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Jurdan Mendiguchia, Adrián Castaño-Zambudio, Pedro Jiménez-Reyes, Jean–Benoît Morin, Pascal Edouard, Filipe Conceição, Jonas Tawiah-Dodoo, and Steffi L. Colyer

Purpose: Sprint kinematics have been linked to hamstring injury and performance. This study aimed to examine if a specific 6-week multimodal intervention, combining lumbopelvic control and unning technique exercises, induced changes in pelvis and lower-limb kinematics at maximal speed and improved sprint performance. Methods: Healthy amateur athletes were assigned to a control or intervention group (IG). A sprint test with 3-dimensional kinematic measurements was performed before (PRE) and after (POST) 6 weeks of training. The IG program included 3 weekly sessions integrating coaching, strength and conditioning, and physical therapy approaches (eg, manual therapy, mobility, lumbopelvic control, strength and sprint “front-side mechanics”-oriented drills). Results: Analyses of variance showed no between-group differences at PRE. At POST, intragroup analyses showed PRE–POST differences for the pelvic (sagittal and frontal planes) and thigh kinematics and improved sprint performance (split times) for the IG only. Specifically, IG showed (1) a lower anterior pelvic tilt during the late swing phase, (2) greater pelvic obliquity on the free-leg side during the early swing phase, (3) higher vertical position of the front-leg knee, (4) an increase in thigh angular velocity and thigh retraction velocity, (5) lower between-knees distance at initial contact, and (6) a shorter ground contact duration. The intergroup analysis revealed disparate effects (possibly to very likely) in the most relevant variables investigated. Conclusion: The 6-week multimodal training program induced clear pelvic and lower-limb kinematic changes during maximal speed sprinting. These alterations may collectively be associated with reduced risk of muscle strain and were concomitant with significant sprint performance improvement.

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Ernest Baiget, Joshua Colomar, and Francisco Corbi

Purpose: (1) To analyze the associations between serve velocity (SV) and various single-joint upper-limb isometric force–time curve parameters, (2) to develop a prediction model based on the relationship between these variables, and (3) to determine whether these factors are capable of discriminating between tennis players with different SV performances. Method: A total of 17 high-performance tennis players performed 8 isometric tests of joints and movements included in the serve kinetic chain (wrist and elbow flexion [EF] and extension; shoulder flexion [SHF] and extension [SHE], internal [SHIR] and external rotation). Isometric force (IF), rate of force development (RFD), and impulse (IMP) at different time intervals (0–250 ms) were obtained for analysis. Results: Significant (P < .05 to P < .01) and moderate to very large correlations were found between SV and isometric force (IF), RFD and impulse (IMP) at different time intervals in all joint positions tested (except for the EF). Stepwise multiple regression analysis highlighted the importance of RFD in the SHIR from 0 to 50 milliseconds and isometric force (IF) in the SHF at 250 milliseconds on SV performance. Moreover, the discriminant analyses established SHIR RFD from 0 to 30 milliseconds as the most important factor discriminating players with different serve performances. Conclusions: Force–time parameters in upper-limb joints involved in the serve moderate to very largely influence SV. Findings suggest that the capability to develop force in short periods of time (<250 ms), especially in the shoulder joint, seems relevant to develop high SV in competition tennis players.

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Sally Taunton Miedema, Ali Brian, Adam Pennell, Lauren Lieberman, Larissa True, Collin Webster, and David Stodden

Many interventions feature a singular component approach to targeting children’s motor competency and proficiency. Yet, little is known about the use of integrative interventions to meet the complex developmental needs of children aged 3–6 years. The purpose of this study was to examine the effects of an integrative universally designed intervention on children with and without disabilities’ motor competency and proficiency. We selected children (N = 111; disability = 24; no disability = 87) to participate in either a school-based integrative motor intervention (n = 53) or a control condition (n = 58). Children in the integrative motor intervention both with and without disabilities showed significant improvement in motor competency and proficiency (p < .001) as compared with peers with and without disabilities in a control condition. Early childhood center directors (e.g., preschool and kindergarten) should consider implementing integrative universally designed interventions targeting multiple aspects of motor development to remediate delays in children with and without disabilities.

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Nima Dehghansai, Ross A. Pinder, and Joseph Baker

This three-part investigation conducted a comprehensive analysis of 213 Australian and Canadian athletes’ developmental trajectories, training histories, and experiences in organized sports from 18 Paralympic sports (PS). While athletes with early-onset impairments (i.e., congenital, preadolescent) reached milestones and commenced various types of training at a significantly younger age than athletes with later-onset impairments (i.e., early adulthood, adulthood), the latter groups progressed through their careers and incorporated various trainings at a faster pace (i.e., fewer years). Preferences to certain training conditions varied between groups. Eighty-two percent of the athletes with acquired impairments had experience in able-bodied sports before the onset of their impairment, with 70% noting involvement in sports similar to their current PS. The participation rates (38%) and sport similarity (53%) were lower in PS. The amalgamation of findings from this series of studies highlights the complexity associated with PS athletes’ development and demonstrates the importance of taking an individualized approach.

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J.D. Adams, Miranda Badolato, Ethan Pierce, Abbie Cantrell, Zac Parker, and Donya Farzam

The purpose of this investigation was to quantify the effects of storage temperature and duration on the assessment of urine electrolytes. Twenty-one separate human urine specimens were analyzed as baseline and with the remaining specimen separated into eight vials, two in each of the following four temperatures: 22, 7, −20, and −80 °C. Each specimen was analyzed for urine electrolytes (sodium, potassium, and chloride) after 24 and 48 hr. After 24 hr, no significant difference was detected from baseline in urine sodium, potassium, and chloride at all four storage temperatures (p > .05). Similarly, after 48 hr, urine sodium, potassium, and chloride were not significantly different from baseline in all four storage temperatures (p > .05). In conclusion, these data show that urine specimens analyzed for urine sodium, chloride, and potassium are stable up to 48 hr in temperatures ranging from deep freezing to room temperature.

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Andreia Bauermann, Karina S.G. de Sá, Zilda A. Santos, and Anselmo A. Costa e Silva

This systematic review aimed to identify nutritional interventions and supplements that improve the performance for wheelchair athletes. Intervention trials involving high-performance wheelchair athletes were analyzed, including those that comprised a nutritional intervention, defined as any intervention related to food, beverages, and supplementation aiming at evaluating the performance of wheelchair athletes. Of the included studies, four evaluated caffeine supplementation, of which one also evaluated sodium citrate supplementation; two studies evaluated vitamin D supplementation; one study assessed creatine monohydrate supplementation; and one assessed carbohydrate supplementation. Most studies were conducted on athletes with spinal cord injury. Athletes who consumed caffeine exhibited an improvement in performance, but this finding is not strong enough to become a recommendation.

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Sara R. Sherman, Clifton J. Holmes, Alexander P. Demos, Tori Stone, Bjoern Hornikel, Hayley V. MacDonald, Michael V. Fedewa, and Michael R. Esco

Introduction: The parasympathetically derived marker of heart rate variability, root mean square of successive R-R differences (RMSSD), and the daily fluctuations as measured by the coefficient of variation (RMSSDCV) may be useful for tracking training adaptations in athletic populations. These vagally derived markers of heart rate variability may be especially pertinent when simultaneously considering a female athlete’s menstrual cycle. Purpose: The purpose of this study was to observe the perturbations in RMSSDCV, while considering RMSSD, across a season in the presence and absence of menses with training load in female collegiate rowers. Methods: Thirty-six (20 [1] y, 25.6 [3.4] kg·m−2) National Collegiate Athletic Association Division I female rowers were monitored for 18 consecutive weeks across a full season. Seated, ultrashortened RMSSD measurements were obtained by the rowers on at least 3 mornings per week using a smartphone photoplethysmography device. Following the RMSSD measurement, athletes indicated the presence or absence of menstruation within the application. Individual meters rowed that week and sessions rate of perceived exertion were obtained to quantify training load. Results: Longitudinal mixed-effects modeling demonstrated a significant effect of menses and time, while also considering RMSSD, such that those who were on their period had a significantly greater RMSSDCV than those who were not (11.2% vs 7.5%, respectively; P < .001). These changes were independent of meters rowed, sessions rate of perceived exertion, body mass index, birth-control use, and years of rowing experience, which were all nonsignificant predictors of RMSSDCgV (P > .05). Conclusion: The presence of menses appears to significantly impact RMSSDCV when also considering RMSSD, which may allow coaches to consider individualized training plans accordingly.

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Jos J. de Koning