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Matheus Barbalho, Ana Francisca Rozin Kleiner, Bianca Callegari, Ramon Costa de Lima, Givago da Silva Souza, Anselmo de Athayde Costa e Silva and Victor Silveira Coswig

Background: Jumps are important evaluation tools for muscle strength and power and for interlimb asymmetries. Different jump tests are well related to athletic performance, prediction of injury risk, and common motor gestures of several sports such as soccer. Low-cost mobile applications (apps) have gained popularity for this measure. The authors hypothesized that the My Jump 2 app would be a valid tool to assess drop-jump performance and interlimb asymmetry in soccer players. Methods: Eleven male soccer players took part in this study (18.2 [1.3] y, 69.9 [9.5] kg, 174 [6.6] cm). The athletes performed each test twice on a force plate (gold-standard method), while the jumps were recorded through the mobile app. Measures with the My Jump 2 app were applied by 2 evaluators, independently and in duplicate (interrater and intrarater reliability). The agreement analysis between both evaluations was done using an intraclass correlation coefficient and Bland–Altman plots. Results: Compared with the force platform, the app tested showed excellent reliability for the drop jump’s flight time and interlimb asymmetry (intraclass correlation coefficient > .98). For interlimb contact-time asymmetry, the values were 18.4 (9.9) and 19.1 (9.9) milliseconds for the My Jump 2 app and the force platform, respectively (P = .88). For flight-time asymmetries, the values were 389.7 (114.3) and 396.8 (112.5) milliseconds for the My Jump 2 app and the force platform, respectively (P = .88). Conclusion: The My Jump 2 app is a valid tool to assess drop-jump and interlimb asymmetry in soccer players.

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José Oliveira-Santos, Rute Santos, Carla Moreira, Sandra Abreu, Luís Lopes, César Agostinis-Sobrinho and Jorge Mota

Background: To explore the associations between birth weight and body mass index (BMI) from 6 months to 6 years of age, with cardiorespiratory fitness (CRF), physical activity, and sedentary time in adolescence. Methods: Retrospective school-based study with 539 adolescents (292 girls), mean age of 13.94 (1.62) years. Anthropometric data from birth up to 6 years were extracted from individual child health booklets. CRF was estimated by 20-m shuttle run test. Physical activity and sedentary time were assessed with accelerometers. Results: Birth weight was not associated with any outcome measured in adolescence. From the age of 6 months onwards in girls, and from 3 years in boys, BMI associated inversely with CRF in adolescence. In girls, BMI (at 12 mo and at 3 y of age) associated positively with sedentary time in adolescence, but not with physical activity. In boys, positive associations between BMI at the ages of 3, 5, and 6 years old and time spent in some intensities of physical activity in adolescence were found. Conclusions: BMI during the early years was negatively associated with CRF in adolescence, in a consistent way, for both genders, but with physical activity and sedentary time the associations were scarce and inconsistent, depending on the gender.

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Guneet Chawla, Madelon Hoppe, Nina Browner and Michael D. Lewek

The purpose of this study was to determine the difference in spatiotemporal gait measures induced by stepping to the beat of a metronome and to music cues of various frequencies in individuals with Parkinson’s disease. Twenty-one participants with Parkinson’s disease were instructed to time their steps to a metronome and music cues (at 85%, 100%, and 115% of overground cadence). The authors calculated cadence, cadence accuracy, and step length during each cue condition and an uncued control condition. The music and metronome cues produced comparable results in cadence manipulation, with reduced cadence accuracy noted at slower intended frequencies. Nevertheless, the induced cadence elicited a concomitant alteration in step length. The music and metronome cues produced comparable changes to gait, but suggest that temporal control is more limited at slower frequencies, presumably by the challenge of increasing the step length.

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Sandy J. Slater, Anmol Sanghera, Yadira Herrera and Jamie F. Chriqui

Background: Head Start serves over 1 million diverse low-income preschool children and is an ideal setting for developing and implementing obesity prevention efforts, which is expected to have positive impacts on behavior as youth age. This study examined how regional- and state-level Head Start offices have supported implementation of the recently updated physical activity (PA) requirement within the teaching and learning environment Head Start Program Performance Standard (1302.31). Methods: Key informant telephone interviews were conducted with 8 regional- and 36 state-level Head Start representatives. Interviews were recorded and professionally transcribed. Data were coded and analyzed using constant comparative methods in ATLAS.ti (version 8). Audit trails were maintained, and disagreements in codes were discussed and resolved among coders. Results: The following 3 overarching themes emerged: communication, resources and technical assistance, and challenges. Results showed variation in respondent knowledge regarding the Standards. Although regional contacts provide technical assistance, state-level contacts have many information sharing strategies for programs. Implementation challenges included the need for frequent professional development opportunities given staff turnover and low PA competency, and additional PA curricula. Conclusion: Findings can help identify existing or potential strategies that could be adopted more widely or developed to assist Head Start programs incorporate PA into daily activities.

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Sophie E. Carter, Richard Draijer, Andrew Thompson, Dick H.J. Thijssen and Nicola D. Hopkins

Background: Sedentary behavior is negatively associated with cognition and mood. Adults often engage in high levels of sedentary behavior at work through sitting, which may impact productivity. Consequently, replacing sitting with standing and physical activity (PA) is recommended. However, the associations between sitting, standing, and PA at work and cognition and mood are unknown; this study, therefore, aimed to explore these relationships. Methods: A total of 75 healthy full-time workers (33 male, mean [SD]; 33.6 [10.4] y, 38 [7] work hr/wk) wore sedentary behavior (activPAL) and PA (SenseWear Pro) monitors for 7 days and recorded their work hours. The day after this monitoring period, participants completed cognitive tests (executive function, attention, and working memory) and mood questionnaires (affect, alert, content, and calm). Multiple linear regression analyses examined the associations between cognition and mood and the time spent sitting, standing, and in each PA intensity during work hours, weekday leisure time, and weekends. Results: Workplace sitting, standing, or PA were not significantly associated with cognition or mood (P > .05). No significant associations were observed between these variables during weekday leisure time or weekends (P > .05). Conclusions: In a cohort of healthy workers, workplace sitting, standing, and PA are not associated with cognition or mood. Further research in this population is needed, examining the influence of workplace behaviors on cognition and mood, because this will contribute to evidence-based workplace guidelines to increase productivity.

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João Paulo Limongi França Guilherme, Ekaterina A. Semenova, Hirofumi Zempo, Gabriel L. Martins, Antonio H. Lancha Junior, Eri Miyamoto-Mikami, Hiroshi Kumagai, Takuro Tobina, Keisuke Shiose, Ryo Kakigi, Takamasa Tsuzuki, Noriko Ichinoseki-Sekine, Hiroyuki Kobayashi, Hisashi Naito, Oleg V. Borisov, Elena S. Kostryukova, Nikolay A. Kulemin, Andrey K. Larin, Edward V. Generozov, Noriyuki Fuku and Ildus I. Ahmetov

Purpose: To replicate previous genome-wide association study identified sprint-related polymorphisms in 3 different cohorts of top-level sprinters and to further validate the obtained results in functional studies. Methods: A total of 240 Japanese, 290 Russians, and 593 Brazilians were evaluated in a case-control approach. Of these, 267 were top-level sprint/power athletes. In addition, the relationship between selected polymorphisms and muscle fiber composition was evaluated in 203 Japanese and 287 Finnish individuals. Results: The G allele of the rs3213537 polymorphism was overrepresented in Japanese (odds ratio [OR]: 2.07, P = .024) and Russian (OR: 1.93, P = .027) sprinters compared with endurance athletes and was associated with an increased proportion of fast-twitch muscle fibers in Japanese (P = .02) and Finnish (P = .041) individuals. A meta-analysis of the data from 4 athlete cohorts confirmed that the presence of the G/G genotype rather than the G/A+A/A genotypes increased the OR of being a sprinter compared with controls (OR: 1.49, P = .01), endurance athletes (OR: 1.79, P = .001), or controls + endurance athletes (OR: 1.58, P = .002). Furthermore, male sprinters with the G/G genotype were found to have significantly faster personal times in the 100-m dash than those with G/A+A/A genotypes (10.50 [0.26] vs 10.76 [0.31], P = .014). Conclusion: The rs3213537 polymorphism found in the CPNE5 gene was identified as a highly replicable variant associated with sprinting ability and the increased proportion of fast-twitch muscle fibers, in which the homozygous genotype for the major allele (ie, the G/G genotype) is preferable for performance.

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Antonis Kesisoglou, Andrea Nicolò and Louis Passfield

Purpose: To examine the effect of cycling exercise intensity and duration on subsequent performance and to compare the resulting acute performance decrement (APD) with total work done (TWD) and corresponding training-load (TL) metrics. Methods: A total of 14 male cyclists performed a 5-minute time trial (TT) as a baseline and after 4 initial exercise bouts of varying exercise intensity and duration. The initial exercise bouts were performed in a random order and consisted of a 5- and a 20-minute TT and a 20- and a 40-minute submaximal ride. The resulting APD was calculated as the percentage change in 5-minute TT from baseline, and this was compared with the TWD and TL metrics for the corresponding initial exercise bout. Results: Average power output was different for each of the 4 initial exercise bouts (ηp2=.971; P < .001), and all bouts resulted in an APD. But APD was only different when comparing maximal with submaximal bouts (ηp2=.862; P < .001). The APD contradicted TWD and TL metrics and was not different when comparing 5- and 20-minute maximal TTs or the 20- and 40-minute submaximal bouts. In contrast, TL metrics were different for all training sessions (ηp2=.970; P < .001). Conclusion: An APD is found after initial exercise bouts consisting of 5- and 20-minute TTs and after 20- and 40-minute of submaximal exercise that is not consistent with the corresponding values for TWD or TL. This discrepancy highlights important shortcomings when using TWD and TL to compare exercise bouts of different intensity and duration.

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Taylor K. Dinyer, Pasquale J. Succi, M. Travis Byrd, Caleb C. Voskuil, Evangeline P. Soucie and Haley C. Bergstrom

This study determined the load- and limb-dependent neuromuscular responses to fatiguing, bilateral, leg extension exercise performed at a moderate (50% one-repetition maximum [1RM]) and high load (80% 1RM). Twelve subjects completed 1RM testing for the bilateral leg extension, followed by repetitions to failure at 50% and 80% 1RM, on separate days. During all visits, the electromyographic (EMG) and mechanomyographic (MMG), amplitude (AMP) and mean power frequency (MPF) signals were recorded from the vastus lateralis of both limbs. There were no limb-dependent responses for any of the neuromuscular signals and no load-dependent responses for EMG AMP, MMG AMP, or MMG MPF (p = .301–.757), but there were main effects for time that indicated increases in EMG and MMG AMP and decreases in MMG MPF. There was a load-dependent decrease in EMG MPF over time (p = .032) that suggested variability in the mechanism responsible for metabolite accumulation at moderate versus high loads. These findings suggested that common drive from the central nervous system was used to modulate force during bilateral leg extension performed at moderate and high loads.