Search Results (537)

It is unclear if following a vegetarian diet affects muscle recovery after exercise-induced muscle damage (EIMD). Sixteen vegetarians (VEG) and sixteen mixed dieters (MIX) performed a vertical jump, quadriceps femoris maximal isometric, and isokinetic concentric strength tests prior to and five days following the EIMD protocol. The quadriceps muscle was injured by performing eccentric contractions. Diet: MIX consumed more g/kg of animal protein (p < 0.001) and EAA (p < 0.05) except for isoleucine. VEG consumed more plant protein (p = 0.001). Isometric strength: MIX recovered post-day 2, VEG recovered post-day 4 (group (p = 0.07), time (p < 0.001)). Concentric contractions at 60 degrees per second: Both recovered post-day 1 (group (p = 0.27), time (p = 0.05)); 180 degrees per second: MIX recovered post-day 2, VEG recovered post-day 5 (group (p = 0.10), time (p < 0.001)); and 240 degrees per second: MIX recovered post-day 1, VEG did not recover by post-day 5 (group (p = 0.01), time (p < 0.001)). Vertical jump: Both recovered post-day 3 (group (p = 0.45), time (p < 0.001)). MIX recovered isometric strength 2 days faster, concentric strength was up to 5 days faster, and soreness was 1–4 days faster when compared to VEG. Both groups had similar recovery time for power. Full article

This study addresses concerns surrounding the assessment of competence through various fitness tests in physical education, specifically assessments misaligning with the conceptualization of physical literacy. The study aimed to deductively analyze student assessment experiences with principles of self-determination theory, focusing on the role of competence in supporting autonomy. Particular instruments, such as the vertical jump and 30 m sprint tests, observed high levels of student preference and perceived significance. Interestingly, while the multistage fitness test was identified by students as a reliable indicator of physical fitness, it garnered limited student selection. While specific movement recommendations are not outlined, the findings underscore several noteworthy considerations. Notably, various factors influence student choices in student-selected fitness assessments, and purpose-driven fitness assessments can contribute to student motivation. The study’s insights provide valuable guidance for structuring physical education programs to foster engagement and autonomy among students. Full article

Background: The lack of knowledge about physical responses to pickleball creates a clear gap about performance in this sport. The purpose of this study was to investigate neuromuscular fatigue caused by playing doubles pickleball. Methods: Recreational pickleball players (n = 32, mean age = 60.0 years) were recruited to perform sets of four countermovement jumps (CMJs) on a force plate before and after doubles pickleball matches. Results: For players who had not played a match prior to testing, there was a significant learning effect across trials within the baseline set of jumps for five outcomes from the CMJ test, including propulsive peak force (p = 0.005); however, there was no significant learning effect for jump height. There were significant improvements in the large effect size for all except one dependent variable (propulsive phase time) between the first and second set of jumps (i.e., after one match). Neither further increases nor decreases were seen after the second set of jumps. Conclusions: Participants saw significant increases in CMJ performance across trials after one pickleball match, indicating learning and potentiation effects. After three matches of doubles pickleball, no fatigue effect was detected. Full article

Tennis is an individual sport characterised by high-intensity action, including sprints and changes of direction (COD). However, there is a gap in the knowledge of limb asymmetries in adolescent tennis players and their association with performance. The aim of this study was to investigate the relationship between asymmetry in vertical and horizontal jump tests (CMJ and HJ) and COD with lower limb performance variables in adolescent tennis players. Forty-five adolescent tennis players (age: 13.81 ± 1.08 years; height: 167.64 ± 9.9 cm; body mass: 57.48 ± 10.94 kg; body mass index: 20.27 ± 2.18 kg/m²) performed the CMJ test (unilateral and bilateral), horizontal jumps (unilateral and bilateral), 25 m sprint, and 180° COD test. The single-leg countermovement jump showed the greatest asymmetries among the different tests (6.62 ± 9.35%). Notable negative relationships were found between CMJ asymmetry and COD asymmetry with unilateral horizontal jump variables (r = −0.30 to −0.53). In addition, CMJ asymmetry showed notable relationships with CMJR (r = 0.49) and COD180R (r = 0.29), whereas COD asymmetry showed a notable relationship with COD180L (r = 0.40). On the other hand, HJ asymmetry showed no notable relationships with any variable. The main findings of this study indicate that greater imbalances in the CMJ and COD tests are associated with a reduced capacity to perform unilateral horizontal jumps. These results suggest the incorporation of training protocols to reduce interlimb asymmetries in growing athletes to improve their performance. This practical application is important for coaches and physical trainers who aim to improve the physical performance of adolescent tennis players. Greater asymmetry results in a reduced ability to produce unilateral horizontal force. Full article

Objective: To construct and validate a physical fitness evaluation index system for elite male singles badminton players. Methods: Utilizing the Delphi method to establish a comprehensive evaluation system, the analytic hierarchy process (AHP) was employed to calculate the influence weights of various indicators. The validity of the comprehensive evaluation system was verified using testing methods. Results: After three rounds of expert selection, the physical fitness evaluation index system for elite male singles badminton players includes three primary indicators, nine secondary indicators, and twenty-one tertiary indicators. Among the primary indicators, specialized physical fitness holds a significant weight in the evaluation with a value of 0.651, whereas body morphology has a smaller weight of 0.077. Among the secondary indicators, specialized agility, strength, and endurance have higher weights of 0.223, 0.217, and 0.210, respectively. Among the tertiary indicators, four-corner ball touch, 400 m × 5 shuttle run, smash-and-rush, and vertical jump height hold higher weights of 0.119, 0.114, 0.104, and 0.096, respectively. The results after randomly selecting ten elite male singles badminton players and applying the evaluation index system demonstrated that this system has high feasibility and validity. It can not only comprehensively assess the physical fitness of athletes but also provide significant practical guidance for enhancing their competitive performance. Conclusions: The evaluation system and weight assignments constructed in this study can scientifically and comprehensively reflect the physical fitness status of athletes. It can guide coaches in formulating targeted training plans and optimizing training outcomes. Full article

Background: β-alanine, a non-essential amino acid found in the diet and produced through nucleotide catabolism, is significant for muscle performance due to its role in carnosine synthesis. This study aims to assess the impact of a 4-week β-alanine supplementation on neuromuscular fatigue in individuals engaging in High-Intensity Functional Training (HIFT) and its subsequent effect on sports performance, distinguishing between central fatigue from the CNS and peripheral fatigue from the muscular system. Materials and methods: This study (a randomized controlled trial) comprised a total of 27 subjects, who were divided into two groups. Group A (the control group) was administered sucrose powder, while Group B (the experimental group) was given β-alanine powder. The subjects were randomly assigned to either the experimental or control groups. This study lasted four weeks, during which both groups participated in high-intensity interval training (HIFT) on the first day to induce fatigue and work close to their VO₂ max. Results: Statistically significant changes were in the sports performance variables, specifically vertical jump and jumping power (p = 0.027). These changes were observed only in the group that had been supplemented with β-alanine. Nevertheless, no alterations were observed in any other variables, including fatigue, metabolic intensity of exercise, or perceived intensity (p > 0.05). Conclusions: A four-week β-alanine intake program demonstrated an improvement in the capacity of subjects, as evidenced by enhanced vertical jump and power performance. Nevertheless, it does result in discernible alterations in performance. Full article

This study aimed to investigate the longitudinal evolution of vertical jump height in soccer players and its association with their genotypic profiles. The genotypes of 37 soccer players were characterized and the countermovement jump (CMJ) height, concentric mean power, force, and jump strategy were assessed at two time points: at the onset of the regular season (Pre) and at the conclusion of the first half (Mid). AMPD1 (rs17602729), ACE (rs4646994), ACTN3 (rs1815739), CKM (rs8111989), and MLCK (rs2849757 and rs2700352) polymorphisms were genotyped. No significant differences were found between Pre and Mid in concentric power (p = 0.068; d = 0.08) or force (p = 0.258; d = 0.04), while jump height displayed trivial increases (p = 0.046; d = 0.15). Individual analysis revealed that 38% of participants increased the vertical jump height and mean concentric power over the smallest worthwhile change (SWC), while 27% experienced an increased mean concentric force. The positive responders were characterized by a decreased frequency of the AA genotype and an increased frequency of the CA genotype for the c.37885C>A polymorphism of MLCK (p = 0.035), as well as a decreased frequency of the TT genotype of ACTN3 (p = 0.042) and the CC genotype of AMPD1 (p = 0.022). Our findings suggest that genetic analysis could explain some variability in neuromuscular adaptations during the in-season. Full article

The minimum connected dominating set problem is a combinatorial optimization problem with a wide range of applications in many fields. We propose an efficient local search algorithm to solve this problem. In this work, first, we adopt a new initial solution construction method based on three simplification rules. This method can reduce the size of the original graph and thus obtain a high-quality initial solution. Second, we propose an approach based on a two-level configuration checking strategy and a tabu strategy to reduce the cycling problem. Third, we introduce a perturbation strategy and a vertex weighting strategy to help the algorithm be able to jump out of the local optimum effectively. Fourth, we combine the scoring functions Cscore and Mscore with the aforementioned strategies to propose effective methods for selecting vertices. These methods assist the algorithm in selecting vertices that are suitable for addition to or removal from the current candidate solution. Finally, we verify the performance advantages of the local search algorithm by comparing it with existing optimal heuristic algorithms on two sets of instances. The experimental results show that the algorithm exhibits better performance on two sets of classical instances. Full article

This study aims to assess oculomotor and vestibular endurance by utilizing the Oculomotor and Vestibular Endurance Screening (MoVES) assessment in athletes’ pre-season and post-season and after a suspected head injury to detect impairment. Athletes (N = 311, 19.4 ± 1.3 years) were recruited to perform the following seven tasks: (1) horizontal saccades, (2) vertical saccades, (3) vergence jumps, (4) horizontal vestibular-oculomotor reflex (VOR), (5) vertical VOR, (6) amplitude of accommodation (AoA), and (7) near point of convergence (NPC). At pre-season, the observed number of eye movements in 60 s are horizontal saccades (74 ± 13 initial 30 s; 67 ± 11 latter 30 s), vertical saccades (70 ± 13; 66 ± 10), vergence jumps (48 ± 12; 45 ± 13), horizontal VOR (38 ± 11; 38 ± 11), and vertical VOR (8 ± 11; 38 ± 11). These results establish a normative database for eye movements within the MoVES assessment and show consistency in the number of movements from pre-season to post-season. The initial results show a trending decrease in the number of eye movements in the initial days post-head injury, which improves to pre-season measures 14–21 days post-injury. This foundation can be used by future studies to explore the extent of binocular and vestibular endurance dysfunctions caused by head injuries that subside within two weeks. Full article

This research aims to evaluate whether a basketball-specific warm-up (Basket-Up) provides immediate benefits in terms of the essential physical performance requirements of basketball and to compare these effects to those obtained from FIFA 11+. In total, 95 highly trained basketball athletes (49 women, 46 men), aged between 13 and 17, were randomly divided to either perform the FIFA 11+ program (n = 48) or the Basket-Up program (n = 47). Immediate evaluation encompassed the assessment of vertical jump (countermovement jump), agility (Lane Agility Test), and 20 m sprint. A two-way mixed analysis of variance was conducted with time (preintervention and postintervention), sex (men and women), and training group (FIFA 11+ and Basket-Up) as the within- and between-participant factors, respectively. Agility (p < 0.001, F = 66.759) and jumping (p < 0.001, F = 78.062) outcomes exhibited significant differences between pre- and postintervention values in both groups. Basket-Up agility values were significantly higher than those from FIFA 11+ (p = 0.001, F = 12.998). The implementation of a specific basketball warm-up program (Basket-Up) appears to be both safe and effective in enhancing immediate athletic performance among highly trained young basketball athletes. Moreover, the effects of this program are comparable to those obtained by a nonspecific basketball warm-up (FIFA 11+) in terms of sprint and jumping performance but demonstrate superiority in agility outcomes, favoring the Basket-Up program. Full article

It is of great significance for coal safety production and water resource protection in the Yuheng mining area to master the evolution law of water-conducting fractures under the condition of thick and hard overburden. This research focuses on the 2102 fully mechanized mining face in the Balasu Coal Mine as the research background. The fracture evolution and strata movement characteristics in thick and hard overlying strata are simulated and analyzed by combining numerical simulation with physical simulation, and the formation mechanism of a water-conducting fracture in the overlying strata is revealed and verified by field measurements of the development height of “two zones”. The results show that the anisotropy of fracture propagation in low-position overlying strata is high, and the fracture propagation in high-position overlying strata is mainly vertical, which indicates characteristics of leapfrog development. The number and development height of fractures undergo the change–growth process of “slow–rapid–uniform”. Multiple rock strata together form a complex force chain network with multiple strong chain arches. The local stress concentration leads to the initiation of micro-cracks in contact fractures, and the cracks gradually penetrate from bottom to top and then the strong chain arches are broken. The water-conducting cracks in overlying strata show a dynamic expansion process of “local micro-cracks–jumping cracks–through cracks–water-conducting cracks”. The fracture between the caving zone and fracture zone presents obvious layered characteristics, the overall shape of the water-conducting fracture zone is “saddle-shaped”, and the maximum development height lags behind the coal mining face by about 180 m. Through the observation of water injection leakage and borehole TV observation of three boreholes under underground construction, combined with the results of water pressure tests, it is comprehensively determined that the height of the water-conducting fracture zone is 103.68~107.58, and the fracture–production ratio is 31.42~32.60, which is basically consistent with the results of numerical simulation and physical simulation. This research provides theoretical guidance and a scientific basis for coal mine water disaster prevention under similar geological conditions. Full article

This study adopted a quasi-experimental design to explore the effects of fundamental movement skill intervention on the acquisition and retention of physical activity levels and health-related fitness in children with autism spectrum disorder (ASD). In the experiments, 11 children received fundamental motor skill training (12 weeks, 60 min/session, 4 times/week), and 10 children maintained traditional physical activity. Assessments were performed using an ActiGraph GT3X+ accelerometer, health-related fitness pre–post intervention, and 1-month follow-up tests. The sedentary time during physical activity was significantly decreased (p = 0.01), and there were large changes in health-related physical fitness indicators, including significantly improved body composition (body mass index, F(1,19) = 8.631, p = 0.03, partial η² = 0.312), muscle strength and endurance (sit-ups, F(1,19) = 3.376, p = 0.02, partial η² = 0.151 and vertical jumps, F(1,19) = 5.309, p = 0.04, partial η² = 0.218), and flexibility (sit and reach, F(1,19) = 36.228, p = 0.02, partial η² = 0.656). Moreover, the follow-up tests showed that the children’s sedentary time continued to reduce, and the muscle strength and endurance (sit-ups, F(1,19) = 4.215, p = 0.01, partial η² = 0.426) improved continuously after the intervention. Based on this study, actionable and regular fundamental movement skill programs can be provided in the future as an effective way to achieve the healthy development goals of children with ASD. Full article

Traditional motion analysis systems are impractical for widespread screening of non-contact anterior cruciate ligament (ACL) injury risk. The Kinect V2 has been identified as a portable and reliable alternative but was replaced by the Azure Kinect. We hypothesize that the Azure Kinect will assess drop vertical jump (DVJ) parameters associated with ACL injury risk with similar accuracy to its predecessor, the Kinect V2. Sixty-nine participants performed DVJs while being recorded by both the Azure Kinect and the Kinect V2 simultaneously. Our software analyzed the data to identify initial coronal, peak coronal, and peak sagittal knee angles. Agreement between the two systems was evaluated using the intraclass correlation coefficient (ICC). There was poor agreement between the Azure Kinect and the Kinect V2 for initial and peak coronal angles (ICC values ranging from 0.135 to 0.446), and moderate agreement for peak sagittal angles (ICC = 0.608, 0.655 for left and right knees, respectively). At this point in time, the Azure Kinect system is not a reliable successor to the Kinect V2 system for assessment of initial coronal, peak coronal, and peak sagittal angles during a DVJ, despite demonstrating superior tracking of continuous knee angles. Alternative motion analysis systems should be explored. Full article

(1) Background: The objective of the present study was to analyze the association of physical fitness, specifically lower limb strength, abdominal strength, vertical jump, and grip strength, with cognitive performance, specifically focusing on selective attention and memory in children aged 7 to 12 years. (2) Methods: Two hundred twenty-seven students participated in this study. Pearson correlation was used to analyze potential relationships between the independent variables and dependent variables. (3) Results: In relation to physical fitness, a higher number of abdominal repetitions performed in 30 s showed a significant and positive association with a higher number of correct responses assessed by the Stroop Test. Furthermore, at a functional level, higher grip strength correlated with a greater number of correct responses and a higher average correct response time in the Stroop Test. Additionally, grip strength showed a significant and positive correlation with the number of words recalled assessed by the word recall test. Our key findings showed a significant association of grip strength with the categories of cognitive status, selective attention, and memory. (4) Conclusions: This study reveals that physical fitness levels, especially grip strength and abdominal strength, correlate with selective attention capacity in primary school students. Full article

The Orthelligent Pro sensor is a practicable, portable measuring instrument. This study assessed the validity and reliability of this sensor in measuring single-leg countermovement jumps. Fifty healthy athletic adults participated in two measurement sessions a week apart in time. They performed single-leg countermovement jumps on the force plate while wearing the Orthelligent Pro sensor on their lower leg. During the first measurement session, Tester 1 invited the participants to make three single-leg countermovement jumps; subsequently, Tester 2 did the same. For assessing the sensor’s intratester reliability, Tester 1 again invited the participants to make three single-leg countermovement jumps during the second measurement session. The sensor’s validity was assessed by using the force plate results as the gold standard. To determinate the agreement between two measurements, Bland–Altman plots were created. The intertester reliability (ICC = 0.99; 0.97) and intratester reliability (ICC = 0.96; 0.82) were both excellent. The validity calculated (i) on the basis of the mean value of three jumps and (ii) on the basis of the maximum value of three jumps was very high, but it showed a systematic error. Taking this error into account, physiotherapists can use the Orthelligent Pro sensor as a valid and reliable instrument for measuring the jump height of countermovement jumps. Full article