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Joachim Hüffmeier, Joyce Elena Schleu and Christoph Nohe

Prior research showed that swimmers swim faster in relay than in individual competitions if they start at later relay positions. This finding is typically explained via the swimmers’ relay position and their associated perception that their individual performance is indispensable for their teams’ performance. Using multilevel modeling, the authors disentangled this situational explanation from alternative accounts focusing on individual differences between swimmers. Two studies empirically supported the situational explanation: When using a within-person approach and, thus, controlling for between-person variance (i.e., individual differences between swimmers), the swimmers’ relay position remained a significant predictor of the increases in effort spent in relays. This finding held when controlling for the on-average higher instrumentality in the relay versus the individual competitions. Thus, the often observed effort gains in swimming relays probably are due to the swimmers’ relay position as a situational explanation and stem from the motivating impact of teamwork versus individual work.

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Emma K. Zadow, James W. Fell, Cecilia M. Kitic, Jia Han and Sam S. X. Wu

Context: Time of day has been shown to impact athletic performance, with improved performance observed in the late afternoon–early evening. Diurnal variations in physiological factors may contribute to variations in pacing selection; however, research investigating time-of-day influence on pacing is limited. Purpose: To investigate the influence of time-of-day on pacing selection in a 4-km cycling time trial (TT). Methods: Nineteen trained male cyclists (mean [SD] age 39.0 [10.7] y, height 1.8 [0.1] m, body mass 78.0 [9.4] kg, VO2max 62.1 [8.7] mL·kg−1·min−1) completed a 4-km TT on 5 separate occasions at 08:30, 11:30, 14:30, 17:30, and 20:30. All TTs were completed in a randomized order, separated by a minimum of 2 d and maximum of 7 d. Results: No time-of-day effects were observed in pacing as demonstrated by similar power outputs over 0.5-km intervals (P = .78) or overall mean power output (333.0 [38.9], 339.8 [37.2], 335.5 [31.2], 336.7 [35.2], and 334.9 [35.7] W; P = .45) when TTs were performed at 08:30, 11:30, 14:30, 17:30, and 20:30. Preexercise tympanic temperature demonstrated a time-of-day effect (P < .001), with tympanic temperature higher at 14:30 and 17:30 than at 08:30 and 11:30. Conclusion: While a biological rhythm was present in tympanic temperature, pacing selection and performance when completing a 4-km cycling TT were not influenced by time of day. The findings suggest that well-trained cyclists can maintain a robust pacing strategy for a 4-km TT regardless of time of the day.

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Tuyen Le, Jeffrey D. Graham, Sara King-Dowling and John Cairney

This study examined the effects of perceptions of motor abilities on aerobic and musculoskeletal exercise performance in young children at risk for developmental coordination disorder (rDCD). The participants (N = 539) were part of a larger cohort study, the Coordination and Activity Tracking in Children (CATCH) study. The Movement Assessment Battery for Children (2nd Edition) was used to determine rDCD children. Perceptions of motor abilities were measured by the Perceived Efficacy and Goals Setting system. Aerobic exercise performance was measured using the Bruce Protocol treadmill test, and musculoskeletal exercise performance was assessed using the standing long jump and the Wingate Anaerobic test. The rDCD children reported lower Perceived Efficacy and Goals Setting scores and performed worse on all exercise performance measures. Perceptions of ability also mediated the relationship between developmental coordination disorder and each exercise performance test. It is concerning that children with low motor coordination report lower perceptions of ability even at a very young age.

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Christopher Ring, Maria Kavussanu and Benjamin Walters

Objectives: Self–other divergence refers to individuals judging themselves to be different from others. The authors investigated doping-related self-other divergence.Design: The authors used a quasi-experimental repeated-measures design to compare the effects of an independent variable (perspective: self, other) on doping likelihood and guilt. Method: Rugby players rated doping likelihood and guilt in situations describing two perspectives: self (their own behavior and feelings) and other (another player’s behavior and feelings). They also completed measures of moral agency, identity, perfectionism, and values (moral traits). Results: Doping likelihood was lower and guilt was higher for self-based ratings compared with other-based ratings. The self–other difference in doping likelihood was mediated by guilt and moderated by moral traits (larger for athletes with higher agency and values). Agency and values were more strongly related to self than other doping likelihood. Conclusions: Other-referenced measures differed from self-referenced measures of doping likelihood and guilt, indicating that it is wrong to presume equivalence of measurement.

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Beatriz Rael, Nuria Romero-Parra, Víctor M. Alfaro-Magallanes, Laura Barba-Moreno, Rocío Cupeiro, Xanne Janse de Jonge, Ana B. Peinado and on Behalf of the IronFEMME Study Group

Purpose: The influence of female sex hormones on body fluid regulation and metabolism homeostasis has been widely studied. However, it remains unclear whether hormone fluctuations throughout the menstrual cycle (MC) and with oral contraceptive (OC) use affect body composition (BC). Thus, the aim of this study was to investigate BC over the MC and OC cycle in well-trained females. Methods: A total of 52 eumenorrheic and 33 monophasic OC-taking well-trained females participated in this study. Several BC variables were measured through bioelectrical impedance analysis 3 times in the eumenorrheic group (early follicular phase, late follicular phase, and midluteal phase) and on 2 occasions in the OC group (withdrawal phase and active pill phase). Results: Mixed linear model tests reported no significant differences in the BC variables (body weight, body mass index, basal metabolism, fat mass, fat-free mass, and total body water) between the MC phases or between the OC phases (P > .05 for all comparisons). Trivial and small effect sizes were found for all BC variables when comparing the MC phases in eumenorrheic females, as well as for the OC cycle phases. Conclusions: According to the results, sex hormone fluctuations throughout the menstrual and OC cycle do not influence BC variables measured by bioelectrical impedance in well-trained females. Therefore, it seems that bioimpedance analysis can be conducted at any moment of the cycle, both for eumenorrheic women and women using OC.

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Courtney Sullivan, Thomas Kempton, Patrick Ward and Aaron J. Coutts

Purpose: To develop position-specific career performance trajectories and determine the age of peak performance of professional Australian Football players. Methods: Match performance data (Australian Football League [AFL] Player Rank) were collected for Australian Football players drafted via the AFL National Draft between 1999 and 2015 (N = 207). Players were subdivided into playing positions: forwards (n = 60; age 23 [3] y), defenders (n = 71; age 24 [4] y), midfielders (n = 58; age 24 [4] y), and ruckmen (n = 18; age 24 [3] y). Linear mixed models were fitted to the data to estimate individual career trajectories. Results: Forwards, midfielders, and defenders experienced peak match performance earlier than ruckmen (24–25 vs 27 y). Midfielders demonstrated the greatest between-subjects variability (intercept 0.580, age 0.0286) in comparison with ruckmen, who demonstrated the least variability (intercept 0.112, age 0.005) in AFL Player Rank throughout their careers. Age had the greatest influence on the career trajectory of midfielders (β [SE] = 0.226 [0.025], T = 9.10, P < .01) and the least effect on ruckmen (β [SE] = 0.114 [0.049], T = 2.30, P = .02). Conclusions: Professional Australian Football players peak in match performance between 24 and 27 years of age with age, having the greatest influence on the match performance of midfielders and the least on ruckmen.

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Tom Toolis and Kerry McGawley

Purpose: To evaluate the effects of wearing upper- and lower-body compression garments on cross-country skiing performance in elite winter biathletes. Methods: A total of 7 senior biathletes (4 men and 3 women) from the Swedish national team performed 2 exercise trials in a randomized and counterbalanced order, wearing either commercially available upper- and lower-body compression garments (COMP) or a standard winter-biathlon racing suit (CON). In each trial, the athletes roller-skied on a customized treadmill, completing a time trial simulating the skiing duration of a biathlon sprint race, followed by a time-to-exhaustion test designed to elicit exhaustion within ∼60 to 90 seconds. Heart rate, blood lactate concentration, rating of perceived exertion, thermal sensation, and thermal comfort were monitored throughout each trial, while muscle soreness was measured up to 48 hours after each trial. Results: Pressure exerted by the clothing was significantly higher at all anatomical sites for COMP compared with CON (P ≤ .002). Wearing COMP led to small positive effects on time-trial (d = 0.31) and time-to-exhaustion test (d = 0.31) performances compared with CON, but these differences were not statistically significant (P > .05). No significant differences were found for any physiological (heart rate or blood lactate concentration) or subjective (rating of perceived exertion, thermal sensation, thermal comfort, or muscle soreness) responses between COMP and CON (P > .05). Conclusion: Wearing COMP during maximal cross-country skiing may have small but worthwhile beneficial effects on performance for some individuals. Due to individual variation, athletes are advised to test COMP prior to competition.

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Faezeh Mohammadi Sanjani, Abbas Bahram, Moslem Bahmani, Mina Arvin and John van der Kamp

It has been shown that texting degrades driving performance, but the extent to which this is mediated by the driver’s age and postural stability has not been addressed. Hence, the present study examined the effects of texting, sitting surface stability, and balance training in young and older adults’ driving performance. Fifteen young (mean age = 24.3 years) and 13 older (mean age = 62.8 years) participants were tested in a driving simulator with and without texting on a smartphone and while sitting on a stable or unstable surface (i.e., a plastic wobble board), before and after a 30-min sitting balance training. Analyses of variance showed that texting deteriorated driving performance but irrespective of sitting surface stability. Balance training decreased the negative effects of texting on driving, especially in older adults. Perceived workload increased when drivers were texting, and balance training reduced perceived workload. Perceived workload was higher while sitting on the unstable surface, but less so after balance training. Path analyses showed that the effects on driving performance and perceived workload were (indirectly) associated with changes in postural stability (i.e., postural sway). The study confirms that texting threatens safe driving performance by challenging postural stability, especially in older adults. The study also suggests that it is important to further investigate the role balance training can play in reducing these negative effects of texting.

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Fernando Pareja-Blanco, Eduardo Sáez de Villarreal, Beatriz Bachero-Mena, Ricardo Mora-Custodio, José Antonio Asián-Clemente, Irineu Loturco and David Rodríguez-Rosell

Purpose: This study aimed to compare the effects of unresisted versus heavy sled sprint training (0% vs 40% body mass [BM]) on sprint performance in women. Moreover, the effects of the aforementioned loads on resisted sprint and jump performance were analyzed. Methods: Twenty-eight physically active women were randomly allocated into 2 groups: unloaded sprint training group (G0%, n = 14), and resisted sprint training with 40% BM group (G40%, n = 14). Pretraining and posttraining assessments included countermovement jump, unloaded 30-m sprint, and 20-m sprint with 20%, 40%, 60%, and 80% BM. Times to cover 0 to 10 (T10), 0 to 20 (T20), 0 to 30 (T30), 10 to 20 (T10–20), 20 to 30 (T20–30), and 10 to 30 m (T10–30) were recorded. Both groups were trained once a week for 8 weeks and completed the same training program, but with different loads (0% vs 40% BM). Results: No significant time × group interactions were observed. For unloaded sprint performance, G0% showed significant (P = .027) decreases only in T10–20, while G40% attained significant decreases in T30 (P = .021), T10–30 (P = .015), and T20–30 (P = .003). Regarding resisted sprint performance, G0% showed significant (P = .010) improvements only for the 20% BM condition. The G40% group attained significant improvements in all loading conditions (20%, 40%, 60%, and 80% BM). Both groups showed significant improvements (P < .001) in countermovement jump height. Conclusions: In physically active women, no significant differences in sprint and countermovement jump performance were detected after 8 weeks of resisted and unresisted sprint training programs. Future studies should, therefore, be devoted to how sprint training should be individualized to maximize performance.