool to improve functional movement; however, more research is needed to determine its effectiveness in dynamic tasks in individuals with CAI. This study aimed to assess the effect of real-time external biofeedback via laser on dynamic postural stability indices during a single-limb forward hop-to-stabilization task in participants with CAI. Methods: Eighteen participants with CAI completed five successful forward hop-to-stabilization jumps with and without external biofeedback using a single-dot laser attached to the distal tibia. A single inertial measurement unit fastened to the lower back captured dynamic postural stability indices in the vertical, anterior-posterior, medial-lateral, and the resultant of each plane during the 5 s after landing. The mean difference between biofeedback and no biofeedback was assessed using independent t tests. Results: Our results indicate no significant differences were observed between forward hop-to-stabilization tasks with and without real-time external biofeedback in individuals with CAI. Discussion: More research is needed to determine the appropriate biofeedback tool location and modality type of external biofeedback in addition to the minimum amount of training exposure to improve dynamic postural stability during a single-limb landing task.

This study aimed to investigate both immediate and long-term (3 months) effects of textured insoles on balance control in individuals with knee osteoarthritis (OA). Twenty-four participants were divided into two groups: individuals with knee OA (n = 12) and healthy age-matched controls (n = 12). Balance was assessed using the Sensory Organization Test under three conditions: baseline with smooth insoles, immediate effect with textured insoles, and after 3 months of textured insole use. Individuals with knee OA had significantly lower baseline balance performance in complex sensory integration tasks (p < .05). With textured insoles, both groups showed significant improvements particularly in conditions requiring complex sensory integration. The OA group demonstrated marked improvement in Condition 5 (eyes closed with sway-referenced surface) with textured insoles (p = .001, d = −1.043) compared with baseline. These improvements were retained during the 3-month period without meaningful habituation effects. These findings indicate that textured insoles provide an effective intervention to improve balance control in individuals with knee OA, which may have implications for improving postural stability and sensory integration in this population.

Classification is an essential aspect of parasport. However, the exact roles and responsibilities of parasport administrators related to classification have not yet been fully explored. This study aimed to understand how administrators in national sport organizations support classification. Six administrators participated in semistructured interviews. Critical realist analysis generated three themes: knowledge of classification, classification context, and administrators’ roles related to classification. Knowledge of classification speaks to the importance of administrators’ understanding classification, as well as their reliance on experiential learning and mentorship to understand the classification system and their role within it. Classification context refers to the tension within parasport resulting from competing uses of classification: Some organizations use classification to facilitate participation, while others reserve classification for high-performance athletes. Resultingly, administrators’ roles are responsive to the unique needs of their organization. Altogether, this work describes how administrators may act as knowledge brokers in the parasport context.

This study quantified vertical ground reaction forces (vGRFs) and lower limb stiffness for both sexes walking and running with body-borne load over 2 surfaces. Nine males and 9 females had lower limb biomechanics quantified during a walk (1.3 m/s) and run (4.5 m/s) with (15 kg) and without (0 kg) body-borne load over a firm and soft foam surface. vGRF measures, and leg and lower limb joint stiffness were submitted to a linear mixed model. Loaded walking increased very GRF and stiffness measure (all: P < .016). Loaded running increased every GRF measure and knee stiffness (all: P < .033). The foam surface increased peak vGRF (P = .002, P = .010) and knee stiffness (P < .001, P = .004) during the walk and run, and leg (P < .001) and ankle (P = .025) stiffness during the run. Males walked with greater peak vGRF (P = .012), and stiffer hip and ankle (P = .026; P = .012), but ran with a stiffer knee on the foam (P = .041) and stiffer hip on the firm (P = .005) surface than females. Loaded walking and running may elevate injury risk by increasing vertical GRFs and lower limb stiffness. Injury risk may also increase for locomotion over a foam surface, especially for males.

The review is based on theoretical advances in the field of motor control that view the neural control of movements as a subfield of natural science. We accept the theory of hierarchical control of movements with basic commands, reciprocal, and coactivation, at different levels of the hierarchy, from the control of whole-body actions to the control of individual joints and digits. The principle of abundance views the numerous elements participating in all actions as an important feature that allows movements to combine dynamical stability with adaptability. This principle is readily compatible with the uncontrolled manifold hypothesis. These concepts have been applied to analysis of consequences of fatigue, natural aging, and a range of neurological disorders, from large-fiber peripheral neuropathy to brain disorders. Mechanisms of rehabilitation of movement disorders and improvement of motor performance are discussed. Important pieces of information are missing in the described theoretical frameworks in particular those related to mapping between the theoretical levels of control and coordination and neurophysiological circuitry. New directions of studies are sketched that may lead to progress in understanding applied aspects of motor control.

Plantar fascia (PF) thickness and stiffness have been linked diagnostically to plantar fasciitis. Acute changes to these properties in response to submaximal running have been noted but not yet tested in maximal effort bouts. This study assessed the acute effects of high-intensity interval running on PF thickness and stiffness in healthy adults. Sixteen participants completed 5 maximal effort 400-m sprints with a 1:1 work-to-rest ratio, followed by additional maximal effort trials until fatigue. Thickness and stiffness at the calcaneal origin were measured prerun, postrun, and 30 minutes postrun via ultrasonography and shear wave elastography, respectively. PF thickness and stiffness did not differ between right and left foot (P > .05) and between males and females (P = .067). Thickness and stiffness decreased postrun (0.43 mm, P < .001; 1.54 m·s⁻¹, P < .001) and increased 30 minutes postrun (0.28 mm, P < .002; 1.0 m·s⁻¹, P < .001). No significant difference was found between prerun and 30 minutes postrun thickness (P = .134), but prerun stiffness was higher than 30 minutes postrun (P = .031). These findings indicate that although high-intensity interval running altered both PF thickness and stiffness, 30 minutes of rest allowed some level of recovery in the noninjured PF tissue.