Plyometric Jumps Research Articles

Effects of Plyometric Training on Soft and Hard Surfaces for Improving Running Economy.

The present study investigated the effects of plyometric jump training on hard and soft surfaces on running economy (RE), maximal oxygen uptake (VO2max), running performance and the rate of force development in orienteers. Nineteen orienteers (11 women and 8 men, body mass 61.1 ± 7.3 kg, age 21 ± 5.8 yrs) were randomly stratified based on sex, age, VO2max and RE to plyometric jumping training (8 sessions over 4 weeks) on either a hard or a soft surface. RE, VO2max and running performance were assessed on a treadmill and outdoor on- and off-trail loops. Moreover, ground reaction forces and force development were assessed during a one leg drop-jump test. The training intervention led to an overall 2-7% improvement in treadmill and off-trail RE, independent of the jumping surface and running velocity assessed. These improvements were not explained by force development during drop jump tests, which remained unchanged following the intervention. The changes in time-trial performance were associated with changes in RE. Plyometric training improved RE with no difference between the hard or the soft training surface and improved RE was also independent of the running speed assessed. Furthermore, improved running performance was associated with changes in RE after the intervention.

Effects of Plyometric Jump Training on Electromyographic Activity and Its Relationship to Strength and Jump Performance in Healthy Trained and Untrained Populations: A Systematic Review of Randomized Controlled Trials.

Ramirez-Campillo, R, Garcia-Pinillos, F, Chaabene, H, Moran, J, Behm, DG, and Granacher, U. Effects of plyometric jump training on electromyographic activity and its relationship to strength and jump performance in healthy trained and untrained populations: a systematic review of randomized controlled trials. J Strength Cond Res 35(7): 2053-2065, 2021-This systematic review analyzed the effects of plyometric jump training (PJT) on muscle activation assessed with surface electromyography during the performance of strength and jumping tasks in healthy populations across the lifespan. A systematic literature search was conducted in the electronic databases PubMed/MEDLINE, Web of Science, and SCOPUS. Only randomized controlled studies were eligible to be included in this study. Our search identified 17 studies comprising 23 experimental groups and 266 subjects aged 13-73 years, which were eligible for inclusion. The included studies achieved a median Physiotherapy Evidence Database score of 6. No injuries were reported among the included studies. Significant PJT-related improvements were reported in 7 of 10 studies and in 6 of 10 studies for measures of muscle activation during the performance of strength and jumping tasks, respectively. Moreover, a secondary correlational analysis showed significant positive relationships (r = 0.86; p = 0.012; r2 = 0.74) between changes in muscle activation and changes in jump performance. However, from the total number (n = 287) of muscle activation response variables analyzed for strength and jumping tasks, ∼80% (n = 226) were reported as nonsignificant when compared with a control condition. In conclusion, PJT may improve muscle activation during the performance of strength and jumping tasks. However, conflicting results were observed probably arising from (a) studies that incorporated a large number of outcomes with reduced sensitivity to PJT, (b) methodological limitations associated to muscle activation measurement during strength and jumping tasks, and (c) limitations associated with PJT prescription. Future studies in this field should strive to solve these methodological shortcomings.

Effects of Plyometric Jump Training on Repeated Sprint Ability in Athletes: A Systematic Review and Meta-Analysis.

There is a growing body of research examining the effects of plyometric jump training (PJT) on repeated sprint ability (RSA) in athletes. However, available studies produced conflicting findings and the literature has not yet been systematically reviewed. Therefore, the effects of PJT on RSA indices remain unclear. To explore the effects of PJT on RSA in athletes. Searches for this review were conducted in four databases. We included studies that satisfied the following criteria: (1) examined the effects of a PJT exercise intervention on measures of RSA; (2) included athletes as study participants, with no restriction for sport practiced, age or sex; and (3) included a control group. The random-effects model was used for the meta-analyses. The methodological quality of the included studies was assessed using the PEDro checklist. From 6367 search records initially identified, 13 studies with a total of 16 training groups (n = 198) and 13 control groups (n = 158) were eligible for meta-analysis. There was a significant effect of PJT on RSA best sprint (ES = 0.75; p = 0.002) and RSA mean sprint (ES = 0.36; p = 0.045) performance. We did not find a significant difference between control and PJT for RSA fatigue resistance (ES = 0.16; p = 0.401). The included studies were classified as being of "moderate" or "high" methodological quality. Among the 13 included studies, none reported injury or any other adverse events. PJT improves RSA best and mean performance in athletes, while there were no significant differences between control and PJT for RSA fatigue resistance. Improvements in RSA in response to PJT are likely due to neuro-mechanical factors (e.g., strength, muscle activation and coordination) that affect actual sprint performance rather than the ability to recover between sprinting efforts.

Assessing Overall Exercise Recovery Processes Using Carbohydrate and Carbohydrate-Protein Containing Recovery Beverages.

We compared the impact of two different, but commonly consumed, beverages on integrative markers of exercise recovery following a 2 h high intensity interval exercise (i.e., running 70–80% V̇O2max intervals and interspersed with plyometric jumps). Participants (n = 11 males, n = 6 females) consumed a chocolate flavored dairy milk beverage (CM: 1.2 g carbohydrate/kg BM and 0.4 g protein/kg BM) or a carbohydrate-electrolyte beverage (CEB: isovolumetric with 0.76 g carbohydrate/kg BM) after exercise, in a randomized-crossover design. The recovery beverages were provided in three equal boluses over a 30 min period commencing 1 h post-exercise. Muscle biopsies were performed at 0 h and 2 h in recovery. Venous blood samples, nude BM and total body water were collected before and at 0, 2, and 4 h recovery. Gastrointestinal symptoms and breath hydrogen (H2) were collected before exercise and every 30 min during recovery. The following morning, participants returned for performance assessment. In recovery, breath H2 reached clinical relevance of >10 ppm following consumption of both beverages, in adjunct with high incidence of gastrointestinal symptoms (70%), but modest severity. Blood glucose response was greater on CEB vs. CM (P < 0.01). Insulin response was greater on CM compared with CEB (P < 0.01). Escherichia coli lipopolysaccharide stimulated neutrophil function reduced on both beverages (49%). p-GSK-3β/total-GSK-3β was greater on CM compared with CEB (P = 0.037); however, neither beverage achieved net muscle glycogen re-storage. Phosphorylation of mTOR was greater on CM than CEB (P < 0.001). Fluid retention was lower (P = 0.038) on CEB (74.3%) compared with CM (82.1%). Physiological and performance outcomes on the following day did not differ between trials. Interconnected recovery optimization markers appear to respond differently to the nutrient composition of recovery nutrition, albeit subtly and with individual variation. The present findings expand on recovery nutrition strategies to target functionality and patency of the gastrointestinal tract as a prerequisite to assimilation of recovery nutrition, as well as restoration of immunocompetency.

Effects of Plyometric Jump Training on Balance Performance in Healthy Participants: A Systematic Review With Meta-Analysis / Effects of plyometric-jump training on balance performance in healthy individuals across the lifespan: A systematic review with meta-analysisist

Postural balance represents a fundamental movement skill for the successful performance of everyday and sport-related activities. There is ample evidence on the effectiveness of balance training on balance performance in athletic and non-athletic population. However, less is known on potential transfer effects of other training types, such as plyometric jump training (PJT) on measures of balance. Given that PJT is a highly dynamic exercise mode with various forms of jump-landing tasks, high levels of postural control are needed to successfully perform PJT exercises. Accordingly, PJT has the potential to not only improve measures of muscle strength and power but also balance. To systematically review and synthetize evidence from randomized and non-randomized controlled trials regarding the effects of PJT on measures of balance in apparently healthy participants. Systematic literature searches were performed in the electronic databases PubMed, Web of Science, and SCOPUS. A PICOS approach was applied to define inclusion criteria, (i) apparently healthy participants, with no restrictions on their fitness level, sex, or age, (ii) a PJT program, (iii) active controls (any sport-related activity) or specific active controls (a specific exercise type such as balance training), (iv) assessment of dynamic, static balance pre- and post-PJT, (v) randomized controlled trials and controlled trials. The methodological quality of studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. This meta-analysis was computed using the inverse variance random-effects model. The significance level was set at p <0.05. The initial search retrieved 8,251 plus 23 records identified through other sources. Forty-two articles met our inclusion criteria for qualitative and 38 for quantitative analysis (1,806 participants [990 males, 816 females], age range 9–63 years). PJT interventions lasted between 4 and 36 weeks. The median PEDro score was 6 and no study had low methodological quality (≤3). The analysis revealed significant small effects of PJT on overall (dynamic and static) balance (ES = 0.46; 95% CI = 0.32–0.61; p < 0.001), dynamic (e.g., Y-balance test) balance (ES = 0.50; 95% CI = 0.30–0.71; p < 0.001), and static (e.g., flamingo balance test) balance (ES = 0.49; 95% CI = 0.31–0.67; p < 0.001). The moderator analyses revealed that sex and/or age did not moderate balance performance outcomes. When PJT was compared to specific active controls (i.e., participants undergoing balance training, whole body vibration training, resistance training), both PJT and alternative training methods showed similar effects on overall (dynamic and static) balance (p = 0.534). Specifically, when PJT was compared to balance training, both training types showed similar effects on overall (dynamic and static) balance (p = 0.514). Conclusion: Compared to active controls, PJT showed small effects on overall balance, dynamic and static balance. Additionally, PJT produced similar balance improvements compared to other training types (i.e., balance training). Although PJT is widely used in athletic and recreational sport settings to improve athletes' physical fitness (e.g., jumping; sprinting), our systematic review with meta-analysis is novel in as much as it indicates that PJT also improves balance performance. The observed PJT-related balance enhancements were irrespective of sex and participants' age. Therefore, PJT appears to be an adequate training regime to improve balance in both, athletic and recreational settings.

CORRELATION OF HANDGRIP STRENGHT WITH VERTICAL AND HORIZONTAL PLYOMETRIC JUMPS

Handgrip strength is a good general indicator of physical fitness. It has long been used as a diagnostic tool, the results of which are related to eating habits, rotator cuff weakness, fatigue, and general physical fitness. We did not find any research of correlation of handgrip with the jumping force, so we wanted to test this in our study. We expected correlations between these two areas of power. The study included vertical and horizontal plyometric jumps, handgrip strength, and some body characteristics. Relationships were verified by correlation analysis. The study included 64 students of the Faculty of Sport, who performed 9 plyometric tests, a handgrip test, and measurements of body characteristics. The results in the participants show the dominance of the right hand and a significant correlation between the strength of the handgrip and body weight. Plyometric jumps show large differences between men and women. In men, there was only the significant correlation of handgrip strength with the test standing triple jump (HG_L/STJ: r=0.33; HG_R/STJ: r=0.35). In women, the force of the handgrip is correlated with the standing triple jump (HG_L/STJ: r=- 0.57; HG_R/STJ: r=-0.55) and horizontal jumps on one leg (HG_L/HJOL_L: r=0.60; HG_R/HJOL_L: r=0.56; HG_L/HJOL_R: r=0.62; HG_R/HJOL_R: r=0.58). Handgrip strength is only correlated with some plyometric jumps. Small number of correlations is most likely due to large differences in neuromuscular mechanisms, as handgrip involves isometric, absolute strength, and plyometric jumps involve relative strength, where subjects must overcome their own body weight. However, it is also necessary to consider the low number of subjects, especially female, which reduced the variability of the sample and the possibility of generalization to the wider population. As expected, of the body characteristics, body weight is most correlated to the handgrip strength.

Effects of Plyometric Jump Training in Female Soccer Player's Physical Fitness: A Systematic Review with Meta-Analysis.

We aimed to assess the effects of plyometric jump training (PJT) on female soccer player’s physical fitness. To this aim, a systematic review with meta-analysis (SRMA) was conducted. The electronic databases PubMed, MEDLINE, Web of Science, and SCOPUS were used. To qualify for inclusion, peer-reviewed studies must have included (i) a PJT programme of ≥2 weeks, (ii) healthy athletes, (iii) a control group, and (iv) physical fitness outcomes (e.g., jump; sprint). Studies were excluded if (i) they incorporated injuried female soccer players, (ii) did not involve PJT or an active control group, (iv) lack of baseline and/or follow-up data. Data was meta-analyzed using the inverse variance random-effects model. Ten moderate-to-high quality studies were included in the analyses, comprising 13 training groups (n = 140) and 10 control groups (n = 110). Small to large (ES = 0.60–2.24; p = 0.040 to <0.001) effects were noted for countermovement jump, drop jump, kicking performance, linear sprint, change of direction speed, and endurance. The moderator analyses (i.e., PJT duration, age groups, competitive level, and soccer experience) revealed no significant differences between groups. In conclusion, PJT may improve the physical fitness of female soccer players. Such improvements might be expected after PJT interventions with six or more weeks of duration, and in players with different chronological ages, competitive levels and soccer experience.

Low Body Fat Does Not Influence Recovery after Muscle-Damaging Lower-Limb Plyometrics in Young Male Team Sport Athletes.

Aim: This study assessed the influence of fat mass to fat-free mass ratio (FM:FFM) on recovery from plyometric exercise. Method: After assessment of body composition, 20 male team sport players (age 20.7 ± 1.1 years; body mass 77.1 ± 11.5 kg) were divided into low- (n = 10; 0.11 ± 0.03) and normal- (n = 10; 0.27 ± 0.09) fat groups based on FM:FFM ratio. Thereafter, participants completed measurements of knee extensor torque at 60 and 240°∙s−1, countermovement jump flight time, plasma creatine kinase (CK) activity and perceived muscle soreness (VAS) before and at 0, 24 and 48 h after 10 × 10 maximal plyometric vertical jumps. Results: Evidence of muscle damage was confirmed by alterations in VAS, peak torque at 60 and 240°∙s−1 and flight time at 0, 24 and 48 h after plyometric exercise (P < 0.05). CK was increased at 0 and 24 h (P < 0.05) but returned to baseline values by 48 h. No time by group effects were observed for any of the dependent variables (P > 0.05). Conclusion: The current findings indicate that while muscle damage was present after plyometric exercise, the magnitude was similar across the two body composition groups. Applied practitioners can allow for a similar recovery time after plyometric exercise in those with low and normal body fat.

Remodeling the Skeletal Muscle Extracellular Matrix in Older Age-Effects of Acute Exercise Stimuli on Gene Expression.

With advancing age, the skeletal muscle extracellular matrix (ECM) undergoes fibrotic changes that may lead to increased muscle stiffness, injury susceptibility and strength loss. This study tested the potential of different exercises to counter these changes by stimulating the activity of genes associated with ECM remodeling. Twenty-six healthy men (66.9 ± 3.9 years) were stratified to two of four groups, performing unilateral (i) conventional resistance exercise, (ii) conventional resistance exercise followed by self-myofascial release (CEBR), (iii) eccentric-only exercise (ECC) or (iv) plyometric jumps (PLY). The non-trained leg served as control. Six hours post-exercise, vastus lateralis muscle biopsy samples were analyzed for the expression of genes associated with ECM collagen synthesis (COL1A1), matrix metallopeptidases (collagen degradation; MMPs) and peptidase inhibitors (TIMP1). Significant between-group differences were found for MMP3, MMP15 and TIMP1, with the greatest responses in MMP3 and TIMP1 seen in CEBR and in MMP15 in ECC. MMP9 (3.24–3.81-fold change) and COL1A1 (1.47–2.40-fold change) were increased in CEBR and PLY, although between-group differences were non-significant. The expression of ECM-related genes is exercise-specific, with CEBR and PLY triggering either earlier or stronger remodeling than other stimuli. Training studies will test whether execution of such exercises may help counter age-associated muscle fibrosis.

Effects of Plyometric Jump Training on Jump and Sprint Performance in Young Male Soccer Players: A Systematic Review and Meta-analysis.

Even from a young age, modern soccer requires high levels of physical fitness development, particularly jumping and sprinting. Plyometric jump training (PJT), combined with young athletes' regular soccer sessions, has the potential to improve jumping and sprinting. However, studies exploring the effects of PJT are generally limited by small sample sizes. This problem of underpowered studies may, thus, be resolved by pooling study results in a meta-analysis. The objective of this systematic review with meta-analysis (SRMA) was to assess the effects of plyometric jump training (PJT) on jumping and sprinting among young male soccer players. The SRMA included peer-reviewed articles that incorporated PJT in healthy players (i.e., < 23years of age), a control group, and a measure of jumping or sprinting. Means and standard deviations of outcomes were converted to Hedges' g effect sizes (ES), using the inverse variance random-effects model. Moderator analyses were conducted for PJT duration, frequency, total number of sessions, participants' chronological age, and FIFA age categories (i.e., U-17 vs. U-20 vs. U-23). A multivariate random-effects meta-regression was also conducted. Thirty-three studies were included, comprising 1499 participants. PJT improved vertical jump tests (ES = 0.60-0.98; all p < 0.01) and linear sprint performance (ES = 0.60-0.98; p < 0.03). Interventions of > 7weeks and > 14 PJT sessions induced greater effects compared to PJT with ≤ 7weeks and ≤ 14 total sessions on 10-m sprint performance (between group p = 0.038). PJT is effective in improving jumping and sprinting performance among young male soccer players. Greater 10-m linear sprinting improvements were noted after interventions > 7-week duration and > 14 sessions, suggesting a greater return from exposure to longer PJT interventions, partially in support for the adoption of a long-term approach to athletic development in young athletes. However, with reference to the findings of the meta-regression, and those from the remaining subgroup and single factors analysis, a robust confirmation regarding the moderator role of participant's age or PJT configuration effects on young soccer player's fitness qualities needed.

Jumping Performance of Elite NCAA Division 1 Student-athletes: The Effect of Basketball Shoe Design – Part I

Background: Assessment of basketball shoes as personal protection equipment (PPE) at the collegiate level is unique. Objective: The purpose of Part I in this pilot study was to examine the effect of shoe design on jump height in elite male and female National Collegiate Athletic Association (NCAA) Division 1 basketball student-athletes. Method: Each team selected two pairs of AdidasTM branded shoes. The male student-athletes selected the AdidasTM Harden Vol. 3 and the AdidasTM SM Pro basketball shoes. The female student-athletes selected the AdidasTM Harden Vol. 3 and the AdidasTM Captain Marvel basketball shoes. A total of sixteen basketball student-athletes (six males, ten females) performed an acute series of four styled basketball jumps on two ForceDecksTM Force Platforms while trying to maximize jump height by tapping VertecTM Jump Vanes. Two trials were performed in each shoe and for each type of jump which included a countermovement jump, drop jump from 30cm, step and jump, and a series of plyometric jumps. Results: The results of this pilot study indicated a non-significant effect of basketball shoe design on jump height while performing an acute series of basketball style jumps for either the male or female basketball student-athletes. However, there were significant differences in jump height and peak power between the male and female basketball student-athletes (p = 0.001). Conclusion: In addition to the results, the use of quantitative performance testing on the effectiveness of basketball shoe designs as PPE may assist in the mitigation of non-contact ankle and lower limb injuries.

Effects of Traditional Strength Training Versus Jump Training on Muscular Fitness among Physically Inactive and Sedentary Young Adults

Background: The effects of Traditional Resistance Training (TRT) and Plyometric Jump Training (PJT) had never been compared in participants that are both sedentary and physically inactive. Results derived from such research may allow important practical applications. Objective: The aim of this study was to compare the effects of 4-weeks of TRT versus PJT programs on the muscular fitness of sedentary and physically inactive participants. Methods: Baseline and follow-up tests included the assessment of Squat Jump (SJ), Countermovement Jump (CMJ), elastic index, and maximal strength of the knee extensors (MVS). Males and females (age range, 18-29 years) were randomly assorted into a control group (CG, n=11), TRT (n=8), and PJT groups (n=9). The TRT program emphasized slow-speed movements with free weights. The PJT program emphasized high-speed jump movements without external loads. Both TRT and PJT sessions lasted 30-minutes. Dependent variables were analyzed in separate three (Groups) × two (Time: pre, post) ANOVA, with Bonferroni-adjusted α (p&lt;0.05). Results: Main effects of time (all p&lt;0.05) were observed for SJ (ηp2 = 0.51), CMJ (ηp2 = 0.33), and MVS (ηp2 = 0.33). Post-hoc analyses revealed similar significant (all p&lt;0.05) improvements in the TRT and PJT groups for SJ (∆, 95%CL, 9.0-22.5%), CMJ (∆, 95%CL, 11.7-24.4%), and MVS (∆, 95%CL, 5.8-21.3%). No significant changes were observed in the control group. No changes were observed for the elastic index. Conclusion: In otherwise healthy participants that are both physically inactive and sedentary, both TRT and PJT protocols are equally effective in improving the muscular fitness.

Šešių savaičių trukmės pliometrinių šuolių programos poveikis jaunųjų krepšininkų greitumui, greitumo jėgai ir vikrumui

Šio tyrimo tikslas buvo nustatyti 6 savaičių pliometrinių pratimų programos poveikį jaunųjų krepšininkų greitumui, greitumo jėgai ir vikrumui.Tyrime dalyvavo vienuolika 17–18 metų krepšininkų, kurie buvo suskirstyti į kontrolinę (N = 5) ir eksperimentinę (N = 6) grupes. Eksperimentinės grupės krepšininkai 6 savaites, 2 kartus per savaitę, po pagrindinių krepšinio pratybų atlikdavo pliometrinius šuolius. Programa sudaryta remiantis T. J. Piper ir L. D. Erdmann rekomendacijomis (1998). Įvairių šuolių apimtis per savaitę varijavo nuo 180 iki 280. Poilsio pertraukų trukmė tarp pratimų serijų 45 sekundės, o tarp pratimų 2 minutės.Antropometriniai matavimai atlikti laikantis K. Norton ir kt. (1996) rekomendacijų. Greitumui nustatyti taikytas 20 m bėgimo iš aukšto starto testas, matuojant ir pirmųjų 10 m bėgimo laiką (Duthie ir kt., 2006; Foran ir Pound, 2007). Šuolio aukštis mojant rankas aukštyn matuotas naudojant multifunkcinės įrangos Newtest (Suomija) šuolių matavimo modulį pagal C. Bosco ir kt. (1983) metodiką. Vikrumui nustatyti buvo naudotas T-testas (Pauole ir kt., 2000).Po 6 savaičių eksperimentinės grupės 10 m bėgimo laikas sumažėjo 2,86 % (p &lt; 0,05), o 20 m bėgimo laikas 1,99 % (p &gt; 0,05). Kontrolinės grupės greitumo testo rezultatai per tą patį laikotarpį iš esmės nepasikeitė (p &gt; 0,05). Eksperimentinės grupės šuolio aukštis pagerėjo 9,31 % (p &lt; 0,01), o kontrolinės grupės pakito nereikšmingai (2,07 %; p &gt; 0,05). Eksperimentinės grupės vikrumas pagerėjo vidutiniškai 2,71 % (p &lt; 0,05), o kontrolinės grupės pakito menkai (0,62 %; p &gt; 0,05).Eksperimentinė 6 savaičių trukmės programa didžiausią poveikį turėjo jaunųjų krepšininkų greitumo jėgai ir vikrumui; poveikis greitumui buvo nors ir nedidelis, bet statistiškai reikšmingas.

Handball injuries and their prevention

Handball is one of the most popular team sports in Germany, as well as one of the most dangerous ones. Injury rates in Germany are higher amongst handball professionals than in soccer, with the knee being the most commonly injured joint. To prevent injuries, afunctional inert stability is necessary, but definitions and objective measures are lacking. Establishing valid reference data of functional knee stability in amateur handball players with use of an established test battery giving objective measures METHODS: 261 athletes (f:130; m:131), mean age 25.1 ± 5.8 y were screened during the preseason. The test battery consisted of double and single-leg counter movement jumps, balance tests, agility, parkour, quick feet test and plyometric jumps. Significant differences between males and females were noted in regard to balance scores (favour for females p ≤ 0.001), as well as jump height, agility and speed tests (favour for males [p ≤ 0.002-0.001]). The noted differences once again bring focus to the interindividual presence of risk factors, because female and male handball athletes have gender-specific ground levels. These attributes have to be considered in further screening and prevention programs, as well as in the context of the return-to-sports decision after injury. The given data may serve as objective reference measures.

The Increased Effectiveness of Loaded Versus Unloaded Plyometric Jump Training in Improving Muscle Power, Speed, Change of Direction, and Kicking-Distance Performance in Prepubertal Male Soccer Players.

To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7]y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5]y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie,countermovement jump, standing long jump); speed (ie,5-, 10-, and 20-m sprint); CoD (ie,Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33-0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00-0.09). Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players.

Functional knee stability in non-elite handball: balance and jump performance differ based on players' position.

Despite the great evolvement of sports medicine, there is still a lack of consensus among sports physicians regarding the decision of return to sports after knee injury, especially in non-elite sports. Currently, no sport-specific reference data for an objective reliable evaluation of functional knee stability exist. The purpose of this study was to assess objective measures on knee joint stability from an established test battery in non-elite handball. It was assumed that players' knee stability differs depending on their field position. One-hundred and sixty-five non-elite handball players with a mean age of 24.3 ± 5.5years underwent a test battery including two-legged and one-legged stability tests, two-legged and one-legged counter movement jumps, two-legged plyometric jumps, one-legged speedy jumps, and a quick feed test. Athletes' physical performance differs in terms of field position. Significant differences between handball players of different positions were found in regard to two-legged stability (p < 0.036) and one-legged stability in the dominant leg (p < 0.009). Players of different positions differed in ground contact time of the plyometric jumps (p < 0.017), whereas the other functional tests did not show significant differences. This study is first to report differences in functional knee stability of non-elite handball players on the basis of objective data. Significant differences of functional performance were noted, which were in congruence with position-specific demands. These findings demonstrate the importance of position-specific screening and training to prevent injuries. II.

Effects of Maturation on Physical Fitness Adaptations to Plyometric Jump Training in Youth Females

Romero, C, Ramirez-Campillo, R, Alvarez, C, Moran, J, Slimani, M, Gonzalez, J, and Banzer, WE. Effects of maturation on physical fitness adaptations to plyometric jump training in youth females. J Strength Cond Res 35(10): 2870-2877, 2021-The aim of this study was to compare the effects of maturation on physical fitness adaptations to plyometric jump training (PJT) in youth females. Jumping, sprinting, change of direction speed, endurance, and maximal strength were measured pre-post 6 weeks of PJT in 7th- and 10th-grade subjects. In the seventh grade, subjects formed a PJT group (Plyo-7, n = 10; age, 12.7 ± 0.6 years; breast maturation stages IV [n = 2], III [n = 7], and II [n = 1]) and an active control group (Con-7, n = 9; age, 12.8 ± 0.6 years; breast maturation stages IV [n = 2], III [n = 6], and II [n = 1]). In the 10th grade, subjects conformed a PJT group (Plyo-10, n = 9; age, 16.3 ± 0.5 years; breast maturation stages V [n = 5] and IV [n = 4]) and an active control group (Con-10, n = 9; age, 16.2 ± 0.5 years; breast maturation stages V [n = 5] and IV [n = 4]). Magnitude-based inferences were used for data analysis, with effect sizes (ESs) interpreted as <0.2 = trivial; 0.2-0.6 = small; 0.6-1.2 = moderate; 1.2-2.0 = large; and 2.0-4.0 = very large. The Plyo-7 and Plyo-10 showed meaningful improvements in all physical fitness measures (ES = 0.21-2.22), while Con-7 and Con-10 showed only trivial changes. The Plyo-7 and Plyo-10 showed meaningful (ES = 0.16-2.22) greater improvements in all physical fitness measures when compared with their control counterparts. The Plyo-10 showed meaningful greater improvements in 20-m sprint, 2-km running time trial, maximal strength, squat jump, and drop jump from 20 cm (ES = 0.21-0.42) when compared with Plyo-7. In conclusion, PJT is effective in improving physical fitness in younger and older female youths. However, greater adaptations were observed in more mature subjects.

THE DIFFERENCE OF SQUAT EXERCISE USING CALF RAISES IN PLYOMETRIC JUMP INTERVENTION TO THE BOX ON EXPLOSIVE POWER LOWER EXTREMITY OF BASKETS EXTRACURRICULAR IN DENPASAR HIGH SCHOOL

Explosive power can be increased by Plyometric Jump To Box exercises and can be optimized by combining Squat and Calf Raises exercises. The purpose of this study was to find out the general description of Squat, Calf Raises, and Plyometric Jump To Box exercises on the explosive power of the lower extremities. This research method uses a Randomized Pre and Post Test Group Design research design. A total of 22 study samples were divided into 2 treatment groups. Known difference in mean before and after treatment in group 1 was 06.27 ± 3.165 while in group 2 it was 08.09 ± 3.986 with p = 0.25 (p&gt; 0.05) which means there was no significant difference between groups 1 with group 2. So it can be said that squat exercise is as good as Calf Raises exercise on Plyometric Jump To Box Interventions on increasing explosive lower extremity.Keyword: Explosive Power, Plyometric Jump To Box, squat, calf raises.

The impact of a specific training programme on the selected parameters of swimming turns

The presented study focuses on the impact analysis of a specific training programme primarily focusing on plyometric exercises for the lower limb explosive power, and the selected parameters of swimming turns. The tested set consisted of performance swimmers (n = 20, men n = 12 and women n = 8) in the average age of 17.3 years, average height of 174.2cm, and average weight of 65.8kg. The tested set was divided into two smaller sets. The experimental set (n = 10) used the training process as an extra experimental factor and the supervision set (n = 10) carried out only the main contents of the training process. The specific training schedule was applied during the period of 8 weeks, three times a week for 20 minutes. The effectiveness of the experimental factor was tested through a selected set of tests, focusing primarily on the lower limb explosive power. Three of the tests were conducted on the dryland using the Myotest machine: T1 – Squat jump (SJ), T2 – Countermovement Jump (CMJ) and T3 – Plyometric jump (PJ). The tests conducted in the swimming pool were: T4 – max. length of floating up after the push off from the turning wall, and T5 – the length of push off after 25m of breaststrokes in the maximum speed with a push off from the wall of maximum floating up. The results pointed out a proportionally higher increase in the experimental set, in which the average percentile improvement of the jump height amounted to 17.7% in T1 (the changes in the supervision set were 0.7%); in T2 the jump height was increased by 22% (the changes in the supervision set were 0.6%); in T3 the time of contact increased by 18.5% (the supervision set showed a decrease by 1.2%), T4 by 14.9% (the changes in the supervision set were 4.1%) and in T5 by 22.7% (the changes in the supervision set were 11.0%). Kendall correlation coefficient (r), pointed out the average value of the correlation coefficient between the experimental factor and the individual tests as follows: T1: r = 0.39, p&amp;lt;0.05; T2: r = 0.41, p&amp;lt;0.05; T3: r = 0.43, p&amp;lt;0.05, T4: r = 0.38, p&amp;lt;0.05 a T5: r = 0.41, p&amp;lt;0.05. In conclusion, practice, improvement, and affectivity of the swimming turn can affect the swimmers’ performance in races and improve it.

C-Reactive Protein Is Elevated Only in High Creatine Kinase Responders to Muscle Damaging Exercise.

The purpose of this study was to investigate if exertional rhabdomyolysis induced by an acute bout of plyometric exercise in untrained individuals was associated with histological characteristics of skeletal muscle, creatine kinase (CK) polymorphism or secondary damage. Twenty-six healthy male untrained individuals completed a bout of plyometric exercise (10 sets of 10 maximal squat jumps, with each standardized to achieve at least 95% of individual maximal jump height). Blood samples were taken, and perceived pain was scored immediately before the exercise intervention and 6 h, 1, 2, and 3 days post-intervention. Muscle biopsies were collected 9 or 4 days before (baseline) and 3 days after plyometric jumps. Subjects were divided into two groups, high (n = 10) and low responders (n = 16), based on a cut-off limit for exertional rhabdomyolysis of peak CK activity ≥ 1000 U/L in any post-exercise blood sample. Perceived pain was more severe assessed in squat than standing position. Low responders perceived more pain at 6 h and 1 day, while high responders perceived more pain than low responders on days three and four after exercise; structural (dystrophin staining) and ultra-structural (transmission electron microscopy) analysis of muscle fibers revealed no baseline pathology; damage was evident in all individuals in both groups, with no difference between high and low responders in either damage or fiber type proportion. High responders had significantly higher total white blood cell and neutrophil counts 6 h and significantly higher C-reactive protein (CRP) 6 h and days one and two after exercise compared to low responders. High responders had significantly greater muscle myeloperoxidase (MPO) levels in baseline and 3 day post-exercise biopsies compared to baseline of low responders. MLCK C49T single polymorphism was present in 26% of volunteers, whose CK responses were not higher than those with MLCK CC or CT genotype. In conclusion, perceived pain is more effectively assessed with potentially affected muscle under eccentric strain, even if static. High CK responders also have pronounced CRP responses to unaccustomed plyometric exercise intervention. Exertional rhabdomyolysis after unaccustomed eccentric exercise may be related to underlying inability to resolve intramuscular MPO.