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Purpose: To compare the effects of 6-week barbell weighted-jump-squat (WJS) training with and without eccentric load reduction on explosive performance. Methods: Twenty well-trained male athletes were randomly assigned to either an experimental group (n = 10) or a control group (n = 10). Participants completed 12 WJS training sessions (6 sets of 5 repetitions of barbell back squat at 30% of 1-repetition maximum [1RM]) twice a week over a 6-week period. While the control group used 0% eccentric loading (ie, traditional WJS), the experimental group utilized a 50% eccentric loading reduction with a mechanical braking unit (ie, eccentric load set at 15% of 1RM). Performance assessments, including countermovement jump, 20-m sprint, standing long jump, and 1RM barbell back squat, were conducted both before (pretests) and after (posttests) the intervention. Results: Both the experimental group and the control group demonstrated a significant increase in countermovement-jump height (+6.4% [4.0%] vs +4.9% [5.7%]; P <.001) and peak power output (+2.3% [2.7%] vs +1.9% [5.1%]; P =.017), faster 20-m sprint times (+9.4% [4.8%] vs +9.2% [5.5%]; P <.001), longer standing long jump (+3.1% [2.5%] vs +3.0% [3.3%]; P <.001), and higher 1RM back squat (+6.4% [4.0%] vs +4.9% [5.7%]; P <.001) from pretests to posttests. However, there was no significant condition × time interaction for any variable (all P ≥.294). Conclusions: Both WJS training methods, with and without load reduction in the eccentric phase, effectively enhance explosive performance. Nevertheless, athletes in later stages of injury rehabilitation or intense training may find reducing eccentric load a more tolerable strategy for achieving similar performance gains compared with traditional isoinertial loading. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to compare the maximum and rapid force production of Spanish football players and explore the differences between age group and level of competition. Methods: A cross-sectional study was developed to evaluate the peak force (PF), relative PF, and rate of force development over 250 ms (RFD0−250) during the isometric midthigh pull between groups of football players based on age group (senior vs junior) and level of competition (national vs regional). Using a portable isometric rig, 111 football players performed 2 isometric midthigh-pull trials on a force plate. Two-way analysis of variance with Bonferroni post hoc correction was applied, and statistical significance was set at P ≤.05. The PF, relative PF, and RFD0−250 0, 25, 50, 75, and 100 percentiles were also calculated and descriptively reported, separated by age group and level of competition. Results: The analysis of variance revealed a significant main effect of the level of competition for the PF (P <.001), relative PF (P =.003), and RFD0−250 (P <.001). There was a significant main effect of age group for the PF (P <.001). There was a significant interaction effect of the age group × level of competition for relative PF (P =.014). National players were stronger than regional players on the PF and RFD0−250 (P <.001). Senior players were stronger than junior players for the PF (P <.001). Conclusions: Maximum and rapid force production are crucial for Spanish football players as they progress in both level of competition and age group. Practitioners should encourage young football players to prioritize strength development to improve their athletic performance. [ABSTRACT FROM AUTHOR]

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

Purpose: To compare the effects of graded hypoxia during exhaustive intermittent cycling on subsequent rapid and maximal torque-production capacity. Methods: Fifteen well-trained cyclists repeated intermittent cycling bouts (15 s at 30% of anaerobic power reserve; rest = 45 s) until exhaustion at sea level (FiO2 ∼0.21/end-exercise arterial oxygen saturation ∼96%), moderate hypoxia (FiO2 ∼0.16/∼90%), and severe hypoxia (FiO2 ∼0.12/∼79%). Rapid (rate of torque development [RTD]) and maximal isometric torque-production capacities of the knee extensors were assessed at baseline (visit 1) and exhaustion (visits 2–4). Results: Exercise capacity decreased with hypoxia severity (39 [30], 22 [13], and 13 [6] cycle efforts in sea level, moderate hypoxia, and severe hypoxia, respectively; P =.002). Changes in maximal-voluntary-contraction torque between baseline and postexercise in all conditions were not statistically significant (pooled values: −2.6% [5.7%]; P =.162). Peak RTD measured postexercise was reduced below baseline in all conditions (–21.5% [5.1%]; P ≤.015). Compared with baseline, absolute RTD values were lower at 0- to 30-millisecond (–35.1% [5.3%], P ≤.020), 0- to 50-millisecond (–40.0% [3.9%], P ≤.002), 0- to 100-millisecond (–30.7% [3.7%], P ≤.001), and 0- to 200-millisecond (–18.1% [2.4%], P ≤.004) time intervals in all conditions. Conclusions: Exhaustive intermittent cycling induces substantial yet comparable impairments in RTD of knee extensors between normoxia and moderate to severe hypoxia. [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.)

Objective: The purpose of this systematic review and meta-analysis was to investigates whether transcranial direct current stimulation applied during physical training increases muscle strength in comparison with sham tDCS combined with physical training. Methods: Randomized controlled trials of the effects of tDCS combined physical training intervention on muscle strength and cortical excitability were collected by searching Web of Science, Pubmed, EBSCO, CNKI. The retrieval date ends in April 2024. 11 randomized controlled trials are finally included. The total sample size of the study is 338. The experimental group was subjected to tDCS combined with physical training intervention, and the control group was physical training combined with sham tDCS intervention. Results: There is a significant increase in maximal strength (SMD = 0.38; 95% CI: 0.09, 0.67; p = 0.01) and lower limb explosive strength (MD = 2.90; 95% CI: 1.06, 4.74; p = 0.002) when physical training was performed with tDCS, but not following physical training combined with sham tDCS. Subgroup analysis of the subject population showed an increase in muscle strength in those with training experience following tDCS combined with physical training (SMD = 0.39; 95% CI: 0.08, 0.70; p = 0.01), but not for those without training experience (SMD = 0.29; 95% CI: −0.06, 0.63; p = 0.10). Motor evoked potential (MEP) wave amplitude increased significantly following physical training with tDCS (SMD = 0.71; 95% CI: 0.18, 1.24; p = 0.008), but was not different between groups (SMD = 0.16; 95% CI: −0.33, 0.65; p = 0.52). Conclusions: tDCS combined with physical training intervention can improve muscle strength, lower limb explosive strength and cerebral cortex excitability. Compared to tDCS combined with training of small muscle groups, tDCS combined with training of large muscle groups was more effective in improving muscle strength. Muscle strength was more likely to improve after tDCS combined with physical training in people with physical training experience compared with people without physical training experience. The combination of tDCS with physical training intervention and the sham-tDCS with physical training intervention both increased cortical excitability. Systematic Review Registration: https://www.crd.york.ac.uk/ , PROSPERO, identifier (CRD42024550454). [ABSTRACT FROM AUTHOR]

Introduction: The drop vertical jump (DVJ) is extensively utilized for conditioning and evaluating physical performance, as well as reducing the likelihood of injury by enhancing joint stability through the coactivation of muscles acting on the joint. The execution of DVJ can be controlled by verbal instructions and evaluated by the vertical ground reaction force (vGRF)-time profile. Methods: Our hypothesis was that varying verbal instructions could have an impact on the DVJ's parameter, thereby optimizing vertical performance and minimizing the impact during landing in young female volleyball players. Sixteen female volleyball players volunteered to participate in this study (age: 21.3 ± 2.6 years; stature: 1.66 ± 0.1 m; body mass: 62.0 ± 8.1 kg and BMI: 22.2 ± 1.8). They executed DVJs following verbal instructions ranging from "jump as high as possible" (1A), "jump as quickly as possible" (2A), "jump as high as possible and during the landing attempt to dampen the impact at ground contact" (1B), and "jump as high as quickly as possible and during the landing attempt to damp the impact at ground contact" (2B). The reactive strength index (RSI), vGRF (1st and 2nd peaks), and flight time (FT) were evaluated. Results: The verbal instructions 1A improved the FT and the first peak of the vGRF (P < 0.05), whereas 2A the RSI (P < 0.05). On the contrary, "the damping" required in the 1B, and 2B verbal instruction reduced the 2nd peak of vGRF (P < 0.05), without altering the task required during the jump (P < 0.05). Discussion: The instructions provided for the final landing (the second peak of vGRF) have the potential to enhance safety by reducing the peak of vGRF without affecting the performance required during the jump. When designing DVJ training, coaches or kinesiologists must consider the use of verbal instructions to induce specific adaptation over time. Clinical relevance: The present study supports the use of specific verbal instructions to reduce impact forces in landing and injury risk. [ABSTRACT FROM AUTHOR]

The removal of skeletal muscle tension (unloading or disuse) is followed by many changes in the neuromuscular system, including muscle atrophy and loss of isometric maximal strength (measured by maximal force, Fmax). Explosive strength, i.e. the ability to develop the highest force in the shortest possible time, to maximise rate of force development (RFD), is a fundamental neuromuscular capability, often more functionally relevant than maximal muscle strength. In the present review, we discuss data from studies that looked at the effect of muscle unloading on isometric maximal versus explosive strength. We present evidence that muscle unloading yields a greater decline in explosive relative to maximal strength. The longer the unloading duration, the smaller the difference between the decline in the two measures. Potential mechanisms that may explain the greater decline in measures of RFD relative to Fmax after unloading are higher recruitment thresholds and lower firing rates of motor units, slower twitch kinetics, impaired excitation‐contraction coupling, and decreased tendon stiffness. Using a Hill‐type force model, we showed that this ensemble of adaptations minimises the loss of force production at submaximal contraction intensities, at the expense of a disproportionately lower RFD. With regard to the high functional relevance of RFD on one hand, and the boosted detrimental effects of inactivity on RFD on the other hand, it seems crucial to implement specific exercises targeting explosive strength in populations that experience muscle disuse over a longer time. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this systematic review and meta-analysis was to investigates whether transcranial direct current stimulation applied during physical training increases muscle strength in comparison with sham tDCS combined with physical training. Methods: Randomized controlled trials of the effects of tDCS combined physical training intervention on muscle strength and cortical excitability were collected by searching Web of Science, Pubmed, EBSCO, CNKI. The retrieval date ends in April 2024. 11 randomized controlled trials are finally included. The total sample size of the study is 338. The experimental group was subjected to tDCS combined with physical training intervention, and the control group was physical training combined with sham tDCS intervention. Results: There is a significant increase inmaximal strength (SMD= 0.38; 95%CI: 0.09, 0.67; p = 0.01) and lower limb explosive strength (MD= 2.90; 95% CI: 1.06, 4.74; p = 0.002) when physical training was performed with tDCS, but not following physical training combined with sham tDCS. Subgroup analysis of the subject population showed an increase in muscle strength in those with training experience following tDCS combined with physical training (SMD= 0.39; 95% CI: 0.08, 0.70; p = 0.01), but not for those without training experience (SMD = 0.29; 95% CI: 0.06, 0.63; p = 0.10). Motor evoked potential (MEP) wave amplitude increased significantly following physical training with tDCS (SMD = 0.71; 95% CI: 0.18, 1.24; p = 0.008), but was not different between groups (SMD= 0.16; 95% CI: 0.33, 0.65; p=0.52). Conclusions: tDCS combined with physical training intervention can improve muscle strength, lower limb explosive strength and cerebral cortex excitability. Compared to tDCS combined with training of small muscle groups, tDCS combined with training of large muscle groups was more effective in improving muscle strength. Muscle strength was more likely to improve after tDCS combined with physical training in people with physical training experience compared with people without physical training experience. The combination of tDCS with physical training intervention and the sham-tDCS with physical training intervention both increased cortical excitability. [ABSTRACT FROM AUTHOR]

Problem statement and purpose: Soccer, involves high-intensity bouts and unpredictable demands, requiring a thorough understanding of the sport's physical requirements for to optimize training strategies. Professional players cover substantial distances during matches, frequently shifting between different intensity levels. While most actions are of lower intensity, high-intensity efforts, such as sprints and rapid changes of direction, play a critical role in performance. Approach: Comprehensive evaluations, including the Countermovement Jump (CMJ) and Mognoni Test, are critical to capture physiological results and ensure high-level performance throughout the season. A cohort of 28 male professional soccer players from a Serie C team underwent assessments at three points during the season. Tests included anthropometric measurements, the Mognoni field test for aerobic capacity, CMJ for explosive strength, and a High Intensity Running Test (HIT). All tests were conducted under standardized conditions, and statistical analyses employed ANOVA or Krustal-Wallis tests. Results: Body fat percentage significantly decreased across evaluations, indicating a positive adaptation. Blood lactate concentrations in both Mognoni and HIT tests decreased, suggesting improved aerobic capacity and adaptation to high-intensity training. CMJ parameters remained stable, except for a decrease in CMJ normalized power. Individual variability in vertical jump performance emphasizes the need for continual neuromuscular stimulation. The results showed dynamic physiological adaptations during the soccer season. Conclusion: Our study suggests that optimizing body composition, monitoring training loads, and addressing individual responses are crucial for effective training. Coaches should prioritize monitoring power normalized per weight and blood lactate during the competitive season to tailor interventions for maximal efficiency in explosive movements and overall performance. [ABSTRACT FROM AUTHOR]

Background and Study Aim. The physical demands of the winger position in elite handball require a unique combination of upper body speed and lower body strength. Therefore, identifying the optimal relationship between these two physical characteristics could improve performance for players in this role. This study aims to analyze the relationship between upper body speed capacity and lower body strength in elite handball players specializing in the winger position. Material and Methods. The study included 16 elite handball players specializing in the winger position from various teams in the National Handball League (Liga Zimbrilor). Four of these players were members of the Dinamo Bucharest team. Tests for evaluating the explosive strength of the lower limbs included the Squat Jump (SJ), Counter Movement Jump (CMJ), Counter Movement Jump with Free Arms (CMJb), and the maximum strength test (1RM) in squats. Specific technical training tests included triangular movement, a 30-meter sprint, and long-distance handball throws, focusing on speed and execution technique. Data analysis was conducted using KyPlot 6.0 software. Statistical indicators included median, standard deviation, coefficient of variation, and non-parametric Spearman correlation tests. Statistical significance was set at p < 0.05. Results. The results show no statistically significant differences in lower limb strength between high-performance handball players (HPHP) and those specialized in the winger position (PSW) across various jump and squat tests (p > 0.05). The Countermovement Jump (CMJ) test approached statistical significance (p = 0.084), while the CMJ with free arms (CMJb) and squat strength test did not show significant differences (p = 0.231 and p = 0.789, respectively). In the specific fitness tests, no significant differences were observed in the Triangle Movement test (p = 0.826), the 30-meter sprint (p = 0.404), or the handball throw test (p = 0.147). Correlation analysis indicated that squats and CMJb had positive correlations with improved performance in speed and distance tests, while CMJ showed a negative correlation with technical performance in agility tests. Conclusions. The findings suggest that lower limb strength and technical fitness are similar between elite handball players, regardless of specialization. This supports a unified training approach across player roles. However, targeted exercises like squats and CMJb may enhance specific performance aspects. These exercises improve dynamic strength and stability, which can benefit wingers' technical execution and speed.

Purpose: This study examined the acute influence of a bench press (BP) loading on the explosive squat (SQ) performance and vice versa. Methods: Nineteen strength-trained men completed 2 experimental sessions consisting of either a SQ+BP loading or a BP+SQ loading with 3 × 5 + 3 × 3 repetitions at 80% of the 1-repetition maximum in a randomized order. SQ and BP mean propulsive velocity (MPV) were assessed during both loadings, at baseline (T0) as well as immediately after the first (T1) and second strength loading (T2). Results: Both BP and SQ MPV decreased between T0 and T1 in SQ+BP (−6.13 ± 6.13%, p =.014, g = 0.485 and −9.11 ± 7.23%, p <.001, g = 0.905, respectively) and BP+SQ (−15.15 ± 7.69%, p <.001, g = 1.316 and −7.18 ± 6.16%, p <.001, g = 0.724, respectively). Mean BP MPV was lower in set 2 to set 6 in SQ+BP when compared to BP+SQ (−7.90% − 9.88%, all p <.05, g = 0.523–0.808). Mean SQ MPV was lower in set 1 and set 4 in BP+SQ when compared to SQ+BP (−4.94% − 5.22%, all p <.001, g = 0.329–0.362). Conclusions: These results demonstrate that the presence of non-local muscle fatigue affects the movement velocity. Therefore, if a training program aims to perform strength training exercises with maximal movement velocity, it is essential to carefully evaluate whether upper and lower body exercises should be carried out within close proximity. [ABSTRACT FROM AUTHOR]

Background and Study Aim The physical demands of the winger position in elite handball require a unique combination of upper body speed and lower body strength. Therefore, identifying the optimal relationship between these two physical characteristics could improve performance for players in this role. This study aims to analyze the relationship between upper body speed capacity and lower body strength in elite handball players specializing in the winger position. Material and Methods The study included 16 elite handball players specializing in the winger position from various teams in the National Handball League (Liga Zimbrilor). Four of these players were members of the Dinamo Bucharest team. Tests for evaluating the explosive strength of the lower limbs included the Squat Jump (SJ), Counter Movement Jump (CMJ), Counter Movement Jump with Free Arms (CMJb), and the maximum strength test (1RM) in squats. Specific technical training tests included triangular movement, a 30-meter sprint, and long-distance handball throws, focusing on speed and execution technique. Data analysis was conducted using KyPlot 6.0 software. Statistical indicators included median, standard deviation, coefficient of variation, and non-parametric Spearman correlation tests. Statistical significance was set at p < 0.05. Results The results show no statistically significant differences in lower limb strength between highperformance handball players (HPHP) and those specialized in the winger position (PSW) across various jump and squat tests (p > 0.05). The Countermovement Jump (CMJ) test approached statistical significance (p = 0.084), while the CMJ with free arms (CMJb) and squat strength test did not show significant differences (p = 0.231 and p = 0.789, respectively). In the specific fitness tests, no significant differences were observed in the Triangle Movement test (p = 0.826), the 30-meter sprint (p = 0.404), or the handball throw test (p = 0.147). Correlation analysis indicated that squats and CMJb had positive correlations with improved performance in speed and distance tests, while CMJ showed a negative correlation with technical performance in agility tests. Conclusions The findings suggest that lower limb strength and technical fitness are similar between elite handball players, regardless of specialization. This supports a unified training approach across player roles. However, targeted exercises like squats and CMJb may enhance specific performance aspects. These exercises improve dynamic strength and stability, which can benefit wingers' technical execution and speed. [ABSTRACT FROM AUTHOR]

The aim of the study was to implement a training program consisting of plyometric exercises using modern technologies to improve the explosive strength of junior basketball players. The study addresses this necessity by investigating the transformative impact of a customized plyometric training program on the explosive strength of 19 female basketball players aged 10 to 12. In the study, a two-month program of specific plyometric development exercises adapted to the basketball game was implemented, focused on improving the key parameters of explosive resistance. Specifically, improvements in flight time and height, assessed through five specific tests: Squat Jump Test, Drop Jump Test, Stiffness Test, 15 seconds Jump Test, 30 seconds Jump Test. In all 5 tests, the recorded progress was statistically significant compared to the reference value p < 0.05. Cohen's values reflect a very large effect size > 0.8 for all tests with one exception for the Stiffness Test where the effect size was only large in the 0.5-0.8 range. The research contributes valuable insights into age-specific athletic development, advocating for the optimization of physical and technical readiness in young basketball players through targeted plyometric training sessions. [ABSTRACT FROM AUTHOR]

Volleyball primarily focuses on technical and tactical training with a ball. However, there is growing interest in integrating fitness training into volleyball practice, particularly to enhance explosive strength through plyometric methods, but there is a lack of a direct scientific comparison between training with and without the ball. This study aimed to compare the effects of two training protocols on volleyball players. One protocol combined plyometric exercises with technical gestures (wall drills) using the ball, while the other protocol excluded the ball during plyometric exercises. Twenty male volleyball players (aged 18.6 ± 0.3 years, height 189.8 ± 2.2 cm, weight 79.4 ± 1.6 kg) were divided into experimental (with ball) and control (without ball) groups. The analysis of the results highlights significant improvements in both the squat jumps (SJs) and the countermovement jumps with arm swing (CMJas) for both groups. While there were no significant differences between the groups for SJ, significant differences emerged in CMJas, indicating varied training effects. Specifically, the interaction effect was significant (p = 0.004), demonstrating a meaningful distinction in performance improvements between the two groups. The effect size of the interaction is moderate (ηp2 = 0.37, 95% CI: 0; 0.91). These results suggest that incorporating a ball into plyometric training can be beneficial for developing explosive strength in a different way, thereby improving performance due to the motivational stimulus provided. However, given the specificity of the sample and the training protocols used, further studies are needed to confirm these results and evaluate their applicability to a larger sample of volleyball players. [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]

IntroductionThe drop vertical jump (DVJ) is extensively utilized for conditioning and evaluating physical performance, as well as reducing the likelihood of injury by enhancing joint stability through the coactivation of muscles acting on the joint. The execution of DVJ can be controlled by verbal instructions and evaluated by the vertical ground reaction force (vGRF)-time profile.MethodsOur hypothesis was that varying verbal instructions could have an impact on the DVJ's parameter, thereby optimizing vertical performance and minimizing the impact during landing in young female volleyball players. Sixteen female volleyball players volunteered to participate in this study (age: 21.3 ± 2.6 years; stature: 1.66 ± 0.1 m; body mass: 62.0 ± 8.1 kg and BMI: 22.2 ± 1.8). They executed DVJs following verbal instructions ranging from “jump as high as possible” (1A), “jump as quickly as possible” (2A), “jump as high as possible and during the landing attempt to dampen the impact at ground contact” (1B), and “jump as high as quickly as possible and during the landing attempt to damp the impact at ground contact” (2B). The reactive strength index (RSI), vGRF (1st and 2nd peaks), and flight time (FT) were evaluated.ResultsThe verbal instructions 1A improved the FT and the first peak of the vGRF (P

Explosive strength is fundamental in the performance of athletes. The objective is to identify the criteria used for the prescription of Explosive Strength Training (EST) and to verify the changes it produces in futsal players. A systematic review of studies analyzing the criteria used for the prescription of explosive strength training was conducted in PubMed/MEDLINE and Scielo, considering the period between 2017 and 2023. The search strategy used the terms: players, Futsal, Futsal training, strength, physical exercise, explosive strength, intervention, experimental study. Data extraction included: year of publication, country, sample, protocol performed (content and activity developed, duration, intensity, frequency, total weeks). A total of six studies were identified. Fifty percent of the studies were developed in Brazil, the others in Italy, Spain and Portugal. Five studies applied a training of 2 sessions per week and one indicated 2-3 sessions. Three studies describe the training sessions (study 1: 15-30 minutes, study 2: 20-25 minutes, study 3: 1 hour). Five studies used 1RM and one study used subjective perception of exertion (PSE). The contents of the interventions were varied, from squats with weights, accelerations and decelerations, leg press, leg extension, plyometrics. The training criteria for explosive strength were: intensity controlled by a 1RM, frequency of 2 to 3 sessions per week, duration of 15 to 30 minutes per session and the training contents were varied. These results suggest positive changes in CMJ, increasing explosive strength from ∼2.0 to 4.6 cm (5.8 to 13.7%). These findings highlight the need to develop a more standardized protocol to optimize the benefits of explosive strength training in this athletic population.

Volleyball is a sport that involves dynamic movements characterized by explosive force, including vertical jumping, forward jumping, and overhead ball throwing. The objective of this study was to investigate the impact of inhibition and mobilization techniques on explosive force outputs in female volleyball players. A total of 13 female volunteer athletes, aged between 18 and 27, from a volleyball team in Istanbul, were included in the study. The volunteers were assigned randomly and divided into two groups: the Foam Roller Group (FRG) with a sample size of 7, and the Activation Group (AG) with a sample size of 6. The selection of movements applied to the athletes was based on the muscle groups that are consistently utilized in both indoor and beach volleyball. The foam roller group applied soft cylindrical foam for 30 seconds to the gastrocnemius, biceps femoris, TFL (band), piriformis, and latissimus dorsi muscle groups. The activation group performs two sets of mini band abductions, which consist of four movements lasting 20 seconds each. Additionally, they do swiss ball prone cobra, swiss ball lying leg extensions, and mini band tibialis pull movements. Prior to training, all athletes underwent measurements for vertical jump (VJ), forward jump (FJ), and overhead ball throwing (BT). Once the FRG (Force-Recruitment Gain) and AG (Activation Gain) studies were finished for both groups, the measurements were recorded by repeating the Vertical Jump (VJ), Force Jump (FJ), and Ballistic Throw (BT) tests. This was done to assess how these tests influenced the explosive force outputs. The statistical analysis of the study using the SPSS 25.0 program did not find any notable difference (DS 0.086; IS 0.886; BF 0.174). However, in the FJ test, the FRG showed a statistically significant decrease in the pre-post-test measurement, with values of 2.12 ± 0.16 before the test and 1.99 ± 0.14 after the test. Consequently, while there is no detriment in engaging in short-term FR (flexibility and mobility) and activation exercises prior to sports performance, it can be inferred that these practices are carried out in order to mitigate the likelihood of injury.

Objective: The detection and classification of sarcopenia involves the analysis of many variables (50 to 60), which increases the time and costs required to diagnose and manage this condition. The objective of the study was to develop a synthetic statistical index to diagnose and classify sarcopenia in physically active women over 60 years old. Methodology: We conducted a cross-sectional study on 100 physically active women (64.88 ±4.4 years) on whom body composition measurements, muscle strength, and gait tests were performed. One thousand random selections of both training and test sets (80% and 20%, respectively) were made, logistic regression was fitted, and the regularization procedure (Elastic net regression) was performed. Results: the skeletal appendicular mass index (kg/m2), muscle mass (kg/m2) and SAMI (kg/m2) are highly correlated (0.93) and slow gait speed (m/sec) were the variables that contributed the most to the diagnosis of sarcopenia with a visibly high correlation, (94%). Conclusion: appendicular lean mass, gait speed, and explosive strength sufficiently describe the state of muscle and functional deterioration (sarcopenia) in physically active older women. Also, the precise identification and classification of this condition facilitates comprehensive multidisciplinary intervention, increasing the positive impact of health promotion and disease prevention programs

In the study, the acute effects of two different concurrent training models including high intensity interval training (HIIT) and high intensity interval functional training (HIFT) plus strength training (S) on physiological indicators (lactate and heart rate) and performance (balance and explosive power) parameters were examined in soccer players. A total of 13 moderately active young soccer players (19.92; ±1.44 years) participated in the study. In the study, body composition measurements, heart rate, lactate, explosive strength measurement and balance testing were measured. Training models (S+HIIT-S+HIFT) were applied sequentially with a crossover design. The training sessions were conducted with a three-day interval. Parameters were analyzed with SPSS24 (SPSS Inc., Chicago, IL, USA). Repeated Measure Analysis of Variance (ANOVA) was used for repeated measures and Bonferroni Correction was used for pairwise comparisons. Significance level was accepted as p

Probiotics are posited to enhance exercise performance by influencing muscle protein synthesis, augmenting glycogen storage, and reducing inflammation. This double-blind study randomized 88 participants to receive a six-week intervention with either a placebo, Lactococcus lactis subsp. lactis LY-66, Lactobacillus plantarum PL-02, or a combination of both strains, combined with a structured exercise training program. We assessed changes in maximal oxygen consumption (VO2max), exercise performance, and gut microbiota composition before and after the intervention. Further analyses were conducted to evaluate the impact of probiotics on exercise-induced muscle damage (EIMD), muscle integrity, and inflammatory markers in the blood, 24 and 48 h post-intervention. The results demonstrated that all probiotic groups exhibited significant enhancements in exercise performance and attenuation of muscle strength decline post-exercise exhaustion (p < 0.05). Notably, PL-02 intake significantly increased muscle mass, whereas LY-66 and the combination therapy significantly reduced body fat percentage (p < 0.05). Analysis of intestinal microbiota revealed an increase in beneficial bacteria, especially a significant rise in Akkermansia muciniphila following supplementation with PL-02 and LY-66 (p < 0.05). Overall, the combination of exercise training and supplementation with PL-02, LY-66, and their combination improved muscle strength, explosiveness, and endurance performance, and had beneficial effects on body composition and gastrointestinal health, as evidenced by data obtained from non-athlete participants. [ABSTRACT FROM AUTHOR]

Purpose: The power push-up test can reveal significant differences in evaluating upper extremity strength. The aim of this study was to investigate the test–retest reliability of the parameters produced from the force platform of the power push-up test in young swimmers. Methods: A total of 35 swimmers (age: 15.8 ± 2.6 years) participated in this study. Flight time (FT), peak force (PF), mean force (MF), rate of force development (RFD), and impulse were analyzed from the force platform. Results: There was no difference between the two measurements for all parameters (p > 0.05). Intraclass correlation coefficient (ICC) and coefficient of variation (CV %) showed that some parameters from the force platform were highly reliable (ICC: RFD (0.94) FT, (0.96), PF (0.98), MF (0.97), impulse (0.97), CV%: RFD (50%), FT (20%), PF (17%), MF (18%), impulse (25%). Conclusion: The results of this study showed that the parameters obtained from the power push-up test performed on the force platform are a reliable tool for swimmers and can be used by practitioners by carefully interpreting them. [ABSTRACT FROM AUTHOR]

Background: Generalized joint hypermobility (GJH) is prevalent among young adults, necessitating effective monitoring of musculoskeletal health, particularly among college-aged females. This study aimed to identify physical fitness and health-related quality of life (HR-QoL) characteristics associated with GJH. Methods: A total of 67 participants were assessed: 26 with GJH (mean age 20.06, SD 1.2 years), and 41 without (mean age 20.15, SD 2.2 years). Assessments included hypermobility, anthropometric data, foot posture, balance, flexibility, strength, and HR-QoL. We used the Mann–Whitney test for two independent samples, categorical variables were analyzed with Cramer's V test. The results indicated that participants with GJH exhibited inferior balance and back muscle static strength endurance but greater flexibility compared to those without GJH. Significant differences were observed in foot posture. However, handgrip strength, explosive strength, and abdominal muscle static strength endurance did not differ significantly between groups. No significant differences were observed in HR-QoL components between the two groups. In conclusion, there appears to be a link between GJH and increased flexibility, impaired balance, reduced back muscle static strength endurance, and altered posture of both feet. [ABSTRACT FROM AUTHOR]

This study aimed to compare neuromuscular fatigability of the elbow flexors and extensors between athletes with amputation (AMP) and athletes with spinal cord injury (SCI) for maximum voluntary force (MVF) and rate of force development (RFD). We recruited 20 para-athletes among those participating at two training camps (2022) for Italian Paralympic veterans. Ten athletes with SCI (two with tetraplegia and eight with paraplegia) were compared to 10 athletes with amputation (above the knee, N = 3; below the knee, N = 6; forearm, N = 1). We quantified MVF, RFD at 50, 100, and 150 ms, and maximal RFD (RFDpeak) of elbow flexors and extensors before and after an incremental arm cranking to voluntary fatigue. We also measured the RFD scaling factor (RFD-SF), which is the linear relationship between peak force and peak RFD quantified in a series of ballistic contractions of submaximal amplitude. SCI showed lower levels of MVF and RFD in both muscle groups (all p values ≤ 0.045). Despite this, the decrease in MVF (Cohen's d = 0.425, p < 0.001) and RFDpeak (d = 0.424, p = 0.003) after the incremental test did not show any difference between pathological conditions. Overall, RFD at 50 ms showed the greatest decrease (d = 0.741, p < 0.001), RFD at 100 ms showed a small decrease (d = 0.382, p = 0.020), and RFD at 150 ms did not decrease (p = 0.272). The RFD-SF decreased more in SCI than AMP (p < 0.0001). Muscle fatigability impacted not only maximal force expressions but also the quickness of ballistic contractions of submaximal amplitude, particularly in SCI. This may affect various sports and daily living activities of wheelchair users. Early RFD (i.e., ≤50 ms) was notably affected by muscle fatigability. [ABSTRACT FROM AUTHOR]

Background. Adequate and well-structured sports training is essential for the physical development and improvement of athletic performance in junior female handball players. Strength, plyometric and balance training sessions have the capacity to influence various aspects of physical preparation such as muscular strength, endurance, agility and speed. Aims. The aim of the study is to investigate and evaluate the influence of sports training on physical fitness indices in junior female handball players. Methods. The research subjects were 16 female handball players (aged 14-16) from LPS Slatina. The OptoJump Next Platform was used to assess explosive strength and visual reaction in the lower limbs. Four tests were carried out: Squat Jump, Counter Movement Jump, Stiffness and Visual Reaction. Measured indices: jump height (cm), flight time (sec), power (w/kg). Results. The results of the comparative analysis of the conducted tests, including Squat Jump, Counter Movement Jump, Stiffness and Visual Reaction Tests, demonstrated significant improvements in the physical performance of the participants, namely the development of their muscle strength, muscle efficiency and reaction speed. These improvements were highlighted by statistically significant results (p < 0.001) and homogeneity of the group during tests. Conclusions. In conclusion, regular sports training has a significant and positive influence on physical fitness indices in junior female handball players, contributing to the improvement of the performance and general physical endurance required for this demanding sport. [ABSTRACT FROM AUTHOR]

The Reactive Strength Index (RSI) is used to determine the load and intensity of plyometric training in sports that require explosive strength. Although upper extremity plyometrics are used in athletic' training programmes, there are no studies investigating upper extremity RSI. The aim of this study was to determine the upper and lower extremity reactive strength index generated during different plyometric push-up and jump techniques in boxers, and to examine the relationship between upper and lower extremity RSI. Twenty male boxers aged 18-35 years (age: 20.9±4.83; height: 1.76±.072; BMI: 22.42±2.39) with at least 4 years of boxing experience participated in the study. The RSI values were assessed during depth push-ups (10 cm, 15 cm, 20 cm) and depth jumps (30 cm, 45 cm, 60 cm), pliyometric push-ups and countermovement jumps using a force platform (TekScan, Matscan, model 3150, Boston, USA). The RSI values were calculated from the jump heights and ground contact times obtained from the force platform. No statistically significant correlation was found between the lower and upper extremity RSI for any of the plyometric exercises (p>0.05). When comparing countermovement jump and depth jumps, a statistically significant difference was found between the countermovement jump RSI and all depth jump RSIs (p<0.05). However, when comparing push-up RSIs, there was no statistically significant difference between any of the push ups (p>0.05). Boxers transfer the power generated by the ground reaction force through the trunk to the upper extremities in order to punch quickly and effectively. The lack of a correlation between upper and lower extremity RSI values in this study may be attributed to the significant contribution of the trunk strength in generating power with the upper extremities. In addition, it is believed that the varying RSI values obtained during different plyometric push-up and jump techniques may provide insight into determining the load and intensity of plyometric training. [ABSTRACT FROM AUTHOR]

Purpose: While there is reported superior effectiveness with supervised training, it usually requires specialized exercise facilities and instructors. It is reported in the literature that high-volume stretching improves pectoralis muscles strength under supervised conditions while practical relevance is discussed. Therefore, the study objective was to compare the effects of volume equated, supervised- and self-administered home-based stretching on strength performance. Methods: Sixty-three recreational participants were equally assigned to either a supervised static stretching, home-based stretching, or control group. The effects of 15 min pectoralis stretching, 4 days per week for 8 weeks, were assessed on dynamic and isometric bench press strength and force development. Results: While there was a large magnitude maximal strength increase (p < 0.001–0.023, ƞ2 = 0.118–0.351), force development remained unaffected. Dynamic maximal strength in both groups demonstrated large magnitude increases compared to the control group (p < 0.001–0.001, d = 1.227–0.905). No differences between the intervention group for maximal strength (p = 0.518–0.821, d = 0.101–0.322) could be detected. Conclusions: The results could potentially be attributed to stretch-induced tension (mechanical overload) with subsequent anabolic adaptations, and alternative explanatory approaches are discussed. Nevertheless, home-based stretching seems a practical alternative to supervised training with potential meaningful applications in different settings. [ABSTRACT FROM AUTHOR]

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The Squat Jump (SJ) test is widely recognized as a reliable test for assessing lower-limb explosive strength. However, uncertainty persists in the literature regarding the optimal starting positions for maximizing vertical jump performance. This uncertainty is exacerbated by a disproportionate focus on athletes in existing studies, with insufficient consideration being given to non-athletic women. To address this gap, this study investigated the influence of leg starting angle on explosive jump height in a homogeneous sample of non-athletic women. Thirty-two female students enrolled in a Sports Science master's degree program at the University of Salerno participated in the study. Descriptive statistics were employed to summarize data on various variables, and Pearson's correlations were calculated to assess the relationship between knee angle in the starting position and achieved jump height. The study revealed that different starting positions had a noteworthy impact on jump height among the participants. A strong negative correlation (−0.701) was identified between Squat Jump elevation and the knee angle in the starting position. Notably, 62.5% of the subjects opted for a starting knee position of approximately 70 degrees, with all of them consistently achieving a jump height associated with this specific angle. These findings provide valuable insights into the relationship between leg starting angle and explosive jump height in non-athletic women. The observed correlation underscores the significance of the starting position in Squat Jump performance. The prevalence of a specific knee angle choice among participants suggests potential implications for training and performance optimization in this sample. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the effect of unmodulated low-frequency superficial neuromuscular electrical stimulation (NMES) for 30 and 60 min/day during 7 weeks on muscle contractile functions. Many studies have examined the effect of training intensity during NMES on maximal voluntary isometric strength (MVIS). However, no study has assessed the effect of NMES duration per day and per week on changes in muscle functions. Ten healthy volunteers (23.2 ± 3.2 years; age range 18–28 years) participated in the study and were randomly assigned to group 1 (30 min NMES) and group 2 (60 min NMES) five times a week. The influence of NMES training was estimated by changes in MVIS and speed-strength properties of foot extensors before electrical training and in the beginning of each week of a 7-week training period for all subjects. Contractile abilities were recorded with a Biodex isokinetic dynamometer. After a 7-week training period, MVIS and voluntary maximal explosive strength differed significantly between groups. Referring to electrical stimulation parameters and healthy subjects of this study, electrical training caused an increase in foot extensor muscle strength and a gradient in voluntary explosive strength when used for five trainings per week for 30 min for 7 weeks. [ABSTRACT FROM AUTHOR]

Introduction: Recently, there has been a call for vertical jump testing via force–plate analysis to be included in the assessment of individuals after anterior cruciate ligament reconstruction (ACLR) and as part of return-to-play criteria. However, a synthesis of current literature is needed to help guide clinicians on what tests to perform, which force–plate metrics to assess, and how these may change over the time course of rehabilitation. Methods: Four online databases were searched from inception to July 2022. The Downs and Black checklist was used to assess study quality. Multilevel meta-analyses and meta-regressions were undertaken in conjunction with a best evidence synthesis. Results: Forty-two articles were included, capturing 2375 participants with a history of ACLR. Reconstructed limbs displayed 1) lower peak eccentric forces, concentric forces, landing forces, and lower eccentric and concentric impulses (standardized means difference [SMD] = −1.84 to −0.46) than uninjured contralateral limbs during bilateral countermovement jumps (CMJ) and drop vertical jumps (DVJ); 2) lower jump heights and reactive strength indices (RSI), and longer contact times than uninjured contralateral limbs during unilateral CMJ and DVJ (SMD = −0.86 to 0.26); and 3) lower jump heights, RSI, and longer contact times during bilateral and unilateral CMJ, and unilateral DVJ, than uninjured controls (SMD = −1.19 to 1.08). Meta-regression revealed that time postsurgery was a significant moderator (P < 0.05) for 1) bilateral CMJ height, peak concentric force, and peak landing force; 2) between-limb differences in unilateral CMJ height; and 3) differences in unilateral DVJ height, RSI, and contact time between reconstructed limbs and healthy controls with no history of injury. Conclusions: Individuals with a history of ACLR display chronic deficits in vertical jumping performance during a range of bilateral and unilateral tasks, which may have implications for return-to-play criteria and the design of interventions targeted at restoring long-term deficits in explosive lower limb strength after ACLR. [ABSTRACT FROM AUTHOR]

Nevin, JP, Bowling, K, Cousens, C, Bambrough, R, and Ramsdale, M. The relationship between isometric midthigh pull force-time characteristics and 2-km load-carrying performance in trained British army soldiers. J Strength Cond Res 38(2): 360-366, 2024--Load carriage is a fundamental military occupational task. As such, the aim of this study was to assess the relationship between isometric force-time characteristics and loaded march performance. Furthermore, this study aimed to investigate the relationship between isometric force-time characteristics and standing long jump (SLJ) performance. Thirty-nine, full-trained, male British Army infantry soldiers (age 3166.1 years; height 17667.3 cm; body mass 85.8611.5 kg) performed three isometric midthigh pull trials, three SLJ trials, and a 2-km loadedmarch carrying an external load of 25 kg. Both the isometricmidthigh pull test (intraclass correlation coefficient [ICC] 0.965) and SLJ (ICC 0.916) demonstrated excellent reliability. Relationships between all variables were assessed using Pearson's correlation coefficient. Isometric peak force (r520.059), relative peak force (r520.135), and rate of force development (r520.162) displayed a small correlation with loadedmarch time to completion. However, isometric relative peak force displayed a large relationship with SLJ performance (r50.545; p5,0.01). Our data demonstrate that isometric lower-limb strength measures account for, 2% of the total variance observed in 2-km loaded march performance. As such, the use of isometric lower-limb force-time characteristics as a proxy measure of load-carrying ability should be questioned. However, relative isometric strength seems to demonstrate a significant relationship with SLJ performance. As such, isometric testing may have utility in regard to assessing explosive strength, monitoring neuromuscular fatigue, and assessing training readiness in military populations. [ABSTRACT FROM AUTHOR]

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This study analysed the effects of performing a plyometric training programme on different types of jumping and specific changes of direction, and their respective asymmetries in karatekas. Twenty male karatekas (age 19 ± 4 years) were distributed in two groups, the control group (CG) and the experimental group (EG). The EG group (n = 10) performed a 6-week intervention of unilateral plyometric training, performing countermovement jumps (CMJ), drop jumps (DJ), and long jumps (SH). The tests performed at the beginning and at the end of the intervention were a unilateral and bilateral countermovement jump test (CMJ), single-leg hop test (SH), single-leg side-hop test (SSH), triple hop test (TH), and change of direction in a karate position test (MKUKS). The EG group obtained improvements in the CMJ with the stronger (p = 0.01; ES = 0.39) and weaker leg (p = 0.01; ES = 0.59), in the SH with the weaker leg (p = 0.01; ES = 0.45), in the SSH with the weaker leg (p = 0.03; ES = 0.33), in the MKUKS (p = 0.00; ES = 0.98), and improved the asymmetries obtained in the TH (p = 0.02; ES = −0.85). The GC group obtained significant differences in the CMJ with the stronger (p = 0.03; ES = 0.46) and weaker leg (p = 0.00; ES = 0.69), in the bilateral CMJ (p = 0.02; ES = 0.24), in the SH with the weaker leg (p = 0.00; ES = 0.34), in the TH with the stronger (p = 0.00; ES = −0.15) and weaker leg (p = 0.01; ES = 0.09), and in the MKUKS test (p = 0.04; ES = −0.94). A between-group analysis showed improvements of the EG over the GC in the TH with the stronger leg (p = 0.02; ES = 1.05). Performing plyometric training provides improvements in jumping, mainly in horizontal jumps, reducing inter-limb asymmetries in repetitive jumps. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Sport & Exercise / Türk Spor ve Egzersiz Dergisi is the property of Turkish Journal of Sport & Exercise 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.)

Introduction: The main goal of this study was to investigate the effects of a single cycle of ischemia applied before the bench press exercise on acute bar velocity changes. Materials and Methods: Twelve physically active males participated in the study. The experiment followed a randomized, cross-over design under two testing conditions. The experimental condition involved the application of a single cycle of ischemia (5 minutes; 80% arterial occlusion pressure [AOP]) before the first set of bench press exercise (2 sets at 60% 1RM). The control condition did not use ischemia. The peak and mean bar velocities were measured using a linear position transducer. Results: Twoway repeated measures ANOVA revealed no statistically significant differences in the peak or mean bar velocity between the ischemia and control conditions both during the first and the second set of the bench press exercise. Conclusions: The results of this study indicate that a single cycle of ischemia applied before the bench press exercise did not influence changes in peak or mean bar velocity. [ABSTRACT FROM AUTHOR]

Background: For adolescent soccer players, good sprinting and jumping abilities are crucial for their athletic performance. The application of plyometric training on boosting explosive strength in adolescent soccer players is contingent upon the maturation phase, which can mediate the training-induced adaptations. Purpose: This systematic review and meta-analysis aim to explore the maturation effect of plyometric training on the lower limb explosive power of adolescent soccer players, with vertical countermovement jump (CMJ) and 20-m sprint as the main outcome indicators. Methods: An extensive search of the literature was carried out on various databases including PubMed, Web of Science, Scopus, ProQuest, and the China National Knowledge Infrastructure (CNKI), covering the time period from the establishment of each database to February 6, 2023. The search was conducted using English keywords such as ‘Plyometric,’ ‘Adolescent,’ ‘football,’ and ‘Explosive strength.’ This study utilized the Cochrane risk of bias assessment tool to conduct a standardized quality evaluation of all the included literature. Additionally, the Review Manager 5.4 software was employed to perform data analysis on all the extracted data. Results: A total of 17 studies involving 681 adolescent soccer players aged 10 to 19 were included. Plyometric training significantly improved CMJ performance across different maturation stages, especially in the post-peak height velocity stage (POST-PHV) [MD = 4.35, 95 % CI (2.11, 6.59), P

Volleyball primarily focuses on technical and tactical training with a ball. However, there is growing interest in integrating fitness training into volleyball practice, particularly to enhance explosive strength through plyometric methods, but there is a lack of a direct scientific comparison between training with and without the ball. This study aimed to compare the effects of two training protocols on volleyball players. One protocol combined plyometric exercises with technical gestures (wall drills) using the ball, while the other protocol excluded the ball during plyometric exercises. Twenty male volleyball players (aged 18.6 ± 0.3 years, height 189.8 ± 2.2 cm, weight 79.4 ± 1.6 kg) were divided into experimental (with ball) and control (without ball) groups. The analysis of the results highlights significant improvements in both the squat jumps (SJs) and the countermovement jumps with arm swing (CMJas) for both groups. While there were no significant differences between the groups for SJ, significant differences emerged in CMJas, indicating varied training effects. Specifically, the interaction effect was significant (p = 0.004), demonstrating a meaningful distinction in performance improvements between the two groups. The effect size of the interaction is moderate (ηp2 = 0.37, 95% CI: 0; 0.91). These results suggest that incorporating a ball into plyometric training can be beneficial for developing explosive strength in a different way, thereby improving performance due to the motivational stimulus provided. However, given the specificity of the sample and the training protocols used, further studies are needed to confirm these results and evaluate their applicability to a larger sample of volleyball players.

Purpose: approbation of a complex of speed-strength characteristics for monitoring the dynamics of strength exercises of the world’s leading armwrestlers weighing over 100 kg. Material and Methods. The study involved the 3 best arm wrestlers in the world weighing over 100 kg (116.00 ± 18.03 kg) in 2017–2020. Four power test exercises have been identified that ensure the performance of a competitive action in arm wrestling: flexion of the fingers, stretch with a hammer, hook and bending the hand. These exercises were performed with the left and right hands. Strength indicators in all test exercises were measured with an FL1K 0.5N, 1000N electric strain gauge dynamometer, Kern & Sohn GmbH (China) with an accuracy class of up to 50 g, fixed on a specialized armwrestling table using a specially made an author’s block device. In the course of statistical analysis, the following parameters were determined and calculated: maximum (F) and relative (F1 = ƩF / m) strength, kg; total strength index in four strength exercises (ƩF = F1 + F2 + F3 + F4), kg; time to reach maximum strength (Ʃt = t1 + t2 + t3 + t4), s; speed-strength index (J = ƩF / Ʃt), kg/ms; average strength, index of four exercises ( = ƩF / 4), kg; total strength gradient of four exercises (Ʃt0,5F), ms; speed-strength index in the first 500 ms (J500 = ƩF500 / Ʃt500), kg/ms; time to reach 1 kg force (t1 = Ʃt0.5F / (0.5×F)), ms/kg; Pearson’s correlation analysis; Factor analysis. Results. As a result of the study, the main data on the speed-strength indicators of armwrestlers were obtained and analyzed. In the process of testing, according to the indicators of time periods and these efforts of dynamic strength, the features of the manifestation of explosive, fast and slow strength of arm wrestlers weighing over 100 kg were established. Determining the relationship between strength and speed-strength indicators using factor analysis made it possible to establish two factors that determine the overall variance of the sample. The first factor with a contribution of 70.9 % to the total sample formed the temporal characteristics of effort in test exercises, such as the time to reach maximum effort (r = 0.979), speed-strength index (r = 0.986), force gradient. (r = 0.986) and the time to reach a force of 1 kg (r = 0.979). The second factor with a factor loading of 29.1 % was the maximum force (r = 0.960), the average test strength (r = 0.961) and the achieved force in 500 ms (r = 0.716). Thus, the results of the correlation and factorial analyzes of the strength and speed-strength indicators of armwrestlers weighing more than 100 kg indicate the priority of the temporal characteristics of efforts over strength in a competitive exercise. Conclusions. The study made it possible to test a complex of speed-strength indicators for monitoring the functional state of the world’s leading armwrestlers weighing over 100 kg, an approved system of criteria for time and power characteristics of efforts in competitive exercises allows you to monitor the state of athletes to monitor and predict success in armwrestling. The author’s device used in the study made it possible to automate the process of measurements with high mobility, as well as immediately create a database on the power and speed-strength capabilities of armwrestlers with high accuracy.

• Maximum strength was the only neuromuscular performance affected in Pompe disease. • Our study highlights a proximal-distal gradient in muscle weakness intensity. • The weakest muscles were the hip extensors followed by hip abductors and abductors. • Instrumented assessment of the weakest muscles is essential. • Neural and muscular fibers factors of aLOPD are as functional as those of controls. Adults with late-onset Pompe disease (aLOPD) are characterized by muscular contractile tissue deterioration. However, their neuromuscular performances are poorly known. We aimed to compare maximal muscle strength, activation, explosive strength and neuromuscular fatigue between aLOPD and controls. We studied 20 aLOPD and 20 matched controls. Isometric maximum voluntary contraction (MVC) torque was obtained for the hip, knee and ankle muscles. The voluntary activation level (VAL) during knee extensor MVC was assessed using interpolated twitch technique. Explosive strength was evaluated for knee and ankle muscles through the rate of torque development (RTD) during fast contractions. Neuromuscular fatigue was measured during a 30-second contraction of knee flexors and extensors. All muscle MVC torques were significantly lower in aLOPD than controls (p <0.05). The weakest muscles were the hip extensors followed by hip abductors and abductors. Raw value of RTD was lower in aLOPD for the majority of muscles (p <0.05). No intergroup differences were reported for normalized RTD, VAL and neuromuscular fatigue (p-values> 0.05). Our study shows that maximal strength was the only neuromuscular characteristic affected in aLOPD with a proximal-distal intensity gradient. This suggests that the surviving muscle tissue of aLOPD is as functionally efficient as that of control individuals. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to examine the effects of a back squat exercise with unstable load (UN) and traditional free-weight resistance (FWR) on subsequent countermovement jump (CMJ) performance. After familiarisation, thirteen physically active males with experience in resistance training visited the laboratory on two occasions during either experimental (UN) or control (FWR) conditions separated by at least 72 h. In both sessions, participants completed a task-specific warm-up routine followed by three maximum CMJs (pre-intervention; baseline) and a set of three repetitions of either UN or FWR back squat exercise at 85% 1-RM. During the UN condition, the unstable load was suspended from the bar with elastic bands and accounted for 15% of the total load. Post-intervention, three maximum CMJs were performed at 30 s, 4 min, 8 min and 12 min after the last repetition of the intervention. The highest CMJ for each participant was identified for each timepoint. No significant increases (p > 0.05) in jump height, peak concentric power, or peak rate of force development (RFD) were found after the FWR or UN conditions at any timepoint. The lack of improvements following both FWR and UN conditions may be a consequence of the low percentage of unstable load and the inclusion of a comprehensive task-specific warm-up. Further research is required to explore higher UN load percentages (>15%) and the chronic effects following the implementation of a resistance training programme. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Prescrição e Fisiologia do Exercício is the property of Instituto Brasileiro de Pesquisa e Ensino em Fisiologia do Exercicio 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.)

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Study purpose. High-intensity aerobic capacity (HIAC) is essential for soccer players because they have to perform sprints of short duration in the shortest possible time. At the same time, they need to quickly change direction with and without the ball, which requires agility. The purpose of the study was to investigate the effect of a periodized (8-week) training plan that combines interval training (IT), explosive strength (ES), speed, and game-like situations on agility and HIAC in youth soccer players. Materials and methods. This research is an experimental study in which the population was male youth soccer players (N = 23) (aged 16.7±2.1). The Arrowhead Agility Test and the HIAC Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) have taken the pre- and post-data of agility. By using the formula for YYIR1 test: VO2max (mL kg-1 min-1) = IR1 distance (m) × 0.0084 + 36.4, we get an estimation of the volume of maximum oxygen consumption (VO2max). The data analysis used a t-test at 0.05% as the significance level. Results. Based on the results, the mean of the pre-tests in agility, YO-YO IR1, and VO2max showed 17.911, 14.8100, and 55.25510. After training for eight weeks, there was an improvement: the mean showed 16.667, 15.9750, and 60.06960. As per the results of the data on the hypothesis in the study, it was found that there was a significant effect of periodized IT in combination with ES and speed on agility performance and HIAC of the youth soccer players. Conclusions. There was a significant effect of periodized IT in combination with ES and speed on improving youth soccer players' agility performance and HIAC. [ABSTRACT FROM AUTHOR]

The purpose of this systematic review and meta-analysis was to compare changes in explosive power between blood flow restriction training and traditional resistance training protocols. Searches of PubMed, Scopus, Web of Science, and OVID Medline were conducted for studies. Inclusion criteria were: (a) healthy people; (b) randomized controlled or controlled trials; (c) outcome measures of explosive performance (peak power, rate of force development, jump performance, sprint performance, etc.); (d) involving a comparison between blood flow restriction training and traditional resistance training. Quality assessment was conducted using the Physiotherapy Evidence Database (PEDro) scale. A total of 12 studies (262 subjects) were finally included for analysis. The PEDro scale score had a median of 5 of 10 points (range: 3-6 points). Significant small to moderate improvements were observed in blood flow restriction training [jump: standard mean difference (SMD) of 0.36 (95% CI: 0.02; 0.69); sprint: SMD of 0.54 (95% CI: 0.00; 1.07); power: SMD of 0.72 (95% CI: 0.17; 1.27)] when compared to traditional resistance training. The findings indicate that blood flow restriction training is more effective in improving explosive power of lower limbs compared to traditional resistance training in healthy people. In addition, blood flow restriction with a wide cuff (≥ 10 cm) during training improved explosive power better than with a narrow cuff or during the rest interval. Blood flow restriction training is very suitable for athletes in short competitive seasons and those who are not able to tolerate high loads (i.e., rehabilitators and the elderly). [ABSTRACT FROM AUTHOR]

This study aimed to compare neuromuscular fatigability of the elbow flexors and extensors between athletes with amputation (AMP) and athletes with spinal cord injury (SCI) for maximum voluntary force (MVF) and rate of force development (RFD). We recruited 20 para-athletes among those participating at two training camps (2022) for Italian Paralympic veterans. Ten athletes with SCI (two with tetraplegia and eight with paraplegia) were compared to 10 athletes with amputation (above the knee, N = 3; below the knee, N = 6; forearm, N = 1). We quantified MVF, RFD at 50, 100, and 150 ms, and maximal RFD (RFDpeak) of elbow flexors and extensors before and after an incremental arm cranking to voluntary fatigue. We also measured the RFD scaling factor (RFD-SF), which is the linear relationship between peak force and peak RFD quantified in a series of ballistic contractions of submaximal amplitude. SCI showed lower levels of MVF and RFD in both muscle groups (all p values ≤ 0.045). Despite this, the decrease in MVF (Cohen’s d = 0.425, p < 0.001) and RFDpeak (d = 0.424, p = 0.003) after the incremental test did not show any difference between pathological conditions. Overall, RFD at 50 ms showed the greatest decrease (d = 0.741, p < 0.001), RFD at 100 ms showed a small decrease (d = 0.382, p = 0.020), and RFD at 150 ms did not decrease (p = 0.272). The RFD-SF decreased more in SCI than AMP (p < 0.0001). Muscle fatigability impacted not only maximal force expressions but also the quickness of ballistic contractions of submaximal amplitude, particularly in SCI. This may affect various sports and daily living activities of wheelchair users. Early RFD (i.e., ≤50 ms) was notably affected by muscle fatigability.

Purpose: While there is reported superior effectiveness with supervised training, it usually requires specialized exercise facilities and instructors. It is reported in the literature that high-volume stretching improves pectoralis muscles strength under supervised conditions while practical relevance is discussed. Therefore, the study objective was to compare the effects of volume equated, supervised- and self-administered home-based stretching on strength performance. Methods: Sixty-three recreational participants were equally assigned to either a supervised static stretching, home-based stretching, or control group. The effects of 15 min pectoralis stretching, 4 days per week for 8 weeks, were assessed on dynamic and isometric bench press strength and force development. Results: While there was a large magnitude maximal strength increase (p < 0.001–0.023, ƞ2 = 0.118–0.351), force development remained unaffected. Dynamic maximal strength in both groups demonstrated large magnitude increases compared to the control group (p < 0.001–0.001, d = 1.227–0.905). No differences between the intervention group for maximal strength (p = 0.518–0.821, d = 0.101–0.322) could be detected. Conclusions: The results could potentially be attributed to stretch-induced tension (mechanical overload) with subsequent anabolic adaptations, and alternative explanatory approaches are discussed. Nevertheless, home-based stretching seems a practical alternative to supervised training with potential meaningful applications in different settings.

Study purpose. High-intensity aerobic capacity (HIAC) is essential for soccer players because they have to perform sprints of short duration in the shortest possible time. At the same time, they need to quickly change direction with and without the ball, which requires agility. The purpose of the study was to investigate the effect of a periodized (8-week) training plan that combines interval training (IT), explosive strength (ES), speed, and game-like situations on agility and HIAC in youth soccer players. Materials and methods. This research is an experimental study in which the population was male youth soccer players (N = 23) (aged 16.7±2.1). The Arrowhead Agility Test and the HIAC Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) have taken the pre- and post-data of agility. By using the formula for YYIR1 test: VO₂max (mL kg-1 min-1) = IR1 distance (m) × 0.0084 + 36.4, we get an estimation of the volume of maximum oxygen consumption (VO₂max). The data analysis used a t-test at 0.05% as the significance level. Results. Based on the results, the mean of the pre-tests in agility, YO-YO IR1, and VO₂max showed 17.911, 14.8100, and 55.25510. After training for eight weeks, there was an improvement: the mean showed 16.667, 15.9750, and 60.06960. As per the results of the data on the hypothesis in the study, it was found that there was a significant effect of periodized IT in combination with ES and speed on agility performance and HIAC of the youth soccer players. Conclusions. There was a significant effect of periodized IT in combination with ES and speed on improving youth soccer players’ agility performance and HIAC.