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Jeanette M. Ricci, Todd A. Astorino, Katharine D. Currie and Karin A. Pfeiffer

The majority of studies examining children’s responses to high-intensity interval exercise primarily utilized running; however, this modality does not require/include other important aspects of physical activity including muscular fitness. Purpose: To compare acute responses between a body weight resistance exercise circuit (CIRC) and treadmill-based (TM) high-intensity interval exercise. Method: A total of 17 boys (age = 9.7 [1.3] y) completed a graded exercise test to determine peak heart rate, peak oxygen uptake (VO2peak), and maximal aerobic speed. Sessions were randomized and counterbalanced. CIRC required 2 sets of 30-second maximal repetitions of 4 exercises. TM included eight 30-second bouts of running at 100% maximal aerobic speed. Both included 30-second active recovery between bouts. Blood lactate concentration was measured preexercise and postexercise. Rating of perceived exertion, affective valence, and enjoyment were recorded preexercise, after intervals 3 and 6, and postexercise. Results: Participants attained 88% (5%) peak heart rate and 74% (9%) VO2peak for CIRC and 89% (4%) peak heart rate and 81% (6%) VO2peak for TM, with a significant difference in percentage of VO2peak (P = .003) between protocols. Postexercise blood lactate concentration was higher following CIRC (5.0 [0.7] mM) versus TM (2.0 [0.3] mM) (P < .001). Rating of perceived exertion, affective valence, and enjoyment responses did not differ between protocols (P > .05). Conclusion: HR responses were near maximal during CIRC, supporting that this body-weight circuit is representative of high-intensity interval exercise.

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Rafael E.A. Muchaxo, Sonja de Groot, Lucas H.V. van der Woude, Thomas W.J. Janssen and Carla Nooijen

The classification system for handcycling groups athletes into five hierarchical classes, based on how much their impairment affects performance. Athletes in class H5, with the least impairments, compete in a kneeling position, while athletes in classes H1 to H4 compete in a recumbent position. This study investigated the average time-trial velocity of athletes in different classes. A total of 1,807 results from 353 athletes who competed at 20 international competitions (2014–2018) were analyzed. Multilevel regression was performed to analyze differences in average velocities between adjacent pairs of classes, while correcting for gender, age, and event distance. The average velocity of adjacent classes was significantly different (p < .01), with higher classes being faster, except for H4 and H5. However, the effect size of the differences between H3 and H4 was smaller (d = 0.12). Hence, results indicated a need for research in evaluating and developing evidence-based classification in handcycling, yielding a class structure with meaningful performance differences between adjacent classes.

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Nathan Waite, John Goetschius and Jakob D. Lauver

Runners experience repeated impact forces during training, and the culmination of these forces can contribute to overuse injuries. The purpose of this study was to compare peak vertical tibial acceleration (TA) in trained distance runners on 3 surface types (grass, asphalt, and concrete) and 3 grades (incline, decline, and level). During visit 1, subjects completed a 1-mile time trial to determine their pace for all running trials: 80% (5%) of the average time trial velocity. During visit 2, subjects were outfitted with a skin-mounted accelerometer and performed 18 separate running trials during which peak TA was assessed during the stance phase. Each subject ran 2 trials for each condition with 2 minutes of rest between trials. Peak TA was different between decline (8.04 [0.12] g) and incline running (7.31 [0.35] g; P = .020). On the level grade, peak TA was greater during grass (8.22 [1.22] g) compared with concrete (7.47 [1.65] g; P = .017). On the incline grade, grass (7.68 [1.44] g) resulted in higher peak TA than asphalt (6.99 [1.69] g; P = .030). These results suggest that under certain grade conditions grass may result in higher TA compared with either concrete or asphalt.

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Rena F. Hale, Sandor Dorgo, Roger V. Gonzalez and Jerome Hausselle

Auditory feedback is a simple, low-cost training solution that can be used in rehabilitation, motor learning, and performance development. The use has been limited to the instruction of a single kinematic or kinetic target. The goal of this study was to determine if auditory feedback could be used to simultaneously train 2 lower-extremity parameters to perform a bodyweight back squat. A total of 42 healthy, young, recreationally active males participated in a 4-week training program to improve squat biomechanics. The Trained group (n = 22) received 4 weeks of auditory feedback. Feedback focused on knee flexion angle and center of pressure under the foot at maximum squat depth. The Control group (n = 20) performed squats without feedback. Subjects were tested pre, post, and 1 week after training. The Trained group achieved average target knee flexion angle within 1.73 (1.31) deg (P < .001) after training and 5.36 (3.29) deg (P < .01) at retention. While achieving target knee flexion angle, the Trained group maintained target center of pressure (P < .001). The Control group improved knee range of motion, but were not able to achieve both parameter targets at maximum squat depth (P < .90). Results from this study demonstrate that auditory feedback is an effective way to train 2 independent biomechanical targets simultaneously.

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Danielle R. Madden, Chun Nok Lam, Brian Redline, Eldin Dzubur, Harmony Rhoades, Stephen S. Intille, Genevieve F. Dunton and Benjamin Henwood

Adults with serious mental illness engage in limited physical activity, which contributes to significant health disparities. This study explored the use of both ecological momentary assessments (EMAs) and activity trackers in adults with serious mental illness to examine the bidirectional relationship between activity and affect with multilevel modeling. Affective states were assessed up to seven times per day using EMA across 4 days. The participants (n = 20) were equipped with a waist-worn accelerometer to measure moderate to vigorous physical activity. The participants had a mean EMA compliance rate of 88.3%, and over 90% of completed EMAs were matched with 30-min windows of accelerometer wear. The participants who reported more positive affect than others had a higher probability of engaging in moderate to vigorous physical activity. Engaging in more moderate to vigorous physical activity than one’s usual was associated with more negative affect. This study begins to address the effect of momentary mood on physical activity in a population of adults that is typically difficult to reach.

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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.