The aim of this study was to examine lower limb joint kinetics during the block and first stance phases in athletic sprinting. Ten male sprinters (100 m PB, 10.50 ± 0.27 s) performed maximal sprint ...starts from blocks. External force (1000 Hz) and three-dimensional kinematics (250 Hz) were recorded in both the block (utilising instrumented starting blocks) and subsequent first stance phases. Ankle, knee and hip resultant joint moment, power and work were calculated at the rear and front leg during the block phase and during first stance using inverse dynamics. Significantly (P < 0.05) greater peak moment, power and work were evident at the knee joint in the front block and during stance compared with the rear block. Ankle joint kinetic data significantly increased during stance compared with the front and rear block. The hip joint dominated leg extensor energy generation in the block phase (rear leg, 61 ± 10%; front leg, 64 ± 8%) but significantly reduced during stance (32 ± 9%), where the ankle contributed most (42 ± 6%). The current study provides novel insight into sprint start biomechanics and the contribution of the lower limb joints towards leg extensor energy generation.
This study investigated the effects of upper-body repeated-sprint training in hypoxia vs. in normoxia on world-level male rugby union players' repeated-sprint ability (RSA) during an international ...competition period. Thirty-six players belonging to an international rugby union male national team performed over a 2-week period four sessions of double poling repeated-sprints (consisting of 3 × eight 10-s sprints with 20-s passive recovery) either in normobaric hypoxia (RSH, simulated altitude 3000 m,
= 18) or in normoxia (RSN, 300 m;
= 18). At pre- and post-training intervention, RSA was evaluated using a double-poling repeated-sprint test (6 × 10-s maximal sprint with 20-s passive recovery) performed in normoxia. Significant interaction effects (
< 0.05) between condition and time were found for RSA-related parameters. Compared to Pre-, peak power significantly improved at post- in RSH (423 ± 52 vs. 465 ± 69 W,
= 0.002,
²=0.12) but not in RSN (395 ± 65 vs. 397 ± 57 W). Averaged mean power was also significantly enhanced from pre- to post-intervention in RSH (351 ± 41 vs. 388 ± 53 W,
< 0.001,
²=0.15), while it remained unchanged in RSN (327 ± 49 vs. 327 ± 43 W). No significant change in sprint decrement (
= 0.151,
² = 0.02) was observed in RSH (-17 ± 2% vs. -16 ± 3%) nor RSN (-17 ± 2% vs. -18 ± 4%). This study showed that only four upper-body RSH sessions were beneficial in enhancing repeated power production in international rugby union players. Although the improvement from RSA to game behaviour remains unclear, this finding appears of practical relevance since only a short preparation window is available prior to international games.
We investigated the effect of stair climbing exercise “snacks” on peak oxygen uptake. Sedentary young adults were randomly assigned to perform 3 bouts/day of vigorously ascending a 3-flight stairwell ...(60 steps), separated by 1–4 h of recovery, 3 days/week for 6 weeks, or a nontraining control group (n = 12 each). Peak oxygen uptake was higher in the climbers after the intervention (P = 0.003), suggesting that stair climbing “snacks” are effective in improving cardiorespiratory fitness, although the absolute increase was modest.
BACKGROUND: Handball is a strenuous contact sport placing emphasis on running, jumping, throwing, hitting, blocking, and pushing. Various technical and tactical skills are required for this dynamic ...sport, namely speed, agility, balance, power, strength, and coordination. Hence, the aim of the present study was to assess the changes in the physical fitness components with 8 weeks of plyometric training and core training given to the handball players and to compare the effect of both training methods on the handball players.
METHODS: Sixty players were randomly selected to participate in the study. The players were divided into three groups, namely Group A (plyometric), Group B (core), and Group C (control) (n = 20 each). The speed was assessed with 40 m dash sprint, agility by Illinois agility test, and lower limb power by isokinetic dynamometer (BIODEX). The experimental group underwent their respective trainings, and the control underwent conventional training. The posttraining results were recorded after 8 weeks of training.
RESULTS: There was a significant difference within the groups, but there was no significant difference between the three groups.
CONCLUSION: Both training methods were equally beneficial for the improvement in sprinting speed, Illinois agility test, and lower limb power.
Studying the different sides of 400 m sports preparation is a key factor for the proper development of sports results. Strength training is one of the most important parts of sprint running. The ...object of the study is sports training of athletes in the 400 m sprint, and in particular strength training. The subject is the content and volume of the annual preparation for girls under 18, specializing in 400 m sprint. We used the following methods: sports-pedagogical and technical-tactical analysis of athletes; interview; Case-study analysis; Mathematical and statistical methods. We analyzed: 16 macrocycles. Girls under 18 years have a large set of auxiliary exercises for strength training-total of 52. Volumetric characteristics must be precisely used according to age and individual qualities. We established minimum, maximum, and average volume values of the various means in macro-, meso- and microcycles. In conclusion, we can note the need for more scientific and methodological developments to help the process of applying specific volumes for the different strength exercises, during the different periods of annual preparation. With this study, we present relevant information for the volume and diversity of used athletic means used in practice and can help other coaches.
This study examined the impact of continuous blood flow restriction (BFR) during repeated‐sprint exercise (RSE) on acute performance, peripheral, systemic physiological, and perceptual responses. In ...a randomized crossover design, 26 adult male semi‐professional and amateur team‐sport players completed two RSE sessions (3 sets of 5 × 5‐s sprints with 25 s of passive recovery and 3 min of rest) with continuous BFR (45% arterial occlusion; excluding during between‐set rest periods) or without (non‐BFR). Mean and peak power output were significantly lower (p < 0.001) during BFR compared to non‐BFR (dz = 0.85 and 0.77, respectively). Minimum tissue saturation index during the sprints and rest periods was significantly reduced (p < 0.001) for BFR (dz = 1.26 and 1.21, respectively). Electromyography root mean square was significantly decreased (p < 0.01) for biceps femoris and lateral gastrocnemius muscles during BFR (dz = 0.35 and 0.79, respectively), but remained unchanged for the vastus lateralis muscle in both conditions. Oxygen consumption and minute ventilation were significantly reduced (both p < 0.01) for BFR (dz = 1.46 and 0.43, respectively). Perceived limb discomfort was significantly higher (p < 0.001) for BFR (dz = 0.78). No differences (p > 0.05) in blood lactate concentration or rating of perceived exertion were observed between conditions. Blood flow‐restricted RSE reduced performance and likely increased the physiological and perceptual stimulus for the periphery with greater reliance on anaerobic glycolysis, despite comparable or decreased systemic demands.
Highlights
Continuous cuff inflation reduces external loads during repeated sprints which is suitable for athletes undertaking demanding training blocks or rehabilitating an injury.
Blood flow‐restricted repeated sprints likely increase anaerobic energy contribution from further muscle deoxygenation.
Inflatable cuffs likely reduce antagonistic muscle activation during cycling repeated sprints to maintain efficient inter‐muscle coordination given the deteriorated contractility of prime mover muscles with metabolic stress.
Team sports require athletes to rapidly reduce whole body momentum and velocity, to efficiently change direction, or to avoid defenders. Decelerations often occur following varying approach distances ...and velocities. The aim of this study was to investigate the effects of different sprinting approach distances, and therefore velocities and momenta on measures of horizontal deceleration performance within female NCAA Division I softball players. Athletes performed an acceleration:deceleration assessment (ADA) over 20 yards (18.29 m) (ADA20) and 10 yards (9.14 m) (ADA10), respectively. The sample was divided into high and low performance groups for approach velocity and approach momentum, and between-group differences were studied for each test. Correlations between measures of deceleration were analyzed between the ADA10 and ADA20. Results suggested that during the ADA20 trials, athletes initiated the deceleration phase at greater approach velocities (p < 0.001, ES = 2.71) and momenta (p < 0.001, ES = 2.65), generating greater reductions in velocity (p < 0.001, ES = 1.60) and momentum (p < 0.001, ES = 1.50). Within the ADA10, athletes within the high velocity group saw significantly greater reductions in velocity (p = 0.009, ES = 1.24). This was not observed within the ADA20. A significant negative association was found between average deceleration within the ADA10 and ADA20 (r = -0.443, p = 0.039). Findings suggest that horizontal decelerations are influenced by the approach distance, velocity, and momentum, which athletes are exposed to before initiating the deceleration phase. This should be accounted for when implementing training to enhance such qualities.
Previous studies indicate that there is a large influence of the starting reaction time (RT) on sprint performance, but also that some recent changes in athletic rules may affect this correlation. ...This study aimed to examine the relationship between RT and results in: men’s (M60mH) and women’s (W60mH) disciplines 60 m over hurdles, 60 m hurdles in the heptathlon (H), 60 m hurdles in the pentathlon (P) at the recently held World Indoor Championship 2022 (WIC). The aim was also to determine whether there are differences in RT between M60mH and W60mH, M60mH and H, W60mH, and P, and between H and P. The study included 170 competitors who competed at the WIC. Pearson’s linear correlation coefficient (r) was used for correlation analysis, and the t-test for independent samples was used to examine differences between groups. A statistically significant correlation (r=0.23, N=72, p=0.05) was found between the results and RT in W60mH when observing the entire sample of participants (r2 = 5.29). Considering that in H (r=0.42, N=10, p=0.23, r2=0.18) and P (r=0.54, N=12, p=0.07, r2=0.29), a much higher correlation was obtained between results and RT than in competitors in the 60 m hurdles event, we believe that this is a consequence of different athletic rules that refer to a false start. There are no significant differences between RT for M60mH and W60mH, M60mH and H, W60mH, and P, and between H and P. Coaches should pay attention to developing all parts of the sprint race, including the reaction time.
The microvasculature is important for both health and exercise tolerance in a range of populations. However, methodological limitations have meant changes in microvascular blood flow are rarely ...assessed in humans during interventions designed to affect skeletal muscle blood flow such as the wearing of compression garments. The aim of this study is, for the first time, to use contrast‐enhanced ultrasound to directly measure the effects of compression on muscle microvascular blood flow alongside measures of femoral artery blood flow and muscle oxygenation following intense exercise in healthy adults. It was hypothesized that both muscle microvascular and femoral artery blood flows would be augmented with compression garments as compared with a control condition. Ten recreationally active participants completed two repeated‐sprint exercise sessions, with and without lower‐limb compression tights. Muscle microvascular blood flow, femoral arterial blood flow (2D and Doppler ultrasound), muscle oxygenation (near‐infrared spectroscopy), cycling performance, and venous blood samples were measured/taken throughout exercise and the 1‐hour post‐exercise recovery period. Compared with control, compression reduced muscle microvascular blood volume and attenuated the exercise‐induced increase in microvascular velocity and flow immediately after exercise and 1 hour post‐exercise. Compression increased femoral artery diameter and augmented the exercise‐induced increase in femoral arterial blood flow during exercise. Markers of blood oxygen extraction in muscle were increased with compression during and after exercise. Compression had no effect on blood lactate, glucose, or exercise performance. We provide new evidence that lower‐limb compression attenuates the exercise‐induced increase in skeletal muscle microvascular blood flow following exercise, despite a divergent increase in femoral artery blood flow. Decreased muscle microvascular perfusion is offset by increased muscle oxygen extraction, a potential mechanism allowing for the maintenance of exercise performance.
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