Performance In Soccer Players Research Articles

Monitoring training load in youth soccer players: effects of a six-week preparatory training program and the associations between external and internal loads

This study examined the effects of a six-week preparatory training program on physical performance and physiological adaptations in junior soccer players. Additionally, we investigated whether a relationship existed between external and internal loads. Youth soccer players (aged 16 years old) from a youth football academy participated in six weeks of pre-conditioning training. Wireless Polar Team Pro and Polar heart rate sensors (H10) were used to monitor physical performance indicators (sprint and acceleration scores, covered distance, maximum and average speed and duration), physiological responses (maximum and average heart rate [HR] and R-R interval, time in HR zones 4+5, and heart rate variability [HRV]), and training load score. Additionally, muscle status and rating of perceived exertion (RPE) scores were measured using digital questionnaires. Significant increases were observed in the majority of physical performance indicators [i.e., sprints (p = 0.015, ES = 1.02), acceleration (p = 0.014, ES = 1), total distance (p = 0.02, ES = 0.87), as well as maximum speed (p = 0.02, ES = 0.87)]. A trend towards improvement was observed in the remaining performance indicators (i.e., distance/min and avg speed; ES = 0.6), training load (ES = 0.2), muscle status (ES = 0.3)), and all physiological responses parameters (ES = 0.1 to 0.6). Significant correlations were found between the majority of external load parameters (i.e., performance indicators) and objective (i.e., physiological responses) and subjective (i.e., RPE, muscle status) internal load parameters (p < 0.001). The highest number of moderate-large correlations were registered between performance indicators and time in HR zone 4+5 (0.58 < r < 0.82), training load (0.53 < r < 0.83), average HR (0.50 < r < 0.87), maximal HR (0.51 < r < 0.54) and average R-R interval (0.58 < r < 0.76). HR zone 4+5, average and maximal HR, average R-R interval, and training load score may help control training parameters and reduce the risk of under- or over-training in youth soccer players. However, these conclusions should be confirmed and replicated in future studies with more diverse subject populations.

TREINAMENTO DE APTIDÃO FÍSICA PARA JOGADORES DE FUTEBOL UNIVERSITÁRIO

ABSTRACT Introduction: Physical fitness is an essential factor affecting soccer in China, and its high-level results from the overlapping training effects of various factors on the soccer athlete. Objective: This study aims to analyze the relationship between practical fitness training and performance in college soccer players. Methods: College soccer players volunteered for a fitness training session. Mathematical statistics were used to analyze volunteers’ fitness and competition performance before and after training. The impact of soccer fitness training on the athletes’ physical quality was also considered. Results: After eight weeks of fitness training, improvement in the performance of college soccer players was noticed. There was a statistical difference in performance and physical quality after physical training (P&lt;0.01). Conclusion: College soccer players improved performance after fitness training. Such training can improve the physical fitness of college soccer players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Effects of Aquatic Exercise Training on Physical Performance and Mood States in Male Collegiate Soccer Players

ABSTRACT Introduction/Purpose This study investigated the effects of aquatic exercise training on the physical performance and mood states of male collegiate soccer players. Methods Twenty male collegiate soccer players (age 19.9 ± 0.9 yr) performed aquatic exercise training composed of warm-up exercises, high-intensity interval training, resistance training using tools, and cooldown activities. Training was performed for 30 min·d−1, twice per week for 11 wk. Participants were randomly allocated to the training or control groups (n = 10 each). The participants’ anthropometric measurements, range of motion (ROM), muscle strength, change of direction, endurance performance, and mood states were assessed at baseline and after the 11-wk intervention period. Results After the intervention, the ROM of the shoulder and hip joints and the isokinetic and back muscle strength increased in the training group (P &lt; 0.05 each). Significant group–time interaction effects was observed between the two groups in the ROM of the shoulder and hip joints and in isokinetic and back muscle strength (P &lt; 0.05 each). The Profile of Mood States, Second Edition vigor–activity scores increased in the training group (19.3 ± 6.4 to 24.5 ± 5.6 points, P = 0.007), and a significant interaction effect for group–time was observed for vigor–activity between the two groups (P = 0.005). Conclusions These results suggest that aquatic exercise training helps improve ROM, muscle strength, and mood in male collegiate soccer players.

The Effect of the Quadriceps Muscle Fatigue After an ISOTONIC Contraction on Some Kinematic Variables and the Accuracy of Soccer Players’ Performance of the Corner Kick

Fatigue in muscles is a reason for the low skill performance of soccer players so this study sought to find out the effect of the quadriceps muscle fatigue resulting from an isotonic contraction on some kinematic variables and the accuracy of soccer players’ execution of the corner kick. A test for the accuracy of the corner kick and the leg press exercise was used on a sample of 8 international soccer players, and their means were as follows: age: 26.8 ±2.3 years, height: 174 ±12 cm, mass: 71 ±6 kg, training age: 14.6 ±1.8 years. The performance of the corner kick test was videotaped by three cameras and Kinovea program for kinematic analysis was used. The results showed a negative effect of the quadriceps muscle fatigue after isotonic contractions on kinematic variables and on the accuracy of corner kicks. The study results point to the necessity of enhancing the ability of soccer players in terms of endurance of muscle strength in the quadriceps muscle to the highest possible extent due to the importance of that element in their skillful performance, including the accuracy of the implementation of corner kicks.

Elite young soccer players have smaller inter-limb asymmetry and better body composition than non-elite players

Body composition (BC) and inter-limb anthropometric asymmetries (LA) may influence the physical performance of soccer players. This study aimed to determine differences in BC and LA among soccer across four performance levels. The study involved 110 male soccer players participating in Czech senior teams who were grouped into four different performance levels (i.e. G1: national team, G2: 1st division, G3: 2nd division, G4: 3rd division). The following BC and LA parameters were compared among groups: body height, body mass, absolute fat-free mass, relative fat-free mass (FFMrel), percentage of fat mass (FM), total body water (TBW), intracellular water (ICW), extracellular water (ECW), phase angle, and bilateral muscle mass differences in the upper and lower extremities. Significant differences were observed in BC parameters among all groups (λ = 0.06, F75,246 = 5.38, p = 0.01, ηp 2 = 0.62). High-performance players (i.e. G1, G2) had significantly (p < 0.01) lower FM than lower performance players (i.e. G3, G4). The lowest values of FFMrel, relative TBW, relative ICW and ECW were detected in the lowest-performance players (i.e. G4). Significantly lower bilateral muscle mass differences were detected in G1 players (2.71 ± 1.26%; p < 0.01) compared with G4 players (3.95 ± 1.17%). G1 and G2 players had a higher proportion of muscle mass in the torso (p < 0.01) and upper limbs than G3 and G4 (p < 0.01). Elite and high-performance players have better BC and lower inter-limb anthropometric asymmetries compared with low-performance level players.

Effects of re-warm-up protocols on the physical performance of soccer players: A systematic review with meta-analysis.

This systematic review aimed to (1) identify and summarize studies that have examined the effects of re-warm-up (RWU) protocols on the physical performance of soccer players (vertical jump height and sprint time) and (2) establish a meta-comparison between performing a re-warm-up and not performing one regarding the outcomes of the aforementioned outcomes. A systematic review of EBSCO, PubMed, SciELO, SPORTDiscus, and Web of Science databases was performed on 12 January, 2021, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the 892 studies initially identified, four studies were reviewed, and three of these were included in the present meta-analysis. Compared to a control condition, there was a moderate effect of RWU on vertical jump height (ES = 0.66; p = 0.001; I2 = 0.0%). However, compared to a control condition, there was a trivial effect of RWU on linear sprint time (ES = 0.19; p = 0.440; I2 = 38.4%). The nature of RWU enhances the performance of players with an emphasis on actions requiring vertical jumps. Therefore, the results provide essential information that soccer coaching staff can use to improve the performance of their teams. The limited number of studies available for the meta-analysis may have magnified the impact of heterogeneity on linear sprint time findings. More high-quality studies, with homogeneous study designs, may help to clarify the potential benefits of RWU for linear sprint time.

Comparison of Speed, Agility and Reactive Agility Performance in Soccer Players

Futbolun talepleri son zamanlarda önemli ölçüde değişmiş ve artmıştır. Günümüzde bir futbol müsabakası sırasında, oyuncuların daha fazla güce sahip olmaları, yüksek şiddet gerektiren hareketleri daha sık ve sayıda yapmaları ve daha uzun mesafeleri kat etmeleri gerekmektedir. Bu çalışmanın amacı futbolcuların sprint, çeviklik ve reaktif çeviklik performansları arasındaki farklılıkları araştırmaktır. Çalışmaya toplam 59 erkek futbolcu (14-19 yaşlar arası) gönüllü olarak katılmıştır. Oyuncular yaşlarına göre 15 yaş altı (U-15; n = 20), 17 yaş altı (U-17; n = 20) ve 19 yaş altı (U-19; n = 19) oyuncular olarak 3 grupta değerlendirilmiştir. Katılımcılara 10-30m sprint, çeviklik t testi ve reaktif çeviklik testleri uygulanmıştır. Tüm verilerin normallik testi varsayımını karşılayıp karşılamadığını doğrulamak için Kolmogorov-Smirnov testi kullanılmıştır. Çalışma sonuçlarının karşılaştırmaları ise tek yönlü ANOVA ile yapılmıştır. ANOVA sonuçları, anlamlı bir grup etkisi gösterdiğinde, gruplar arası farklılıkları belirlemede post-hoc Bonferroni testi kullanılmıştır. Anlamlı farklılık tespit edilen tek yönlü varyans analizi deseninde değişkenler arasındaki ilişkinin gücünü hesaplamak için eta-kare (etki büyüklüğü) (η2) katsayısından faydalanılmıştır. Grup karşılaştırmalarında, katılımcıların 10 m sprint (F= 6,29, p

Cardiorespiratory, Metabolic, and Performance Changes from the Effects of Creatine and Caffeine Supplementations in Glucose-Electrolyte-Based Sports Drinks: A Double-Blind, Placebo-Controlled Study.

The purpose of this study is to investigate the additive effects of creatine and caffeine on changes in the cardiorespiratory system, metabolism, and performance of soccer players. Seventeen male soccer players randomly ingested three sports drinks comprising the following: glucose−electrolyte-based (Drink 1, control; D1), glucose−electrolyte-based drink + 5 g creatine (Drink 2; D2), and glucose−electrolyte-based drink + 5 g creatine + 35 mg caffeine (Drink 3; D3) during a 15 min recovery period after the modified Loughborough Intermittent Shuttle Test (LIST) on a standard outdoor soccer field. Then, a 20-m repeated intermittent sprinting activity was performed. The results showed no significant differences in cardiorespiratory and gas exchange variables. The non-significant levels of blood glucose concentrations among drinks with higher blood lactate concentrations were detected in parallel with increased heart rate during intermittent sprinting as a result of exercise intensities. Significantly longer sprinting time was found in D3 than D1 (p < 0.05), with no significant differences between D2 and D3. From this study, we conclude that the additive effect of caffeine−creatine supplements in a glucose−electrolyte drink during the 15 min recovery period enhances repeated 20-m high-intensity running in soccer players with no negative effect on cardiorespiratory functions.

Acute Effects of Kinesio Taping on Functional Performance in Healthy Soccer Players: A Randomized, Controlled Crossover Trial.

This study aimed to investigate the acute effects of the Kinesio tape (KT) application on functional performance in healthy athletes. In this randomized, controlled crossover trial, a total of sixteen healthy soccer players (male = 14; age = 23.28 ± 3.13 years old) were assigned randomly into either KT over quadriceps, KT over hamstring, KT over quadriceps plus hamstring, or no intervention control condition. Four conditions were applied in a crossover design through three consecutive test sessions for each condition with a washout period of 2 days between the trials. Afterwards, all participants performed a 5-min warm-up routine and four sets of 30-s static stretching exercises for the hamstring and gluteal muscles for three consecutive treatment sessions. The running, jump, and flexibility tests were used to assess the functional performance of healthy athletes. A total of sixteen participants completed the study. No significant differences in the jump, flexibility, and running tests among the conditions were reported (p > 0.05). These findings suggest that KT application has no acute effects in improving functional performance in healthy athletes. However, further studies with larger sample sizes are needed to verify our results.

The Three-Level Model of Factors Contributing to High-Intensity Intermittent Performance in Male Soccer Players.

High-intensity intermittent performance in soccer is widely assessed using the yo-yo intermittent recovery level 2 test (YYIR2). This test is usually associated with aerobic-anaerobic performance. However, less is known about the direct or indirect contributions of abilities, including the anaerobic component. This study aims to propose a three-level model of factors contributing to YYIR2 performance, based on the investigation of relationships with aerobic endurance, repeated-sprint ability (RSA), and the linear and change-of-direction speed and power variables. Eighteen soccer players performed the YYIR2, with a 20-m shuttle run test (20mSR), an RSA test with change-of-direction, 5-m and 20-m sprints, and a 505 test, countermovement jump, squat jump, and drop jump. The results showed a significant relationship between the YYIR2 distance and the 20mSR distance (r = 0.721, p = 0.001), as well as with the RSA test mean time (r = -0.594, p = 0.009). In the second level, the 20mSR distance performance was not associated with any of the speed and power variables. However, the RSA test mean time correlated with the 5-m sprint (r = 0.587, p = 0.010), 20-m sprint (r = 0.702, p = 0.001), and 505 test (r = 0.585 p = 0.011) performance. In the third level, the 20-m sprint time was related to the squat jump (r = -0.577 p = 0.012) and countermovement jump (r = -0.768 p &lt; 0.001) heights. In addition to aerobic endurance, this study highlights the importance of the anaerobic component in YYIR2 performance. More specifically, aerobic endurance (52%) and RSA (36%) are the main determinants of YYIR2 performance. Subsequently, the RSA performance is determined by the linear (34-49%) and change-of-direction speed (35%), while the explosive power of lower limbs contributes to sprinting performance (33-59%). Coaches should focus on the development of these abilities to improve the high-intensity intermittent performance of soccer players.

Investigation of Different Training Methods Integrated into Soccer Training on Body Composition and Athletic Performance

Background and Study Aim. The aim of the study is to investigate the effects of 8-week core and plyometric training on body composition and athletic performance in young male soccer players.&#x0D; Material and Methods. 24 young male soccer players participated in the study voluntarily. The subjects were randomly divided into three separate groups: Core training group (CTG), plyometric training group (PTG) and control group (CG). In addition to soccer training two days a week for 8 weeks, the training was applied to the subjects according to the training programs determined. Physical and performance measurements were made 8 weeks before and after the study. Subject's measurements were analyzed in the SPSS 22 program.&#x0D; Results. The largest percentage and significant difference in agility, speed, vertical jump and plyometric jump parameters was obtained in PTG, while the largest percentage and significant difference in horizontal jump parameters was obtained in CTG. While no difference was found in speed and agility performance in CTG; there are significant differences in jump performance but these differences are lower than the other experimental groups in terms of percentage difference. On the other hand in body composition, a significant change was observed only in the height parameter in PTG.&#x0D; Conclusions. If a faster improvement is desired in the determined athletic performance parameters in a period of eight weeks in soccer, it may be recommended to prefer core and plyometric trainings in addition to branch training.&#x0D; &#x0D; Keywords: Soccer, core, plyometrics, body composition, athletic performance

Daytime fluctuations of endurance performance in young soccer players: a randomized cross-over trial

ObjectivesFluctuations of physical performance and biological responses during a repetitive daily 24-h cycle are known as circadian rhythms. These circadian rhythms can influence the optimal time of day for endurance performance and related parameters which can be crucial in a variety of sports disciplines. The current study aimed to evaluate the daytime variations in endurance running performance in a 3.000-m field run and endurance running performance, blood lactate levels, and heart rate in an incremental treadmill test in adolescent soccer players.ResultsIn this study, 15 adolescent male soccer players (age: 18.0 ± 0.6 years) performed a 3.000-m run and an incremental treadmill test at 7:00–8:00 a.m. and 7:00–8:00 p.m. in a randomized cross-over manner. No significant variations after a Bonferroni correction were evident in endurance running performance, perceived exertion, blood lactate levels, and heart rates between the morning and the evening. Here, the largest effect size was observed for maximal blood lactate concentration (9.15 ± 2.18 mmol/l vs. 10.64 ± 2.30 mmol/l, p = .110, ES = 0.67). Therefore, endurance running performance and physiological responses during a field-based 3.000-m run and a laboratory-based test in young male soccer players indicated no evidence for daytime variations.

Testing the effects of 4-week training programs based on extreme and medium-sided soccer games: a study focusing on change-of-direction, vertical jump height and locomotor profile

AimThis study tested the effects of two training programs (one program based on extreme sided-games of 1v1 vs. one program based on the medium-sided game of 5v5) on the physical fitness adaptations of youth soccer players. In specific, it was analyzed the effects of the training programs on the 5–0–5 change-of-direction time (5–0–5 time), countermovement jump (CMJ), and final velocity in the 30–15 Intermittent Fitness test (VIFT).MethodsThis study followed a randomized parallel study design. Twenty male regional-level soccer players (age: 17.0 ± 0.3 years old) were randomly assigned to two groups: (1) the 1v1 format; and (2) the 5v5 format. The training intervention lasted four weeks. The week before (baseline) and the week after the intervention, the participants were assessed in the 5–0–5 change-of-direction test (measured using timing gates), CMJ (measured by photoelectric cells), and 30–15 Intermittent Fitness test. The training intervention consisted of 8 sessions (2 sessions per week). The 1v1 group performed four repetitions of 30 s in each session, while the 5v5 group performed four repetitions of 4 min.ResultsThe 5–0–5 time changed − 4.82% (p = 0.004; d = 1.115) for the 1v1 group and − 4.26% (p = 0.004; d = 0.859) for the 5v5 group. CMJ changes occurred both in the 1v1 and 5v5 group and amounted to 1.7% (p = 0.003; d = 0.509) and 1.2% (p = 0.263; d = 0.155) respectively. VIFT changed 2.6% (p = 0.718; d = 0.178) for the 1v1 group and 3.0% (p = 0.593; d = 0.274) for the 5v5 group. The 1v1 group reported significantly lower post-intervention 5–0–5 time than the 5v5 group (− 4.3%; p = 0.048; d = 0.954), although no significant differences in CMJ (3.2%; p = 0.147; d = 0.678) and VIFT (2.5%; p = 0.697; d = 0.177) were revealed.ConclusionsThe extreme-sided games meaningfully beneficiated the vertical jump height and change-of-direction performance of youth soccer players. The extreme-sided games seem more beneficial than medium-sided games for improving these physical abilities while showing that four weeks were enough to impact the players significantly.

Effects of High-Intensity Position-Specific Drills on Physical and Technical Skill Performance in Elite Youth Soccer Players.

Cuong Le, C, Ma'ayah, F, Nosaka, K, Hiscock, D, and Latella, C. Effects of high-intensity position-specific drills on physical and technical skill performance in elite youth soccer players. J Strength Cond Res 37(5): e332-e340, 2023-Soccer physical preparation has been extensively researched with previous emphasis on high-intensity interval running and small-sided games. However, neither approach considers positional differences. The purpose of this study was to investigate the feasibility and short-term effects of a novel position-specific conditioning training (PSCT) paradigm on physical and technical abilities of young soccer players. Fifteen male Vietnamese professional youth soccer players (16.1 ± 0.4 years, 171.7 ± 4.8 cm, 63.9 ± 3.8 kg) undertook a 3-week control period followed by a 3-week intervention with PSCT drills performed twice per week. Position-specific conditioning training comprised purposely designed drills for attackers, defenders, and wingers, respectively. The intensity and duration were the same for all drills (4 × 4 minutes at ∼90% heart rate maximum [HRmax], separated by a 4-minute recovery at 70% HRmax) but differed in the technical and tactical actions performed. Outcome measures included Yo-Yo intermittent recovery test level 1, repeated sprint ability, 10-m and 30-m sprint time, and the Loughborough Soccer Passing Test for technical skills in a fatigued and nonfatigued state. Position-specific conditioning training drills induced a desirable intensity for effective conditioning purpose (89.0 ± 2.1% HRmax) with low interplayer variability (coefficient of variation = 2.4%). Yo-Yo intermittent recovery test level 1 performance improved ( p < 0.05) after the control (Δ178.7 ± 203.3 m) and intervention (Δ176.0 ± 225.7 m) periods without a difference between. These results confirmed the feasibility of PSCT as a novel high-intensity training approach for soccer players. Improvements in aerobic capacity were noted, despite no effect on other physical and technical measures. PSCT may be suitable for individual training, return-to-play stages of rehabilitation, during off-season, or in academy settings when time is not a constraint.

Effects of Age and Playing Tactics on the Individual Tactical Behavior in U10 and U12 Elite Spanish Soccer Players.

The aim of this paper was to explore the effects of age and playing tactics on the individual tactical behavior and performance in young soccer players. A total of 1247 individual possessions during 16 knockout matches from LaLiga Promises U12 tournament (n = 621) and LaLiga U10 Iscar Cup (n = 626) were analyzed by observational methodology. Multilevel and multivariate logistic regression models were created to explain the interdependent effects of age category and playing tactics on the individual tactical behavior and performance. Youth players performed most of their actions against defensive pressure (72.5%), during offensive support (91.3%) and receiving the ball facing forward (62.6%). The most frequent action was to receive and pass the ball (69.6%) and the level of offensive success was 56.9%. The multilevel mixed models revealed that U10 players presented higher odds of running with the ball vs. passing the ball (OR = 1.823; 95% CI: 1.333-2.493; p &lt; 0.001) and lower odds of achieving offensive success (OR = 0.698; 95% CI: 0.525-0.928; p &lt; 0.05) than U12 players. Regarding playing tactics, technical-tactical dimensions such as the players' body shape when receiving the ball, offensive support, defensive pressure, collective type of attack and type of technical action presented a significant and combined effect on the offensive success regardless of age category, playing position and match status. This study found tactical differences between U10 and U12 age categories and revealed important interactive effects of multiple tactical dimensions on the individual offensive behavior and performance in youth soccer players.

The Effectiveness of Different Training Methods in Soccer for Repeated Sprint Ability: A Brief Review

The purpose of this study was to systematically review the literature on the effect of exercise programs on the Repeated Sprint Ability (RSA) performance of soccer players. PubMed, Scopus and Google Scholar databases were searched for original research articles. The inclusion criteria for a study were to include different groups of intervention in soccer players and present the protocol’s characteristics and the study’s results. Twenty-one (21) studies met the criteria. For each study, the effect size (ES) and 95% confidential interval (CI) were calculated and evaluated as trivial, small, moderate or large. The results showed that in adults, the various programs showed from trivial (e.g., ES 0.185; 95% CI ± 0.089) to large beneficial effects (ES 2.92; 95% CI ± 0.29). At developmental ages, the beneficial effect was from trivial to moderate (ES 0.163; 95% CI ± 0.174, ES 0.787; 95% CI ± 0.074). Concerning the interventional programs, studies carried out by sprint and Small-Sided Games (SSG) interventions presented a large ES, while studies that carried out RSA exercises presented moderate ES. A variety of stimuli can improve the RSA performance of soccer players by causing trivial-to-large improvements. However, more effective are interventional exercises that include stimuli related to repeated sprint ability.

The influence of low power laser (LBP) regarding jumping performance in under-20 field soccer players

The influence of low power laser (LBP) regarding jumping performance in under-20 field soccer players

Despite Good Correlations, There Is No Exact Coincidence between Isometric and Dynamic Strength Measurements in Elite Youth Soccer Players.

Speed strength performances are substantially dependent on maximum strength. Due to their importance, various methods have been utilized to measure maximum strength (e.g., isometric or dynamic) with discussed differences regarding transferability to sport-specific movements dependent upon the testing procedure. The aim of this study was to analyze whether maximum isometric force (MIF) during isometric back squats correlates with maximum strength measurements of the one repetition maximum (1RM) in the squat, with countermovement jump (CMJ) performance, and with drop jump (DJ) performances in elite youth soccer players (n = 16, 18.4 ± 1.5 [range: 17-23] years old). Additionally, concordance correlation coefficients (CCC, [ρc]) between isometric and dynamic measurements were calculated to verify whether one measurement can actually reproduce the results of the other. To improve comprehension, differences between isometric and dynamic testing values were illustrated by providing differences between both testing conditions. For this, the mean absolute error (MAE) and the mean absolute percentage error (MAPE) were calculated. To reach equality in scale, the 1RM measures were multiplicated by 9.81 to obtain a value of N. The 1RM demonstrated correlations of τ = |0.38| to |0.52| with SJ and CMJ performances, while MIF demonstrated correlations of τ = |0.21| to |0.32|. However, the correlations of both 1RM and MIF with the DJ reactive strength index (RSI = jump height /contact time) from different falling heights were of no statistical significance. The data showed significant correlations between both the absolute (τ = |0.54|) and the relative (τ = |0.40|) performances of 1RM and MIF, which were confirmed by CCC of ρc= |0.56| to |0.66|, respectively. Furthermore, the MAE and MAPE showed values of 2080.87 N and 67.4%, respectively. The data in this study show that, despite good correlations, there is no exact coincidence between isometric and dynamic strength measurements. Accordingly, both measurements may only represent an estimation of maximal strength capacity and cannot be substituted for each other. Therefore, maximal strength should be tested by using high similarity in the contraction condition, as it is used in the training process to counteract underestimation in strength because of unfamiliarity with the testing condition.

The influence of short sprint performance, acceleration, and deceleration mechanical properties on change of direction ability in soccer players-A cross-sectional study.

The study investigated the relationship between short sprint performance and mechanical parameters obtained during the acceleration and deceleration tasks with the change of direction (COD) performance in female and male soccer players. The acceleration and deceleration ability were compared in the "High/Fast" versus "Low/Slow" COD performance group based on a median split analysis in each sex group. One hundred three French soccer players were assessed for the sprinting Force-Velocity (F-V) profile (i.e., theoretical maximal force [F0], velocity [V0], power [Pmax]), 10m performance, linear deceleration test (maximal braking force [HBFmax], braking power [BPmax], deceleration [Decmax]), and COD performance using 505-test. The 10m performance was strongly associated with 505-test performance (ES = [0.64 to 0.71]), whereas the sprinting F-V profiles parameters were weakly to moderately correlated with 505- performance (ES = [-0.47 to -0.38]). The BPmax was also moderately associated with 505-test performance (ES: range = [-0.55 to -0.46]). In addition, the High/Fast female COD group presented higher F0, Pmax, HBFmax, and BPmax than the Low/Slow group, whereas the male groups presented very few mechanical differences. Multiple regression analysis shows that the COD performance of male players was determined by 10m performance and maximum deceleration power. In contrast, no statistically significant model could be found to determine the change of direction performance in female players. In conclusion, the current finding indicated that the only variable strongly associated with COD performance was the linear 10m sprint time. In the same way, the mechanical parameters obtained from acceleration and deceleration seemed to play a non-neglectable role in this population.

High-Load Squat Training Improves Sprinting Performance in Junior Elite-Level Soccer Players: A Critically Appraised Topic

Practical Question: Is high-load squat training beneficial in improving sprinting performance in junior elite-level soccer players? Clinical Bottom Line: There is Level 3 evidence to support the validity of high-load squat training as a measure to improve sprinting performance in junior male elite-level soccer players. All three studies included showed significant increases in soccer-related sprinting performance.