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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.

Open access

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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Steven Kottaras, Joshua Stoikos, Brandon J. McKinlay, Izabella A. Ludwa, Andrea R. Josse, Bareket Falk, and Panagiota Klentrou

This study examined differences in resting concentrations of markers of bone formation and resorption, and osteokines between female adolescent (12–16 y) swimmers, soccer players, and nonathletic controls. Resting, morning blood samples were obtained after an overnight fast from 20 swimmers, 20 soccer players, and 20 nonathletic controls, matched for age. carboxyl-terminal cross-linking telopeptide of type I collagen (CTX), amino-terminal propeptide of type I collagen (P1NP), total osteocalcin (OC), sclerostin, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa B ligand (RANKL) were analyzed in serum. After controlling for percent body fat, there were no significant differences between swimmers and nonathletic controls in any of the measured markers. In contrast, soccer players had significantly higher P1NP (89.5 [25.6] ng·mL−1), OC (57.6 [22.9] ng·mL−1), and OPG (1052.5 [612.6] pg·mL−1) compared with both swimmers (P1NP: 66.5 [20.9] ng·mL−1; OC: 24.9 [12.5] ng·mL−1; OPG: 275.2 [83.8] pg·mL−1) and controls (P1NP: 58.5 [16.2] ng·mL−1; OC: 23.2 [11.9] ng·mL−1; OPG: 265.4 [97.6] pg·mL−1), with no differences in CTX, sclerostin, and RANKL. These results suggest that bone formation is higher in adolescent females engaged in high-impact sports like soccer compared with swimmers and controls.

Open access

Robert C. van de Graaf, Leonard Hofstra, and Erik J.A. Scherder

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Abigail G. Swenson, Bari A. Schunicht, Nicholas S. Pritchard, Logan E. Miller, Jillian E. Urban, and Joel D. Stitzel

Hockey is a fast-paced sport known for body checking, or intentional collisions used to separate opponents from the puck. Exposure to these impacts is concerning, as evidence suggests head impact exposure (HIE), even if noninjurious, can cause long-term brain changes. Currently, there is limited understanding of the effect of impact direction and collision speed on HIE. Video analysis was used to determine speed and direction for 162 collisions from 13 youth athletes. These data were paired with head kinematic data collected with an instrumented mouthpiece. Relationships between peak resultant head kinematics and speeds were evaluated with linear regression. Mean athlete speeds and relative velocity between athletes ranged from 2.05 to 2.76 m/s. Mean peak resultant linear acceleration, rotational velocity, and rotational acceleration were 13.1 g, 10.5 rad/s, and 1112 rad/s2, respectively. Significant relationships between speeds and head kinematics emerged when stratified by contact characteristics. HIE also varied by direction of collision; most collisions occurred in the forward-oblique (ie, offset from center) direction; frontal collisions had the greatest magnitude peak kinematics. These findings indicate that HIE in youth hockey is influenced by speed and direction of impact. This study may inform future strategies to reduce the severity of HIE in hockey.

Open access

Olli-Pekka Nuuttila, Santtu Seipäjärvi, Heikki Kyröläinen, and Ari Nummela

Purpose: To assess the reliability of nocturnal heart rate (HR) and HR variability (HRV) and to analyze the sensitivity of these markers to maximal endurance exercise. Methods: Recreational runners recorded nocturnal HR and HRV on nights after 2 identical low-intensity training sessions (n = 15) and on nights before and after a 3000-m running test (n = 23). Average HR, the natural logarithm of the root mean square of successive differences (LnRMSSD), and the natural logarithm of the high-frequency power (LnHF) were analyzed from a full night (FULL), a 4-hour (4H) segment starting 30 minutes after going to sleep, and morning value (MOR) based on the endpoint of the linear fit through all 5-minute averages during the night. Differences between the nights were analyzed with a general linear model, and intraclass correlation coefficient (ICC) was used for internight reliability assessments. Results: All indices were similar between the nights followed by low-intensity training sessions. A very high ICC (P < .001) was observed in all analysis segments with a range of .97 to .98 for HR, .92 to .97 for LnRMSSD, and .91 to .96 for LnHF. HR increased (P < .001), whereas LnRMSSD (P < .01) and LnHF (P < .05) decreased after the 3000-m test compared with previous night only in 4H and FULL. Increments in HR (P < .01) and decrements in LnRMSSD (P < .05) were greater in 4H compared with FULL and MOR. Conclusions: Nocturnal HR and HRV indices are highly reliable. Demanding maximal exercise increases HR and decreases HRV most systematically in 4H and FULL segments.