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The primary aims of this study were to determine acute and longitudinal relationships between static flexibility measures and running economy (RE). Seventy-one healthy recreational runners (34 males/37 females, age: 36.4 [12.4] y, body mass index: 23.3 [3.1] kg/m²) completed an aerobic fitness assessment (VO₂max) based on self-selected half-marathon race pace (RP) and flexibility testing (standing toe-touch test and weight-bearing lunge test) at baseline and 2 to 3 weeks prior to an endurance running or multisport race (70 [21] d apart). Participants resumed self-selected training and physical activity between laboratory visits. Hierarchical linear regressions were used to assess relationships between flexibility and RE across timepoints, and pre–post changes in flexibility and RE. Interactions between age and flexibility, and experience and flexibility were also investigated. No significant differences (P > .05) were found between flexibility measurements and RE at RP from visit 1 to visit 2, nor were there any significant associations between RE at RP and scores on the weight-bearing lunge test or standing toe-touch test. However, there was a significant interaction between age and the weight-bearing lunge test on RE at RP (ß = −0.0270, P = .018) such that older runners with less flexibility and younger runners with greater flexibility were less economical at RP at baseline. Our findings suggest that reduced flexibility may decrease the energetic cost of running for older runners to a greater extent than it does for younger runners. When prescribing run training intensity and mileage, coaches and clinicians working with masters runners should be cognizant of the potential performance benefits of decreased ankle joint flexibility as well as the overall greater risk of calf injury in this population. Future research should consider the underlying mechanism by which age enhances the beneficial effects of decreased flexibility on RE.

This systematic review synthesizes quantitative evidence on school factors associated with physical activity (PA) participation in children and adolescents with disabilities (CAD). A comprehensive search was conducted in four databases, and studies were included if they quantitatively measured PA levels and examined school factors associated with PA participation among CAD. Methodological quality was assessed, and a semiquantitative synthesis was performed. Twenty-four studies with good to excellent methodological quality were included. Five primary and 21 secondary school factors linked to PA engagement in CAD were identified: school time structure, school PA characteristics, school physical environment, school social environment, and school organizational factors. Among these, four factors of the school time structure (i.e., physical education time, recess time, lunch time, and before- and/or after-school time) showed the most consistent positive associations with PA. This review highlights the critical role of structured school time for school-based PA promotion in CAD.

The calf raise test (CRT) is commonly used to assess triceps surae muscle-tendon unit function. Often, a metronome set to 60 beats/min (30 repetitions/min) is used to set the cadence of calf raise repetitions, but studies report using cadences ranging from 30 to 120 beats/min. We investigated the effect of cadence on CRT outcomes, accounting for the potential confounders of sex, age, body mass index, and physical activity. Thirty-six healthy individuals (50% female) performed single-leg calf raise repetitions to volitional exhaustion in 3 randomized cadence conditions, 7 days apart: 30, 60, and 120 beats/min. Repetitions, total vertical displacement, total work, peak height, and peak power were recorded using the validated Calf Raise application. Cadence significantly affected all CRT outcomes (P ≤ .008), except repetitions (P = .200). Post hoc analysis revealed 60 beats/min resulted in significantly greater total vertical displacement and work than 30 and 120 beats/min. Peak height was greater at 60 and 120 than 30 beats/min, and peak power was greater at 120 beats/min. Males generated greater work and peak power (P ≤ .001), whereas individuals with greater body mass index completed less repetitions (P = .008), achieved lower total vertical displacements (P = .003), and generated greater peak power (P = .005). CRT cadence is important to consider when interpreting CRT outcomes and comparing data between studies.

Context: Anterior cruciate ligament reconstruction (ACLR) is a known risk factor for knee osteoarthritis (OA). Since no disease-modifying treatments for OA exist, it is critical to understand joint responses to physical activity following an ACLR. Understanding knee cartilage deformation through ultrasound may provide a better understanding of how knee cartilage responds to running, and how this may contribute to OA pathophysiology and risk. Objective: To compare medial femoral cartilage deformation, outcomes, and forces during running in females with and without a unilateral ACLR knee. Design: Cross-sectional laboratory study. Methods: Sixteen females (8 ACLR history, 8 controls) participated. ACLR participants had an average age of 20.75 (1.83) years, height of 165.07 (7.43) cm, mass of 65.97 (8.55) kg, and were 36.13 (18.74) months postsurgery; controls had an average age of 20.62 (1.84) years, height of 166.00 (5.76) cm, and mass of 63.18 (4.94) kg. Independent variables were group and limb, with dependent variables including patient reported outcomes Knee Injury and Osteoarthritis Outcome Score (KOOS), medial femoral cartilage thickness changes, and indirect measures of stance-averaged vertical ground reaction forces and vertical rate of loading normalized to body weight during treadmill running. Data were analyzed using nonparametric statistics with significance defined as P ≤ .05. Results: All participants exhibited cartilage thickness reduction after 30 minutes of running (P < .001), with no significant group or limb differences in cartilage deformation, vertical ground reaction forces, or vertical rate of loading. ACLR participants reported significantly poorer patient reported outcome scores across all KOOS subscales. Moderate negative correlations were found between involved cartilage percent change and KOOS Symptoms (P = .025) and Sport/Rec (P = .043). Conclusions: Cartilage thickness significantly decreased in all participants after running, with no group or limb differences observed despite lower patient-reported outcomes in the ACLR group. Exploring the relationship between KOOS scores and cartilage response to activity may inform future research and strategies to mitigate OA risk.

In many sports, practitioners must reach their maximal jump height (h _max) under time constraints. This requires a reduction of the countermovement depth and so of the push-off distance (h _PO). The purpose of this study was to investigate how h _PO influences force–velocity (F–v) profiles ( ${\overline{F}}_0$ , ${\overline{v}}_0$ , ${\overline{\mathrm{P}}}_{\max }$ , and S _Fv ) and performance. Eleven participants (age: 26 [5] y, height: 175.6 [11.2] cm, mass: 76 [15] kg; squat 1RM: 129 [34] kg) performed maximal countermovement jumps. Kinetic and kinematic measurements were used to assess individual F–v profiles for 3 different h _PO conditions (h _PO-SMALL, h _PO-MEDIUM, h _PO-LARGE) from countermovement jumps performed under different load conditions (bodyweight [BW], BW + 8 kg, BW + 17 kg, BW + 40%1RM, BW + 70%1RM). Results indicated that ${\overline{F}}_0$ and ${\overline{\mathrm{P}}}_{\max }$ changed across h _PO conditions, while ${\overline{v}}_0$ remained constant. A lower h _PO led to a significantly higher ${\overline{F}}_0$ and ${\overline{\mathrm{P}}}_{\max }$ . These changes resulted in a steeper S _Fv leading to a more force-oriented profile, a lower optimal S _Fv and a greater F–v imbalance. Reducing h _PO and modifying F–v profile led, to some extent, to a reduction in h _max. Performance is a compromise between h _PO, ${\overline{\mathrm{P}}}_{\max }$ , and F–v imbalance, all influenced by countermovement depth. This explains why reducing countermovement depth to meet time constraint may lower performance.

Neck pain ranks among the most prevalent musculoskeletal conditions and is commonly accompanied by altered physical function. With 10.8% of sports-related injuries affecting the head and neck, evaluating neck strength is vital for detecting muscle weakness and monitoring rehabilitation progress. The purpose of this study was to determine the intrasession and intersession reliability of a strain gauge for measuring neck retraction strength in healthy adult men. Ten male participants (age, 22.7 [2.6] y; body mass, 90.8 [13.3] kg; height, 184.2 [7.1] cm) completed a neck retraction isometric test across 3 testing occasions separated by 7 days. Contraction duration, peak and mean force, impulse, and peak rate of force development were quantified within and between sessions. Contraction duration, peak force, and impulse demonstrated moderate to excellent intra- (intraclass correlation coefficient [ICC] [3,1] = .72–.98, coefficient of variation [CV] = 2.7%–2.1%) and intersession reliability (ICC [3,k] = .66–.89, CV = 4.8%–7.1%); however, only acceptable intrasession reliability was found for peak rate of force development and mean force (ICC = .71–.99, CV = 3.4%–22.7%). It appears that a portable fixed strain gauge can be used to reliably measure neck retraction strength in a healthy male population.

Context: Subtalar dislocation is a rare but severe condition that usually requires emergency attention and could be associated with secondary injuries. Most of the research about this injury is case reports focused on the medical management, so there are no guidelines for rehabilitation and return to sport (RTS). This case report describes the rehabilitation and RTS in an amateur basketball player with an isolated medial subtalar dislocation on his right foot. Case Presentation: A 20-year-old amateur basketball player suffered a forced foot inversion after landing on an opponent’s foot. The patient was taken to the emergency department for a closed reduction under anesthesia, followed by 2 weeks in a cast and 3 weeks in a walker boot. Management and Outcomes: Rehabilitation started after the immobilization period with the main objective of returning to the same level of competition. It was organized through a 4 phase continuum with a stepwise approach. After 16 weeks since injury, the patient returned to team training. Conclusions: To our knowledge, this is the first report to inform on rehabilitation and RTS of medial subtalar dislocation. The 4 phases continuum model could be useful for clinicians for safe progression in this rare condition.