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Werner A.F. van de Ven, Jurjen Bosga, Wim Hullegie, Wiebe C. Verra, and Ruud G.J. Meulenbroek

The present study explores variations in the degree of automaticity and predictability of cyclical arm and leg movements. Twenty healthy adults were asked to walk on a treadmill at a lower-than-preferred speed, their preferred speed, and at a higher-than-preferred speed. In a separate, repetitive punching task, the three walking frequencies were used to cue the target pace of the cyclical arm movements. Movements of the arms, legs, and trunk were digitized with inertial sensors. Whereas absolute slope values (|β|) of the linear fit to the power spectrum of the digitized movements (p < .001, η2 = .676) were systematically smaller in treadmill walking than in repetitive punching, sample entropy measures (p < .001, η2 = .570) were larger reflecting the former task being more automated but also less predictable than the latter task. In both tasks, increased speeds enhanced automatized control (p < .001, η2 = .475) but reduced movement predictability (p = .008, η2 = .225). The latter findings are potentially relevant when evaluating effects of task demand changes in clinical contexts.

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Jackie D. Zehr, Jessa M. Buchman-Pearle, Tyson A.C. Beach, Chad E. Gooyers, and Jack P. Callaghan

The relationship between internal loading dose and low-back injury risk during lifting is well known. However, the implications of movement parameters that influence joint loading rates—movement frequency and speed—on time-dependent spine loading responses remain less documented. This study quantified the effect of loading rate and frequency on the tolerated cumulative loading dose and its relation to joint lifespan. Thirty-two porcine spinal units were exposed to biofidelic compression loading paradigms that differed by joint compression rate (4.2 and 8.3 kN/s) and frequency (30 and 60 cycles per minute). Cyclic compression testing was applied until failure was detected or 10,800 continuous cycles were tolerated. Instantaneous weighting factors were calculated to evaluate the cumulative load and Kaplan–Meier survival probability functions were examined following nonlinear dose normalization of the cyclic lifespan. Significant reductions in cumulative compression were tolerated when spinal units were compressed at 8.3 kN/s (P < .001, 67%) and when loaded at 30 cycles per minute (P = .008, 45%). There was a positive moderate relationship between cumulative load tolerance and normalized cyclic lifespan (R 2 = .52), which was supported by joint survivorship functions. The frequency and speed of movement execution should be evaluated in parallel to loading dose for the management of low-back training exposures.

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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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Hiromasa Ueno, Tadashi Suga, Kenji Takao, Masafumi Terada, Akinori Nagano, and Tadao Isaka

This study examined the relationship between body segment mass and running performance in endurance runners. The total (muscle, fat, and bone masses), lean (muscle mass), and fat masses of the leg, arm, and trunk segments in 37 well-trained endurance runners were measured using dual-energy X-ray absorptiometer. The relative segment mass was calculated by normalizing the absolute mass to body mass. There were no significant correlations between absolute total, lean, and fat masses of all 3 segments and personal best 5000-m race time. No significant correlations were also observed between all 3 relative masses of the arm segment and personal best 5000-m race time. In contrast, medium positive correlations were observed between the relative total and lean masses of the leg segment and personal best 5000-m race time (r = .387 and .335, respectively, both P ≤ .031). Furthermore, large negative correlations were observed between the relative total and lean masses of the trunk segment and personal best 5000-m race time (r = −.500 and −.548, respectively, both P ≤ .002). These findings suggest that a mass distribution with smaller leg mass and greater trunk mass may be advantageous for achieving better running performance in endurance runners.

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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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Courtney C. Walton, Serena Carberry, Michael Wilson, Rosemary Purcell, Lisa Olive, Stewart Vella, and Simon Rice

The mental health of young people is of increasing concern, and early intervention prevention strategies are required. Youth sports are potentially effective environments within which to situate interventions due to high participation rates, familiarity to young participants, and the typically positive relationships held with adults within such spaces. However, coaches identify that they require more knowledge to better respond to mental health concerns that may be present among players. Here, we describe a research translation process in which an open-access, evidence-informed resource was developed to support coaches and sports clubs to better respond to athletes in need as well as to create environments that may protect against mental ill-health and promote well-being. The resource includes a toolkit—with an associated checklist—for recreational sport clubs to follow, a guide to responding to young people in need, and a short educational video. We suggest that these practical and applied resources, which can be immediately implemented, may assist in the provision of targeted and structured guidance for coaches’ first response intervention with vulnerable young people. Furthermore, these resources can support future efforts by being specifically tailored for the unique locations and cultures that vary among youth sport environments.

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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.