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Sport Science, Geopolitics, and How Each of Us Can Make a Difference

Jos J. de Koning, Carl Foster, David B. Pyne, Ralph Beneke, and Øyvind Sandbakk

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The Relationship of Open- and Closed-Kinetic-Chain Rate of Force Development With Jump Performance Following Anterior Cruciate Ligament Reconstruction

Megan C. Graham, Kelsey A. Reeves, Tereza Janatova, and Brian Noehren

Purpose: To determine between-limbs differences in isometric rate of force development (RFD) measured during open- (OKC) and closed-kinetic-chain (CKC) strength testing and establish which method had the strongest relationship to single-leg vertical-jump performance and knee mechanics after anterior cruciate ligament (ACL) reconstruction. Methods: Subjects (n = 19) 1 to 5 years from ACL reconstruction performed isometric knee extensions (OKC), unilateral isometric midthigh pulls (CKC), and single-leg vertical jumps on the ACL-involved and -noninvolved limbs. Between-limbs differences were assessed using paired t tests, and the relationship between RFD, jump performance, and knee mechanics was assessed using correlation coefficients (r; P ≤ .05). Results: There were significant between-limbs differences in OKC RFD (P = .008, d = −0.69) but not CKC RFD. OKC RFD in the ACL-involved limb had a strong association with jump height (r = .64, P = .003), knee-joint power (r = .72, P < .001), and peak knee-flexion angle (r = .72, P = .001). CKC RFD in the ACL-involved limb had a strong association with jump height (r = .65, P = .004) and knee-joint power (r = .67, P = .002) but not peak knee-flexion angle (r = .40, P = .09). Conclusions: While both OKC and CKC RFD were strongly related to jump performance and knee-joint power, OKC RFD was able to detect between-limbs RFD asymmetries and was strongly related to knee-joint kinematics. These findings indicate that isometric knee extension may be optimal for assessing RFD after ACL reconstruction.

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Absence of Monotony and Strain Effects on Referees’ Physical Performance During International Basketball Federation World Cup Basketball Competition

Rūtenis Paulauskas, Alejandro Vaquera, and Bruno Figueira

Purpose: The study aimed to conduct a comparative analysis of physical performance indicators and assess the levels of performance monotony and strain experienced by basketball referees. Methods: The study involved the participation of 12 basketball referees (mean age: 40.0 [4.9] y) affiliated with the International Basketball Federation. The investigation was carried out throughout 2 density tournaments, wherein the maximum heart rate, average heart rate, performance monotony, and performance strain were documented for 3 variables. Results: The findings indicated significant variations in the mean heart rate, maximum heart rate, total distance monotony, total distance strain, the total number of sprints monotony, the total number of sprints strain, calories monotony, and calories strain (P < .05). Decreasing the density of elite-level basketball competitions has been observed to reduce the monotony and strain experienced by referees. However, this action does not increase motion distance or speed zones. Conclusions: The environmental stressors experienced by senior-level athletes (World Cup) differ from those encountered by younger athletes (World Cup Under 19). Further investigation is required to ascertain the potential effects of competition monotony and strain on decision-making processes and the overall quality of refereeing.

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Erratum. Absence of Monotony and Strain Effects on Referees’ Physical Performance During International Basketball Federation World Cup Basketball Competition

International Journal of Sports Physiology and Performance

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Is the 5-Minute Time-Trial Cycling Test a Valid Predictor of Maximal Oxygen Uptake? An External Cross-Validation Study

Fernando Klitzke Borszcz, Artur Ferreira Tramontin, Ricardo Dantas de Lucas, and Vitor Pereira Costa

Purpose: This study aimed to cross-validate a recently proposed equation for the prediction of maximal oxygen uptake ( V ˙ O 2 max ) in cycling exercise by using the average power output normalized by the body mass from a 5-minute time trial (RPO5-min) as the independent variable. Further, the study aimed to update the predictive equation using Bayesian informative prior distributions and meta-analysis. Methods: On different days, 49 male cyclists performed an incremental graded exercise test until exhaustion and a 5-minute time trial on a stationary cycle ergometer. We compared the actual V ˙ O 2 max with the predicted value obtained from the RPO5-min, using a modified Bayesian Bland–Altman agreement analysis. In addition, this study updated the data on the linear regression between V ˙ O 2 max and RPO5-min, by incorporating information from a previous study as a Bayesian informative prior distribution or via meta-analysis. Results: On average, the predicted V ˙ O 2 max using RPO5-min underestimated the actual V ˙ O 2 max by −6.6 mL·kg–1·min–1 (95% credible interval, −8.6 to −4.7 mL·kg–1·min–1). The lower and upper 95% limits of agreement were −17.2 (−22.7 to −12.3) and 3.8 (−1.0 to 9.5) mL·kg–1·min–1, respectively. When the current study’s data were analyzed using the previously published data as a Bayesian informative prior distribution, the accuracy of predicting sample means was found to be better when compared with the data combined via meta-analyses. Conclusions: The proposed equation presented systematic bias in our sample, in which the prediction underestimated the actual V ˙ O 2 max . We provide an updated equation using the previous one as the prior distribution, which could be generalized to a greater audience of cyclists.

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Volume 41 (2024): Issue 2 (Apr 2024)

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Effect of Level of Competition and Drill Typology on Internal and External Load in Male Volleyball Players During the Preseason Period

Gilbertas Kerpe, Aurelijus Kazys Zuoza, and Daniele Conte

Purpose: This study aimed at evaluating the effect of level of competition and drill typology on loads during the preseason period in male volleyball players. Methods: Internal (percentage of peak heart rate [HR] and summated HR zone) and external (PlayerLoad per minute, total and high accelerations per minute [tACCmin and hACCmin], decelerations per minute [tDECmin and hDECmin], and jumps per minute [tJUMPmin and hJUMPmin]) loads were monitored across a 5-week preseason period in 12 Division 1 (age: 22.5 [3.9] y; stature: 188 [6.2] cm; body mass: 85 [11.6] kg; training experience: 9.4 [4.2] y) and 12 Division 2 (age: 20.7 [2.9] y; stature: 186 [6.2] cm; body mass: 77.8 [9.6] kg; training experience: 5.6 [2.3] y) male volleyball players. Furthermore, differences in load were assessed for each drill typology (warm-up, conditioning, technical, tactical, and integral). Results: No effects (P > .05) of level of competition on the internal (except for summated HR zone, P = .05) and external loads (except for tJUMPmin, P = .002) were found. Differently, drill typologies showed an effect (P < .001) on all the investigated internal- and external-load measures. The main post hoc results revealed higher (P < .05) percentage of peak HR, summated HR zone, PlayerLoad per minute, and tACCmin in warm-up and conditioning drills, while higher (P < .05) hDECmin and hJUMPmin were found in tactical and integral drills. Conclusions: These results suggest that volleyball coaches use warm-up and conditioning drills when aiming at increasing the internal loads, PlayerLoad per minute, and tACCmin, while tactical and integral drills should be preferred to enhance the number of hDECmin and hJUMPmin.

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Greater Psychophysiological Intensities in Conditioned Games May Impair Technical Performance: An Exploratory Study in Youth Male Soccer Players

Filipe Manuel Clemente

Purpose: The aim of this study was 2-fold: (1) to examine the relationships between psychophysiological responses and locomotor demands with variations in technical performance during 2v2 and 4v4 conditioned games and (2) to compare psychophysiological and locomotor responses among players exhibiting higher and lower technical performance levels during the conditioned games. Methods : Twenty-four male youth soccer players (16.3 ± 0.8 y old) participating at the trained/developmental level underwent monitoring for psychophysiological responses (including heart rate, rating of perceived exertion, and visual analog scale), locomotor demands (such as distance covered), and technical performance variables (including successful and unsuccessful passes and shots, as well as lost balls) across 2v2 and 4v4 formats. These formats were applied 4 times within a single session and were replicated twice over 2 weeks. Results: Large correlations between the number of lost balls per minute and mean heart rate were found in both the 2v2 and 4v4 games (r = .586 and r = .665, respectively). Successful shots were inversely and largely correlated with mean heart rate (r = −.518) in 4v4 games. The number of interceptions per minute was inversely and significantly correlated with the visual analog scale in 2v2 and 4v4 games (r = −.455 and r = −.710, respectively). The frequency of lost balls was significantly higher among players who attained a higher mean heart rate (2v2: +42.9%, P = .031, d = −0.965; 4v4: +57.1%, P < .001, d = −2.072). Conclusions: Coaches should be aware that highly psychophysiologically demanding scenarios may significantly impair technical performance. Therefore, prioritizing technical performance by deliberately adjusting the intensity should be considered.

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The Influence of Blind Tennis on Subjective Inclusion Experiences—An Ableism-Critical Analysis

Felix Oldörp, Martin Giese, and Michelle Grenier

In this paper, we analyze the subjective inclusion experiences of visually impaired (VI) adult tennis players from an ableism-critical perspective. The primary focus of this research is the inclusive potential of blind tennis from the perspective of VI individuals. Episodic interviews were conducted to capture subjective perspectives. A qualitative text analysis revealed that the interviewees were confronted with multiple ability assumptions by sighted people in their everyday lives. Deficit notions on the performance of VI people included sports, work, and general activities. Participation in blind tennis helped the interviewees build a “competent identity” and acquire various skills useful for their everyday lives as participation in blind tennis was a pathway for competence in sports. Further research is needed to identify exclusion experiences from the perspective of disabled people to recognize the potential of different sports in reducing barriers to participation.

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Volume 19 (2024): Issue 4 (Apr 2024)