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In this study, we aimed to analyze the magnitude and direction of inter-limb asymmetries in ankle dorsiflexion range of motion (ROM), power (using iso-inertial devices), and a neuromuscular skill (change of direction). Secondarily, we aimed to determine the relationship between inter-limb asymmetry scores for each test and also between these scores and the scores for the different performance tests. Sixteen semiprofessional male soccer players (age: 25.38 ± 6.08 years; body height: 1.78 ± 0.64 m; body mass: 79.5 ± 14.9 kg) participated in this study. We calculated inter-limb asymmetries using five tests: ankle dorsiflexion ROM, change of direction (COD 180º), and iso-inertial resistance tasks in the open (leg extension strength (LE), leg curl strength (LC)) and closed (crossover step (CRO)) kinetic chain. Our results showed that asymmetry magnitudes differed between all tests with highest inter-limb asymmetries displayed during iso-inertial overloading. In addition, we observed that the direction of asymmetries varied depending on the testspecificity, and that the CRO asymmetries had a negative association with LE and CRO performance. These findings highlight the independent nature of asymmetries and that CRO could be an appropriate test to detect asymmetries related with the performance of soccer-specific actions (such as changes of direction). Practitioners are encouraged to use multiple tests to detect existing inter-limb differences according to the specific characteristics of each sport. info:eu-repo/semantics/publishedVersion

BACKGROUND: Previous studies have analysed the effect of wearing high-heeled shoes (HHS) on gait analysis, balance and its relation to health. However, further research is needed to study its effect on the difference of chain reactions in the transfer of body impacts from the lower to the upper limbs. OBJECTIVES: The aims of the present research were: (a) to compare the effects of wearing HHS on impacts across body joints during walking with sport shoes (SS) as a reference, and (b) to examine such effects at different speeds. METHODS: Seven well-trained women completed this study. Incremental treadmill walking test were performed with two different footwear: SS and HHS. Inertial devices were used to quantify the chain reactions at selected anatomical lower limbs and trunk locations. Statistical analysis included the Wilcoxon test with ranges and Cohen’s d effect size with percentage of differences. RESULTS: The highest values were found at the heel in both footwear and in both legs (SS: right =0.76 ± 0.27, left = 0.79 ± 0.27; HHS: right = 1.07 ± 0.38, left = 1.11 ± 0.41), while the lowest values were registered at lower and upper back. Furthermore, significant differences were found with the HHS load being higher at all locations (p< 0.05; %=𝑑𝑖𝑓𝑓 12.20–36.36%), influenced by the walking speed. In addition, a strong influence of footwear in the change of the laterality profile was found (p< 0.05). CONCLUSIONS: These findings suggest that the use of HHS increase the load on the lower limb and the trunk. Until reaching 5 km/h during walking, no significant differences were found between wearing HHS or SS in accelerometer load, producing exponential differences from this speed. The great between-subject variability implies that within-subject analysis is recommended, as it is more related to real clinical practice.

An association between accelerometer workload and injury risk has been found previously. However, any research has assessed the absorption dynamics of external workload through the measurement in different anatomical locations simultaneously. A cross-sectional study was designed to: (i) to describe the multi-joint external workload profile of youth soccer players, (ii) to identify differences between-participants related to anatomical locations, (iii) to analyze the workload dynamics at different speeds at joints and body segments, (iv) to characterize the multi-joint individual workload and the within-participants difference in each body segment. Twenty-one U-18 male players, that were part of a Youth Spanish First Division soccer team, performed an incremental running treadmill test and wore four WIMU PROTM inertial devices in lower limb (ankle-knee) and spine (lower-upper back) locations to register cumulative tri-axial accelerometry-based workload (PlayerLoad, PLRT). The main results have shown that the highest PLRT was detected at the lower limb, especially at the ankle. Different dynamics of accelerometer workload have been found between lower and upper limb, being them between ankle-knee at 12-km/h and lower-upper back at 9.5-km/h (p

To date, there is a lack of information about the optimal conditions of the warm-up to lead to a better performance in elite tennis players. The aim of this study was to compare the effects of two different warm-up protocols (dynamic vs. self-myofascial release with foam rolling) on neuromuscular variables associated with physical determinants of tennis performance. Using a crossover randomised experimental design, eleven professional men tennis players (20.6 ± 3.5 years) performed either a dynamic warm-up (DWU) or a selfmyofascial release with foam rolling (SMFR) protocol. DWU consisted of 8 min of dynamic exercises at increasing intensity and SMFR consisted of 8 min of rolling on each lower extremity unilaterally. Just before (baseline) and after completing warm-up protocols, players performed a countermovement jump (CMJ), the 5-0-5 agility test, a 10-m sprint test and the Straight Leg Raise and Thomas tests to assess range of motion. Compared to baseline, the DWU was more effective to reduce the time in the 5-0-5 test than SMFR (-2.23 vs. 0.44%, respectively, p = 0.042, ηp2 = 0.19). However, both warm-up protocols similarly affected CMJ (2.32 vs. 0.61%, p = 0.373, ηp2 = 0.04) and 10-m sprint time changes (-1.26 vs. 1.03%, p = 0.124, ηp2 = 0.11). Changes in range of motion tests were also similar with both protocols (p = 0.448–1.000, ηp2 = 0.00–0.02). Overall, both DWU and SMFR were effective to prepare well-trained tennis players for highly demanding neuromuscular actions. However, DWU offered a better preparation for performing change of direction and sprint actions, and hence, in high-performance tennis players, the warm-up should include dynamic exercises. post-print 402 KB

The aim of this study is to investigate inter-tester and intra-tester reliability of a novel clam test (CLAMT) for the measurement of gluteal muscle strength and to detect possible differences between CLAMT values in football players with and without a history of groin injuries. Twenty male football players participated in the test-retest and sixty-two male professional football players participated in the case-control study. Hip abductor maximal muscle strength was evaluated either using CLAMT or in a supine position with the hip in a neutral pose. For CLAMT, intraclass correlation coefficient (ICC) for inter-tester-intra-day reliability was 0.80 (95% CI: 0.60-0.90), with a standard error of measurement of 34.2 N. The intra-tester-intra-day ICC was 0.92 (95% CI: 0.87-0.95), with a standard error of measurement of 23.6 N. The inter-week ICC was 0.96 (95% CI: 0.92-0.98), with a standard error of measurement of 18.9 N. CLAMT showed lower (but not significant) strength values in football players with a history of groin injuries to non-injured players. CLAMT showed good to excellent levels of reliability, intraday and inter-week, with low standard errors of measurement while it was effective (possible) to identify residual weakness in players with previous groin injuries.

Objective: Beetroot juice is a source of dietary nitrate (NO3-) recognized as a potential ergogenic aid to enhance tolerance during endurance exercise of submaximal-to-maximal intensity. However, little is known about the effects of beetroot juice on exercise performance in intermittent sports such as tennis. The present study aimed to determine the effect of acute beetroot juice supplementation on movement patterns during a competitive tennis match in professional players. Methods: In a double-blind and randomized experiment, nine professional tennis players performed two experimental trials 3 h after ingesting either 70 mL of a commercially-available concentrated beetroot juice (6.4 mmol NO3-) or placebo (0.005 mmol NO3-). In each experimental trial, players completed a 3-set tennis match and two performance tests (i.e., serve speed and isometric handgrip strength) before and after the match. Match-play running performance was recorded using wearable GPS and accelerometer units. Results: In comparison to the placebo trial, the acute beetroot juice supplementation did not modify any match-play running performance (p = 0.178 to 0.997, d = 0.01 to 0.42). Furthermore, beetroot juice supplementation did not alter the pre-to-post match change in serve speed (p = 0.663, ηp 2 = 0.03) or isometric handgrip strength (p = 0.219, ηp 2 = 0.18). Conclusions: The current results indicated that acute ingestion of a commercialized shot of nitrate-rich beetroot juice (70 mL containing 6.4 mmol of NO3-) did not produce any performance benefit on tennis matchplay. Thus, acute beetroot juice supplementation seems an ergogenic aid with little value to enhance physical performance in professional tennis players. SIN FINANCIACIÓN 3.071 JCR (2021) Q3, 56/90 Nutrition & Dietetics 0.564 SJR (2021) Q2, 64/131 Nutrition and Dietetics No data IDR 2021 UEM

The monitoring of the high intensity activity-demands profile during official matches (OMs) and training sessions (TSs) provides a deeper understanding of the relationship between training and competition loads as well as players’ fitness characteristics. The aims of this study were to: 1) describe the training and match high intensity activity-demands profile in U-19 soccer players; 2) compare the profile depending on the type of session (OM or TS) throughout match-weeks; and 3) differentiate between profiles depending on the match location (home or away). Twenty-five U-19 Spanish soccer players were monitored during TSs and OMs for a one-month competitive period using a WIMU PROTM wearable inertial device. The variables of the study were: high speed running distance (HSRD), total sprints (SPs), maximum speed (MS) and player load (PL). OMs required higher demands than TSs in HSRD (460.99 ± 206.18 vs. 315.45 ± 180.12 m; p < 0.01; d = 0.75), SPs (10.86 ± 6.64 vs. 7.23 ± 4.82; p < 0.01; d = 0.69), MS (29.99 ± 2.54 vs. 28.50 ± 2.4 km/h; p < 0.01; d = 0.59) and PL (103.08 ± 24.15 vs. 83.18 ± 17.96 a.u.; p < 0.01; d = 0.94). The interaction between the type of session and mean week’s demands presented differences with medium effect size in MS (p < 0.01; ωp 2 = 0.06) and small effect size in HSRD (p = 0.04; ωp 2 = 0.03), and SP (p = 0.05; ωp 2 = 0.03), but there were no differences in PL (p = 0.18; ωp 2 = 0). Finally, no differences were found in the match location comparison (p > 0.33; d = 0.22–0.33). Therefore, the profiles presented could be useful for future scientific purposes and serve as valid information for coaches trying to optimize performance.

To investigate the effects of a badminton competition with 2 matches in a day on hip strength and range of motion (ROM) and exercise-induced muscle damage in elite junior badminton players. Twenty players (age: 17±0.8 years; body mass: 62.9±6.5 kg, height: 173.8±8.9 cm) participated in this study. Passive hip internal (IR) and external rotation (ER), abduction (ABD) and adduction (ADD) hip ROM, isometric hip ADD and ABD muscle strength, countermovement vertical jump (CMJ) height and blood creatine kinase concentration (CK) were measured before and after a badminton competition during an international tournament. Blood samples were collected 24 h after the end of the last match. Compared to baseline values, hip IR and ER ROM were significantly decreased at post-competition in the dominant (IR=-9.0%; p=0.007 and ER=-15.2%; p=0.002) and non-dominant limbs (IR=-9.08%; p=0.004 and ER=-19.4%; p, Funding received from Badminton World Federation (BWF), Kuala Lumpur (Malaysia).

This study examined the effect of caffeine supplementation (CAFF) in a Wingate test (WT), and the behaviour of blood lactate concentrations (BLa) and neuromuscular fatigue (NMF), measured as reduced countermovement jump (CMJ) performance, in response to the WT. In a double-blind crossover study, 16 participants attended the laboratory twice, separated by a 72-hour window. In the sessions, participants first ingested 6 mg·kg-1 of either CAFF or placebo (PLAC), and then performed a WT. BLa was measured before (L-pre), and 0.5 min (L-post-0.5) and 3.5 min (L-post-3.5) after conducting the WT. The CMJ test was conducted before (CMJ pre), after (CMJ post), and 3 min after completing (CMJ post-3) the WT. The results indicated that CAFF enhanced peak power (Wpeak: + 3.22%; p = 0.040), time taken to reach Wpeak (T_Wpeak: -18.76%; p = 0.001) and mean power (Wmean: + 2.7%; p = 0.020). A higher BLa was recorded for CAFF at L-post-0.5 (+ 13.29%; p = 0.009) and L-post-3.5 (+ 10.51%; p = 0.044) compared to PLAC. CAFF improved peak power (PP; + 3.44%; p = 0.003) and mean power (MP; + 4.78%; p = 0.006) at CMJ pre, compared to PLAC, whereas PP and MP were significantly diminished at CMJ post and CMJ post-3 compared to pre (p < 0.001 for all comparisons) under both the CAFF and PLAC conditions. PP and MP were increased at post-3 compared to post (p < 0.001 for all comparisons) for both conditions. In conclusion, CAFF increased WT performance and BLa without affecting NMF measured by CMJ. Thus, CAFF may allow athletes to train with higher workloads and enhance the supercompensation effects after an adequate recovery period. post-print 756 KB

Background: Previous investigations have associated weakness of hip muscles with a higher likelihood of developing hip groin injury. However, no previous investigation has examined the influence of soccer training and match-play during the season on maximal isometric hip adductor and abductor muscle strength. Hypothesis: Maximal hip adductor and abductor muscle strength would increase after the preseason, maintaining relatively constant levels across the soccer season. Design: Cross-sectional study. Level of Evidence: Level 3. Methods: A total of 26 semiprofessional male soccer players underwent measurements of maximal isometric hip adductor and abductor muscle strength at 3 time points of the soccer season: preseason, midseason, and end-season to investigate the longitudinal effect of soccer training and competition during a complete season on maximal isometric hip adductor and abductor muscle strength in the semiprofessional Spanish soccer player. Results: Compared with preseason, hip abductor muscle strength increased in the midseason (14.2% and 17.1%, for dominant and nondominant limb, respectively; P < 0.001) and in the end-season (13.1%; P = 0.005, and 14.1%; P < 0.005). In contrast, hip adductor muscle strength remained unchanged across the season in both limbs. As a result, the adductor/abductor strength ratio in the nondominant limb was reduced at midseason and end-season time points (−14.6% and −18.4%, respectively; P < 0.001) with a corresponding tendency in the dominant limb (−9.3% and −15.0%, respectively; P > 0.05). Conclusion: While maximal hip abductor muscle strength increased throughout the season, hip adductor muscle strength remained stable across the season. This produced a substantial deficit in hip adductor/abductor strength ratio at midseason and end-season. Clinical Relevance: The progressive imbalance in adductor/abductor strength across the soccer season may be an indicator of increased risk of groin injury and may reinforce the need for preventive rehabilitation activities focused on enhancing adductor muscle strength.

Background There is a lack of epidemiological data comparing the characteristics of injuries sustained during basketball matches vs. training taking into account incidence, type of injury, body location and risk factors associated with the development of the injury. Purpose The main aim of the present study was to analyse the incidence and characteristics of training vs. competition injuries sustained by professional basketball players. Methods The injuries incurred by 61 professional basketball players (mean ± SD, age: 25.7 ± 5.1 years; height: 200.2 ± 9.2 cm; body mass: 98.2 ± 13.8 kg) from the same team were prospectively recorded by the team's medical staff for 6 consecutive seasons (2014/15 to 2019/20). The team competed in a top national basketball division and in the EuroLeague among other national-level competitions. The injuries were recorded using a validated medical questionnaire that included information according to type, severity, location, and injury mechanism. Training and match times were also recorded for each player in order to calculate injury incidence. Results A total of 306 injuries were reported, representing 12.59 injuries per 1000 h of basketball play. Most injuries occurred without direct contact with another player/object (70.9%) and were located in the lower limbs (74.8%), particularly in the knee (22.9%). The incidence of injuries was higher during competition than during training: 77.83 vs. 8.29 injuries per 1000h of basketball play. However, there were no differences in the mechanism and mode of onset between training and competition injuries while the proportion of time-loss injuries was also similar in training and competition. Conclusions In summary, injury incidence in professional basketball was ~10-times higher during competition than during training. Beyond differences in incidence, injury characteristics were similar for basketball training and competition.

The aim of this study was to determine the association of playing style and efficacy variables with football success in a professional football league. Match statistics were obtained from 23 football teams competing in the 2017-2018 and 2018-2019 seasons of the Spanish national league(

The aim of this study was to investigate the acute (a football match) and chronic (a whole season) effects of competition on ankle dorsiflexion ROM in professional football players. Forty football players participated in this study. Ankle dorsiflexion ROM was recorded to examine acute (pre-match, immediately post-match and 48 h post-match) and chronic (pre-season, mid-season and post-season) effects of competitive football. In addition, it was found that players had restricted mobility measures on ankle dorsiflexion as >2 cm change between baseline measures (pre-match and pre-season). The training load of all played matches was estimated using a global positioning system (GPS) and RPE. Pre-season ankle dorsiflexion ROM was greater compared to mid-season (8.1% in the dominant, and 9.6% in the non-dominant leg) and post-season (13.8% in the dominant, and 12.5% in the non-dominant leg). In addition, around 30% of all players showed restricted ankle dorsiflexion ROM values in post-season compared with pre-season. Related to acute effects, ankle dorsiflexion ROM increased after a match (5.8%) in the dominant ankle, and this value decreased (2.65%) 48 h post-match when post-match measurements in both dominant and non-dominant ankles were compared. The progressive decrease in ankle dorsiflexion ROM throughout a season can be an indicator of increased risk of injury and may be reinforce the need of prevention actions such as stretching exercises and eccentric strength training in professional football players. In addition, these findings suggest to implement specific recovery strategies aiming at minimizing alteration in ankle dorsiflexion ROM 48 h post-match. pre-print 594 KB

There are recent data suggesting an association between the R577X polymorphism (rs1815739) in the gene encoding α-actinin-3 (ACTN3) and the risk of musculoskeletal injuries. The purpose of this study was to analyze the association of rs1815739 with risk of, and recovery time from non-contact soft-tissue muscle injuries in professional soccer players. Forty-six (22 male and 24 female) players from a top-level professional soccer team were assessed during five consecutive seasons: the genotype distribution was: RR, 41.3%; RX, 47.8%; and XX, 10.9%. There was a trend towards a higher risk of muscle injury associated with the XX genotype (p = 0.092, with no injury-free XX player during the 5-year study period) and a significant genotype effect for the time needed to return to play (p = 0.044, with the highest value shown for the XX genotype, i.e., 36 ± 26 days, vs. 20 ± 10 and 17 ± 12 days for RR and RX, respectively). In conclusion, the XX genotype might be associated not only with a higher risk of non-contact muscle injuries, but also of recovery time from these conditions. However, more research in larger cohorts is needed to confirm this preliminary hypothesis. Sin financiación 4.141 JCR (2021) Q2, 72/175 Genetics & Heredity 1.032 SJR (2021) Q2, 110/347 Genetics No data IDR 2021 UEM

In the first wave of the COVID-19 outbreak (spring 2020), the first division of professional soccer in Spain (LaLiga) was suspended for 12 weeks as part of the lockdown imposed by the Spanish health authorities. Professional soccer players were confined to home for 8 weeks and then a retraining period of 4 weeks was set before the first competitive match. When competition was resumed, professional soccer teams competed in a congested calendar (11 matchdays in 39 days) while some in-game regulations were altered (up to 5 substitutions, refreshment pauses). The current research presents an analysis of running patterns before suspension and after resumption of LaLiga to determine how the lockdown affected players’ physical performance. To aid in this purpose, a pairwise comparison was performed of running patterns of the 2019–2020 vs. 2018–2019 season (i.e., control season). Using a two-way ANOVA (season x matchday), it was found that there was no main effect of the season on total running distance per match (P = 0.288) nor in the distances covered < 14.0 km/h (P = 0.294), at 21.0–23.9 km/h (P = 0.266), and at ≥ 24.0 km/h (P = 0.112). Only the distance at 14.0–20.9 km/h was affected by the season (P = 0.019) with a lower running distance on matchday 34 in the 2019–2020 vs. 2018–2019 season. The number of substitutions (from 2.9 to 4.5 substitutions per game; P < 0.001) and match duration (96 vs. 100 min; P < 0.001) significantly increased after resumption respect to the previous season. These data suggest that high-intensity running performance of professional soccer teams was maintained after the resumption of the competition while the alterations likely aided in the in-game regulations facilitated the maintenance of soccer physical performance.

OBJECTIVE: The aim of this study was to compare the potential post-activation performance enhancement (PAPE) effects of two different warm-up strategies, involving dynamic stretching (DS) or heavy load leg press (HL) on several key physical qualities in tennis players. METHODS: Twenty-six elite male tennis players (age: 19.22 ± 4.20 years; body mass: 67.37 ± 8.19 kg; height: 1.77 ± 0.07 m) performed both warm-ups, with 48-hours between protocols (DS and HL), performed in a randomized order. Pre- and post-tests included: countermovement jump, 5-m and 10-m sprint, 5-0-5 agility test, and hip extension and flexion range-of-motion which were performed before and after DS and HL warm-up protocols. RESULTS: The DS warm-up led to substantial improvements in 5-m and 10-m sprint, 5-0-5 agility test, countermovement jump, and also to higher hip flexion range-of-motion. The HL warm-up caused impairments in 5-m and 10-m sprints, but improvements in 5-0-5 agility test, countermovement jump and hip extension range-of-motion. Compared to HL, DS warm-up induced possibly to likely positive effects on 5-m and 10-m linear sprint performance, as well as in hip flexion range-of-motion. Nevertheless, no differences in performance improvements in 5-0-5 agility test, countermovement jump and hip extension range-of-motion were found when comparing DS and HL warm-up protocols. CONCLUSION: DS seems to be more effective than HL when performing a short warm-up protocol in elite tennis players.

To date, no previous investigation has studied the effect of acute caffeine ingestion on futsal performance during futsal-specific testing and during a simulated match. Therefore, the aim of this investigation was to establish the effects of acute caffeine intake on futsal-specific tests and match-play running performance in male futsal players. Sixteen high-performance futsal players participated in a randomized, crossover, placebo-controlled and double-blind experiment. Each player completed two identical trials after ingesting either caffeine (3 mg/kg) or a placebo (cellulose). The trials consisted of a battery of futsal-specific tests (countermovement jump, 20-m sprint test, and a futsal kicking velocity and accuracy test) followed by a simulated futsal match (2 halves of 7.5 min). During the match, players’ running performance was assessed with local positioning system devices. In comparison to the placebo, caffeine ingestion increased jump height by 2.8% (p = 0.048; ES = 0.29) and reduced the time to complete the 20-m sprint test by -2.2% (p = 0.044; ES = − 0.54). Additionally, acute caffeine intake improved the distance covered at above 14.4 km/h by 19.6% (p = 0.021; ES = 0.58), the number of body impacts by 8.1% (p = 0.040; ES = 0.27) and the number of accelerations/decelerations by 4.2% (p = 0.044; ES = 0.57) during the simulated futsal match. However, no differences were reported in ball velocity or shooting accuracy in the futsal kicking test. There were no differences in the prevalence of side effects reported in the hours after the ingestion of the treatments. Three mg/kg of caffeine enhanced several physical variables associated with futsal such as jump and sprint performance, and improved high-speed running and accelerations/decelerations during a simulated futsal match. Caffeine supplementation with a moderate dose can be considered as an effective ergogenic aid for futsal performance with low prevalence of side effects. The study was registered in ClinicalTrials.gov with the following ID: NCT04852315. The study was retrospectively registered by 18 April 2020.

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling.

BACKGROUND: To describe the lower limb range of motion (ROM) profile in professional road cyclists. METHODS: Cohort study. One hundred and twenty-one road cyclists volunteered to participate. ROM measurements of passive hip flexion, extension, internal rotation, external rotation, knee flexion and ankle dorsiflexion in dominant and non-dominant limbs were performed using an inclinometer. ROM scores were individually categorized as normal or restricted according to reference values. RESULTS: Overall, hip flexion was smaller in the non-dominant limb than in the dominant limb (F=12.429, P

This study aimed to analyze the effects of match congestion in a short period on isometric hamstring strength and hip/ankle range of motion in female field hockey players. Fourteen professional female field hockey players (age: 20.0 ± 5.4 years) played two consecutive hockey matches in 24 h and maximal isometric hamstring strength and hip and ankle range of motion were obtained before and after the first match, after the second match, and 48 h after the second match. Furthermore, locomotion patterns and ratings of perceived exertion were recorded during hockey competitions. Isometric knee flexion strength showed significantly higher values 48 h after the second match for the non-dominant limb (p ≤ 0.005, ηp2 = 0.19), while no differences were reported in the dominant limb (p = 0.370, ηp2 = 0.05). In addition, no differences were reported in the range-of-motion (ROM) variables such as the straight leg raise test or ankle dorsiflexion test (p = 0.075–0.217, ηp2 = 0.01–0.03). The countermovement jump height steadily increased over the matches except between post-match 2 and 48 h after post-match 2 (p &lt, 0.001, η2 = 0.382). Two consecutive official league field hockey matches played within 24 h did not have a negative effect on lower-limb risk factors (strength, hip and ankle ranges of motion, and ratings of perceived exertion) in female field hockey players directly, but they improved 48 h after the matches. This could indicate that 48 h recovery period following matches might be ideal for female field hockey players.

The aim of this study was to examine the acute effect of officiating a football (soccer) match on isometric knee flexion strength and passive hip flexion range-of-motion (ROM) in referees and assistant football referees. Twelve referees (25.3 ± 3.3 years) and twenty-three assistant referees (25.1 ± 4.8 years) underwent measurements on isometric knee flexion strength and passive hip flexion ROM before and after officiating an official football match. Referees’ and assistant referees’ running patterns were monitored during the match using GPS technology. In comparison to pre-match values, referees reduced their isometric knee flexion strength (−12.36%, p = 0.046, Effect size [ES] = −0.36) in the non-dominant limb, while no significant differences were reported in the dominant limb (−0.75%, p = 0.833, ES = −0.02). No effect of the match was found in hip flexion ROM values in dominant (−4.78%, p = 0.102, ES = −0.15) and non-dominant limb (5.54%, p = 0.544, ES = 0.19). In assistant referees, the pre-to-post-match changes in isometric knee flexion strength (dominant limb −3.10%, p = 0.323, ES = −0.13, non-dominant limb −2.18%, p = 0.980, ES= 0.00) and hip flexion ROM (dominant limb 1.90% p = −0.816, ES = 0.13, non-dominant limb 3.22% p = 0.051, ES = 0.23) did not reach statistical significance. Officiating a match provoked a reduction in isometric knee flexion strength in the non-dominant limb of football referees, while no differences were reported in assistant referees.

In the health sciences, professionals must keep up to date to conduct their evidence-based practise. Hence, there is a growing need to share medical knowledge efficiently among healthcare professionals, patients, and undergraduate health science students. Infographics (text and image) are a hybrid element that serves to represent information in an attractive and meaningful visual format. Actually, with the use of the Internet and social networks, infographics have become a popular format for sharing medical information around the world.On the basis of a published literature review, we provide 12 tips in this article to make a successfully health-related infographic with the aim of assisting clinicians, educators, and researchers in their task of communicating and transforming complex information into a visual, attractive, didactic and shareable format.By following these basic recommendations, it is possible to improve the dissemination of scientific and health-related knowledge to different audiences who can benefit from infographics.

The maximum running speed that a football player can attain during match play has become one of the most popular variables to assess a player&rsquo, s physical talent. However, the influence of a player&rsquo, s maximum running speed on football performance has not yet been properly investigated. The aim of this study was to determine the influence of a player&rsquo, s peak/maximum running speed on the team&rsquo, s ranking position at the end of a national league. A second aim was to investigate differences in maximum running speed among playing positions. To fulfil this aim, the peak/maximum running speeds of 475 male professional football players were recorded for 38 fixtures of the Spanish first-division league (LaLiga) from the 2017&ndash, 2018 season (7838 data points). Players&rsquo, peak running speeds in each match were assessed with a validated multicamera tracking system and associated software (Mediacoach&reg, ). Players&rsquo, maximum running speed was established as the fastest running speed they attained during the entire season. Most players (53.5% of the total) had a maximum running speed in the range of 32.0&ndash, 33.9 km/h, with only three players (0.6%) with a maximum running speed of over 35.0 km/h. Overall, forwards were faster than defenders and both types of players were faster than midfielders (33.03 &plusmn, 1.35 &gt, 32.72 &plusmn, 1.32 &gt, 32.08 &plusmn, 1.63 km/h, p &lt, 0.001). There was no association between teams&rsquo, maximum running speed and ranking position at the end of the league (r = &minus, 0.356, p = 0.135). The correlations between teams&rsquo, maximum speeds and ranking position were low for defenders (r = &minus, 0.334, p = 0.163), midfielders (r = 0.125, p = 0.610), and forwards (r = &minus, 0.065, p = 0.791). As a result, the variance in the ranking position at the end of the season explained by a team&rsquo, s maximum speed was of only 7.5%. Finally, as an average for all teams, players&rsquo, peak running speeds remained stable at ~30.7 &plusmn, 0.6 km/h throughout the whole season. These results suggest that successful and less successful football teams have squads with players able to obtain similar maximum running speeds during match play throughout the season. Hence, players&rsquo, maximum running speeds have a poor association with the team&rsquo, s ranking position at the end of the Spanish professional national league.

This study examined the association and predictive ability of several markers of internal workload on risk of injury in high-performance junior tennis players. Fifteen young, high-level tennis players (9 males, 6 females; age: 17.2 ± 1.1 years; height: 178.5 ± 8.7 cm; mass: 68.1 ± 4.8 kg) participated in this investigation. Data on injury epidemiology and internal workload during training were obtained for one competitive season. The session-rating of perceived exertion (s-RPE) was used to calculate internal workload markers in absolute (acute workload and chronic workload for 2-weeks, 3-weeks and 4-weeks) and relative terms (acute:chronic workload ratios [ACWR] for 2-weeks, 3-weeks and 4-weeks). Associations and diagnostic power for predicting tennis injuries were examined through generalised estimating equations and receiver operating characteristics analyses. During the season, a total of 40 injuries were recorded, corresponding to 3.5 injuries per 1000 h of tennis practice. The acute workload was highly associated with injury incidence (

Previous investigations have found that several genes may be associated with the interindividual variability to the ergogenic response to caffeine. The aim of this study is to analyze the influence of the genetic variations in CYP1A2 (&minus, 163C&thinsp, &gt, A, rs762551, characterized such as &ldquo, fast&rdquo, (AA genotype) and &ldquo, slow&rdquo, caffeine metabolizers (C-carriers)) and ADORA2A (1976T&thinsp, C, rs5751876, characterized by &ldquo, high&rdquo, (TT genotype) or &ldquo, low&rdquo, sensitivity to caffeine (C-carriers)) on the ergogenic response to acute caffeine intake in professional handball players. Thirty-one professional handball players (sixteen men and fifteen women, daily caffeine intake = 60 &plusmn, 25 mg&middot, d&minus, 1) ingested 3 mg&middot, kg&minus, 1&middot, body mass (bm) of caffeine or placebo 60 min before undergoing a battery of performance tests consisting of a countermovement jump (CMJ), a sprint test, an agility test, an isometric handgrip test, and several ball throws. Afterwards, the handball players performed a simulated handball match (2 &times, 20 min) while movements were recorded using inertial units. Saliva samples were analyzed to determine the genotype of each player for the &minus, A polymorphism in the CYP1A2 gene (rs762551) and for the 1976T&thinsp, C polymorphism in the ADORA2A gene (rs5751876). In the CYP1A2, C-allele carriers (54.8%) were compared to AA homozygotes (45.2%). In the ADORA2A, C-allele carriers (80.6%) were compared to TT homozygotes (19.4%). There was only a genotype x treatment interaction for the ball throwing from 7 m (p = 0.037) indicating that the ergogenic effect of caffeine on this test was higher in CYP1A2 AA homozygotes than in C-allele carriers. In the remaining variables, there were no genotype x treatment interactions for CYP1A2 or for ADORA2A. As a whole group, caffeine increased CMJ height, performance in the sprint velocity test, and ball throwing velocity from 9 m (2.8&ndash, 4.3%, p = 0.001&ndash, 0.022, effect size = 0.17&ndash, 0.31). Thus, pre-exercise caffeine supplementation at a dose of 3 mg&middot, bm can be considered as an ergogenic strategy to enhance some neuromuscular aspects of handball performance in professional handball players with low daily caffeine consumption. However, the ergogenic response to acute caffeine intake was not modulated by CYP1A2 or ADORA2A genotypes.

Objectives To investigate the relationship between one eccentric and two isometric tests commonly used to assess hamstring strength in professional soccer. Settings Professional soccer club. Design Cross-sectional study. Participants Twenty male professional soccer players. Main outcome measures Hamstring force was quantified during 3 tests (Nordic hamstring eccentric, 90:20 isometric posterior-chain strength and isometric 15° knee flexion) using a load cell, a handheld dynamometer and a force platform, respectively. Results Poor relationships and low concordance were observed between isometric and eccentric tests, showing different ability to discriminate hamstring weakness and asymmetries. The Nordic hamstring test identified between-limb asymmetry >15% in 30% of the players, 25% in the 15° knee flexion and 5% in the 90:20 test. All players obtained different results in the three tests with only one showing asymmetry >15% in two tests. Conclusion Results obtained in each test cannot inform the others. Mechanical outputs of these tests must be used for particular purposes during the prevention, rehabilitation and monitoring process of hamstring injury. Isometric testing might be preferable during the initial phases of the recovery process of a hamstring injury while the Nordic hamstring test might be used in the last stages or detect muscle weakness/asymmetries in non-injured players.

External workload from matches is considered one of the most important muscle injury risk factors for football teams. However, there is scarce published evidence to support this belief. This study examined whether a particular profile of external match workload existed prior to a muscle injury. A total of 144 professional football players belonging to 2 teams were monitored over three seasons. For each muscle injury, a profile of external workload variables was determined for 5 to 8 games and expressed as: time playing exposure, total distance (TD) covered and high-speed running (HSR) covered. In addition, acute:chronic workload ratio (ACWR) was calculated. Sixty players (41.6%) reported a total of 86 muscle injuries during the three seasons. Muscle injuries occurred principally in matches (79.1%), the hamstring being the most affected muscle (44.1%). Injured players displayed substantially lower accumulated exposure time (ES = 0.45), TD (ES = 0.45) and HSR (ES = 0.39) in comparison with uninjured players in the last 5 games prior to injury. Compared to the uninjured players, ACWR for exposure (ES = -0.29/0.02) and running load (ES = -0.24/0.00) did not differ between match 5 and 2 prior to the injury, although uninjured players displayed a substantially greater ACWR in all 3 variables (ES = 0.31/0.35) than injured players in match 1 prior to the injury. Lower playing exposure (minutes played) and associated reduced running distances (TD and HSR) were observed in injured football players. Being under-loaded in official games could be a mediator for muscle injury in this cohort of elite football players.

The aim of the present study was to analyse the effects of playing two badminton matches on the same day on the shoulder profile (i.e., range of motion (ROM) and strength) of young badminton players.Cross-sectional study.Indoor sports facility.Thirty-one elite junior badminton players (age 16.6 ± 1.0 years, body mass 63.9 ± 6.1 kg, height 174.8 ± 6.1 cm), including 19 boys and 12 girls.Shoulder passive internal rotation (IR) and external rotation (ER) ROM as well as shoulder IR/ER maximal isometric strength were measured before and after a competition including two competitive matches.Significant decreases (p 0.05) were found in the shoulder ROM (i.e., dominant and non-dominant ER ROMs as well as in the dominant and non-dominant total arc of motion [TAM]) in boys, while in girls, significant increases (p 0.05) were found in the non-dominant ER absolute strength, with significant decreases were found in the non-dominant ER ROM and the non-dominant TAM.Playing two badminton matches on the same day led to gender-specific changes on the shoulder profile (i.e., ROM and strength) of young elite badminton players, with more impact on the shoulder profile of boys compared to girls.

Objective: To cross-culturally adapt and validate the Functional Assessment Scale for acute hamstring injury for professional Spanish-speaking soccer players. Design: Clinical measurement study. Cross-cultural adaptation was conducted following international recommendations. Indicators of validity, reliability and responsiveness are provided. Subjects: The Spanish version of the Functional Assessment Scale for acute hamstring injury scale was administered to 165 participants: 45 professional soccer players with acute hamstring muscle injury diagnosis, 40 healthy subjects, 40 individuals at-risk for a hamstring muscle injury and 40 patients with injuries of the lower limb other than hamstring muscle injury. Main measures: The Functional Assessment Scale for acute hamstring injury. Reference measures: Spanish version of the Quality of Life Short-Form 36 questionnaire (SF-36) and the Lower Limb Functional Index (LLFI). Results: Cronbach’s alpha (internal consistency) for the Spanish version of the Functional Assessment Scale for acute hamstring injury scale was >0.8. The intraclass correlation coefficient using the two-way random model (ICC2,1) (test–retest) was 0.993 (95% confidence interval (CI): 0.991–0.995; P s > 0.6; P s = 0.42; P 95%) were 2.6 and 7.2 points, respectively. The responsiveness indicators have an effect size of 3.62, and the standardized response mean is 3.24. Conclusion: The Spanish version of the Functional Assessment Scale for acute hamstring injury scale showed satisfactory psychometric properties. It can be considered a reliable and valid instrument to assess the functional impact of acute hamstring muscle injury in professional Spanish-speaking football players.

The COVID-19 pandemic has produced a major disruption for professional football leagues that has affected the physical preparation of both football players and referees. In Spain, health authorities decreed home confinement for eight weeks, supressing the normal training routines of professional referees. After home confinement, referees had four weeks to retrain as the national football league was set to resume matches to complete the 11 games remaining. The aim of the present investigation was to assess changes in eccentric hamstring muscle strength during football competition suspension/resumption due to the COVID-19 pandemic in 21 professional football referees (mean ± SD, age: 33.4 ± 5.1 years; height: 182.4 ± 5.0 cm; body mass: 75.1 ± 4.4 kg). Eccentric hamstring muscle strength was measured with the Nordic hamstring exercise at four time points. During home confinement, referees presented the lowest value of bilateral eccentric muscle strength (300 ± 14 N). Eccentric muscle strength increased by 13.2 ± 3.7% one week after the end of home confinement (339 ± 16 N; p = 0.001, effect size (ES) = 2.8) and remained stable before the first match (343 ± 17 N; p = 0.001, ES = 3.1) and after the end of the national league (328 ± 13 N; p = 0.001, ES = 2.0). In summary, home confinement produced detraining effects in professional football referees associated with hamstring muscle weakness. In this regard, strength-based activities with body loads may be insufficient to avoid muscle weakness and other means (e.g., weights) may be necessary to maintain muscle strength. However, the 4-weeks retraining period was sufficient to resolve hamstring muscle weakness induced by the restrictions of home confinement. This information may be helpful in the case of future sport competition suspension or home quarantine due to new waves of COVID-19 pandemic.

Moreno-Pérez, V, Machar, R, Sanz-Rivas, D, and Del Coso, J. ACTN3 R577X genotype in professional and amateur tennis players. J Strength Cond Res 34(4): 952-956, 2020-Several investigations have concluded that the RR genotype in the ACTN3 R577X polymorphism is overrepresented in elite athletes of strength- and power-based sports when compared with nonelite populations, suggesting a positive role of this genotype on physical performance. However, no investigation has been geared to determine the distribution of this polymorphism in elite tennis players. The aim of this study was to compare the frequency distribution of the ACTN3 R577X genotype in professional and nonprofessional tennis players to determine whether this polymorphism has an association with tennis performance. A total of 128 tennis players volunteered to participate in this study. From the total, 56 were professional tennis players (16 were top 10 in Women Tennis Association/Association of Tennis Professionals [WTA/ATP] rankings, 22 were top 100 in WTA/ATP rankings, and 18 were rankedtop 100 in the WTA/ATP rankings), and the remaining 72 were categorized as nonprofessional. Chi-squared tests were used to assess differences in the distribution of RR, RX, and XX genotypes between the different performance categories. The distribution of the RR, RX, and XX genotypes was similar in professional (33.9, 48.2, and 17.9%) and nonprofessional tennis players (37.5, 40.3, and 22.2%; p = 0.650). Furthermore, the distribution of the ACTN3 R577X polymorphism was not different in top 10 (25.0, 50.0, and 25.0%), top 100 (31.8, 50.0, and 18.2%), and WTA/ATP-ranked players (44.4, 44.4, and 11.2%; p = 0.847). These results indicate that the distribution of the ACTN3 R577X genotype is similar in tennis players of very different performance levels. This outcome suggests that the ACTN3 genotype was not associated with elite tennis performance.

Background The aim of this study was to investigate the effects of basketball match-play on ankle dorsiflexion range of motion (ROM) and countermovement (CMJ) performance, and their association with internal match load. Methods Thirty semi-professional basketball players participated in this study. Ankle dorsiflexion ROM and bilateral CMJ performance were evaluated before (pre-match) and immediately after match-play (post-match). In addition, ankle dorsiflexion ROM was measured 48 hours post-match. Furthermore, for each player, the ankle dorsiflexion ROM scores were categorized as normal or restricted according to previously reported reference values (>2 cm change from baseline pre-match to post-match and to 48 hours post-match). Results Ankle dorsiflexion ROM was increased post-match from pre-match in dominant and non-dominant limbs (most likely small) and decreased 48 hours post-match (most likely moderate) compared with immediately post-match measures in both limbs. Approximately 20% of all players showed restricted ankle dorsiflexion ROM values 48 hours post-match. CMJ performance was higher post-match than pre-match. Conclusions Ankle dorsiflexion ROM is still reduced 48 h after a competitive basketball match in semi-professional basketball players. The implementation of specific recovery strategies aiming at minimizing a decrease in ankle dorsiflexion after a match might be considered to reduce the likelihood of ankle injury.

Sports supplements are commonly used by elite athletes with the main goal of enhancing sport performance. Supplements use might be substantially different depending on the sport discipline, sex, and competitive level. To date, data about prevalence and the most-commonly used supplements in handball are scarce. Thus, the aim of this investigation was to determine the patterns of supplements use by handball players of both sexes and with different competitive levels: One hundred and eighty-seven handball players (112 men and 75 women) of different competitive levels (106 professional and 81 amateur) completed a validated self-administered questionnaire about supplements use. Supplements were classified according to the categorization of the Australian Institute of Sport (AIS). Overall, 59.9% of the handball players (n = 112) declared the use of at least one supplement and there were no significant differences between men and women (58.9% vs. 61.3%, p = 0.762) nor between professional vs. amateur handball players (67.1% vs. 53.8%, p = 0.074). The most prevalent supplements were sports drinks (42.2%), followed by energy bars (35.3%) and caffeine-containing products (31.6%). However, a greater consumption of group A supplements (those with strong scientific evidence, p = 0.029) and group B supplements (those with emerging scientific support, p = 0.012) was observed in male compared to female handball players. Supplements categorized as medical supplements were more commonly consumed in professional vs. amateur players (0.48 &plusmn, 0.80 vs. 0.21 &plusmn, 0.44, supplements p &lt, 0.006). Additionally, a higher consumption of group B supplements was observed in professional compared to amateur players (0.58 &plusmn, 0.88 vs. 0.33 &plusmn, 0.72 supplements, p = 0.015). Handball players revealed a moderate use of supplements while sex and competitive level slighted changed the pattern of supplements use. A high portion of handball players use supplements as fuel during exercise and reported the use of caffeine-containing supplements to enhance performance.

Beetroot juice (BJ) contains high levels of inorganic nitrate (NO3&minus, ) and its intake has good evidence in increasing blood nitrate/nitrite concentrations. The ingestion of BJ has been associated with improvements in physical performance of endurance sports, however the literature in intermittent sports is scarce. The aim of this study was to investigate whether BJ could improve physical performance in tennis players. Thirteen well-trained tennis players (25.4 &plusmn, 5.1 years) participated in the study during their preparatory period for the tennis season. Subjects were randomly divided into two groups and performed a neuromuscular test battery after either BJ or placebo (PLA) consumption. Both trials were executed on two separate days, in randomized order, with one week of wash out period. The test battery consisted of serve velocity test (SVT), countermovement jump (CMJ), isometric handgrip strength (IHS), 5-0-5 agility test (5-0-5), and 10 m sprint (10-m). No significant differences were found in SVT (1.19%, p = 0.536), CMJ (0.96%, p = 0.327), IHS (4.06%, p = 0.069), 5-0-5 dominant and nondominant side (1.11&ndash, 2.02%, p = 0.071&ndash, 0.191) and 10-m (1.05%, p = 0.277) when comparing BJ and PLA ingestion. Thus, our data suggest that low doses of BJ (70 mL) consumption do not enhance tennis physical performance.

Whereas beetroot juice (BJ) supplementation is shown to increase physical performance in endurance activities, its benefits in team sports has been barely studied. In this randomized placebo-controlled study, we investigated the effects of BJ acute supplementation in improving neuromuscular performance and physical match activity in basketball. Ten young male competitive basketball players aged 15&ndash, 16 years received 140 mL of BJ or placebo (PLA) on two separated days in a balanced cross-over design. Testing sessions comprised a neuromuscular test battery consisting of a countermovement jump (CMJ), isometric handgrip strength, 10-m/20-m sprint and agility T-test, followed by a 40-minute simulated basketball match. Physical match activity (distances, speeds, accelerations, and decelerations) was monitored using an inertial tracking system (Wimu ProTM) Results revealed no significant effects of BJ on CMJ (p = 0.304, ES = 0.13), isometric handgrip strength (p = 0.777, ES = 0.06), 10-m (p = 0.820, ES = 0.10), and 20-m sprint (p = 0.540, ES = 0.13), agility T-test (p = 0.979, ES &le, 0.01) and any physical match demands (p &gt, 0.151, ES = 0.13&ndash, 0.48). Acute moderate doses of BJ (12.8 mmol of NO3&minus, ) was not effective in improving neuromuscular performance (jump height, isometric handgrip strength, sprint, and agility) or physical match requirements in young trained basketball players the day of the competition.

The aim of this study was to determine the acute effect of simulated field hockey match-play on isometric knee flexion, adductor (ADD) and abductor (ABD) strength, adductor/abductor (ADD/ABD) strength ratio, countermovement jump height (CMJ), hip flexion and ankle dorsiflexion range of motion (ROM). Thirty competitive female field hockey players (23.0 &plusmn, 3.9 years old) participated in the study. Apart from the afore-mentioned variables, external (through GPS) and internal load (through RPE) were measured before (pre-match) and immediately after simulated hockey match-play (post-match) in both limbs. Isometric knee flexion strength (+7.0%, p = 0.047) and hip flexion ROM (+4.4%, p = 0.022) were higher post-match in the non-dominant limb, while CMJ values reduced (&minus, 11.33%, p = 0.008) when comparing from pre-match data. In addition, no differences were observed for isometric hip ADD, ABD, ADD/ABD strength ratio, passive hip flexion ROM and ankle dorsiflexion ROM test. A simulated field-hockey match produces an increment in hip isometric strength and hip flexion ROM values in the non-dominant limb and a decrease in jump height capacity. As a result, CMJ assessment should be considered post-match in order to identify players who would require further rest before returning to training.

Background Groin injuries are some of the most common injuries tennis players suffer. Several factors (e.g., post-match decrease in hip adductor (ADD) strength) have been proposed as possible mechanisms for increasing the incidence of this type of injury. However, the risk factors of developing groin injuries after a tennis match have not yet been delineated. Objective The aim of this study was to determine the effect of tennis match-play on isometric ADD and abductor (ABD) strength and passive hip range of motion (ROM). Methods Twenty-six male tennis players (20.30 ± 4.98 years) took part in this study. Participants completed an evaluation of strength and flexibility hip measurements before and after a simulated tennis match. Dominant and non-dominant passive hip ROM, ADD and ABD isometric strength, and the ADD/ABD strength ratio were measured before and immediately post-match. A global positioning system (GPS) and a session rating of perceived exertion (RPE) were used to assess the locomotive demands and internal match load. Results Isometric dominant ADD strength (17.8%, p ≤ 0.01) and ADD/ABD strength ratio (11.6%, p = 0.04) were lower post-match compared to the pre-match values. No between-limbs differences were observed for isometric ADD strength, ABD strength, and passive hip ROM tests. RPE showed an expected increase between pre- vs. post-match (pre- vs. post-warming-up, 3.42 ± 2.08 vs. 5.62 ± 2.29, p < 0.01). In addition, a significant relationship between ADD strength and the volume of tennis practice per week was found, stablishing that tennis players with lower volume of training per week suffered a reduction in ADD strength in their dominant limb after match-play (r = 0.420, p = 0.04). Conclusion The assessment of ADD strength and the ADD/ABD strength ratio in the dominant limb may be considered a post-match tool that can be used to identify players who require rest and additional recovery strategies before competing again.

Beato, M, Madruga-Parera, M, Piqueras-Sanchiz, F, Moreno-Pérez, V, and Romero-Rodriguez, D. Acute effect of eccentric overload exercises on change of direction performance and lower-limb muscle contractile function. J Strength Cond Res 35(12): 3327-3333, 2021-This study aimed to evaluate the postactivation potentiation (PAP) effects following eccentric overload (EOL) exercises on change of direction (COD) performance and muscle contractile function. Thirty-one male soccer players (age 21 ± 4 years; body mass 77.0 ± 5.2 kg) were involved in a cross-sectional study. Dominant-leg (COD-5mD) and non-dominant-leg (COD-5mND) shuttle tests were performed 4 minutes after the EOL exercises. Muscle contractile function was assessed by tensiomyography (TMG) such as muscle contraction time (Tc), time delay (Td) and displacement of the muscle belly (Dm) of vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF). Eccentric overload exercises were: (a) cross-cutting step with inertial conical pulley (INC = 11 subjects), (b) flywheel leg extension (EXT = 10 subjects), and flywheel yo-yo squat exercise (SQU = 10 subjects). Differences baseline-post were found on COD-5mD (p0.001) and on COD-5mND (p0.001), but not between groups (p0.05) following EOL exercises. Differences from baseline were found in VL Td (p0.001), VM Td (p = 0.003), RF Tc (p0.001), and RF Td (p0.001) with no significant differences between the EOL exercises. This study reported a significant positive PAP response on COD-5mD and COD-5mND after 4 minutes of recovery after EOL exercises (INC, EXT and SQU) in soccer players. For the first time, it has been reported that EOL exercises acutely affect TMG variables (e.g., Tc and Td) in lower limbs. Such results related to changes in muscular contractile functions may contribute to explain the physiological mechanisms (e.g., neuromuscular factors) associated with PAP effect.