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BACKGROUND: Trunk muscle thickness and brightness are associated with injuries. OBJECTIVE: This study compared trunk muscle thickness and brightness between female college athletes with and without history of low back pain. METHODS: 15 sprinters, 22 volleyball-, and 18 basketball players, all females, were included. The participants were grouped based on the presence of low back pain. Short-axis ultrasound images of the rectus abdominis, external oblique, internal oblique, transverse abdominis, and lumbar multifidus were obtained. The muscle brightness was calculated after selecting the region of interest for each muscle. Muscle thickness and brightness in both groups were compared. RESULTS: In sprinters, the right lumbar multifidus thickness was significantly thinner in the low back pain group (24.66 ± 2.98 mm) than in the healthy group (28.13 ± 2.84 mm). Volleyball and basketball players showed no significant differences in muscle thickness between the two groups for any muscle type. In volleyball players, the right transverse abdominis thickness is inclined toward thinness in the low back pain group than in the healthy group, but the difference was not significant. In all sports, there were no significant differences in muscle brightness between the two groups. CONCLUSIONS: Low back pain in female college athletes may not be related to trunk muscle thickness and brightness. [ABSTRACT FROM AUTHOR]

Purpose: This paper focuses on image-to-text manuscript processing through Handwritten Text Recognition (HTR), a Machine Learning (ML) approach enabled by Artificial Intelligence (AI). With HTR now achieving high levels of accuracy, we consider its potential impact on our near-future information environment and knowledge of the past. Design/methodology/approach: In undertaking a more constructivist analysis, we identified gaps in the current literature through a Grounded Theory Method (GTM). This guided an iterative process of concept mapping through writing sprints in workshop settings. We identified, explored and confirmed themes through group discussion and a further interrogation of relevant literature, until reaching saturation. Findings: Catalogued as part of our GTM, 120 published texts underpin this paper. We found that HTR facilitates accurate transcription and dataset cleaning, while facilitating access to a variety of historical material. HTR contributes to a virtuous cycle of dataset production and can inform the development of online cataloguing. However, current limitations include dependency on digitisation pipelines, potential archival history omission and entrenchment of bias. We also cite near-future HTR considerations. These include encouraging open access, integrating advanced AI processes and metadata extraction; legal and moral issues surrounding copyright and data ethics; crediting individuals' transcription contributions and HTR's environmental costs. Originality/value: Our research produces a set of best practice recommendations for researchers, data providers and memory institutions, surrounding HTR use. This forms an initial, though not comprehensive, blueprint for directing future HTR research. In pursuing this, the narrative that HTR's speed and efficiency will simply transform scholarship in archives is deconstructed. [ABSTRACT FROM AUTHOR]

Wet-cupping therapy (WCT) is one of the oldest known medical techniques, used as a traditional and complementary therapy with a wide application all around the world for general health. Research on the effects of WCT on sports performance are sparse and inconsistent. Thus, we aimed to explore the effects of WCT on repeated sprint ability, wellness, and exertion in young active males. Forty-nine active adult males (age: [28 ± 5] years; body height [177 ± 8] cm; body mass: [79 ± 7] kg; body mass index: [25.4 ± 1.8] kg/m²) were selected for the study. The participants performed a running-based sprint test on two separate occasions (Control and Post-WCT). WCT was performed 24 h before the testing session. They completed the Hooper questionnaire to assess their well-being (i.e., sleep, stress, fatigue, and soreness) before each session. The rating of perceived exertion (RPE) was collected after each testing session. A higher maximum power (p < 0.05, effect size [ES] = 0.6), mean power (p < 0.01, ES = 0.5) and minimum power (p < 0.01, ES = 0.6) were recorded post-WCT as compared to Control session along with a better perceived sleep (p < 0.01, ES = 0.85). Perceived stress (p < 0.01, ES = 0.6) and RPE (p < 0.001; ES = 1.1) were lower during the post-WCT compared to the Control session. The present findings demonstrated that WCT moderately enhanced repeated sprint ability and had positive effects on perceived sleep, stress, and exertion. WCT may be an effective ergogenic aid to improve repeated sprint ability and general well-being in young adult males. Future large-scale multicentric clinical studies are paramount to confirm the results of our study. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: This crossover trial compared the effects of varying feedback approaches on sprint performance, motivation, and affective mood states in female athletes. Methods: Eligibility criteria were being competitive female athletes, where participants completed sprint tests in 4 randomized feedback conditions on grass, including augmented feedback (sprint time; AUG-FB), technical feedback (cues; TECH-FB), a competition-driven drill (CDD) sprinting against an opponent, and a control condition (no feedback; CON). Participants completed a 20-m sprint (maximum sprint), 30-m curved agility sprint, and a repeated sprint ability test, with sprint times, motivation level, and mood states recorded. The participants were blinded from the number of trials during the repeated sprint ability test. Results: About 12 rugby league players completed all feedback conditions. The maximum sprint times were faster for AUG-FB (3.54 [0.16] s) and CDD (3.54 [0.16] s) compared with TECH-FB (3.64 [0.16] s), while there were no differences compared with CON (3.58 [0.17] s). The curved agility sprint times were faster for AUG-FB (5.42 [0.20] s) compared with TECH-FB (5.61 [0.21] s) and CON (5.57 [0.24] s), although CDD (5.38 [0.26] s) produced faster sprint times than TECH-FB. Effort and value were higher with AUG-FB (6.31 [0.68]; 6.53 [0.05]) compared with CON (5.99 [0.60]; 4.75 [2.07]), while CON exhibited lower enjoyment ratings (4.68 [0.95]) compared with other feedback conditions (AUG-FB: 5.54 [0.72]; CDD: 5.56 [0.67]; TECH-FB: 5.60 [0.56]). Conclusions: Providing AUG-FB prior to sprint tasks enhances more immediate performance outcomes than TECH-FB. AUG-FB also benefited athlete enjoyment, task effort, and coaching value. Female athletes should receive AUG-FB in testing and training environments, to improve immediate physical performance and motivation. [ABSTRACT FROM AUTHOR]

Purpose: Submaximal sprinting allows for larger accumulated work to be reached before the onset of fatigue, compared with maximal efforts. The aim of this study was to investigate the effect of sprint running at 90% to 95% of maximal velocity (Vmax) on sprint performance. Methods: Recreationally active adults were randomly assigned into a control group (n = 12, 27 [5] y, 172 [9] cm, 72 [15] kg) and a training group (n = 14, 26 [4] y, 171 [9] cm, 69 [11] kg). Both groups completed pretesting and posttesting in form of a 30-m sprint separated by a 6-week period. The training group performed a weekly sprint-training session consisting of 30-m flying sprints at 90% to 95% of Vmax, while the control group performed no intervention training. Results: Significant improvements in the training group were observed for 10- (P =.003), 20- (P =.001), and 30-m sprint time (P =.002). These improvements were accompanied by higher step rate (P =.006) and theoretical Vmax (P =.007) and maximal power (P =.004). Significant between-groups differences were observed for 10- (P =.008), 20- (P <.001), and 30-m sprint time (P <.001), as well as for step rate (P =.015), theoretical Vmax (P =.016), and maximal power (P =.008). All within- and between-groups differences were in the range of trivial to small. Conclusion: Sprint running at 90% to 95% of Vmax can enhance 10- to 30-m sprint performance in recreationally active adults. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this systematic review was to (1) determine the muscle fiber-type composition (or muscle fiber typology [MFT]) of team-sport athletes and (2) examine associations between MFT and the physical characteristics and performance tasks in team-sport athletes. Methods: Searches were conducted across numerous databases—PubMed, SPORTDiscus, MEDLINE, and Google Scholar—using consistent search terms. Studies were included if they examined the MFT of team-sport athletes. Included studies underwent critical appraisal using the McMasters University critical appraisal tool for quantitative research. Results: A total of 10 studies were included in the present review, wherein the MFT of athletes was measured from 5 different team sports (soccer, rugby union, rugby league, handball, and volleyball). There was large variability in the MFT of team-sport athletes both within (up to 27.5%) and between sports (24.0% relative difference). Male football players with a higher proportion of type II fibers had faster 10- and 30-m sprint times, achieved a greater total distance sprinting (distance at >6.67 m·s−1), and a greater peak 1-minute sprint distance. Conclusions: MFT varies considerably between athletes both within and between different team sports. The results from some studies suggest that variation in MFT is associated with high-intensity running performance in a football match, as well as 10- and 30-m sprint times. Further experimental studies should focus on how determination of the MFT of team-sport athletes could be utilized to influence talent identification, team selection, and the individualization of training. [ABSTRACT FROM AUTHOR]

Purpose: Although recommendations for effective heat acclimation (HA) strategies for many circumstances exist, best-practice HA protocols specific to elite female team-sport athletes are yet to be established. Therefore, the authors aimed to investigate the effectiveness and retention of a passive HA protocol integrated in a female Olympic rugby sevens team training program. Methods: Twelve elite female rugby sevens athletes undertook 10 days of passive HA across 2 training weeks. Tympanic temperature (TTymp), sweat loss, heart rate, and repeated 6-second cycling sprint performance were assessed using a sport-specific heat stress test Pre-HA, after 3 days (Mid-HA), after 10 days (Post-HA), and 15 days post-HA (Decay). Results: Compared with Pre-HA, submaximal TTymp was lower Mid-HA and Post-HA (both by −0.2 [0.7] °C; d ≥ 0.71), while resting TTymp was lower Post-HA (by −0.3 [0.2] °C; d = 0.81). There were no differences in TTymp at Decay compared with Pre-HA, nor were there any differences in heart rate or sweat loss at any time points. Mean peak 6-second power output improved Mid-HA and Post-HA (76 [36] W; 75 [34] W, respectively; d ≥ 0.45) compared with Pre-HA. The observed performance improvement persisted at Decay by 65 (45) W (d = 0.41). Conclusions: Ten days of passive HA can elicit some thermoregulatory and performance benefits when integrated into a training program in elite female team-sport athletes. However, such a protocol does not provide a sufficient thermal impulse for thermoregulatory adaptations to be retained after 15 days with no further heat stimulus. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on strength, power, speed, and leg stiffness (Kleg) in rugby league players during a 6-week mesocycle. Methods: Twenty-four rugby league players competing in the British University and Colleges Sport Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (CON; n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk) that involved alternating high-load resistance exercise with plyometric exercise within the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Back-squat 1RM, countermovement jump peak power, reactive strength index, sprint times, and Kleg were assessed pretraining and posttraining. Results: VRCT and TCT significantly improved 1RM back squat, countermovement jump peak power, and 5-m sprint time (all P <.05). VRCT also improved Kleg, whereas TCT improved 10- and 20-m sprint times (all P <.05). Between groups, both VRCT and TCT improved 1RM back squat compared with CON (both P <.001). Additionally, VRCT improved Kleg compared with CON (right leg: P =.016) and TCT improved 20-m sprint time compared with CON (P =.042). Conclusions: VRCT and TCT can be implemented during the competitive season to improve strength, power, and 5-m sprint time. VRCT may lead to greater improvements in reactive strength index and Kleg, whereas TCT may enhance 10- and 20-m sprint times. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate changes in physical performance indicators after executing a flywheel or machine-based neuromuscular training program in young female tennis players. Methods: Twenty-four players were divided into a machine-based group (MG), flywheel group (FG), and control group. Countermovement jump (CMJ), sprint time (5, 10, and 15 m), change-of-direction (COD) performance (right and left), medicine-ball throws (overhead, forehand, and backhand), and serve velocity were included as tests at baseline, week 4, and week 8. Results: Both MG and FG largely improved from baseline to weeks 4 and 8 of training in CMJ (11.6, 10.6%; effect size [ES] = 1.24, 1.95). Also, sprint time 5 m and 10 m, COD performance-right, and COD performance-left improved moderately to very largely at week 4 in MG (−5.0% to −6.2%; ES = −1.79 to −4.19) and FG (−2.9% to −5.1%; ES = −1.13 to −1.64), respectively. Regarding medicine-ball throw, only FG improved moderately to very largely from weeks 4 to 8 in overhead (9.3%; ES = 1.46), forehand (8.0%; ES = 1.08), and backhand (6.1%; ES = 1.15). Serve velocity improved moderately from weeks 4 to 8 in MG (5.8%; ES = 0.87). Conclusions: Four weeks of the tested programs seem sufficient to improve physical determinants in young female participants. Greater improvements in CMJ and medicine-ball throw following flywheel neuromuscular training indicate the importance of including exercises that emphasize the stretch-shortening cycle and involve the entire kinetic chain. Performing the same intervention with no load adjustments may stall or even decrease performance in some parameters from weeks 4 to 8. [ABSTRACT FROM AUTHOR]

Purpose: To compare the acute performance and psychophysiological responses of repeated cycling sprints to exhaustion with a short exercise-to-rest ratio (1:6), between different effort durations and inspired oxygen fractions. Methods: On separate visits, 10 active participants completed 6 repeated cycling sprint exercises to exhaustion with 3 different effort durations (5, 10, and 20 s) and 2 conditions of inspired oxygen (20.9% and 13.6%). Exercise-to-rest ratio was 1:6 for all trials (ie, 5:30, 10:60, and 20:120). Vastus lateralis muscle oxygenation (near-infrared spectroscopy), blood lactate concentration, and lower-limb and breathing discomfort, using ratings of perceived exertion, were measured. Results: Number of sprints and peak power output decreased while blood lactate increased (all P <.001) during 5:30 compared with 10:60 or 20:120. No condition or interaction effects were reported for blood lactate and exercise-related sensation. Muscle deoxyhemoglobin increased (P <.001) and total hemoglobin decreased (P =.002) during sprint with increasing sprint duration (no condition or interaction). Conclusion: During repeated-sprint exercise to exhaustion with a short exercise-to-rest ratio, the psychophysiological responses did not differ between normoxia and moderate hypoxia, probably due to an extended recovery period. It means that hypoxia did not modify repeated-sprint exercise performance with a short exercise-to-rest ratio. The sprint duration was the primary underlying factor of the observed differences in performance and muscle oxygenation reported between the repeated-sprint exercise sessions. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed the cardiorespiratory capacity, anaerobic speed reserve, and anthropometric and spatiotemporal variables of a 75-year-old world-class middle-distance runner who previously obtained several European and world records in the age categories of 60–70 years, achieved 13 European titles and 15 world champion titles, and also holds several European records for the 75-year-old category. Methods: Heart rate, oxygen uptake, carbon dioxide production, ventilation, step frequency, contact time, and velocity at maximal oxygen uptake (VO2max) were measured during treadmill running. Maximal sprinting speed was assessed during track sprinting and used to compute anaerobic speed reserve. Body fat percentage was assessed using air displacement plethysmography. Results: Body fat percentage was 8.6%, VO2max was 50.5 mL·kg−1·min−1, maximal ventilation was 141 L·min−1, maximum heart rate was 164 beats·min−1, maximum respiratory exchange ratio was 1.18, and velocity at VO2max was 16.7 km·h−1. The average stride frequency and contact time during the last 30 seconds of the 4-minute run at 10 km·h−1 were 171 steps·min−1 and 241 ms and 187 steps·min−1 and 190 ms in the last 40 seconds at 17 km·h−1, respectively. The anaerobic speed reserve was 11.4 km·h−1, corresponding to an anaerobic speed reserve ratio of 1.68. Conclusion: This 75-year-old runner has an exceptionally high VO2max and anaerobic speed reserve ratio. In addition, his resilience to injuries, possibly due to a relatively high volume of easy runs, enabled him to sustain regular training since his 50s and achieve international performance in his age group. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to analyze the effects of plyometric training direction on jumping, sprinting, and change-of-direction ability in basketball players. Methods: Forty male basketball players (21.8 [3.8] y), from 4 teams that competed in regional and national championships, were randomly assigned to 1 of 4 groups: (1) vertical jump group, (2) horizontal jump group, (3) vertical and horizontal jump group, and (4) control group. The subjects followed a plyometric training program twice a week for 6 weeks, differing in the execution direction of the jumps. All groups performed the same total training volume of acyclic and cyclic jumps controlled through the number of contacts per session. Pretraining and posttraining measurements included (1) rocket jump, (2) Abalakov jump, (3) horizontal jump, (4) 20-m linear sprint, and (5) V-Cut change-of-direction test. Results: The vertical and horizontal jump group showed significant increases in all performance variables examined, except for linear sprint performance, in which no group improved. The vertical jump group showed significant improvements in rocket jump and Abalakov jump (P <.01), but worsened significantly in terms of sprint performance (P <.05). The horizontal jump group showed significant increases in rocket jump and horizontal jump (P <.001–.01). Furthermore, all experimental groups showed improved V-Cut change-of-direction test performance. Conclusions: These results indicate that combining vertical and horizontal jumps induces improvements in more capabilities than does training only vertical or horizontal jumps with the same training volume. Training only vertical or horizontal jumps will improve performance mainly in vertically or horizontally oriented tasks, respectively. [ABSTRACT FROM AUTHOR]

Purpose: Muscle power is a component of muscular fitness and is proportional to its volume. Reduced muscular fitness in children is linked to negative health outcomes. Associations between muscle volume (MV) and power have not been examined in young children and could reveal important insights into early neuromuscular development. Method: Forty-four children (2-8 y) completed 3 tests of short-term muscular power: repeated anaerobic sprint test, vertical jump, and horizontal jump. MV was assessed using 3D ultrasound for 3 lower limb muscles (rectus femoris, medial gastrocnemius, and tibialis anterior) and summed for across legs. Associations between muscular power and summed MV were assessed using Pearson correlation (r). Sex-based differences in muscular power and MV were assessed using 1-way analysis of covariance. Results: Moderate-strong associations (r =.57 - .87) were found between muscular power and summed MV. No differences were found between boys and girls for height, weight, MV, or muscular power. Conclusions: Young children who have larger lower limb muscles perform better at tasks dependent on short-term muscular power, such as running and jumping, compared with children with smaller muscles. Sex-based differences in short-term muscular power do not exist in young children and reflect similar anthropometry, including lower limb MV. [ABSTRACT FROM AUTHOR]

Resisted and assisted training methods aim to increase neural activation, or post-activation potentiation (PAP), to enhance sprint performance. A preloaded stimulus causes a temporary performance increase that is more significant than what warm-up alone can provide. Resistance activities have traditionally been used to induce post-activation potentiation. Little is known when assisted and resisted sprints are combined and their effect on PAP. Therefore, this study aimed to examine the acute potentiating effect of combined resisted and assisted sprints on subsequent 20 m sprint performance. Sixteen physically active young males performed a baseline 20 m sprint followed by four assisted 20 m and four 20 m resisted sprints using a bungee cord. After the assisted-resisted stimulus, the participants performed one 20 m sprint at 4, 6, and 8 minutes. There was no significant improvement in 5, 10, or 20-m sprint times following the assisted-resisted stimulus. Therefore, the additive effect of assisted-resisted sprints failed to induce post-activation potential. The additive effect of assisted-resisted sprints could not induce post-activation potential to enhance subsequence sprint performance.

Organizations creating software commonly utilize software development lifecycles (SDLCs) to structure development activities. Secure development lifecycles (SDLs) integrate into SDLCs, adding security or compliance activities. They are widely used and have been published by industry leaders and in literature. These SDLs, however, were mostly designed before or while cloud services and other hosted solutions became popular. Such offerings widen the provider's responsibilities, as they not only deliver software but operate and decommission it as well. SDLs, however, do not always account for this change. Security maturity models (SMMs) help to assess SDLs and identify improvements by introducing a baseline to compare against. Multiple of these models were created after the advent of hosted solutions and are more recent than commonly referenced SDLs. Recent SMMs and SDLs may therefore support hosted solutions better than older proposals do. This paper compares a set of current and historic SDLs and SMMs in order to review their support for hosted solutions, including how support has changed over time. Security, privacy, and support for small or agile organizations are considered, as all are relevant to hosted solutions. The SDLs analyzed include Microsoft's SDL, McGraw's Touchpoints, the Cisco's SDL, and Stackpole and Oksendahl's SDL2. The SMMs reviewed are OWASP's Software Assurance Maturity Model 2 and DevSecOps Maturity Model. To assess the support for hosted solutions, the security and privacy activities foreseen in each SDLC phase are compared, before organizational compatibility, activity relevance, and efficiency are assessed. The paper further demonstrates how organizations may select and adjust a suitable proposal. The analyzed proposals are found to not sufficiently support hosted solutions: Important SDLC phases, such as solution retirement, are not always sufficiently supported. Agile practices, such as working in sprints, and small organizations are often not sufficiently considered as well. Efficiency is found to vary based on the application context. A clear improvement trend from before the proliferation of hosted solutions cannot be identified. Future work is therefore found to be required. [ABSTRACT FROM AUTHOR]

Background: While several clinical factors have independently been linked to anterior cruciate ligament (ACL) injury risk factors, their collective impact on knee loading during the sidestep maneuver is unknown. To better understand these factors, we assessed the relationship between strength, balance, and sprint kinetics and external knee abduction moments during sidestepping on each leg. Methods: Sixteen male academy-level rugby union athletes (age, 20 ± 3 years; body-height, 186 ± 9 cm; body-mass, 99 ± 14 kg) were bilaterally assessed in single-leg: isokinetic concentric and eccentric knee and concentric hip strength, balance at 2 difficulty levels, vertical and horizontal force production during maximal sprinting, and 3-dimensional motion capture while sidestepping on the preferred and non-preferred leg. A hierarchical multiple regression analysis based on this theoretical approach of the mechanics of ACL injury risk was performed. Results: When sidestepping on the preferred leg, larger abduction moments were explained by less concentric hip extension strength and vertical force production during maximal sprinting (R 2 = 41%; ES = 0.64); when sidestepping on the non-preferred leg, larger abduction moments were explained by more concentric hip flexion strength (R 2 = 8%; ES = 0.29). Larger symmetry scores between the legs (representing greater abduction moments) were explained by more horizontal force production during maximal sprinting and less eccentric knee flexion strength (R 2 = 32%; ES = 0.56). Conclusions: Independently, the preferred and non-preferred legs contribute to increased knee abduction moments via unique distributions of strength and/or sprint kinetics. The allocations of strength and sprint kinetics appear interrelated through weaker posterior muscular strength and may be modifiable through a targeted strength training approach. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the non-linear evolution of position-specific physical and technical performance indicators across different tactical formations in the Chinese Super League (CSL) from the 2015 to the 2021 seasons. Match data were collected from 800 games played in six common formations (3-5-2, 4-3-3, 4-2-3-1, 4-4-2, 3-4-3, and 4-1-4-1). Players were classified into five positions: central defenders (CD; match observations = 2,219), fullbacks (FB; match observations = 2,060), central midfielders (CM; match observations = 2,786), wide midfielders (WM; match observations = 1,587), and forwards (FW; match observations = 1,680). Generalized additive models (GAMs) were constructed to analyze the nonlinear evolution trends in position-specific physical and technical performance across seasons and formations. The results showed that the total distance covered by CDs in the 3-5-2 formation showed a non-linear upward trend from the 2015 to 2021 seasons (R2 = 0.3, p = 0.006); FBs in the 3-4-3, 4-1-4-1, and 3-5-2 formations exhibited non-linear upward trends in number of sprints and sprint distance from the 2015 to 2021 seasons (R2 = 0.189–0.448; P < 0.03, respectively); the high-speed running of FWs in the 4-2-3-1 formation displayed a non-linear decline trend from the 2015 to 2021 seasons (R2 = 0.477; P < 0.001); CMs in the 4-2-3-1 formation demonstrated a non-linear increasing trend in the ball retention percentage (R2 = 0.369; p = 0.001); WMs in the 4-4-2 formation showed a non-linear decreasing trend in ball retention percentage and passes from the 2015 to 2021 seasons (R2 = 0.259–0.29; P = 0.006, respectively). These findings revealed non-linear evolutionary trends in physical and technical performances across positions and formations, providing an in-depth understanding of the changing match demands placed on players during matches. This enables the optimization of training and tactics by developing targeted strategies tailored to meet the specific requirements of different formations and playing positions. [ABSTRACT FROM AUTHOR]

This study aimed to elucidate the impact of combining Beta-Alanine (BA) supplementation with short sprint interval training on cardiorespiratory fitness, anaerobic power, and bio-motor abilities in volleyball players. Twenty young male athletes were randomly divided into 2 equal groups and performed 8 weeks of short sprint interval training while supplementing 4.8 g daily BA or placebo (polydextrose). The players were evaluated for volleyball-specific bio-motor abilities (vertical jump, horizontal jump, spike jump, block jump, 10-m linear sprint, and T-test change of direction speed) and physiological parameters (cardiorespiratory fitness and anaerobic power) pre- and post-intervention. Both groups demonstrated significant (p ≤ 0.05) improvements in all measured variables over time. A time-regimen interaction was observed in jumping ability enhancement from pre- to post-training, wherein BA elicited more significant changes in both vertical and horizontal jumps compared to the placebo. Analyzing residuals in changes and the coefficient of variations (CV) in mean group changes demonstrated that BA supplementation results in uniformly inducing adaptive changes among individuals. Therefore, in light of these results, it is recommended that coaches and trainers take into consideration the utilization of BA as an ergogenic aid to enhance the vertical and horizontal jumps of volleyball players and increase the homogeneity in adaptive responses over the training period. [ABSTRACT FROM AUTHOR]

Purpose: Very low intensity endurance training (LIT) does not seem to improve maximal oxygen uptake. The purpose of the present study was to investigate if very high volume of LIT could compensate the lack of intensity and is LIT affecting differently low and high intensity performances. Methods: Recreationally active untrained participants (n = 35; 21 females) cycled either LIT (mean training time 6.7 ± 0.7 h / week at 63% of maximal heart rate, n = 16) or high intensity training (HIT) (1.6 ± 0.2 h /week, n = 19) for 10 weeks. Two categories of variables were measured: Low (first lactate threshold, fat oxidation at low intensity exercise, post-exercise recovery) and high (aerobic capacity, second lactate threshold, sprinting power, maximal stroke volume) intensity performance. Results: Only LIT enhanced pooled low intensity performance (LIT: p = 0.01, ES = 0.49, HIT: p = 0.20, ES = 0.20) and HIT pooled high intensity performance (LIT: p = 0.34, ES = 0.05, HIT: p = 0.007, ES = 0.48). Conclusions: Overall, very low endurance training intensity cannot fully be compensated by high training volume in adaptations to high intensity performance, but it nevertheless improved low intensity performance. Therefore, the intensity threshold for improving low intensity performance is lower than that for improving high intensity performance. Consequently, evaluating the effectiveness of LIT on endurance performance cannot be solely determined by high intensity performance tests. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the morphometric features affecting 20-m sprint performance in children at the first level of primary education using machine learning (ML) algorithms. In this study, 130 male and 152 female volunteers aged between 6 and 11 years were included. After obtaining demographic information of the participants, skinfold thickness, diameter and circumference measurements, and 20-m sprint performance were determined. The study conducted three distinct experiments to determine the optimal ML technique for predicting outcomes. Initially, the entire feature space was utilized for training the ML models to establish a baseline performance. In the second experiment, only significant features identified through correlation analysis were used for training and testing the models, enhancing the focus on relevant predictors. Lastly, Principal Component Analysis (PCA) was employed to reduce the feature space, aiming to streamline model complexity while retaining data variance. These experiments collectively aimed to evaluate different feature selection and dimensionality reduction techniques, providing insights into the most effective strategies for optimizing predictive performance in the given context. The correlation-based selected features (Age, Height, waist circumference, hip circumference, leg length, thigh length, foot length) has produced a minimum Mean Squared Error (MSE) value of 0.012 for predicting the sprint performance in children. The effective utilization of correlation analysis in the selection of relevant features for our regression model suggests that the features selected exhibit robust linear associations with the target variable and can be relied upon as predictors. [ABSTRACT FROM AUTHOR]

This document discusses the use of wearable and portable devices in sport biomechanics and training science. It highlights the limitations of traditional laboratory testing and the benefits of using wearable devices for more ecologically valid assessments. The document features twelve original articles and a systematic review that cover various topics such as biomechanical changes in running shoes, metabolic power and energy cost in sprinting, assessment of torque-velocity profile in cycling, motor development and training, reliability of wearable systems, effects of pressurization modes on muscle activation, real-time monitoring in fencing, thermoregulation in athletes, and the discriminatory power of physical tests. The document concludes that wearable devices offer valuable insights into sports biomechanics and training science, particularly for real-time monitoring and biofeedback. [Extracted from the article]

This study aimed to quantify the influence of the playing surface on workload-related variables (i.e., external load, Rate of perceived exertion (RPE), and mental load) in training sessions with a Spanish professional soccer team. Twenty professional male players from the same soccer team were involved. A total of thirty training sessions related to the preseason period were included. All the players completed training sessions on three playing surfaces: natural turf of poor quality, natural turf of high quality, and third-generation artificial turf. Monitoring during sessions involved assessing internal load (i.e., RPE and mental load) via self-reported questionnaires, and external load using Global Positioning System devices. Linear mixed models showed that RPE was significantly higher on natural turf of high quality than on natural turf of poor quality (p < 0.001). Total distance, relative total distance, the number of accelerations, decelerations, and high metabolic load distance were significantly lower on third-generation artificial turf compared to natural turf of poor quality (p < 0.001) and high quality (p < 0.001). In addition, high-speed running, sprint running distances, and the number of sprints reached higher values on third-generation artificial turf compared to the other two playing surfaces. These findings highlight the need for coaches to consider the type of training surface in soccer to optimize training load planning and prevent injuries. [ABSTRACT FROM AUTHOR]

Practitioners place importance on high-speed running (HSR) to monitor training practice and match-play demands, whilst attempting to maximise fitness and minimize the risk of injury occurrence. Practitioners apply various methods to quantify HSR, such as absolute thresholds, percentage of maximum sprint speed and maximal aerobic speed (MAS). A recent survey demonstrates the 5-minute run and 1200m shuttle test (ST) to be implemented among rugby league practitioners to quantify HSR by incorporating MAS. However, it is unclear as to how valid these methods are to accurately quantify MAS. Therefore, the aim of this study was to assess the validity of the 5-minute run and 1200m ST when compared to a gold standard measure for MAS. Twenty 1st team professional rugby league players competing in the European Super League participated in this study. Players were required to complete an incremental treadmill test, 5-minute run and 1200m ST over a two-week period in pre-season. MAS, peak heart rate (HRmax), peak lactate (Lapeak) and rating of perceived exertion (RPE) where collected upon completion of each test. Results demonstrated the 1200m ST to have a higher correlation for MAS than the 5-minute run (1200m ST: r = 0.73, 5-minute run: r = 0.64). However, when assessing validity using the level of agreement between data, the 5-minute run underreported MAS by 0.45 m·s-1 whereas the 1200m ST underreported MAS by 0.77 m·s-1. Ultimately, both field-based tests used in this study underreport MAS when compared to an incremental treadmill test, although the 5-minute run provides a closer agreement and therefore a more valid measurement for MAS than the 1200m ST. [ABSTRACT FROM AUTHOR]

Combining traditional resistance and ballistic exercises in a complex training (CT) format has shown improved physical fitness compared to the control conditions. However, no meta-analysis has directly compared CT with traditional resistance training (RT) alone. A systematic search was conducted in PubMed, Scopus, and WoS. Thirty-two studies involving 726 participants were included. Both RT and CT similarly improved one-repetition maximum (1RM) squat and bench press, 10 m and 30–60 m linear sprint time, squat jump height, jump power, reactive strength index, and standing long jump distance. Compared to RT, CT favoured 5-m (ES = 0.96) and 20-m linear sprint (ES = 0.52), change-of-direction speed (CODS; ES = 0.39), and countermovement jump height (CMJ; ES = 0.36). Furthermore, moderating effects of training frequency, duration, and complex training type were reported. Certainty of evidence was considered low for 5-m and 20-m linear sprints and CODS and very low for other outcomes. Compared to traditional resistance training, complex training may improve 5-m and 20-m linear sprints, CODS, and CMJ height. The effects of complex training may be optimised by longer interventions (≥7 weeks), with ~ 3 weekly training sessions, and using ascending and contrast training formats. However, the certainty of evidence ranges from very low to low. [ABSTRACT FROM AUTHOR]

The greater muscle fiber cross-sectional area (CSA) is associated with greater skeletal muscle mass and strength, whereas muscle fiber atrophy is considered a major feature of sarcopenia. Muscle fiber size is a polygenic trait influenced by both environmental and genetic factors. However, the genetic variants underlying inter-individual differences in muscle fiber size remain largely unknown. The aim of our study was to determine whether 1535 genetic variants previously identified in a genome-wide association study of appendicular lean mass are associated with the CSA of fast-twitch muscle fibers (which better predict muscle strength) in the m. vastus lateralis of 148 physically active individuals (19 power-trained and 28 endurance-trained females, age 28.0 ± 1.1; 28 power-trained and 73 endurance-trained males, age 31.1 ± 0.8). Fifty-seven single-nucleotide polymorphisms (SNPs) were identified as having an association with muscle fiber size (p < 0.05). Of these 57 SNPs, 31 variants were also associated with handgrip strength in the UK Biobank cohort (n = 359,729). Furthermore, using East Asian and East European athletic (n = 731) and non-athletic (n = 515) cohorts, we identified 16 SNPs associated with athlete statuses (sprinter, wrestler, strength, and speed–strength athlete) and weightlifting performance. All SNPs had the same direction of association, i.e., the lean mass-increasing allele was positively associated with the CSA of muscle fibers, handgrip strength, weightlifting performance, and power athlete status. In conclusion, we identified 57 genetic variants associated with both appendicular lean mass and fast-twitch muscle fiber size of m. vastus lateralis that may, in part, contribute to a greater predisposition to power sports. [ABSTRACT FROM AUTHOR]

The aims of this study were to determine the effect of different compositions in transition games (TGs) on the load of soccer players and to evaluate their performance in physical tests. Using a GPS system, 18 players were monitored during: 3vs2, 2vs1 and 1vs1. Distance covered (DC), DC 18–20.9 km·h-1 , 21–23.9 km·h-1 ,>24 km·h-1 , peak speed, accelerations (Acc) and decelerations (Dec)>1.0 m·s-2 and>2.5 m·s-2 and rate of perceived exertion (RPE) were recorded. Before and after each TG, countermovement-jump (CMJ), 15- (S15) and 30 m (S30) speed tests were assessed. TG3vs2 showed greater DC and Dec>1.0 m·s-2 than TG2vs1 , and DC, DC 18.0–23.9 km·h-1 , Acc>1.0 m·s-2 and Dec>2.5 m·s-2 than TG1vs1 (p <0.01). TG2vs1 achieved higher DC, DC 18.0–23.9 km·h-1 , and Acc>2.5 m·s-2 (p <0.01) but lower peak speed (p =0.02) and RPE (p =0.02) than TG1vs1. Post-intervention, TG1vs1 showed lower CMJ and higher S15 (p =0.02), while TG3vs2 , showed improvements in CMJ (p <0.01). The three tasks showed large variations for DC>24 km·h-1 , Acc>1.0 m·s-2 , Dec>1.0 m·s-2 and Dec>2.5 m·s-2. The load of TGs is sensitive to their player composition. [ABSTRACT FROM AUTHOR]

This study investigated the reliability and validity of linear sprint tests (LS) and curvilinear sprint tests (CS) using a GPS device (GPEXE lt). Twenty-one (21) student athletes completed a 40 m LS as well as a left and right CS. Maximum sprint speed (MSS) and split times at short (0–10 m), intermediate (0–20 m), and long (0–30 m) distances were determined using the GPEXE lt and single-beam timing gates (TG). Intrasession reliability and concurrent validity of GPEXE lt were assessed. The GPEXE lt consistently showed high reliability for MSS (ICC ≥ 0.95; CV ≤ 1.8%), despite underestimation compared to TG (bias = −2.57 to −0.95%; ICC ≥ 0.87). Acceptable reliability was observed for CS and LS intermediate and long distance split times (ICC ≥ 0.91; CV ≤ 2.1%), with lower reliability for short distances (ICC ≥ 0.70; CV ≤ 3.6%). The GPEXE lt split times for CS and LS showed good agreement with TG (ICC ≥ 0.66), but were overestimated at long distances (5.5–9.7%) and short distances (11.1–14.6%). Although the MSS was found to be the most reliable and valid variable to assess LS and CS speed performance with GPEXE lt, caution is needed due to limited validity. [ABSTRACT FROM AUTHOR]

The Force-velocity (F-v) and Power-velocity (P-v) relationships quantify athlete’s horizontal force production capacities during sprinting. Efforts are underway to enhance ecological validity for practitioners and sports coaches. This study provides detailed data comparison of a low frames per second setup (30 Hz; FPSlow) with splits from a high FPS camera to derive F-v and P-v relationships. Sixty-six sprints performed by 11 university track and field athletes (6 male, 5 female) were evaluated. Data were recorded using FPSlow, photocells, and a high-speed camera (240 Hz; MySprint). In the FPSlow setup, bias was 0.17s, and Limits of agreement was 0.09s compared to photocells. ICC was 1.00, and the coefficient of variation (CV) was 1.0% [0.8–1.1%]. Time acquisition comparison between MySprint and FPSlow setups revealed high consistency (ICC = 0.99) and low CV (2.9% [2.8–3.1%]). F-v profile variables exhibited biases from trivial to small, with ICC ranging from moderate to nearly perfect. CV ranged from 2.7% to 11.8%, and improved using the average of three sprints (CV between 1.8% and 8.6%). The ‘simple method’ applied to data from the low FPS video setup yielded kinetic and kinematic parameters comparable to those obtained by the validated previous method and photocells. [ABSTRACT FROM AUTHOR]

Background: The varied position of squatting involves bending the knees and hips while maintaining the body's weight on the feet. Variations of used tools in squat and angles of joints affect the neuromuscular activity of the muscles. The muscles in the lower limbs are crucial for maintaining a good gait as well as for doing various exercises like jumping and sprinting. Objective: This study aimed to investigate how the inclination of ankle joint affects the activity of gluteus medius (GMed) and gastrocnemius (GC) muscles. Methods: Thirty normal children were included in this study. Two wooden wedges covered by rubber with inclination angles 5 and 10 degrees were used. To examine the muscle activity of the GMed and GC, a comparison analysis with electromyography was conducted. Results: The muscle activity of GMed and GC muscles increased with increased the angle of inclination. When squatting on 5 degrees inclined board, the muscle activity of both muscles was significantly higher than during squatting on the ground, and when squatting on 10 degrees inclined board, the muscles activity was significantly higher than squatting on 0 and 5 degrees inclination. Conclusion: Squatting on an incline board is a good position for increasing muscle activation in the GMed and GC. [ABSTRACT FROM AUTHOR]

Background. Recognizing the significance of maturity-related adaptations is imperative for specialists and coaches when designing training regimens to nurture long-term athlete development. Objective. This study aims to explore how both chronological age and maturity status influence anthropometric measurements and physical performance in elite youth male soccer-players. Additionally, our goal is to establish percentile values for anthropometric variables and physical performance across different maturity groups. Methods. Two-hundred-eighty-seven soccer-players aged between 12-17 years participated in this study. Anthropometric measurements, including leg-muscle-volume (LMV), along with soccer-specific-physical-performances (SPP) such as Squat-Jump (SJ), Countermovement-Jump (CMJ), sprinting performances, and intermittent-endurance tests were assessed. Players were categorized into age groups (U12 to U17) and six maturational groups based on their maturity offset, ranging from -2.5 to +2.5 years. Results. Significant differences (p < 0.05) were observed in anthropometric variables and SPP among different maturity groups. Body mass, leg length, and leg muscle volume exhibited consistent changes across consecutive maturity groups. Notably, jumping performances, particularly CMJ/SJ, were significantly influenced by maturity status, showing a progression of changes from -0.5 to +0.5 maturity groups for CMJ and from -0.5 to +0.5 maturity groups for SJ. Similarly, sprinting performances were significantly affected by maturity status, particularly in the -1.5 maturity group. Conclusions. Our findings highlight the significant role of growth and peak height velocity (PHV) in the anthropometric development and SPP potential of youth soccer players. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine physiological and metabolic responses to two different sprint interval exercises (SIE) matched for total sprint duration and sprint-rest ratio. Methods: After having measured peak oxygen uptake (...), 14 healthy males (27.1 ± 4.8 yr, 169.6 ± 6.0 cm, 64.5 ± 8.4 kg, ... 47.2 ± 7.7 mL⋅kg-1⋅min-1) performed four 10-s sprints with 80-s recovery (SIE10) and two 20-s sprints with 160-s recovery (SIE20) on different occasions in a counterbalanced crossover manner. Pulmonary ... and changes in tissue oxygenation index (ΔTOI) at vastus lateralis (VL) and rectus femoris (RF) were measured during the SIE. Furthermore, T2-weighted magnetic resonance imaging was taken immediately before and after the SIE to determine the activation levels of VL, RF, vastus medialis, vastus intermedius, adductor magnus, biceps femoris long head, semitendinosus, and semimembranosus at 50% of right thigh length. Results: In SIE10, increases in ... and ΔTOI at VL and RF plateaued after the second sprint, whereas session-averaged ΔTOI was greater in SIE20 than SIE10 in both muscles (VL: 20.9 ± 7.4 vs 14.2% ± 5.9%, RF: 22.8 ± 9.3 vs 12.9% ± 6.6%, P = 0.00). Although both SIE significantly increased T2 values in all eight muscles, those magnitudes were similar between the conditions (SIE10 vs SIE20: 5%-16% vs 8%-16%). Conclusions: This study showed blunted responses of whole-body (...) and peripheral (ΔTOI) oxidative responses with successive sprints (sprint 1 < sprints 2-4) in SIE10, suggesting that increasing sprint repetitions does not necessarily induce greater oxidative metabolism or stimulus. Moreover, greater peripheral oxygen extraction (ΔTOI) was achieved with SIE20, whereas %changes of T2 indicates that the thigh muscles were similarly activated between the SIE conditions. [ABSTRACT FROM AUTHOR]

To examine the effects of 7-days juçara powder (JP) intake on oxidative stress biomarkers and endurance and sprint cycling performances. In a randomized, placebo-controlled, crossover, and triple-blind study, 20 male trained cyclists were assigned to intake 10 g of JP (240 mg anthocyanins) or placebo (PLA) for 7 days and performed a cycling time-to-exhaustion (TTE). A 5 s cycling sprint was performed before and after the cycling TTE. Blood oxidative stress biomarkers and lactate concentration where evaluated 1 h before (T-1), immediately after (T0), and 1 h after (T1) the cycling TTE. The mean duration time for the cycling TTE was 8.4 ± 6.0% (63 ± 17 s) longer in the JP condition (JP: 751 ± 283 s) compared to PLA (688 ± 266 s) (P < 0.019). Two-way repeated measures Analysis of variance showed an increase in the JP condition for reduced glutathione (GSH) (P = 0.049) at T0 (P = 0.039) and T1 (P = 0.029) compared to PLA with a moderate effect size at T0 (d = 0.61) and T1 (d = 0.57). Blood lactate levels increased over time in both conditions (P ≤ 0.001). No differences were observed for the post-TTE sprint fatigue index, total phenols, protein carbonyls, and glutathione peroxidase activity. Seven-day intake of JP improved cycling endurance performance and increased GSH levels but had no effect on lactate and cycling sprint-induced fatigue. [ABSTRACT FROM AUTHOR]

Running is one of the most popular sport practices in the world. However, to our knowledge, none of the previous research about the characteristics of outdoor running makes a distinction between the different modalities of runners. Sixty-five healthy runners classified in sprinters, middle distance and long-distance runners performed five series of 100 metres on the synthetic outdoor track at competition pace. Muscle activity of lower limb muscles at initial contact and toe-off, involving the gluteus medius (GMED), gluteus maximus (GMAX), biceps femoris (BF), rectus femoris (RF), tiabilis anterior (TA) and medial gastrocnemius (MGAS), and spatiotemporal parameters were analysed. Sprinters showed high percentages of muscle activity at initial contact, in particular, the TA activity was the highest. The RF activity was significantly the lowest activity registered. At toe-off, sprinters showed the highest activity in all muscles analysed. Middle-distance runners had the highest activity of GMAX, BF and MGAS during the initial contact. In long-distance runners, the GMED and RF activity during the initial contact is highlighted, showing the highest activity of this phase. Different patterns of lower limb muscle activity and spatiotemporal parameters exist depending on the modality of the runner. [ABSTRACT FROM AUTHOR]

The practice of the wheelchair rugby is becoming more and more worldwide. However, few biomechanical studies have focused on this sport. The aim of this study was to compare kinematic parameters of wheelchair rugby players, classified as defensive players (LP-D) versus offensive players (HP-O). Twenty-nine wheelchair rugby players (17 LP-D and 12 HP-O) performed a 20-m sprint test. The peak velocities, temporal parameters (propulsion phase time, deceleration phase time, cycle time and cycle frequencies) and asymmetries (the difference in peak velocities between the right and the left wheels) were measured at the acceleration and constant peak velocity phases of the sprint by an inertial measurement unit which was placed on each rear wheel. At the acceleration and constant peak velocity phases, peak velocities and cycle frequencies were higher in HP-O players than LP-D players. The deceleration phase times and the cycle times were higher in LP-D players than HP-O players. However, no significant difference in asymmetry was found between LP-D players and HP-O players. The HP-O players showed superior performance than the LP-D players, but they could be more exposed at risk of injury at their upper limbs than LP-D players. [ABSTRACT FROM AUTHOR]

Athletes use either a seven-step or eight-step strategy to reach the first hurdle in the 110 m hurdle event. This study investigated the effect of step strategy on the start position, the block exit and the first four approach steps. Two-dimensional video data were collected in the sagittal plane from 12 male sprinters, grouped as seven-step (n = 6) or eight-step (n = 6) strategists. Mean block spacing was 0.08 m further apart, block contact time 0.06s longer, first step 0.25 m longer and first ground contact 0.03s longer for seven-step athletes compared with eight-step athletes. There was also a greater vertical displacement of the centre of mass (CoM) (0.04 m) for the seven-step athletes compared with the eight-step athletes. Additionally, the front hip mean angular acceleration was 197°/s2 slower for the seven-step athletes than the eight-step athletes. There was limited difference between groups for mean horizontal velocity at the moment of block exit (0.14 m/s). These technical alterations provide an important first insight into start kinematics. The findings of this study identify the position in the starting blocks, and the key parameters which pertain to the initial phases for a successful seven-step approach strategy to be employed. [ABSTRACT FROM AUTHOR]

Adolescence is a fundamental period for female athletes to develop athletic performance, mitigate injury risk, and gain collegiate sport scholarships, but there is also a high incidence of sport-related injuries. Physical profiling and athlete screening can support the individualisation of training programmes; however, there is a lack of data pertaining to the reliability of athletic performance and injury surrogate measures in adolescent female athletes. The aim of this study was to quantify the between-session reliability of an athletic performance and injury mitigation testing battery in female adolescent athletes. A total of 31 post-peak height velocity (PHV) (3.00 ± 0.82 years) female athletes (age: 16.20 ± 1.20 years; standing height: 166.00 ± 6.00 cm; mass: 65.5 ± 10.70 kg) from various sports (track and field = 1; lacrosse = 2; basketball = 2; soccer = 3; softball = 11; volleyball = 12) completed two sessions of a multicomponent testing battery 48 h to 1 week apart including the assessment of 33 measures addressing lower-limb isometric strength, eccentric strength, reactive strength, linear sprint and change of direction speed, and lower limb control. Of the 33 measures, between sessions, 29 had a high to nearly perfect intraclass correlation coefficient (ICC) (0.508–0.979), and 26 measures were not statistically significantly different between sessions (p ≤ 0.05). All measures demonstrated low to acceptable coefficient variation (CV%) (0.61–14.70%). The testing battery used can be utilised for recruitment and longitudinal monitoring within sports organisations for female adolescent athletes. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of 8-week combined vertical-oriented vs. horizontal-oriented training interventions in basketball athletes. Eighteen highly trained U-16 basketball players participated in this study and were randomly assigned to either a combined vertical-oriented training group (CVG, n = 9) or a combined horizontal-oriented training group (CHG, n = 9). Bilateral and unilateral vertical jump height, unilateral horizontal jump distance, 5-m, 10-m, and 20-m sprint times, change- of-direction sprint times, and a limb symmetry index were among the measured performance variables. Combined strength training was performed twice a week for 8 weeks. CVG was compounded by the squat exercise (3 sets of 6-8 R at 30-45% 1 repetition maximum [1RM]), jump squats (2 sets of 6 R, at 5-12.5% body mass [BM]), and vertical jumps (3-4 sets × 6 R). CHG included the hip thrust exercise (3 sets of 6-8 R at 30-45% 1RM), sled towing sprints (2-3 R, at 5-12.5% BM), and sprints (3-4 R of 20-m). Within-group differences showed significant (p < 0.05 and statistical power >80%) improvements in unilateral vertical jumping with the right leg after both training interventions. By contrast, only CHG improved 5-m, 10-m, and 20-m sprint times (p < 0.05 and statistical power >80%). Significant effects were observed for CHG compared with CVG in 5-m, 10-m, and 20-m sprint times (p < 0.05 and statistical power >80%). This study reinforces the importance of oriented-combined training based on force-vector specificity target, mainly in horizontal-oriented actions. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the effects of different plyometric training volumes on jumping, sprinting, and change-of-direction performances in youth basketball players. Thirty-one young male basketball players (age: 15.1 ± 1.8 years) from 4 squads belonging to an elite basketball club were randomly assigned to 1 of 3 groups: (a) low-volume (LV) plyometric training, (b) high-volume (HV) plyometric training, and (c) control group (CG). The subjects followed a plyometric training program twice a week for 6 weeks, differing in the training volume controlled through the number of jumps per session. Both experimental groups performed 8 repetitions in each set of bilateral vertical jumps with free arms, but HV completed twice the training volume of LV (98.7 vs. 49.3 jumps per session). Pretraining and Post-training measurements included the following: (a) squat jump (SJ); (b) countermovement jump (CMJ); (c) horizontal jump (HJ); (d) straight-line sprint in 20 m (Sprint); and (e) V-Cut change-of-direction test (V-Cut). The LV and HV groups showed similar increases in vertical jump performance. The LV group significantly increased its performance in SJ, CMJ, and HJ (p < 0.001-0.05), whereas the HV group showed significant improvements only in SJ and CMJ (p < 0.001). Furthermore, neither group increased their sprint or change of direction performance. Control group did not improve in any performance variable analyzed. Therefore, the LV and HV plyometric training programs produce similar benefits on jump performance variables, but LV is more repetition-efficient than HV in young basketball players. This supports the statement that there is a nonlinear relationship between training volume and performance improvements. [ABSTRACT FROM AUTHOR]

The impact of two priming exercise protocols using traditional (TS) or cluster-set (CS) arrangements on explosive performance 6 hours later were examined. Sixteen male collegiate athletes performed three testing sessions (one baseline without any prior exercise in the morning and two experimental sessions) separated by 72 hours. Participants completed two morning (9-11 am) priming protocols in a randomized order, either using a TS (no rest between repetitions) or CS (30 seconds of rest between repetitions) configuration. The protocols consisted of 3 sets x 3 repetitions of barbell back squat at 85% of 1 repetition maximum, with 4 minutes of rest between sets. In the afternoon (3-5 pm) of each trial, after a 6-hour rest period, a physical test battery was conducted that replicated baseline testing, including countermovement jump, 20-meter straight-line sprint, and T-test abilities. Across both conditions, participants exhibited increased countermovement jump height, 20-meter sprint time and T-test time compared to baseline (P < 0.05). Improvements in countermovement jump height (+4.4 ± 5.4%; P = 0.008) and 20-meter sprint time (+1.3 ± 1.7%; P = 0.022), but not T-test time (+1.1 ± 3.3%; P = 0.585), were significantly greater for CS than TS. In conclusion, compared to a traditional set arrangement, a morning-based priming protocol using a cluster-set configuration led to superior explosive performance benefits in the afternoon. [ABSTRACT FROM AUTHOR]

To generate a taxonomy of potentially morally injurious events (PMIE) encountered in veterinary care and develop an instrument to measure moral distress and posttraumatic growth following exposure to PMIE in the veterinary population. Development and preliminary evaluation of the Moral Distress-Posttraumatic Growth Scale for Veterinary Professionals (MD-PTG-VP) employed data from veterinary professionals (veterinarians, veterinary nurses, veterinary technicians) from Australia and New Zealand across three phases: (1) item generation, (2) content validation, and (3) construct validation. In Phase 1 respondents (n = 46) were asked whether they had experienced any of six PMIE and to identify any PMIE not listed that they had experienced. In Phase 2 a different group of respondents (n = 11) assessed a list of 10 PMIE for relevance, clarity and appropriateness. In Phase 3 the final instrument was tested with a third group of respondents (n = 104) who also completed the Short Post-Traumatic Stress Disorder Rating Interview (SPRINT), a measure of posttraumatic stress, and the Stress-Related Growth Scale–Short Form (SRGS-SF) a measure of perceived posttraumatic growth. Spearman's correlation coefficients were calculated between respondent scores on each of the MD-PTG-VP subscales, the SPRINT, and the SRGS-SF to assess construct validity. A 10-item taxonomy of PMIE encountered in veterinary care was generated in Phase 1. Items were deemed relevant, clear and appropriate by veterinary professionals in Phase 2. These were included in the developed instrument which measures frequency and impact of exposure to 10 PMIE, yielding three subscale scores (exposure frequency, moral distress, and posttraumatic growth). Assessment of construct validity by measuring correlation with SPRINT and SRGS-SF indicated satisfactory validity. The MD-PTG-VP provides an informative tool that can be employed to examine professionals' mental health and wellbeing following exposure to PMIE frequently encountered in animal care. Further evaluation is required to ascertain population norms and confirm score cut-offs that reflect clinical presentation. Once fully validated this instrument may be useful to quantify the frequency and intensity of positive and negative aspects of PMIE exposure on veterinary professionals so that accurate population comparisons can be made and changes measured over time. [ABSTRACT FROM AUTHOR]

This article, published in Marine Mammal Science, describes a rare observation of potential altruistic behavior by a male northern elephant seal. Altruism, the act of assisting another in need, is commonly seen in social birds and mammals, but male altruism is rarely observed in marine mammals. The researchers document an incident where an adult male elephant seal responded to a distressed pup and helped it return to shore, despite the potential cost to his own survival and reproduction. The authors speculate that kin selection and the low harem density at the colony may have contributed to this behavior. Further research is needed to understand the development of altruistic traits in marine mammals. [Extracted from the article]

This study analyzed differences in body composition, jump performance, running speed, and ball-kicking speed according to playing position in amateur female soccer players. This cross-sectional study involved 160 females distributed into groups of goalkeepers (n = 20), defenders (n = 38), midfielders (n = 52), and forwards (n = 50), with a mean age of 27.1 ± 3.23 years. They were assessed for body fat percentage (BFP), fat-free mass (FFM), squat jump, countermovement jump, drop jump (DJ), and running sprint speed for 10 m, 20 m, and 30 m, and ball-kicking speed (BKS) with both feet. Significant differences were found between groups in FFM (F(3,96) = 17.4; p = 0.000) and BFP (F(3,96) = 7.00; p = 0.000), with a higher FFM in midfielders with respect to goalkeepers (p = 0.00; ES = 1.77; ∆ = 27%), defenders (p = 0.00; ES = 2.14; ∆ = 26.5%), and forwards (p = 0.00; ES = 1.13; ∆ = 15.8%), and a lower BFP in midfielders with respect to goalkeepers (p = 0.00; ES = 1.41; ∆ = 26.7%) and forwards (p = 0.00; ES = 1.05; ∆ = 27%). In addition, significant differences were found between groups in DJ (F(3,96) = 20.8; p = 0.000), with midfielders achieving greater height compared to goalkeepers (p = 0.00; ES = 1.94; ∆ = 25.1%), defenders (p = 0.00; ES = 1.59; ∆ = 19%), and forwards (p = 0.00; ES = 1.73; ∆ = 16.3%). Significant differences were found between groups in BKS for dominant (F(3,96) = 5.84; p = 0.001) and non-dominant (F(3,96) = 3.29; p = 0.02) feet, and these were lower in goalkeepers than defenders (p = 0.00; ES = 0.99; ∆ = 8.83%) and midfielders (p = 0.00; ES = 1.21; ∆ = 11.8%). In conclusion, midfielders presented significantly better body composition and physical performance than other playing positions. [ABSTRACT FROM AUTHOR]

In professional sports, motion analysis has become a fundamental tool for the creation of training menu and to prevent injuries. However, motion analysis techniques are not among amateurs due to the associated high costs and the need for a certain degree of expertise to process and analyze the data. Although video cameras and IMUs are successfully used to monitor athletes’ motion in short-distance running sports, they require to place subjects in a controlled environment that is far from the real conditions met during a competition. Therefore, we propose a non-intrusive speed, stride, and pitch estimation method using 3D-LiDAR, which is compact and can measure real competitions. Our preliminary results show that the maximum error of the proposed method is 2.2%, indicating that the performance of the proposed method is comparable to that of video-based methods. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the energy system contributions to different repeated sprint protocols and also to determine sex-related differences in these contributions. Sixteen men and fourteen women team sport athletes randomly performed two cycling repeated sprint protocols with the same total duration (10 x 6 s and 6 x 10 s). Relative peak power (RPP), relative mean power (RMP), performance decrement (PD), oxygen uptake (VO2), blood lactate (LA), heart rate (HR) and ratings of perceived exertion (RPEs) were measured. The contributions of energy systems were calculated from oxygen consumption and lactate values during rest, exercise and recovery phases based on mathematical methods. Findings indicate that men had higher RPP and RMP. RPP did not differ according to protocols, while RMP was higher in the 10 x 6 s protocol. The sex effect in PD was similar; however, it was higher in the 6 x 10 s protocol. The effects of protocols on the maximum HR and LA were similar; however, the 6 x 10 s protocol resulted in higher RPEs. In both protocols women had higher ATP-PCr and men had higher glycolytic system contribution with similar oxidative system contribution. In addition, the 10 x 6 s protocol had higher ATP-PCr system contribution and the 6 x 10 s protocol had higher glycolytic system and oxidative system contributions. In conclusion, the contribution of energy systems, physiological and performance variables showed variations according to sex and different protocols. [ABSTRACT FROM AUTHOR]

Background and Study Aim The aim of this study was to examine the acute effects of whole-body vibration applied to the dominant and non-dominant leg during repetitive lunge movements on jump and sprint performance. Material and Methods Thirty-five male students from the Faculty of Sport Sciences voluntarily participated in the study. Participants performed squat jumps and countermovement jumps, and a 30-m sprint test on a nonmotorized treadmill as pre- and post-tests. Participants were divided into the experimental group (n = 19, age: 22.0 ± 1.9 years, height: 177.7 ± 6.3 cm, body weight: 75.5 ± 12.6 kg) and the control group (n = 16, age: 21.9 ± 1.9 years, height: 173.4 ± 4.1 cm, body weight: 67.7 ± 7.1 kg). In the experimental group, a whole-body vibration of 50 Hz frequency and 4 mm amplitude was continuously applied to the dominant front leg. This was done on the whole-body vibration platform for 60 seconds throughout the repetitive lunge movement. At the end of the time, the leg was changed, and wholebody vibration was applied to the non-dominant leg using the same method. The control group performed the same movement without whole-body vibration. Pre- and post-test results were compared with an independent sample t-test within the group and a paired sample t-test between the groups. The statistical significance level was determined as p = 0.05. Results The experimental group showed statistically significant pre-test and post-test differences in 30-m sprint power, non-dominant leg power, and non-dominant leg horizontal force parameters (p < 0.05, p < 0.01, and p < 0.05, respectively). It was determined that performing dynamic lunge movements with the dominant and non-dominant legs using whole-body vibration significantly increased mean power and non-dominant leg horizontal force. Conclusions The acute effect on power, particularly on non-dominant leg power and non-dominant leg horizontal force during the 30-m sprint, was significant. This showed that whole-body vibration can be used as a short-term training method. In studies aiming to determine the acute and chronic effects of exercises with whole-body vibration on various performance parameters, it is important to focus on the frequency and amplitude differences in certain protocols. [ABSTRACT FROM AUTHOR]

Background and Study Aim Sprinting performance is crucial in many sports, and even marginal improvements in sprint mechanics can provide significant competitive advantages. The aim of this study is to examine the influence of step distance, contact time, and flight time on sprint speed. Material and Methods The study was conducted on 26 athletes (20 males and 6 females). Body composition was measured using a bioimpedance analysis device. Sprint kinematics (step distance, contact time, and flight time) and sprint speed parameters were assessed using an optical measurement system during a 30-meter sprint test. Multiple linear regression analysis was employed to determine the effects of sprint kinematic parameters on sprint speed, as well as the effects of body composition parameters on sprint kinematics and speed. The linear regression models included one dependent variable and three independent variables. Results Linear regression analysis revealed that step distance, contact time, and flight time were significant predictors of sprint speed, with the exception of the first step of sprint running (p < 0.05). Furthermore, the effects of body composition parameters (age, body weight, and height) on sprint kinematics and speed were found to be significant (p < 0.05). The proportions of variance explained by body composition parameters were highest for step distance and sprint speed, with R2 values of 0.719 and 0.686, respectively. Conclusions This study confirms that step distance, contact time, and flight time are significant predictors of sprint speed. Additionally, the results underscore the substantial influence of body composition parameters such as age, body weight, and height on sprint kinematics and speed. These findings highlight the importance of considering both kinematic and physiological factors in the training and development of athletes for optimized sprint performance. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the potential differences in the match running performance of professional soccer players 5 min. before scoring and conceding a goal in the Polish Ekstraklasa. The sample consisted of 278 matches with 570 goals scored during official matches of the 2022/23 Polish Ekstraklasa season. All data was collected utilising the computerised multiple-camera optical tracking system TRACAB. Total distance covered (TD), standing distance (StD; < 0.72 km h−1), walking distance (WD; 0.73–7.2 km h−1), jogging distance (JG; 7.21–14.4 km h−1), running distance (RD; 14.41–19.8 km h−1), high-speed running distance (HSR; 19.81–25.2 km h−1) and sprinting distance (SprD; > 25.2 km h−1) were analysed in 5-min intervals prior to a goal scored for both teams. The employed linear mixed models showed that all examined match-running performance metrics were higher in teams that scored a goal compared to teams that conceded a goal. Within 5 min before scoring a goal in Polish Ekstraklasa matches, the scoring team produced significantly greater TD (∆ 95%CI 256.8–300.4 m; p = 0.001), WD (∆ 95%CI 52.3–95.8 m; p = 0.001), JG (∆ 95%CI 100.5–144.1 m; p = 0.001) and RD (∆ 95%CI 16.2–59.8 m; p = 0.001) compared to the conceding team, although no differences were found for HSR and SprD. These results demonstrate the enhanced identification potential of key physical performance factors influencing goal scoring in the Polish Ekstraklasa, thereby optimising the training process and improving overall performance. To enhance the effectiveness of soccer training, coaching and performance staff should consider this study's findings, that indicate an increase in the volume of medium- and low-intensity running efforts preceding a goal. [ABSTRACT FROM AUTHOR]