Saltatory Research Articles

Effectiveness of maximum, explosive and combined strength training on endurance runners performance indicators: a systematic review and meta-analysis

Objective: This study aimed to analyze the effect of practicing maximum strength (MAX), explosive strength (EXP), or both combined (COMB) on seven runners’ performance indicators: vertical jump (VJ), one-repetition maximum squat (1RM), peak velocity/peak running speed (PV), lactate threshold (LT), middle-distance time trial (TT), maximum oxygen consumption (VO2max), and running economy (RE). Methods: A systematic review (Scopus, Web of Science, Sports Discuss, PubMed) with meta-analysis was conducted following PRISMA standards. Inclusion criteria (PICOS) were: Recreational or well-trained athletes aged 18-45 performing concurrent training for at least five weeks. The search terms used were related to different types of strength/endurance and participants’ age and sports modality. Twenty manuscripts were selected, and quality assessed with PEDro. Results: MAX training is more effective than EXP and COMB in improving VJ, 1RM, and PV, while COMB is more effective than MAX and EXP to enhance TT. MAX is more effective than EXP in improving LT. Concurrent workouts do not provide additional benefits to VO2max. It is unknown which strength modality (MAX, EXP, or COMB) is more effective in improving RE. Conclusion: Concurrent training is more effective than single-mode endurance training for enhancing specific performance variables in adult endurance runners. Middle- and long-distance runners may consider incorporating MAX training to target specific goals (i.e., improving VJ, 1RM, LT, PV) while utilizing COMB training to enhance TT. Certain variables may benefit from EXP. New randomized controlled trials are required to confirm these findings. Keywords: endurance, running, concurrent training, maximum strength, explosive strength

Assessing the Relationship of Psychological Sport Readiness, Single-leg Vertical Jump, and Non-Sagittal Single-Leg Hops to Quadriceps Strength After Anterior Cruciate Ligament Reconstruction.

Limitations exist with current ACLR functional testing assessments that may be mitigated by including single-leg multi-directional testing. To compare Anterior Cruciate Ligament-Return to Sport after Injury Scale (ACL-RSI) scores, limb symmetry index (LSI) of the single-leg vertical jump (SLVJ), single-leg medial rotation hop (SLMRH), single-leg lateral hop (SLLH), and isokinetic quadriceps strength between participants with an ACLR and healthy controls and assess predictors of quadriceps strength asymmetry. It was hypothesized that ACL-RSI scores and LSIs for all tests would differ between ACLR and healthy control groups and within the ACLR group a strong correlation would exist between all outcome measures and quadriceps strength. Cross-Sectional Study. Twenty-six participants with an ACLR (median 13 months after surgery) and twenty-six matched healthy controls were recruited to participate in this study. Performance was assessed via SLVJ, SLMRH, SLLH, and isokinetic quadriceps strength. Between-group comparisons were made with independent t-tests and Mann-Whitney U test. Within the ACLR group, bivariate correlation and multivariate regression analysis were performed to assess the relationship between the outcome measures and quadriceps strength asymmetry. Significant between-limb differences were only identified in the ACLR group (p< 0.05): SLVJ LSI: 88.5%, SLMRH LSI: 93.6%, SLLH LSI: 92.7%, quadriceps strength LSI 80.9% - 83.9%, which were significantly lower (p <0.05) than the healthy control group. Within the ACLR group, a moderate-strong significant (p < 0.05) correlations existed with quadriceps strength and SLVJ (r=0.44-0.65), SLMRH (r =0.43-0.83), and SLLH (r=0.54-0.63); while ACL-RSI had a weak non-significant (p > 0.05) correlation with quadriceps strength (r= 0.12-0.30). Single-leg multidirectional test LSIs were less in ACLR participants than matched healthy controls and all were directly related to quadriceps strength. Psychological readiness to return to sport was not related to quadriceps strength.

Predicting Sprint Performance From the Vertical and Horizontal Jumps in National Football League Combine Athletes.

Agar-Newman, DJ, MacRae, F, Tsai, M-C, and Klimstra, M. Predicting sprint performance from the vertical and horizontal jumps in National Football League Combine athletes. J Strength Cond Res 38(8): 1433-1439, 2024-Identifying fast athletes is an important part of the National Football League (NFL) Combine. However, not all athletes partake in the 36.58-m sprint, and relying on this single test may miss potentially fast athletes. Therefore, the purpose of this study was to determine whether sprinting times can be predicted using simple anthropometric and jumping measures. Data from the NFL Combine between the years 1999-2020 inclusive were used (n = 4,149). Subjects had a mean (±SD) height = 1.87 ± 0.07 m and body mass = 111.96 ± 20.78 kg. The cross-validation technique was used, partitioning the data into a training set (n = 2,071) to develop regression models to predict time over the 9.14-, 9.14- to 18.29-, 18.29- to 36.58-m, and 36.58-m segments using vertical jump, broad jump, height, and mass as the independent variables. The models were then evaluated against a test set (n = 2,070) for agreement. Statistically significant (p < 0.01) models were determined for 9.14-m time (adjusted R2 = 0.76, SEE = 0.05 seconds), 9.14- to 18.29-m time (adjusted R2 = 0.74, SEE = 0.04 seconds), 18.29- to 36.59-m time (adjusted R2 = 0.79, SEE = 0.07 seconds), and 36.58-m time (adjusted R2 = 0.84, SEE = 0.12 seconds). When evaluated against the test set, the models showed biases of -0.05, -0.04, -0.02, and -0.02 seconds and root-mean-square error of 0.07, 0.05, 0.07, and 0.12 seconds for the 9.14-, 9.14- to 18.29-, 18.29- to 36.58-m, and 36.58-m segments, respectively. However, 5-6% of the predictions lay outside of the limits of agreement. This study provides 4 formulae that can be used to predict sprint performance when the 36.58-m sprint test is not performed, and practitioners can use these equations to determine training areas of opportunity when working with athletes preparing for the NFL Combine.

The Effects of Open and Closed Kinetic Chain Exercises on Visual Reaction Times and Certain Motor Skills in Young Male Boxers

This study aimed to determine the effects of open kinetic chain (OKC) and closed kinetic chain (CKC) exercises on visual reaction times and certain motor skills in young male boxers. Twelve young male athletes (mean age: 16.92±1.08 years) voluntarily participated in this study, which employed a pretest-posttest experimental research model, a quantitative research method, without a control group. The Ethics Committee Approval required for the research was received from Muş Alparslan University Scientific Research and Publication Ethics Committee with decision number 9/73 dated 08.11.2023. Prior to and following training in OKC and CKC exercises, the athletes were tested on visual reaction times, vertical jumping, and flexibility. The paired samples t-test was applied to normally distributed data. According to our findings, there were no significant differences in the visual reaction time and flexibility tests with respect to the pre- and post-test results for the OKC exercises (p ˃ .05), although a significant difference was detected for the vertical jump test (p ˂ .05), with the post-test values determined to be lower than the pre-test values. While there were no significant differences in the CKC exercise pre-and post-test results for the vertical jump and flexibility tests (p ˃.05), a significant difference was observed in the visual reaction test (p ˂ .05), for which the post-test values were lower than the pre-test values. Based on these results, OKC exercises were determined to have a negative impact on jumping ability, whereas CKC exercises exhibited positive effects on visual reaction times. The use of CKC exercises can thus be recommended for studies aimed at improving visual reaction performance in young male boxers.

Velocity-Load Jump Testing Predicts Acceleration Performance in Elite Speed Skaters: But Does Movement Specificity Matter?

In this study, we compared the influence of movement specificity during velocity-load jump testing to predict on-ice acceleration performance in elite speed skaters. Elite long-track speed skaters (N = 27) performed velocity-load testing with 3 external loads during unilateral horizontal jumping, lateral jumping, and bilateral vertical countermovement jumping. For the unilateral tests, external load conditions were set to 10N, 7.5% and 15% of external load relative to body weight. For the countermovement jumping, load conditions were body weight and 30% and 60% of external load relative to body weight. On-ice performance measures were obtained during maximal 50-m accelerations from a standing start, including maximal skating speed, maximal acceleration capacity, and maximum horizontal power. The 100-m split time from a 500-m race was also obtained. Regularized regression models were used to identify the most important predictors of on-ice acceleration performance. In addition to regularized regression coefficients, Pearson correlation coefficients (r) were calculated for all variables retained by the model to assess interrelationships between single predictors and on-ice performance measures. The countermovement jump with 30% of body mass demonstrated the strongest association with maximal skating speed, maximum horizontal power, and 100-m time (regularized regression coefficient = .16-.49, r = .84-.97, P < .001). Horizontal jump with 15% of body mass was the strongest predictor of maximal acceleration capacity performance (regularized regression coefficient = .08, r = .83, P < .001). The findings of this study suggest that mechanical specificity rather than movement specificity was more relevant for predicting on-ice acceleration performance.

Muscle structure predictors of vertical jump performance in elite male volleyball players: a cross-sectional study based on ultrasonography.

The objective of this investigation is to examine the contribution of key muscle groups in the lower limbs to vertical jumping performance in elite male volleyball players. Specifically, the study focuses on the rectus femoris (RF), vastus lateralis (VL), and lateral gastrocnemius (LG), as well as exploring differences between attack jump and other vertical jump types. To achieve this, we employed B-mode ultrasound to evaluate the anatomical cross-sectional area (ACSA), muscle thickness (MT), pennation angle (PA), and fascicle length (FL) of the RF, VL, and LG in the participants. Fifteen elite male volleyball players were recruited as participants for this study. Jump heights were measured for four types of vertical jumps: attack jump (AJ), countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ). We conducted regression analyses to assess whether the previously mentioned muscle structures could predict jump performance. Our findings reveal that the muscle structure of the RF does not exhibit any significant correlation with the height of any jump. However, VL-ACSA displays a significant and the most potent predictive effect on jump height for all four jump types (AJ: R 2 = 0.32, p = 0.001; CMJ: R 2 = 0.37, p = 0.005; SJ: R 2 = 0.52, p = 0.001; DJ: R 2 = 0.25, p = 0.021). Conversely, LG-FL only demonstrates a significant and stronger predictive effect on AJ jump height (R 2 = 0.18, p = 0.009). Combining VL-ACSA, LG-FL, and training age through multiple linear regression analysis resulted in a highly significant model for predicting AJ jump height (F = 13.86, R 2 = 0.73). Moreover, the model incorporating VL-ACSA and training age is also important for predicting CMJ, SJ, and DJ jump heights (F = 8.41, R 2 = 0.51; F = 13.14, R 2 = 0.63; F = 5.95, R 2 = 0.41; respectively). The muscle structure indicators in the lower limbs significantly predict jump performance among elite male volleyball players. However, different jump types are influenced by distinct indicators, particularly in the case of AJ, which is associated with LG-FL. This suggests that enhancing LG-FL may positively impact AJ ability, thereby emphasizing the importance of specificity in training. To optimize specialized jump performance in volleyball players, practitioners are advised to assess VL-ACSA and LG-FL and incorporate step-up and eccentric strength training targeting the calf muscles to yield considerable benefits.

The Effect of Biomechanical and Viscoelastic Properties of Gastrocnemius (Lateral-Medial) Muscle and Achilles Tendon on Jumping Performance in Professional Soccer Players

Anaerobic performance (vertical jumps) is an important indicator in determining athletic performance in soccer. The aim of this study was to investigate the effects of biomechanical and viscoelastic properties of lateral and medial gastrocnemius (LG&amp;amp;MG) muscle and achilles tendon (AT) on jumping performance of professional soccer players. A total of 21 male professional soccer players with a mean age of 18.19±0.40 years, a mean height of 180.48±6.25 cm, a mean body weight of 70.71±7.82 kg, and a mean BMI of 21.66±1.65 kg/m₂ were included in this study. LG and MG muscle, as well as AT biomechanical and viscoelastic properties were evaluated with Myoton Pro device. Measurements were performed in the prone position of the soccer players, LG and MG at 50° plantar flexion, and AT at 0° (neutral position) at an angle of 4 cm above the calcaneal tubercle. Counter movement jump (CMJ) were recorded with the high-speed camera in the validated My Jump 2 application. A significant correlation was observed between the LG (F) tension value and CMJ (P) value and between the MG (R&amp;amp;C) values and the CMJ (F&amp;amp;P) value of professional soccer players (p&amp;lt;0.05). There was no significant relationship between AT values and CMJ values (p&amp;gt;0.05). It should not be forgotten that training coaches on this subject and applying this information to soccer players by conscious coaches will bring about increases in the athletic performance of soccer players, and all these performance characteristics can be achieved with planned and programmed training.

Physiological and performance adaptations to beta alanine supplementation and short sprint interval training in volleyball players

This study aimed to elucidate the impact of combining Beta-Alanine (BA) supplementation with short sprint interval training on cardiorespiratory fitness, anaerobic power, and bio-motor abilities in volleyball players. Twenty young male athletes were randomly divided into 2 equal groups and performed 8 weeks of short sprint interval training while supplementing 4.8 g daily BA or placebo (polydextrose). The players were evaluated for volleyball-specific bio-motor abilities (vertical jump, horizontal jump, spike jump, block jump, 10-m linear sprint, and T-test change of direction speed) and physiological parameters (cardiorespiratory fitness and anaerobic power) pre- and post-intervention. Both groups demonstrated significant (p ≤ 0.05) improvements in all measured variables over time. A time-regimen interaction was observed in jumping ability enhancement from pre- to post-training, wherein BA elicited more significant changes in both vertical and horizontal jumps compared to the placebo. Analyzing residuals in changes and the coefficient of variations (CV) in mean group changes demonstrated that BA supplementation results in uniformly inducing adaptive changes among individuals. Therefore, in light of these results, it is recommended that coaches and trainers take into consideration the utilization of BA as an ergogenic aid to enhance the vertical and horizontal jumps of volleyball players and increase the homogeneity in adaptive responses over the training period.

Correlation of Pronated Foot Posture and Vertical Jump Measurement in Adolescent Recreational Basketball Players - An Observational Study

Background: Osteoarthritis (OA); a whole joint disorder is a most common and progressive disease that worsens with age. Synovitis and synovial effusion can play important role in early OA diagnosis and progression. Limited Background: Jumping is a significant move commonly performed by basketball players, with an average of 44 jumps completed by each player during a competitive game. The influence of foot pronation on the mechanics of the lower extremities in basketball players' movements, particularly during repeated jumps and various landing techniques, is a significant area under investigation. Methodology: After receiving ethical approval, a total of 250 individuals underwent screening. Out of these, 85 participants were selected for the study on specific criteria and convenience sampling. Prior to the commencement of the study, written consent was obtained from the parents of the participants, along with their assent. The participants were then categorized into different groups based on their navicular drop, with Group 1 (consisting of 42 individuals) exhibiting a pronated foot posture, and Group 2 (comprising 43 individuals) displaying a neutral foot posture. Subsequently, the Sargent jump test was conducted on all participants, and the data obtained was analyzed for both groups. Results: Data from basketball players were examined using SPSS 16.0. After conducting an unpaired t-test (p=0.15, Df= 83, t= 1.43) and a Pearson correlation test (r=0.12 and r=0.08), it was found that there was no statistically significant correlation between pronated foot posture and vertical jump performance. Conclusion: This research study has determined that there is no connection between a pronated foot position and the vertical jump height among young recreational basketball players. Keywords: Pronated foot, Navicular drop, Vertical jump, Adolescent, Basketball players.

The relationship between isokinetic knee flexion andsquat jump performance

BACKGROUND: Explosive power of the lower limbs is considered a powerful diagnostic method of the performance level of athletes. In the past, this issue has not yet been sufficiently explored. In the theoretical part, we tried using the available literature to approach the solved problem from the point of view of other authors. PURPOSE: The work aimed to verify and determine the existence of relationships between the isokinetic strength of the extensor joint and during the entire period in adolescent athletes of the Presov club. MATERIALS and METHODS: This study was carried out on adolescent athletes (n=21) who compete at the national level in the category of junior age. Average age 15.3 years, height 173 cm, weight 56 kg. Individual jumps SJ, CMJ, and CMJ FA were measured on Optojump. Isokinetic measurement of peak force and average force was performed in a bilateral version using a special adapter and IsoForce2 device at angular speeds of 50.s-1, 70.s-1, 90.s-1, 125.s-1, 155. s-1. We determined the relationships between individual variables using the Pearson correlation coefficient (r). RESULTS: Peak force values measured at an angular velocity of 155.s-1 on Izoforce2 correlated with SJ and CMJ jumps at the p &lt; .05000 significance level. With average force values measured on isokinetic equipment, a significant relationship was demonstrated at an angular velocity of 155.s-1 in SJ, CMJ, and CMJ FA jumps at the level of significance p &lt; .05000. The measured average values at an angular velocity of 125.s-1 were correlated at the level of significance p &lt; .05000 only in SJ and CMJ FA jumps. CONCLUSIONS: The results of the work indicate that there is a relationship between vertical jumps and the values measured on isokinetic devices, which strengthens the claim about the importance of these muscle parts during the vertical jump as one of the limiting factors of performance in athletics. Due to the small number of people examined and the high variability of the results of similar studies, we recommend confirming the results that further measurements are also carried out at higher angular velocities of 180.s-1 to 230.s-1, in different periods of the athletes' training.

Access to test selection in children’s athletics – Prediction of reaching maximum speed level and result in sprint based on dynamickinematic parameters, speed-strength abilities and morphological characteristics

Running speed in the form of sprinting is one of the most important abilities that can significantly define performance success in many sports. From the perspective of genetically inherited motor functions, running speed can be classified as a primary phylogenetic human movement, manifested in the form of a “threesegment model” consisting of speed, power, and coordination. By comprehensively analyzing the general and partial predictive contributions of dynamic-kinematic parameters of running, speed-power abilities, and morphological characteristics, on a sample of 80 boys aged 10-12 years, it can be concluded that regardless of the choice of criteria, achieved maximal speeds (KVMAX) or results in children’s athletic sprint over 50 meters (KT50m), the same or related predictor variables contributed to the explanation. The variable running time for 20m from a flying start (KTLS20m) has the greatest predictive contribution (β=0.83, p&lt;0.001) to explaining both criteria, which may indicate the importance of conducting this test in the identification and selection for athletic sprint. Additionally, the selection of tests to assess speed-power abilities is extremely important for the identification and selection for athletic sprint. It can be concluded that tests of horizontal and vertical jumps are significant for identification, as well as tests for assessing neuro-muscular excitation. Tests for assessing continuous horizontal jump are also important, although there is an impression that, in boys aged 10-12 years, coordinatively simpler tests should be used. In the analysis of morphological characteristics, variables that significantly contributed to the explanation of criteria at a partial level were body height, back skinfold, and ankle diameter, indicating that in the identification of talented individuals, it should be considered that elite sprinters are characterized by light bones, optimal muscle mass, and low levels of subcutaneous fat tissue.

The Relationship between Genetic Variability and Seasonal Changes in Vertical Jump Performance in Amateur Soccer Players

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

Acute Effects of Intracontrast Rest After Back Squats on Vertical Jump Performance During Complex Training.

Houlton, LJ, Moody, JA, Bampouras, TM, and Esformes, JI. Acute effects of intracomplex rest after back squats on vertical jump performance during complex training. J Strength Cond Res XX(X): 000-000, 2024-Postactivation performance enhancement and complex-contrast sets are prevalent in sports science research. Typical complex-contrast sets consist of heavy back squats, an intracontrast rest period (ICRP) and vertical jumps (countermovement jumps [CMJs], or squat jumps [SJs]). Propulsive impulse (Jprop) is considered the leading indicator of jump performance. However, studies evaluating jump performance during complex-contrast sets use jump height as the primary performance measure, limiting insight into ICRP's effect on jump performance. We assessed the effect of a 3 repetition maximum (3RM) back squat and 6 ICRPs on vertical jump Jprop and associated force-time components. Fourteen subjects completed 12 experimental conditions, assigned equally to 4 testing sessions. Independent variables, in a 6 × 2 randomized, counterbalanced design, were ICRP (0, 60, 120, 180, 240, 300 seconds; ICRP0, ICRP60, ICRP120, ICRP180, ICRP240, ICRP300, respectively) and vertical jump (CMJ and SJ). Conditions consisted of baseline vertical jumps, followed by 3 back squat repetitions at 100% 3RM, an ICRP and experimental jumps. Symmetrized percentage changes between experimental and baseline jumps were assessed using repeated measures analysis of variance (ANOVA) and pairwise effect sizes. Results showed significant effects (p ≤ 0.05) on CMJ average rate of force development (RFD) between ICRP0 and ICRP120 and ICRP0 and ICRP300. Pairwise comparisons showed medium and large effect sizes for and increases in CMJ RFD (g = 0.83-2.69) whereas SJ RFD decreased (g = 0.81-2.57). Small effect sizes were found for Jprop, peak force, and mean force. Results suggest limited change in Jprop (g = 0.01-0.58), but back squats may potentiate RFD via the stretch-shortening cycle.

Seasonal Variations in Performance and Asymmetry Data for Jump and Change of Direction Abilities in Female Soccer Players.

Mainer-Pardos, E, Bishop, C, and Gonzalo-Skok, O. Seasonal variations in performance and asymmetry data for jump and change of direction abilities in female soccer players. J Strength Cond Res XX(X): 000-000, 2024-The study aimed to evaluate the progression of the percentage-based change of direction (COD) deficit (%CODD) over a competitive season, along with its correlation with performance tests and to examine the impact of the magnitude and direction of asymmetry at 4 stages of the season. Forty-seven (U-16, U-18, and U-20), highly trained, female soccer players performed unilateral vertical jumping (countermovement jump [CMJ]) and horizontal jumping (HJ), 10-m sprint, and 180° change of direction (COD180) tests. The %CODD was also calculated. Significant group and time effects (p < 0.05) were observed in CMJ, HJ, 10-m sprint, and COD180 tests, with U-20 players generally outperforming the U-18 and U-16 groups. Nonsignificant differences were reported in the %CODD between any time point or groups throughout the season. Moderate or large significant (r = 0.44-0.64; p < 0.05) relationships were found between %CODD and 10 m. The direction of asymmetry within and between tests at all time points was slight to moderate (k = -0.29 to 0.57). Notwithstanding, 51% of the players showed the best performance in the horizontal jump with the same leg throughout the season, whereas only 36% in %CODD. This study highlights the importance of developing strategies to improve %CODD depending on the player's position demands. Finally, individually monitoring the magnitude and direction of asymmetry can help practitioners monitor the effects of training and competition throughout the season.

Comparison of the Effects of Compound Training, Plyometric Exercises, and Kettlebell Exercises on Strength, Power, Dynamic Balance, and Pitched Ball Velocity in 30 Male High School Baseball Pitchers Aged 16-19 Years.

BACKGROUND The purpose of this study was to determine how the combination of plyometric training (PT), which builds strength through fast, repetitive extensions and contractions, and kettlebell training (KT), using a device that is smaller than a barbell and allows for strength and full-body work, affects the physical performance and performance of high school pitchers during the season. MATERIAL AND METHODS Participants (n=30 males; age group=16-19 years) were randomized into 3 groups: compound training group (CTG) (n=10), plyometric training group (PTG) (n=10), and kettlebell group (KTG) (n=10). All groups performed training twice weekly for 4 weeks. Pre- and post-intervention assessments were conducted on isokinetic strength to measure strength, vertical jump (VJ) to measure power, dynamic balance (Y-balance), and ball speed (BS) to measure baseball performance. RESULTS We found there was increased strength, VJ, Y-balance, and BS in the CTG, PTG, and KTG (p=.000). CTG had significantly different results than PTG and KTG (p=.000). There was a significant difference in increased strength of the right knee joint flexors between PTG and KTG (p=.000). CONCLUSIONS CTG, PTG, and KTG for pitchers during the season improved significantly. These results suggest that combination training, rather than just 1 type of training, affects pitchers' strength, VJ, Y-balance, and BS during the season.

Reliability and validity of "My Jump 2" application for countermovement jump free arm and interlimb jump symmetry in different sports of professional athletes.

Vertical jumping is an important evaluation tool to measure muscle strength and power as well as lower limb symmetry. It is of practical importance and value to develop and utilize a portable and low-cost mobile application (APP) to evaluate jumping. The "My Jump 2" app is an iPhone camera-based application for measuring jumping movements, which is applied to the countermovement jump (CMJ) vertical jumps of the lower limbs of athletes in different sports. The validity of this application and previous versions applied to different forms of vertical jump tests has been preliminarily demonstrated in different population, which has an obvious progress in research. Therefore, the reliability and validity of the jump height, time of flight parameters and symmetry of the CMJ vertical jump of athletes in different sports are needed to be verified by more experiments. The purpose of this study is to verify whether "My Jump 2" can effectively and reliably assess jump height, flight practice and lower limb symmetry in CMJAM (countermovement jump free arm) tests in fencing, swimming and diving athletes. Seventy-nine fencers, swimmers and divers with training experience participated in this study. They completed a total of three CMJAM vertical jump and lower limb symmetry tests in 1 day, while being assessed by using the "My Jump 2" application and a force platform. The intra-group correlation coefficient (ICC) was used to verify reliability, while the Cronbach's alpha and coefficient of variation (CV%) was used to analyze the stability of the CMJAM vertical jump test over three jumps. The Pearson correlation coefficient was used to verify the strength of the relationship between methods (i.e., concurrent validity), and the Bland-Altman plot was used to represent consistency, meanwhile, the t-test was used to determine the systematic bias between methods. Compared with the force platform, the cumulative height values of the total number of jumps (r = 0.999; p = 0.000), the cumulative time to vacate (r = 0.999; p = 0.000) for the CMJAM test obtained by the "My Jump 2" application, the height (ICC = 0.999-1, p = 0.000), the time to vacate flight (ICC = 0.999-1, p = 0.000), contact time symmetry (ICC = 0.976-0.994, p = 0.000), and flight time symmetry (ICC = 0.921-0.982, p = 0.000), respectively. Showed high correlation between the results of "my jump 2" app and the force platform. The "My Jump 2" application is a valid tool to assess CMJAM vertical jump and lower limb symmetry in fencing, swimming and diving athletes with training experience.

Moderate-dose caffeine enhances anaerobic performance without altering hydration status.

The effects of direct nutritional supplements on athletic performance are still being investigated and arouse curiosity. Only one study in the literature was found that investigated the kicking speed performance of futsal players following low-dose caffeine supplementation (3 mg/kg); thus, the question of whether caffeine supplementation improves kicking speed as well as essential physical parameters in soccer players is still controversial. Therefore, the aim of this study was to determine the effect of caffeine supplementation on vertical jump (VJ), sprint, reaction time, balance, change of direction (COD), and ball-kicking speed in soccer players. In a double-blind, cross-over design, nine moderately trained male soccer players (21.11 ± 2.02 years, 171.22 ± 6.14 cm, 71.78 ± 10.02 kg) consumed caffeine (6 mg/kg) or a placebo 60 min before completing balance, reaction time, vertical jump, agility, 30 m sprint, and ball-kicking speed tests. Greater VJ height (p = 0.01) and power (p = 0.08), and faster completion time according to the Illinois Agility Test (p = 0.08) were found following caffeine supplementation compared to placebo. Elapsed time (p = 0.01), average (p = 0.01) time, and the slowest reaction times (p = 0.016) were significantly reduced after caffeine consumption compared to placebo supplementation. Caffeine intake significantly improved VJ, agility, and reaction time (p < 0.05) but did not affect 30 m sprint, ball-kicking speed, balance, and RPE values in soccer players (p > 0.05). Although non-significant, caffeine intake also improved sprint (0.67%) and ball kicking (2.7%) performance percentages. Also, caffeine consumption did not induce dehydration, and the athletes' body hydration levels were normal. These findings support the use of caffeine supplementation as an effective nutritional ergogenic aid to enhance anaerobic performance, at least for vertical jumps, COD speed, and reaction time, in trained male soccer players.

Functional Performance Testing to Evaluate Stretching Programs for Sprinters and Jumpers

Flexibility is a crucial element for success in various sports, notably in athletics, especially for runners and jumpers. Inadequate flexibility heightens the risk of strains, sprains, and other musculoskeletal issues. This article forms part of a project aimed at devising warm-up and cool-down stretching routines. The study population is adolescent athletes. The following assessment methods are used: Trunk Power Test (Backward Overhead Medicine Ball Throw); Lower Extremity Power Tests (Vertical Jump; Standing Long Jump); Upper Extremity Power Test (Seated Shot-Put Medicine Ball Throw); Sprint Test (30 Meter Flying Start). Conclusion. The warm-up program is designed to facilitate dynamic muscle engagement and prepare the body for activity. Meanwhile, the relaxation program focuses on enhancing muscle and tendon flexibility; thereby decreasing the risk of overuse injuries and improving overall lower extremity resilience. Determining the influence of various stretching programs on speed-power metrics will aid in adjusting training protocols and enhancing competitive performances.

The effects of plyometric training on physical fitness and skill-related performance in female basketball players: a systematic review and meta-analysis.

This study aims to analyze the effects of plyometric training (PT) on physical fitness and skill-related performance in female basketball players. Five databases, including Web of Science, Scopus, PubMed, EBSCOhost, and Google Scholar, were used to select articles published up to 20 December 2023, using a combination of keywords related to PT and female basketball players. The risk of bias and the certainty of evidence in included articles were assessed using the Cochrane risk of bias (RoB2) tool and "The Grading of Recommendations Assessment, Development, and Evaluation" (GRADE). Ten studies were included for the systematic review, and eight for the meta-analysis, totalling 246 female basketball players aged 14.5-22.5years. Most of these players were highly trained. Most of the included studies exhibited concerns regarding the risk of bias. The PT programs lasted 4-8weeks, conducted 2-3 sessions per week, with sessions lasting 20-90min and including 29-190 jumps. In the systematic review, most studies showed that PT significantly improved performance in countermovement jump (CMJ), squat jump (SJ), Sargent jump, standing long jump, lateral hop, medicine ball throw, t-Test, Illinois agility, lane agility drill, linear 20-m sprint, stable and dynamic leg balance, dribbling, passing, shooting, and various basketball-specific tests, as well as increased muscle volume and thigh cross-sectional area. However, some studies showed PT to induce no significant changes in performance during CMJ, t-Test, Illinois agility, knee extensor/flexor strength, linear sprint, and single leg balance tests. In the meta-analysis, CMJ height (ES = 0.37; p = 0.036), vertical jump (VJ) peak power (ES = 0.57; p = 0.015), VJ peak velocity (ES = 0.26; p = 0.004), and t-Test performance time (ES = 0.32; p = 0.004) were significantly improved with small effects following PT. The effect of PT on performance in female basketball players was mixed. Most studies indicated that PT could improve various measures of physical fitness and skill-related performance, but performance remained unchanged in some tests. More studies with established tests are needed to investigate the effect of PT on female basketball players in the future. https://inplasy.com/, Identifier INPLASY2023120078.

Measuring Vertical Jump Height With Artificial Intelligence Through a Cell Phone: A Validity and Reliability Report.

Erik, HT, Onn, SW, and Montalvo, S. Vertical jump height with artificial intelligence through a cell phone: a validity and reliability report. J Strength Cond Res 38(9): e529-e533, 2024-This study estimated the reliability and validity of an artificial intelligence (AI)-driven model in the My Jump 2 (My Jump Lab ) for estimating vertical jump height compared with the Force Platform (FP). The cross-sectional study involved 88 athletes (33 female and 55 male athletes), performing a total of 264 countermovement jumps with hands on hips. "Jump heights were simultaneously measured using the FP and the My Jump 2 app." The FP estimated jump heights using the impulse-momentum method, whereas My Jump 2 used the flight-time method, with the latter using an AI feature for automated detection of jump take-off and landing. Results indicated high reliability for the AI model (intraclass correlation coefficient [ICC 1,3 ] = 0.980, coefficient of variation [CV] = 4.12) and FP (ICC 1,3 = 0.990, CV = 2.92). Validity assessment showed strong agreement between the AI model and FP (ICC 2,k = 0.973). This was also supported by the Bland-Altman analysis, and the ordinary least products regression revealed no significant systematic or proportional bias. The AI-driven model in My Jump 2 is highly reliable and valid for estimating jump height. Strength and conditioning professionals may use the AI-based mobile app for accurate jump height measurements, offering a practical and efficient alternative to traditional methods.