20-m Sprint Research Articles

Effect of Pre-Participation Aquatic Training Program on Running Performance in Marathon Runners

Objective: The most important objective was to determine the effect of an aquatic pre-participation training program for improving the running performance of middle-aged marathon runners. Method: The study was conducted among 100 recreational male and female runners (aged 25 to 35 years) fulfilling the inclusion and exclusion criteria. The subjects were randomly divided into two equal groups, the control group (n=50) and the experimental group (n=50) by using SPSS software. 6 weeks of aquatic training was conducted for the experimental group for 5 days per week while the control group underwent swimming. The scores were statistically examined by paired ‘t-test. Results: Results showed that there was a significant reduction in pain in both groups with a p-value <0.0001. Both groups showed significant improvement in cardiac endurance VO2 max. The mean post-VO2 max of the experimental group and control group showed significant improvement in VO2 max with p-value <0.0001. Experimental group showed more improvement in 1RM leg press test as compared to the control group. Mean pre and post-1RM leg press test was (pre:66.10±14.0) (post:73.40±15.20) with p value <0.0001. While of the control group was (pre:68.02±15.09) (post:69.40±13.94) with p value 0.0275. There was significant improvement in 50m sprint run test in the experimental group with pre mean 6.23±0.44 and post mean 6.00±0.46 with (p value <0.0001). Much improvement was not seen in 50m SRT of the control group, the pre mean was 6.11±0.44 and post mean was 6.06±0.48 with ( p value 0.0832). Conclusion: It concluded that the pre-participation aquatic training program had shown a significant positive response in improving speed strength and reducing pain.

Efficacy of FIFA 11+ Training Program on Performance and Functional Movement in Collegiate Football Players

Background: Football is the most common sport played around the world with 300 million registered players.To decrease injury rates and promote fair play in football, the FIFA-Medical and Assessment Research Centredesigned the FIFA 11+ training program.Purpose: The aim of this study was to investigate the effect of FIFA 11+ training program on functional performanceand functional movement in collegiate football players.Materials and Methods: A total of thirty subjects were chosen. Fifteen adult male football players were randomlyassigned into one of two groups: Group A (traditional training) or Group B (FIFA 11+ training). Both the groupsreceived the training for six weeks. And to check the performance speed was calculated using a 20m sprint test andaerobic capacity was measured using treadmill test. To check the functional movement FMS score was measured.Results:A Pearson correlation test shows a positive correlation (r = 0.208) but the weaker relationship between thevariables. Paired t test analysis shows a significant improvement after the treatment in terms of Gluteus Maximusmuscle activity, Hamstring muscle length and pain reduction with a P value < 0.001.Conclusion: This study concluded that FIFA 11+ training programs were better than the conventional trainingprogram in terms of functional performance, functional movement, and injury prevention. This was attributed tothe effect of the program on stability, muscle strength, proprioception, and postural alignment, which makes it abetter training program for preventing injuries.

A Study to Compare the Effectiveness of Serratus Anterior Training Versus Subscapularis Training in Improving Performance in Swimmer’s Shoulder

Background: The purpose of this study was to investigate the effectiveness of 6-week Serratus Anterior trainingVersus Subscapularis training in improving the performance in a Swimmer’s Shoulder.Purpose: To compare the effect of Serratus Anterior strength training versus Subscapularis strength training onshoulder pain in terms of performance in Swimmer’s.Materials and Methods: Subjects were randomly assigned into two groups i.e. Group A and B. The subjects wereassessed using an assessment form, UQYBT, DASH score, and 50 meters (m) freestyle sprint for disability andevaluate performance before the commencement of treatment and also reassessed after 6 weeks of treatment.The sample of 40 subjects has been randomized into either Group A (Serratus Training) or Group B (SubscapulisTraining) in a 1:1 ratio.Results: The study results suggest that Group B has an effect on performance improvement in Swimmers withshoulder pain after a 6-week intervention. The mean 50m sprint scores in Group A before treatment is 29.9960 andit is decreased to 29.0425.Conclusion: Hence, this study concludes that the mean difference of Group B is slightly more effective than GroupA in terms of performance in swimmers’ shoulders in all standard measures.

Relationship between individual hip extensor muscle size and sprint running performance: sprint phase dependence

ABSTRACT The muscle size of the hip extensors has been suggested to be important in sprint running performance; however, reported findings are partly inconsistent. Here, we hypothesised that the association between hip extensor size and sprint performance may vary by sprint phase (early-acceleration, maximal-velocity and deceleration phases). To test this hypothesis, we measured the volumes of individual hip extensors of 26 male sprinters via magnetic resonance imaging and their sprint velocities for each 10-m interval during a maximal-effort 100-m sprint. Based on the sprint velocities, the maximal-velocity phase was determined for each sprinter. At the individual muscle level, the semimembranosus volume relative to body mass was positively correlated with sprint velocity only in the early-acceleration phase (0–10 m, r = 0.592, corrected p = 0.003). On the other hand, the semitendinosus volume relative to body mass was positively correlated with sprint velocities in the maximal-velocity (r = 0.483, corrected p = 0.020) and deceleration (90–100 m, r = 0.605, corrected p = 0.003) phases. These results show that the association between hip extensor size and sprint performance is not constant but changes through the sprint phases.

No ageing-related increase in fibre type grouping in sprint-trained masters runners: A 10-year follow-up study.

Previous research suggests that an ageing-associated remodelling and loss of motor units due to motor neuron death contributes significantly to muscle weakness in old age. In histological sections, motor unit remodelling is reflected by increased fibre type grouping. While regular exercise may not attenuate the loss of motor units during ageing, it has been suggested to facilitate reinnervation resulting in larger motor units, and a higher number and larger fibre type groups in histological sections of muscles from aged individuals. In a 10-year follow-up study, we assessed changes in the prevalence and size of fibre type groups in the vastus lateralis muscle from 34 male masters sprinters (40-85years at start). Over the 10years, there was an ageing-related reduction in performance in the 60-m sprint (P<0.001) without significant changes in fibre type composition and fibre cross-sectional area. Neither the number of fibre type groups, defined as a fibre surrounded exclusively by fibres of the same type, nor the group size changed significantly in the 10-year period. These histological data show that there is limited to no significant fibre type grouping over a 10-year period in masters athletes who continued sprint run training. This observation challenges the paradigm that ageing, at least in systematically trained sprinters, is associated with motor unit remodelling.

Assessment of inter-individual variability in hamstring muscle recovery after a sport-specific sprint training in women and men.

Background: Hamstring muscles are most affected by multiple sprint-based sports as a result of muscle strain during sprinting, leading to reduced performance and increased risk of injury. Therefore, the purpose of the study was to assess inter-individual variability in hamstrings recovery after a sport-specific repeated-sprint training (RST), through sprint-specific markers of muscle recovery and associated muscle damage biomarkers in women and men. Methods: Healthy females (n = 14) and males (n = 15) underwent 10 repeated 40-m sprints with a 3-min rest pause between each repetition. Force-generating capacity (FGC) by the 90° hip :20° knee test and range of motion Jurdan test, together with serum biomarkers [sarcomeric mitochondrial creatine kinase (sMtCK), oxidative stress, irisin] were tested at baseline and 24-, 48- and 72-h post-exercise through a repeated measures design. Participants were classified according to FGC loss into high responders (HR) and low responders (LR). Results: 21 individuals (10 females, 11 males) were classified as HR (FGC loss >20% and recovery >48h), while 8 individuals (4 females, 4 males) were classified as LR. HR individuals showed unrecovered maximal voluntary isometric contraction (MVIC) torque until 72h post-training (p = 0.003, np 2 = 0.170), whereas only HR males showed decreased range of motion (p = 0.026, np 2 = 0.116). HR individuals also showed increased sMtCK (p = 0.016, np 2 = 0.128), oxidative stress (p = 0.038, np 2 = 0.106) and irisin (p = 0.019, np 2 = 0.123). Conclusion: There is inter-individual variability in the muscular response to a sport-specific RST, identifiable by MVIC torque assessment. The findings support that the 90° hip :20° knee test is a powerful indirect test to screen hamstrings recovery in both women and men, in a cost-effective way. However, the Jurdan test might not be able to monitor hamstrings recovery in sportswomen after RST. Decreases in muscle capacity are linked to damage to muscle sarcolemma and mitochondria until 72h post-exercise. Overall, 72h will not be adequate time to restore hamstrings structure and function after a sport-specific RST in both female and male responders.

The effects of single and combined jump exercises utilizing fast and slow stretch-shortening cycle on physical fitness measures in healthy adult males: A randomized controlled trial

This study aimed to compare the effects of six-week volume-equated jump training using drop jump (DJ), countermovement jump (CMJ), or a combination of both (COMB) on the physical fitness of adult males. Participants were randomly assigned to DJ (n=10), CMJ (n=9), or COMB (n=10) training groups or an active control group (n=7). Performance data were collected for 10-m and 30-m sprint, DJ, CMJ, standing long jump (SLJ), triple-hop jump, change of direction speed (CODS), and maximal isometric strength. The DJ demonstrated improvements in the 10-m sprint, CMJ, and SLJ (g=0.62–1.13, %Δ=3.0–10.8). The CMJ group improved in the 10-m and 30-m sprints, CODS, CMJ and SLJ (g=0.34–1.17, %Δ=3.4–10.5). The COMB group displayed progress in CMJ and SLJ (g=0.46–0.61, %Δ=6.4–8.6). In comparison to the control and COMB groups, the DJ and CMJ groups improved the 10-m sprint (p=0.008, ηp2=0.311), and in comparison to the control group, the CMJ group improved SLJ (p=0.037, ηp2=0.220). To conclude, the findings presented here deviate from the training principle of specificity, particularly in relation to ground contact time. This suggests that the classification of jump exercises into fast- and slow-SSC categories based solely on ground contact time might oversimplify a more intricate phenomenon.

Physical Determinants of Sprint and Long Jump Performance in Male Youth Track-and-Field Athletes With Differing Maturity Statuses.

This study examined the physical determinants of 60-m sprint and long jump (LJ) performance and differences between maturity groups in physical characteristics in young male track-and-field athletes. Competition results, countermovement jump, isometric leg press, 10-5 repeated jump test, and 50-m sprint were collected over 3 seasons for 54 male athletes (age 13 [1]y; stature 160.0 [8.9]cm; body mass, 48.0 [9.8]kg; percentage predicted adult height 92.2% [5.5%]) grouped by maturity status: approaching- (n = 16), circa- (n = 19), and post-peak height velocity (PHV) (n = 19). There were significant between-group differences in 60m, LJ, and all physical testing variables (P < .001, g = 0.88-5.44) when comparing the approaching- and circa-PHV groups with the post-PHV group. Significant differences were identified between the approaching- and circa-PHV groups in 40-m (P = .033, g = 0.89), 50-m (P = .024, g = 1.64), and 60-m (P < .001, g = 0.89) sprint times. Countermovement jump and 50-m sprint variables were consistently important for projection of 60m and LJ performance across the valid multivariate models. Large differences in performance across maturity groups highlight the importance of understanding athletes' maturity status to accurately interpret performance. Several physical performance variables were important for projecting competition 60m and LJ performance.

Are Young Female Basketball Players Adequately Prepared for a Force-Velocity Jumping and Sprinting Assessment?

The aim of this study was to explore the interday reliability of mechanical variables obtained from the horizontal and vertical force-velocity (FV) profiles in adolescent female basketball players. If found to be reliable, the associations between FV parameters (theoretical maximal force, velocity, and power), squat jump (SJ) height, 30-m sprint, and change of direction (COD) times were evaluated. After familiarization, SJ against incremental loads, 30-m sprint, and 505-COD tests were obtained twice in 36 adolescent female basketball players (age = 15.4 [1.2]y). Reliability for vertical FV parameters was unacceptable, whereas 505-COD times and FV horizontal parameters (except for theoretical maximal power) showed a moderate to high reliability. 505-COD time was correlated with FV horizontal parameters (range: r = -.821, -.451), and a large association was observed with both SJ height (r = -.678, -.600) and 30-m sprint time (r = .813, .858). Due to low levels of strength, our athletes were not adequately prepared to obtain a reliable vertical FV profile. Practitioners can expect acceptable reliability of the horizontal FV profile. Given the association between COD performance and SJ height and 30-m sprint time, we encouraged practitioners with limited equipment at their disposal to use COD and/or 30-m sprint tests.

The effect of supplementing regular training with short-duration sprint-agility training on sprint-ability performance in university level badminton players

Abstract: BACKGROUND: The badminton being a highly explosive sport involves a unique movement technique and strength with a combination of speed (anaerobic fitness) and endurance (aerobic fitness). Strength, power, agility, and flexibility are key components of fitness as a part of a player’s fitness training. This training helps to promote recovery from exercise as well as restoring muscle energy for the next bout of activity. OBJECTIVE: The objective of this study was to evaluate the effect of supplementary regular training and short-duration sprint-agility training versus regular training on sprint-ability performance in university-level badminton players. METHODOLOGY: Thirty university-level badminton players were selected randomly and divided into Group A as regular training along with short-duration sprint-agility training and Group B as regular training group. Groups A and B received regular training for 5 days for 4 weeks and short-duration sprint-agility training for 2 days a week, respectively. Pre- and postset of performance tests were conducted which consist of 10-m sprint, 20-m sprint, 300-m shuttle run, badminton-specific repeated-agility sprint-ability test, and 20-m multistage shuttle run test for oxygen consumption (VO2). RESULTS: There was a significant increase between both the groups in badminton shuttle distance (Group-A 34.51% &gt;Group-B 13.87%), 20 m sprint time (Group-A 15.02% &gt;Group-B 9.57%), and VO2 max (Group-A 5.61% &gt;Group-B 3.94%). CONCLUSION: Supplementing regular training with sessions of short-duration sprint training led to substantial increase in repeated-agility sprint performance which helps to restore muscle energy and improve activity performance in university-level badminton players.

The relationship between countermovement jump performance and sprinting speed in elite sprinters

Data regarding associations between vertical jumping and sprinting ability is lacking in elite sprinters. Therefore, the aim of this study was to evaluate relationship between variables such as countermovement jump (CMJ) height, relative peak power, and sprint time including flight time and ground contact time across various distances in the 50-m sprint among elite sprinters. Twenty- three male sprinters performed two CMJ attempts followed by two 50-m sprints on an indoor track. Jumping performance was assessed via force plates, while sprint times were recorded using timing photocells, with gates at 0, 5, 20, 30, and 50-m. Results showed a statistically significant negative correlations ranging from large to very large, between CMJ height and sprint time (p&lt;0.01; r= -0.56 to -0.73) across specific distances. Similarly, a significant large to very large correlations was found between CMJ relative peak power and sprint time (p&lt;0.01; r= -0.61 to -0.85) at the studied distances. Furthermore, a large significant correlations was indicated between sprint contact time and sprint time at certain distances (p&lt;0.01; r= -0.55 to 0.62), while sprint flight time correlated with distances above 20-m sprint time (p&lt;0.05; r= 0.45 to 0.48) and with the 20-50-m flying start sprint time (p&lt;0.05; r= 0.48), reaching a moderate magnitude. These findings suggest a significant negative correlation between relative peak power, CMJ height and sprint times across various distances, highlighting the potential for individualized training based on distinct sprint phases. Remarkably, the strength of these correlations increase with longer sprint distance.

Four Sessions of Repeated-Sprint Cycling Training With or Without Severe Hypoxia Do Not Modify Overground Running Sprint Force-Velocity Profile.

To investigate the effect of cycling-based repeated-sprint training in hypoxia versus in normoxia on single overground running sprint performance and associated force-velocity (F-V) profile in world-class female rugby sevens players. Eighteen world-class female rugby sevens players were randomly assigned to repeated-sprint cycling training in normobaric hypoxia (n = 9) or normoxia (n = 9) groups. Training consisted of 4 sessions ofrepeated-sprint cycling training in normobaric hypoxiaor in normoxia (4 × 5 × 5-s cycle sprints-25-s intersprint recovery performed in simulated altitude of ∼5000m or in normoxia with 3-min interset rest in normoxia for both groups) in addition to rugby sevens training and strength and conditioning sessions within a 9-day intervention period before an international competition. Before and 1day after the intervention, single 50-m overground running "all-out" sprint performance and associated F-V-related mechanical output were assessed. No interaction (group × time; all P > .088), time effect(before vs 1d after; all P > .296), or group effect(repeated-sprint cycling training in normobaric hypoxia vs in normoxia; all P > .325) was detected for 50-m overground running sprint performance and any derived F-V profiling variables. Four sessions ofrepeated-sprint training either in hypoxia or in normoxia performed over 9days had no influence on single 50-m overground running sprint performance and associated F-V profile. In world-class female rugby sevens players, the intervention (training camp before an international competition) might have been too short to induce measurable changes. It is also plausible that implementing a similar program in players with likely different F-V profile may result in negligible mechanical effect.

Chronotype as a predictor of athletic performance in youth with mild intellectual disabilities.

This study aimed to explore the influence of circadian rhythms on athletic performance in individuals with mild intellectual disabilities (ID), with a specific focus on elucidating the association between chronotype and various performance metrics. The study was a cross-sectional study consisting of 30 male participants aged between 11 and 19years and diagnosed with mild ID. The chronotypes of all participants were assessed using the Childhood Chronotype Questionnaire (CCQ). Performance assessments were divided into three groups. Group A tests [sit and reach, medicine ball throw (MBT), plank], group B tests [handgrip strength (HGS), standing long jump (SLJ), 20-m sprint (20ms)] and group C tests [vertical jump (VJ), hanging with bent arm (HBA), Illinois agility test) in order to ensure adequate rest periods between tests and not to affect the results. These group tests were performed 48h apart, between 09:00-10:00 and 17:00-18:00, after a dynamic warm-up session. Significant variations were observed in the sit-and-reach test (t = -4.154, d = -0.75, p < .001), HGS (t = -2.484, d = -0.45, p = .019), SLJ (t = -2.117, d = -0.38, p = .043), VJ (t = -5.004, d = -0.91, p < .001), and plank duration (t = -4.653, d = -0.84, p < .001). Evening performances showed improvement in MBT, HBA, 20ms, and the Illinois agility test, although these differences were not statistically significant (p > .05). Notably, positive correlations were identified between participants' chronotypes and their performance in HBA (morning/evening; r = .693, p = .026; r = .656, p = .039, respectively) and the plank (evening; r = .717, p = .020), with negative correlations noted in the 20ms (morning/evening; r = -.703, p = .023; r = -.710, p = .021, respectively). The findings suggest that individuals with mild ID exhibit enhanced athletic performance during evening hours. These insights underscore the importance of considering chronotype in tailoring exercise interventions for this population to optimize outcomes.

The validity and reliability of a hydraulic resistance device for assessing resisted sprint time.

The aim of this study was to assess the validity and reliability of a hydraulic resistance device (HRD) for monitoring sprint split times under different loads within and between sessions. Three 20-m sprints with low (15 N), medium-low (40 N), medium-high (50 N), and high (130 N) HRD resistance levels (loads) were performed on two separate occasions 14 days apart. Twenty-four student athletes (24.8 ± 3.8 years) participated in the first session and 13 (24.1 ± 3.2 years) of them in the second session. Resisted sprints split times over a distance of 0-20 m (t0-5, t0-10, t0-20, t5-10, t10-15, t15-20) were measured simultaneously with magnetic incremental encoder embedded in the HRD and a system of single-beam timing gates. The results showed acceptable to high within session (ICC3,1 = 0.91-0.99; CV = 0.92%-3.38%) and between session (ICC3,1 = 0.82-0.99; CV = 1.62%-4.84%) reliability of HRD for measuring all split times at all loads. The minimal detectable change between sessions ranged from 3.3% at high load to 9.9% at low load. The HRD systematically underestimated timing gates times at all loads (bias = 2.01-11.08%), yet good to excellent consistency was observed between the HRD and timing gates, specifically for t0-10 and t0-20 (ICC3,k lower 95% CI = 0.84-0.99). Due to high reliability and good validity in monitoring resisted sprint times, the HRD holds potential for practical and research applications.

Evaluating the Validity of Tests to Predict Sprint and Change of Direction Speed in Para-Athletes With Brain Impairments.

Maximum running speed is a performance determinant in para-athletics and cerebral palsy football. Sixty international para-athletes with brain impairments completed five activity-limitation tests (standing broad jump, four bounds for distance, split jumps, 10-m speed skip, and running in place) and two criterion tests (40-m sprint and modified agility test). The same three tests (standing broad jump, four boundsfor distance, and 10-m speed skip) that correlated with running performance in nondisabled runners (.67 < r < -.82; p < .05; 75% of variance) also correlated in para-athletes with brain impairments (.41 < r < -.62; p < .01; 55% of variance). Standing broad jump, four bounds for distance, split jumps, and running in place also correlated with change-of-direction speed (.43 < r < -.63; p < .01; 58% of variance). Results indicate that methods of classification for para-athletics with nondisabled runners are also valid with para-athletes with brain impairments, and new sport-specific relationships were found for assessing the performance of rapid and short sprints toward different directions, specific of a team para-sport like cerebral palsy football.

Assessment of the Relationship Between Physical Performance and Percentage Change-of-Direction Deficit in Highly Trained Female Football Players.

Different studies indicate that female players in team sports such as soccer tend to have a lower change-of-direction (COD)deficit (CODD) than their male counterparts and that players who performed better in linear and curved sprints tended to have a worse CODD, suggesting that maximum speed does not equate to a faster COD. This study assessed how performance variables related to speed and jumping influence the variability of %CODD among adult highly trained female soccer players. Fifty-two highly trained female soccer players (age 23.1 [3.25]y; height 163.6 [5.49]cm; weight 59.7 [5.71]kg) participated in this study and performed 180COD, 40-m sprint, countermovement jump, and standing broad jump tests. Significant correlations were found between 180CODL, %CODDR, %CODDL, and between-limbs standing broad jump asymmetry (r = .28-.74). A very large correlation existed between %CODDR and %CODDL (r = .91). Regression analyses indicated a strong inverse relationship between the 10-m sprint time and %CODDR and %CODDL. No predictive models were found for 180COD in either limb. Differences in performance variables suchas 180CODR, 180CODL, and asymmetry %CODD were significant between the high- and low-%CODD groups, with moderate to large effect sizes. The present study suggests that specific physical-performance variables, particularly acceleration and unilateral horizontal jumping, are vital to improving COD in highly trained female soccer players, highlighting the need for specific training interventions.

The Quantification of Physical Performance and Internal Training Load in Youth Male Soccer Players During Preseason.

The monitoring of training loads and quantification of physical performance are common practices in youth soccer academies to support coaches in prescribing and programming training for individuals. The interaction between training load and physical performance is unknown during a preseason period in youth soccer players. The current study assessed changes in training load and physical assessments across a 4-week preseason period. The relationship between physical performance and match playing time in youth male soccer players was also investigated. The training loads of 25 professional youth academy male soccer players were monitored throughout a 4-week preseason period. Assessments of power, agility, speed, and aerobic capacity were undertaken in the first training session. Session ratings of perceived exertion (sRPE) and well-being questionnaires were collected during all training sessions and preseason matches. Playing time during subsequent competitive matches was recorded. T test and 30-m-sprint assessments, conducted on the first day of preseason, were predictors of sRPE throughout preseason (t test χ2/df = 2.895, poor adjustment; 30-m sprint χ2/df = 1.608, good adjustment). YoYo Test performance was related with changes in perceived fatigue (χ2/df = 0.534, very good adjustment). Faster players reported higher values of sRPE, and players with higher aerobic capacity reported higher levels of fatigue across preseason. Well-being, perceived fatigue and soreness, and sRPE decreased across preseason. Greater match durations were related to higher levels of fatigue during preseason (P < .05). The current study highlights the relationship between training load, physical assessments, and playing time. Coaches and practitioners can use physical test data at the start of preseason as an indication of players that report higher sRPE, perceived fatigue, and reduced well-being across preseason, supporting decisions around individualized training prescriptions.

Chronobiological Insights in Plyometric Jump Training: Optimizing Sport-Performance Adaptations for Volleyball Players.

The objective of this study was to investigate the effects of morning versus evening plyometric training (PT) on performance adaptations in male volleyball players. A total of 30 collegiate national-level young male volleyball players (age = 21.9 [2.1]; height = 186 [4.1]; body mass = 82.4 [4.6]) were randomly divided into 3 groups: morning PT (MPT), evening PT (EPT), and an active control group, each group consisting of 10 subjects. The players engaged in PT sessions twice weekly for a period of 6weeks. The evaluation of biomotor abilities such as countermovement vertical jump, standing long jump, spike jump, block jump, 10-m sprint, T-test, sit and reach, and Y-balance test took place in the morning and evening before and after the intervention. Both the MPT and EPT groups indicated significant (P < .05) improvements in all biomotor abilities from pretraining to posttraining during both the morning and evening testing sessions. Furthermore, the MPT group displayed greater adaptive responses in the vertical jump (P = .001), standing long jump (P = .023), and Y-balance test (P ≤ .01) compared to the EPT group. Time-of-day fluctuations were the same between the MPT and EPT groups at the pretest. Conversely, EPT demonstrated significantly more daytime variations than MPT in the jump, sprint, and balance tests at postintervention (P < .05). Engaging in PT at specific times of the day has a significant impact on biomotor ability adaptations, with a focus on morning being more favorable than the evening for achieving greater gains in jump and balance performance of volleyball players.

Computer vision-based instantaneous speed tracking system for measuring the subtask speed in the 100-meter sprinter: Development and concurrent validity study

The 100-m sprint is one of the track events, and the pace of the runner can be measured using a variety of tools, such as a hand stopwatch, timing gate, laser device, radar device, photocell timing, etc. The data measured is the mean travel time. Nonetheless, monitoring an individual sprinter's instantaneous speed tracking is essential for assisting staff trainers in developing an appropriate training schedule for the individual sprinter. The purpose of this study was to construct a computer vision-based system for assessing the sprinting speed of the 100-m subtasks and also to investigate the concurrent validity of video analysis software among athletes. Five athletes participated in the research to determine its validity. Over the course of two trials, the sprinting pace of each participant's subtasks (a 100-m split to 10 m for each subtask) was measured. The application of the computer vision-based system to video analysis software was validated using the Pearson correlation coefficient. The agreement between the two measurement systems was quantified using Bland-Altman plots. The results revealed a significant relationship between the two systems and all 100-m subtask sprinting speeds (r = 0.961–1.000, p 0.0001). The Bland-Altman analyses indicated that the mean differences in 100-m subtask speeds were consistently close to zero, falling within the 95 % limits of agreement. The scatter plot distribution showed symmetry. The computer vision-based system proved to be a valid tool, suggesting its potential value in measuring and monitoring the 100-m subtask sprinting speed of athletes.

Association between BMI and health-related physical fitness in adolescents with hearing impairment in China: a cross-sectional study.

This cross-sectional study aimed to address a critical gap in the understanding of the association between body mass index (BMI) and physical fitness levels in adolescents with hearing impairment (HI) in China. This study investigated how different BMI levels impact the physical fitness index (PFI) of HI adolescents. This study employed a physical fitness test for HI adolescents attending special education schools. The test included eight components: height, weight, 50-m sprint, standing long jump, sit and reach, endurance run, bent-knee sit-up (for girls), and pull-up (for boys). Test scores for each student were standardized by age and gender. Individual Z-scores were then calculated, and the sum of these Z-scores constituted the PFI. Logistic regression was used to analyze the relationship between BMI and PFI across different gender and age groups. Statistical significance was set at P < 0.05. The linear regression model showed an inverted U-shaped relationship between BMI and PFI. At the same BMI level, boys exhibited superior physical fitness compared to girls with the same BMI (P < 0.05). Statistically significant differences in PFI levels were observed between normal-weight and obese males, as well as between underweight and obese boys (P < 0.05). In the 13-15 and 16-18 age groups, the increase in BMI has a greater impact on boys PFI than on girls. Adolescents with HI generally demonstrated good physical fitness. Compared to individuals with normal weight, those who were underweight, overweight, or obese exhibited lower levels of physical fitness. Future interventions should focus on adolescents with HI with abnormal BMI.