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Erika M. Pliner, April A. Dukes, Kurt E. Beschorner and Arash Mahboobin

There is a need for pedagogical techniques that increase student engagement among underrepresented groups in engineering. Relating engineering content to student interests, particularly through biomechanics applications, shows promise toward engaging a diverse group of students. This study investigates the effects of student interests on engagement and performance in 10th grade students enrolled in a summer program for students underrepresented in the science, technology, engineering, and mathematics fields. The authors assessed the effects of interest-tailored lectures on student engagement and performance in a 5-week program with bioengineering workshops, focusing on the delivery of biomechanics content. A total of 31 students received interest-tailored lectures (intervention) and 23 students received only generic lectures (control) in biomechanics. In addition, the authors assessed the effects of teaching method (lecture, classroom activities, and laboratory tours) on student engagement. The authors found interest-tailored lectures to significantly increase student engagement in lecture compared with generic lectures. Students that received interest-tailored lectures had an insignificant, but meaningful 5% increase in student performance. Students rated laboratory tours higher in engagement than other teaching methods. This study provides detailed examples that can directly assist student teaching and outreach in biomechanics. Furthermore, the pedagogical techniques in this study can be used to increase engagement of underrepresented students in engineering.

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Mikkel Oxfeldt, Line B. Dalgaard, Astrid A. Jørgensen and Mette Hansen

Objective: To identify the prevalence of hormonal contraceptive (HC) use, menstrual cycle disturbances, and self-perceived physical and emotional symptoms related to the menstrual cycle/pill cycle in elite female athletes. Methods: One hundred eighty-six Danish elite female athletes completed an online questionnaire to assess menstrual status and history, use of HCs, and self-perceived physical and emotional symptoms related to the menstrual cycle or HC use. Results: Fifty-seven percent of elite female athletes in Denmark use HC, with 74% using combined HCs and 26% using progestin only. Sixty percent of oral contraceptive users reported having manipulated their menstrual cycle by continuous oral contraceptive use. Forty-nine percent of non-HC users had a regular menstrual cycle, while 51% experienced menstrual disturbances, with 1 athlete being primary amenorrheic and 13 athletes having secondary amenorrhea. Menstrual disturbances were experienced by a larger proportion of endurance athletes (69%) compared with athletes performing power and technical disciplines. In endurance athletes amenorrhea was associated with a higher cardiovascular training volume (P < .001). Negative symptoms related to the menstrual/pill cycle were reported by both HC and non-HC users, whereas positive physical symptoms were experienced more often among the non-HC (14%) versus HC users (2%) (P < .01). Notably, 13% of the athletes reported that negative symptoms sometimes/always caused them to not participate in or complete the scheduled training. Conclusion: HC use is common among elite athletes, and continuation of HC is used to manipulate the menstrual cycle in relation to sport competitions. HC use does not abolish dysmenorrhea, but it may reduce emotional-related side effects. Menstrual disturbances are frequent in endurance athletes and are associated with cardiovascular training volume.

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Andrew Renfree, Arturo Casado, Gonzalo Pellejero and Brian Hanley

Purpose: To determine different relationships between, and predictive ability of, performance variables at intermediate distances with finishing time in elite male 10,000-m runners. Methods: Official electronic finishing and 100-m split times of the men’s 10,000-m finals at the 2008 and 2016 Olympic Games and IAAF World Championships in 2013 and 2017 were obtained (125 athlete performances in total). Correlations were calculated between finishing times and positions and performance variables related to speed, position, time to the leader, and time to the runner in front at 2000, 4000, 6000, 8000, and 9900 m. Stepwise linear-regression analysis was conducted between finishing times and positions and these variables across the race. One-way analysis of variance was performed to identify differences between intermediate distances. Results: The SD and kurtosis of mean time, skewness of mean time, and position and time difference to the leader were either correlated with or significantly contributed to predictions of finishing time and position at at least one of the analyzed distances (.81 ≥ r ≥ .30 and .001 ≤ P ≤ .03, respectively). These variables also displayed variation across the race (.001 ≤ P ≤ .05). Conclusions: The ability to undertake a high degree of pace variability, mostly characterized by acceleration in the final stages, is strongly associated with achievement of high finishing positions in championship 10,000-m racing. Furthermore, the adoption and maintenance of positions close to the front of the race from the early stages are important to achieve a high finishing position.

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Qiao Zhu, Hejun Shen and Ang Chen

The purpose of the study was to determine the extent to which practicum teaching could lead to value orientation change of preservice physical education teachers. A group of preservice physical education teachers (N = 28) in China were randomly assigned to practicum-teach either a health-related fitness unit or a traditional sport unit. Their value orientations were measured before and after the practicum teaching. Their middle school learners were tested for knowledge gain. A repeated-measures model shows that the practicum teaching led to little change in their value orientations. The learners in the health-fitness curriculum gained more knowledge than those in the traditional curriculum. The findings suggest that an attempt to influence the value orientation in one practicum teaching experience may not be successful. The findings imply that physical education teacher education training programs may emphasize not only how to teach (via teaching methods courses), but also nurturing the values of teaching to meet the society needs.

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Matthew D. Wright, Francisco Songane, Stacey Emmonds, Paul Chesterton, Matthew Weston and Shaun J. Mclaren

Purpose: To understand the validity of differential ratings of perceived exertion (dRPE) as a measure of girls’ training and match internal loads. Methods: Using the centiMax scale (CR100), session dRPE for breathlessness (sRPE-B) and leg muscle exertion (sRPE-L) were collected across a season of training (soccer, resistance, and fitness) and matches from 33 players (15 [1] y). Differences and associations between dRPE were examined using mixed and general linear models. The authors’ minimal practical important difference was 8 arbitrary units (AU). Results: Mean (AU [SD] ∼16) sRPE-B and sRPE-L were 66 and 61 for matches, 51 and 49 for soccer, 86 and 67 for fitness, and 45 and 58 for resistance, respectively. Session RPE-B was rated most likely harder than sRPE-L for fitness (19 AU; 90% confidence limits: ±7) and most likely easier for resistance (−13; ±2). Match (5; ±4) and soccer (−3; ±2) differences were likely to most likely trivial. The within-player relationships between sRPE-B and sRPE-L were very likely moderate for matches (r = .44; 90% confidence limits: ±.12) and resistance training (.38; ±.06), likely large for fitness training (.51; ±.22), and most likely large for soccer training (.56; ±.03). Shared variance ranged from 14% to 35%. Conclusions: Practically meaningful differences between dRPE following physical training sessions coupled with low shared variance in all training types and matches suggest that sRPE-B and sRPE-L represent unique sensory inputs in girls’ soccer players. The data provide evidence for the face and construct validity of dRPE as a measure of internal load in this population.

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Alexia Tam, Gretchen Kerr and Ashley Stirling

Inspired by the #MeToo movement, women worldwide are coming forward to publicly share their accounts of sexual violence. These harmful experiences have been reported in a range of domains, including sport. As such, providing safe sport experiences for athletes is at the forefront of current discussions for all stakeholders in the sport environment, particularly coaches. Thus, the purpose of this research was to explore coaches’ perspectives of the #MeToo movement in sport and its influence on coaches’ practices and relationships with athletes. Semistructured interviews were conducted with 12 Canadian coaches, including male (n = 7) and female coaches (n = 5) from a variety of sports and competition environments. The study highlights that coaches expressed strong support for the #MeToo movement, while also noting an associated fear of false accusation. Coaches reflected on how the movement has impacted their coaching practices and relations with athletes and expressed a desire for greater professional development in this area. Implications include a need for greater coach education on safe touch, appropriate boundaries in the coach–athlete relationship, and clarifications regarding the process of investigating athletes’ accusations of sexual violence in order to alleviate coaches’ fears of being falsely accused.

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Amin Daneshfar, Carl J. Petersen, Majid S. Koozehchian and Daniel E. Gahreman

This study aimed to identify the acute effects of caffeinated chewing gum (CAF) on bicycle motocross (BMX) time-trial (TT) performance. In a randomized, placebo-controlled, double-blind cross-over design, 14 male BMX riders (age = 20.0 ± 3.3 years; height = 1.78 ± 0.04 m; body mass = 72 ± 4 kg), consumed either (300 mg; 4.2 ± 0.2 mg/kg) caffeinated (300 mg caffeine, 6 g sugars) or a placebo (0 mg caffeine, 0 g sugars) gum, and undertook three BMX TTs. Repeated-measure analysis revealed that CAF has a large ergogenic effect on TT time, F(1, 14) = 33.570, p = .001, ηp2=.71; −1.5% ± 0.4 compared with the placebo. Peak power and maximal power to weight ratio also increased significantly compared with the placebo condition, F(1, 14) = 54.666, p = .001, ηp2=.79; +3.5% ± 0.6, and F(1, 14) = 57.399, p = .001, ηp2=.80; +3% ± 0.3, respectively. Rating of perceived exertion was significantly lower F(1, 14) = 25.020, p = .001, ηp2=.64 in CAF (6.6 ± 1.3) compared with the placebo (7.2 ± 1.7). Administering a moderate dose (300 mg) of CAF could improve TT time by enhancing power and reducing the perception of exertion. BMX coaches and riders may consider consuming CAF before a BMX race to improve performance and reduce rating of perceived exertion.

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Ade B. Pratama and Tossaporn Yimlamai

Purpose: To compare the effectiveness of 3 recovery protocols on muscle oxygenation, blood lactate, and subsequent performance during a 200-m repeated swim session. Methods: Twelve collegte swimmers completed 3 sessions of 2 consecutive 200-m front-crawl trials separated by 1 of 3 recovery protocols: a 15-minute active recovery (AR), a 15-minute passive recovery (PR), and a combination of 5-minute AR and 10-minute PR (CR) in a counterbalanced design. Tissue saturation index at biceps femoris, blood lactate concentration, arterial oxygen saturation, and heart rate were measured at rest, immediately after the trial, and at 5, 10, and 15 minutes of recovery. Two-way analysis of variance (recovery × time) with repeated measures was used to determine measurement variables. A level of significance was set at P < .05. Results: No significant changes in swimming time were observed between trials (AR: 156.79 [4.09] vs 157.79 [4.23] s, CR: 156.50 [4.89] vs 155.55 [4.86] s, PR: 156.54 [4.70] vs 156.30 [4.52] s) across recovery conditions. Interestingly, tissue saturation index rapidly declined immediately after a 200-m swim and then gradually returned to baseline, with a greater value observed during CR compared with AR and PR after 15-minute recovery (P = .04). These changes were concomitant with significant reductions in blood lactate and heart rate during the recovery period (P = .00). Conclusion: The CR in the present study was more effective in enhancing muscle reoxygenation after a 200-m swim compared with AR and PR, albeit its beneficial effect on subsequent performance warrants further investigation.

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Katelyn M. Nelson, Elizabeth H.K. Daidone, Katherine M. Breedlove, Debbie A. Bradney and Thomas G. Bowman

The study objective was to determine the magnitude and frequency of head impacts in NCAA Division III soccer athletes based on player position and type of play (offense, defense, transition). Across player position, male and female soccer defenders sustained the most head impacts (males IR = 18.89, 95% CI = 16.89–20.89; females IR = 8.45, 95% CI = 7.25–9.64; IRR = 2.23, 95% CI = 1.87–2.67). The study revealed a nonstatistically significant interaction between sex, player position, and type of play for both linear (p = .42) and rotational accelerations (p = .16). Defenders sustained the majority of the head impacts in the study sample, suggesting preventative initiatives should be focused on back row players.

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Isao Saito, Koutatsu Maruyama, Tadahiro Kato, Yasunori Takata, Kiyohide Tomooka, Ryoichi Kawamura, Yuichi Uesugi, Yoshihiko Naito, Haruhiko Osawa and Takeshi Tanigawa

Background: Autonomic activity is possibly influenced by physical activity (PA). However, it remains unclear whether this association is modified by insulin resistance. Methods: This population-based study between 2009 and 2012 included 2016 men and women aged 30–79 years. The PA was assessed using a validated questionnaire based on sleep, occupation, transportation, household characteristics, and leisure-time PA. Heart rate (HR) and heart rate variability (HRV) in the sitting position were determined from 5-minute recordings of pulse waves detected by a fingertip sensor. The HRV was calculated as frequency (standard deviation of normal-to-normal [NN] intervals [SDNN]), root mean square of successive differences (RMSSD), and percentage differences between normal NN intervals >50 milliseconds [pNN50]) and time domains. Insulin resistance was evaluated using the homeostasis model assessment index (HOMA-IR). Results: HR, RMSSD, and pNN50 were related to the total and moderate/vigorous PA tertiles in models that included HOMA-IR. The partial regression coefficient of total PA per 1-SD increase was .05 (P = .019) for log-transformed RMSSD and 1.86 (P = .001) for pNN50. No interactive associations were observed between PA and HOMA-IR. Conclusions: Low total PA was associated with increased HR and low levels of RMSSD and pNN50, reflecting parasympathetic modulation that was not modified by insulin resistance.