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Jožef Šimenko and Vedran Hadžić

Purpose: This study investigates bilateral performance with the Special Judo Fitness Test (SJFT) and its associations with competition performance (CP) and competition volume (CV) in judo. Methods: The SJFT compared movement patterns of the dominant (D) and nondominant (ND) sides on a sample of 27 youth judoka. Repeated-measures analysis of variance was used to determine differences in SJFT execution to the D and ND side, and for associations, the Pearson correlation was used (P < .05). Results: The total number of throws is significantly higher on the D side, with better performance in the final SJFT index. The CP showed positive correlations with the D side of SJFT executions in the second part of SJFT (P = .042) and the total number of throws (P = .036). On the ND side, the CP showed a positive correlation with the second part of the SJFT (P = .014), a negative correlation with the third part of the SJFT (P = .035), and a positive correlation in the total number of throws (P = .027). CV shows significant correlations with all parameters of the SJFT in the D and ND sides, with stronger correlations on the ND side. Conclusions: The study presents significantly better performance in judokas’ D side in SJFT. Associations between CP and CV with the SJFT were significant in connection to both body sides. It highlights the importance of bilateral movement development and good execution of the throwing techniques for the D and ND body sides of youth judoka to achieve greater CP all year round.

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Felipe Guimarães Teixeira, Paulo Tadeu Cardozo Ribeiro Rosa, Roger Gomes Tavares Mello, and Jurandir Nadal

Purpose: The study aimed to identify the variables that differentiate judo athletes at national and regional levels. Multivariable analysis was applied to biomechanical, anthropometric, and Special Judo Fitness Test (SJFT) data. Method: Forty-two male judo athletes from 2 competitive groups (14 national and 28 state levels) performed the following measurements and tests: (1) skinfold thickness, (2) circumference, (3) bone width, (4) longitudinal length, (5) stabilometric tests, (6) dynamometric tests, and (7) SJFT. The variables with significant differences in the Wilcoxon rank-sum test were used in stepwise logistic regression to select those that better separate the groups. The authors considered models with a maximum of 3 variables to avoid overfitting. They used 7-fold cross validation to calculate optimism-corrected measures of model performance. Results: The 3 variables that best differentiated the groups were the epicondylar humerus width, the total number of throws on the SJFT, and the stabilometric mean velocity of the center of pressure in the mediolateral direction. The area under the receiver-operating-characteristic curve for the model (based on 7-fold cross validation) was 0.95. Conclusion: This study suggests that a reduced set of anthropometric, biomechanical, and SJFT variables can differentiate judo athlete’s levels.

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Logan T. Markwell, Andrew J. Strick, and Jared M. Porter

Sports, along with nearly all facets of life, have been impacted by the COVID-19 pandemic. The National Basketball Association quickly adopted a unique method to finish the 2019–2020 regular season and playoffs. The entire league quarantined for months in what was known as the “NBA bubble” where games were played in spectator-less arenas. During this time, increases in shooting accuracy were reported, suggesting that free throws and field goals were made at record-breaking levels. This study examined differences in free throw shooting accuracy with and without spectators. Archival data were retrieved and analyzed to evaluate the potential differences. Free throw shooting accuracy with and without spectators were examined in multiple analyses. Our examination revealed free throw percentages were significantly greater in spectator-less arenas compared with the 2018 and 2019 seasons with spectators. Changes of the environmental characteristics, due to spectator-less arenas, were likely contributors to the improved free throw phenomenon reported in this study.

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Alexandra Stribing, Adam Pennell, Emily N. Gilbert, Lauren J. Lieberman, and Ali Brian

Individuals with visual impairments (VI) trend toward lower motor competence when compared with peers without VI. Various forms of perception often affects motor competence. Thus, it is important to explore factors that influence forms of perception and their differential effects on motor competence for those with VI. Therefore, the purposes of this study were to explore and describe the differential effects of age, gender, and degree of vision on self-perceptions, parents’ perceptions, metaperceptions, and locomotor skills, and to examine potential associations among all variables with actual locomotor competence for adolescents with VI. Adolescents with VI completed two questionnaires and the Test of Gross Motor Development-Third Edition. Parents completed a parent perception questionnaire. Mann–Whitney U and Kruskal–Wallis H analyses showed no differential effects for gender or age on any dependent measures. Degree of vision affected locomotor skills, but not any other factor. Spearman rho correlations showed significant associations among locomotor and self-perceptions, degree of vision and locomotor, and metaperceptions with parents’ perceptions. Adolescents reported relatively high self-perceptions and metaperceptions; however, their actual locomotor competence and parents’ perceptions were relatively low. Findings may help situate future intervention strategies targeting parents supporting their children’s locomotor skills through self-perceptions.

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Alannah K.A. McKay, Trent Stellingwerff, Ella S. Smith, David T. Martin, Iñigo Mujika, Vicky L. Goosey-Tolfrey, Jeremy Sheppard, and Louise M. Burke

Throughout the sport-science and sports-medicine literature, the term “elite” subjects might be one of the most overused and ill-defined terms. Currently, there is no common perspective or terminology to characterize the caliber and training status of an individual or cohort. This paper presents a 6-tiered Participant Classification Framework whereby all individuals across a spectrum of exercise backgrounds and athletic abilities can be classified. The Participant Classification Framework uses training volume and performance metrics to classify a participant to one of the following: Tier 0: Sedentary; Tier 1: Recreationally Active; Tier 2: Trained/Developmental; Tier 3: Highly Trained/National Level; Tier 4: Elite/International Level; or Tier 5: World Class. We suggest the Participant Classification Framework can be used to classify participants both prospectively (as part of study participant recruitment) and retrospectively (during systematic reviews and/or meta-analyses). Discussion around how the Participant Classification Framework can be tailored toward different sports, athletes, and/or events has occurred, and sport-specific examples provided. Additional nuances such as depth of sport participation, nationality differences, and gender parity within a sport are all discussed. Finally, chronological age with reference to the junior and masters athlete, as well as the Paralympic athlete, and their inclusion within the Participant Classification Framework has also been considered. It is our intention that this framework be widely implemented to systematically classify participants in research featuring exercise, sport, performance, health, and/or fitness outcomes going forward, providing the much-needed uniformity to classification practices.

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Paul Bernard Rukavina

The deleterious effects of weight bias in physical activity spaces for children, adolescents, and adults are well documented. Different types of weight bias occur, and they interact at multiple levels within a person’s ecology, from the messaging of often unattainable sociocultural thin/muscular ideals and physical inequities (e.g., equipment not appropriate for body shapes and sizes) to interpersonal and public discriminatory comments. However, the most damaging is the internalization and application of negative weight-bias stereotypes by those with overweight and obesity to themselves. An imperative for social justice is now; there is great need to advocate for, provide support for, and design inclusive physical activity spaces to reduce weight bias so that all individuals feel welcome, accept their bodies, and are empowered to live a healthy, active lifestyle. To make this a reality, an interdisciplinary and preventive approach is needed to understand bias and how to minimize it in our spaces.

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Tyler M. Saumur, Jacqueline Nestico, George Mochizuki, Stephen D. Perry, Avril Mansfield, and Sunita Mathur

This study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate–derived timing measures of reactive stepping. Nineteen young, healthy adults responded to 6 perturbations using an anterior lean-and-release system. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = −.582, P = .009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = −.459, P = .048); however, this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (P > .025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.

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Kayla M. Fewster, Jackie D. Zehr, Chad E. Gooyers, Robert J. Parkinson, and Jack P. Callaghan

Background: Recent work has demonstrated that low back pain is a common complaint following low-speed collisions. Despite frequent pain reporting, no studies involving human volunteers have been completed to examine the exposures in the lumbar spine during low-speed rear impact collisions. Methods: Twenty-four participants were recruited and a custom-built crash sled simulated rear impact collisions, with a change in velocity of 8 km/h. Randomized collisions were completed with and without lumbar support. Inverse dynamics analyses were conducted, and outputs were used to generate estimates of peak L4/L5 joint compression and shear. Results: Average (SD) peak L4/L5 compression and shear reaction forces were not significantly different without lumbar support (compression = 498.22 N [178.0 N]; shear = 302.2 N [98.5 N]) compared to with lumbar support (compression = 484.5 N [151.1 N]; shear = 291.3 N [176.8 N]). Lumbar flexion angle at the time of peak shear was 36° (12°) without and 33° (11°) with lumbar support. Conclusion: Overall, the estimated reaction forces were 14% and 30% of existing National Institute of Occupational Safety and Health occupational exposure limits for compression and shear during repeated lifting, respectively. Findings also demonstrate that, during a laboratory collision simulation, lumbar support does not significantly influence the total estimated L4/L5 joint reaction force.

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Harry Beal, Jo Corbett, Danielle Davis, and Martin J. Barwood

Purpose: The Doha 2019 women’s World Championship marathon took place in extreme hot (32 °C), humid conditions (74% relative humidity) culminating in unprecedented (41%) failure rates. We explored whether extreme heat or suboptimal pacing was responsible for diminished performance against a temperate “control” (London 2017: 19 °C, 59% relative humidity) and whether physical characteristics (eg, body surface area, estimated maximal oxygen uptake, habitual heat exposure) explained performance. Method: Five-kilometer-pace (km·h−1) data underwent repeated-measures analyses of hot (Doha, n = 40) versus temperate pacing and performance (London, n = 78) within and between marathon pacing (finisher quartiles normalized against personal best; n = 10 per group) and within hot marathon finishers versus nonfinishers (up to 10 km; normalized data). Possible predictors (multiple regression) of hot marathon pacing were explored. Tests to .05 alpha level, partial eta squared (ηp2) indicates effect size. Results: Mean (SD) of Doha (14.82 [0.96] km·h−1) pace was slower (London: 15.74 [0.96] km·h−1; P = .00; ηp2=.500). In hot conditions, athletes finishing in positions 1 to 10 (group 1) started more conservatively (93.7% [2.1%] of personal best) than slower runners (groups 3 and 4; 96.6% [2.8%] of personal best; P < .05, ηp2=.303). Groups were not different at 15 km and then slowed immediately (groups 3 and 4) or after 20 km (group 2). Finishers and nonfinishers adopted similar pace up to 10 km (P > .05, ηp2=.003). World ranking predicted (P = .00; r 2 = .248) average pace in Doha. Conclusion: Extreme hot conditions reduced performance. Top 10 athletes adopted a conservative initial pace, whereas lower-placing athletes adopted a faster, aggressive start. Pacing alone does not explain high failure rates in nonfinishers. Athletes competing in the heat should initially pace conservatively to optimize performance.