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Purpose: The aim of this study was to examine the short and long-term effects of a simple strength training program on muscle injury prevention in soccer players. Methods: Twenty-seven U-19 elite male soccer players participated in the study. The investigation was conducted over two consecutive and similar seasons (e.g., the same staff, players, weekly training schedule), the first being the control and the second the experimental season. The strength program was carried out 2 times per week, for 10 weeks, during part of the preseason and in-season. Injury incidence and absence days were compared between both seasons, according to the injury rate ratio (IRR), with 95% CI and the Z test. Results: A lower number of total and hamstring injuries were recorded during the experimental (9 and 2, respectively) compared to the control (15 and 7, respectively) period. During the 10 weeks intervention period, the injury rate ratio (IRR) was lower in the experimental season than in the control season (IRR = 8.12; 95% CI: 1.00-66.03; effect size (ES) = 3.30, large). In addition, there was a decline in absence days per injury and in the number of absence days/1000 h (IRR = 2.44; 95% CI: 1.90-3.14; ES = 1.12) during the experimental season. Conclusion: The results of this study suggest that this simple strength-training program could reduce the muscle injury incidence during its application period in young soccer players.

We aimed to (1) compare external training loads obtained in futsal players during pre-season and in-season training weeks to explore how these loads are periodized by the coaching staff; and (2) compare the external training loads using the match day minus approach during the pre-season and in-season periods to determine how the within-microcycle training load varies between these periods. A total of 432 recordings were obtained of twelve national-level male amateur players using IPS devices. These data were collected over four consecutive microcycles from the beginning to the end of the pre-season, as well as during four additional consecutive microcycles at the start of the in-season. The external load variables evaluated were: total distance covered (TD; m), relative distance covered (Drel; m/min), high-speed running (HSR; m > 18.8 km/h), sprint distance (SPR; m > 25.2 km/h), number of intense accelerations (ACC; >2.5 m/s2) and decelerations (DEC; >−2.5 m/s2). Results indicated significant week-by-week variation (p < 0.05) in all external load variables during the pre-season. During the in-season, significant variations (p < 0.05) were observed only in Drel, HSR, and ACC. In both phases, all variables were higher (p < 0.05) two days before the match. In conclusion, it is important to consistently quantify the external loads of futsal players to ensure appropriate variation in loading and tapering within the microcycle, as well as during the pre-season and in-season periods. [ABSTRACT FROM AUTHOR]

The aims of this study were to: (a) determine the differences in external load quantification between arbitrary and individual speed thresholds over the weekly microcycle in professional soccer players, and (b) analyse the association between internal load and different external load quantification strategies (ELQSs). Ten professional outfield players were monitored during training sessions and official matches using 10 Hz GPS devices over a 6-week in-season period. The absolute and relative ("R" before the distance category) distances covered were calculated for the following external load variables: medium-intensity running distance (MIR), highintensity running (HIR), sprint distance (SD), and very high-intensity running (VHIR). Individualized thresholds were determined based on maximal sprinting speed (MSS) and the last speed achieved during the 30-15 Intermittent Fitness Test (VIFT) of each player. In terms of match-day workload, significant differences (p < 0.05) were observed between arbitrary and individualized strategies (i.e., MSS and VIFT) for the distance covered in MIR, HIR, SD, VHIR, RHIR, RSD, and RVHIR. The MSS strategy compared to arbitrary thresholds revealed significant differences (p < 0.05) for distance covered in HIR, RHIR, and VHIR during all training sessions. The present results showed that arbitrary thresholds lead to underestimation of external load absolute and relative metrics compared to the MSS strategy throughout the microcycle. The VIFT strategy mainly revealed differences in external load quantification regarding MD compared to arbitrary thresholds. Individualized speed threshold strategies did not achieve better associations with internal load measures in comparison with arbitrary thresholds in professional soccer players. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effects of a 4-week detraining period on the neuromuscular performance of highly trained soccer players. Pre and post detraining, 18 adult soccer players (age: 27 64.9 years; height: 180.267.1 cm; body mass [BM]: 78.967.6 kg) performed vertical jumps, 20-m linear sprints, curve sprint and change of direction speed tests, and a progressive loading test in the half-squat exercise with loads corresponding to 50, 100, and 150% of the players' BM to assess the peak-force (PF), mean power (MP), and strength-deficit (SDef). Pre and post differences in the variables of interest were analyzed using paired t-tests and effect sizes (ES). No significant changes were detected for vertical jumping height and sprint times. Higher PF at 50 and 100% BM and lower SDef were shown when comparing pre- and post-assessments (ES = 0.66, 0.68, 0.55; p = 0.018, 0.016, and 0.046, respectively). The MP at 50 and 100% BM increased significantly after the detraining phase (ES = 0.56, 0.82; p = 0.049 and 0.007, respectively). The results indicate that these athletes were able to maintain and achieve satisfactory levels of performance after a short period of training cessation. Interestingly, some strength- and power-derived parameters improved significantly after short-term detraining, which may have important implications for training programs aimed at maximizing speed and power performance. It is recommended that coaches test their players not only at the beginning but also at the end of the season, to better evaluate variations in performance and thus create more efficient and tailored training strategies. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether daily perceived recovery is explained from a multifactorial single-session classification of recovery (ie, faster vs slower) or other circumstantial factors (ie, previous training load, self-reported sleep, or phase of the microcycle). Methods: Nineteen elite male futsal players were initially allocated to a recovery-classification group (faster recovery, slower physiological, or slower perceptual) based on previous research using a multifactorial cluster-analysis technique. During 4 ensuing weeks of preseason, training loads were monitored via player load, training impulse, and session rating of perceived exertion. Before each day's training, players reported their perception of recovery (Total Quality of Recovery scale [TQR]) and the number of hours and perceived quality of sleep the night prior. A hierarchical linear mixed model was used to analyze the effect of the different recovery profiles, training load, sleep, and phase of the microcycle (ie, start, middle, end) on daily TQR. Results: The recovery classification of players (P =.20), training load (training impulse, P =.32; player load, P =.23; session rating of perceived exertion, P =.46), and self-reported hours slept the night before (P =.45) did not significantly influence TQR. However, perceived sleep quality (P <.01) and phase of the microcycle (P <.01) were significantly associated with TQR (r2 =.41). Conclusions: Neither recovery classification nor prior training load influenced perceived recovery during the preseason. However, higher TQR was evident with better self-reported sleep quality, whereas lower values were associated with phases of the training week. [ABSTRACT FROM AUTHOR]

Literature lacks evidence about the physiological recovery of tennis players between points. This study aimed to: (i) verify the heart rate (HR) and oxygen uptake (V̇O2) recovery variance in young tennis players from the end of a tennis drill until the 25-s mark and onwards (65-s limit), performed at several intensities, and (ii) test the curve fitting that better characterizes the players' HR and V̇O2 recovery, from the end of the drill until the 65-s mark. The sample was composed of 13 male tennis players (age: 16.80 ± 1.61 years) recruited from a National Tennis Association. Players were instructed to perform a drill test ("two-line drill wide mode") based on an intensity increment protocol. Three levels of intensity were used based on the reserve HR and V̇O2. A significance level effect was observed on the HRreserve and V̇O2reserve (P <.001). At all three levels of intensity, the first 25 s were enough to significantly (P <.001) recover the HRreserve and V̇O2reserve. The same significance trend (P <.001) was maintained until the 65 s but with a lower magnitude over time. Overall, the HR and V̇O2 curve fitting indicated a cubic relationship at the three levels of intensity (except the V̇O2 at the first level). Considering the specific test performed, players significantly elicited their physiological profile for every additional 10 s (after the 25-s rule) in the three levels of intensity performed. Despite this being a drill test and not a competitive point, coaches, players, and tennis organizations should be aware of these findings. [ABSTRACT FROM AUTHOR]

This study examined the intra-session reliability of sprint performance on a non-motorized treadmill amongst healthy, active male and female adults. One hundred and twenty participants (males n = 77; females n = 45) completed two familiarization sessions, followed by a third session that consisted of three trials (T1, T2, T3) of maximal sprints (4-s), interspersed by three minutes of recovery. Combining males and females exhibited moderate-to-excellent test-retest reliability (intra-class correlation coefficient, ICC), minimal measurement error (coefficient of variation, CV) and trivial differences between trials (effect size, ES) for speed, power, total work and acceleration (ICC = 0.82-0.98, CV = 1.31-8.45%, ES = 0.01-0.22). The measurement error was improved between comparisons of T1 vs. T2 (CV = 1.62-8.45%, ES = 0.12-0.22) to T2 vs. T3 (CV = 1.31-6.56%, ES = 0.01-0.07) and better for females (CV = 1.26-7.94%, ES = 0.001-0.26) than males (CV = 1.33-8.53%, ES = 0.06-0.31). The current study demonstrated moderate-to-excellent reliability and good-moderate measurement error during a 4-s sprint on a non-motorized treadmill. However, sex had a substantial impact with females exhibiting better values. Practitioners should employ at least two separate trials within a session, in addition to multiple familiarization sessions, to achieve reliable non-motorized treadmill sprint performances. [ABSTRACT FROM AUTHOR]

The present study aimed to select the most critical external workload variables that explain sports performance in the Mexican male professional soccer League (Liga BBVA-Bancomer) and analyse the effect of match period and match outcome in workload demands. 480 professional soccer players that belonged to 16 Liga BBVA-Bancomerteams were registered during the 2018–2019 opening and closing tournament by inertial measurement units. The statistical analysis was composed of: (1) principal component analysis (PCA) to select the most critical performance indicators, and (2) mixed analysis of variance to explore match outcome and match period effects. Through PCA analysis, eight variables were selected and distributed in three components that represented the 59.47% (opening tournament) and 58.85% (closing tournament) of total variance with three different PC´s as: high-intensity actions (RelDist, ExplDist, Speed18-21 km/h and Speed21-24 km/h), speed changes (Acc and Dec) and actions at maximum capacity (AccMax and SpeedMax). Differences in tournaments and match periods were found in almost all variables, finding the highest external workload in draw matches when match outcome was considered a factor. PCA analysis seems to be a helpful method to discriminate the most representative variables of performance. [ABSTRACT FROM AUTHOR]

This study aimed to identify the most important variables of male and female beach handball workload demands and compare them by sex. A total of 92 elite Brazilian beach handball players (54 male: age 22.1 ± 2.6 years, height 1.8 ± 0.5 m, weight 77.6 ± 13.4 kg; and 38 female: age 24.4 ± 5.5 years, height 1.7 ± 0.5 m, weight 67.5 ± 6.5 kg) were analyzed in 24 official matches during a four-day congested tournament. From 250 variables measured by the inertial measurement unit, fourteen were extracted for analysis using Principal Component Analysis as selection criteria. Five Principal Components (PC) were extracted that explained 81.2--82.8% of total variance (overview of workload demands during beach handball). Specifically, 36.2--39.3% was explained by PC1 (DistanceExpl, Distance, Distance4--7 km/h, and Acc), 15--18% by PC2 (AccMax, Acc3--4 m/s, Dec4--3 m/s), 10.7--12.9% by PC3 (JumpsAvg Take-Off, JumpsAvg Landing and PLRT), 8--9.4% by PC4 (Distance >18.1 km/h, SpeedMax), and 6.7--7.7% by PC5 (HRAvg and Step Balance). Sex-related differences were found in the PC distribution of variables, as well as in selected variables (HRAvg, Dec4--3 m/s, Acc3--4 m/s, JumpsAvg Take-Off, JumpsAvg Landing, AccMax, Distance, Distance4--7 km/h, Acc, SpeedMax) with higher values in male players (p < .05). In conclusion, the sex-related PC distribution and workload demands in beach handball should consider for training design and injury prevention programs. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the existence of faster vs slower recovery profiles in futsal and factors distinguishing them. Methods: 22 male futsal players were evaluated in countennovement jump, 10-m sprint, creatine kinase, total quality of recovery (TQR), and Brunei Mood Scale (fatigue and vigor) before and immediately and 3, 24, and 48 h posttraining. Hierarchical cluster analysis allocated players to different recovery profiles using the area under the curve (AUC) of the percentage differences from baseline. One-way ANOVA compared the time course of each variable and players' characteristics between clusters. Results: Three clusters were identified and labeled faster recovery (FR), slower physiological recovery (SLphy), and slower perceptual recovery (SLperc)- FR presented better AUC in 10-m sprint than SLphy (P = .001) and SLperc (P = .008), as well as better TQR SLphy {P = .018) and SLperc (P = .026). SLperc showed better AUC in countermovement jump than SLphy (P = .014) but presented worse fatigue AUC than SLphy (P = .014) and FR (P = .008). AUC of creatine kinase was worse in SLphy than in FR (P = .001) and SLperc {P < .001). The SLphy players were younger than SLperc players (P = .027), whereas FR were slower 10-m sprinters than SLphy players (P = .003) and SLperc (P = .013) and tended to have higher maximal oxygen consumption than SLphy (effect size = 1.13). Conclusion: Different posttraining recovery profiles exist in futsal players, possibly influenced by their physical abilities and age/experience. [ABSTRACT FROM AUTHOR]

Flatt, AA, Hornikel, B, Nakamura, FY, and Esco, MR. Effect of competitive status and experience on heart rate variability profiles in collegiate sprint-swimmers. J Strength Cond Res 36(10): 2898–2904, 2022—Interindividual differences in training history may be a determinant of heart rate variability (HRV) profiles in collegiate sprint-swimmers and may account for differences observed between elite and subelite athletes. We therefore compared HRV profiles among national-level and conference-level sprint-swimmers while accounting for individual swim-training history. Twenty-eight short-distance swimmers (18 men and 10 women) recorded postwaking HRV throughout a 4-week standardized training period. The 4-week mean (M) and coefficient of variation (CV, a marker of daily fluctuation) were calculated for resting heart rate (RHR) and the natural logarithm of the root mean square of successive differences (LnRMSSD). Swimmers were categorized as national-level (n = 12) or conference-level (n = 16) competitors. Years of competitive experience was documented for each individual to index training history. p < 0.05 was considered statistically significant. No sex-related differences were observed for any variables (p > 0.05). LnRMSSDM (effect size [ES] = 0.95), LnRMSSDCV (ES = −1.18), RHRCV (ES = −1.05), and competitive experience (ES = 1.23) differed between status groups (p < 0.05). Accounting for multicollinearity between competitive experience and LnRMSSD variables (p < 0.05), competitive experience remained associated with LnRMSSDM (r = 0.44, p = 0.02). With competitive experience included as a covariate, differences in LnRMSSDM between status groups disappeared (p > 0.05, ES = 0.31). National-level swimmers exhibit higher and more stable LnRMSSD than that of their conference-level teammates throughout standardized training. Differences in trend characteristics were attributed to training age. This information may assist practitioners with interpreting interindividual differences in HRV profiles throughout training periods among a mixed roster of athletes. [ABSTRACT FROM AUTHOR]

This study aimed to determine if the OMNI scale with cycle ergometer pictorial format can be used to estimate perceived exertion threshold ([PET.sub.OMNI]) and nonexhaustive PET ([PET.sub.OMNI5-8]) and to compare and to correlate these PET estimates with [PET.sub.Borg], [PET.sub.Borg14-17], and critical power (CP). During different days, 13 men performed 4 different high-intensity constant-loads work bouts until exhaustion on a cycle ergometer using the Borg scale, whereas the OMNI scale was used during the other 4 work bouts using previous constant loads. The PET for both scales was determined by plotting the increasing rates of perceived exertion against power outputs, PET being the intersection point of the regression line. In addition, a hyperbolic relationship between power and time to exhaustion was used to determine CP. The [PET.sub.OMNI] (183 [+ or -] 36 W) was similar to [PET.sub.Borg] (178 [+ or -] 46 W), and they were also significantly correlated (r = 0.77). The [PET.sub.OMNI5-8] (175 [+ or -] 36 W) was similar to [PET.sub.Borg14-17] (181 [+ or -] 38 W); however, they were not significantly correlated (r = 0.36). All the PET estimates were similar to [CP.sub.OMNI] (167 [+ or -] 36 W) and [CP.sub.Borg] (169 [+ or -] 40 W) and also significantly correlated (r = 0.79-0.94), excepting [PET.sub.OMNI5-8] (r = 0.46). In conclusion, OMNI cycling scale can be used to estimate PET and CP with high accuracy. However, the nonexhaustive PET derived from the 5-8 range in the OMNI scale did not provide a valid estimate of maximal sustainable power output because of the absence of correlation with [PET.sub.Borg14-17] and with CP. Therefore, professionals and practitioners can assess the subjects' aerobic fitness through the PET estimation using the OMNI scale during exhaustive tests. KEY WORDS rating of perceived exertion, Borg scale, critical power, cycle ergometer

The aim of this study was to investigate the effects of preferred and nonpreferred music on exercise distance, Heart Rate (HR), and Rating of Perceived Exertion (RPE) during continuous cycling exercise performed at high intensity. Fifteen participants performed five test sessions. During two sessions, they cycled with fixed workload on ergometer to determine the Critical Power (CP) intensity. Then, they performed three more sessions cycling at CP intensity: listening to Preferred Music, listening to Nonpreferred Music, and No Music. The HR responses in the exercise sessions did not differ among all conditions. However, the RPE was higher for Nonpreferred Music than in the other conditions. The performance under Preferred Music (9.8 [+ or -] 4.6km) was greater than under Nonpreferred Music (7.1 [+ or -] 3.5km) conditions. Therefore, listening to Preferred Music during continuous cycling exercise at high intensity can increase the exercise distance, and individuals listening to Nonpreferred Music can perceive more discomfort caused by the exercise. DOI 10.2466/PMS.110.1.257-264

This study tested the concurrent and construct validity of a newly developed OMNI-Kayak Scale, testing 8 male kayakers who performed a flatwater load-incremented 'shuttle' test over a 500-m course and 3 estimation-production trials over a 1,000-m course. Velocity; blood lactate concentration, heart rate, and rating of perceived exertion (RPE), using the OMNI-Kayak RPE Scale and the Borg 6-20 Scale were recorded. OMNI-Kayak Scale RPE was highly correlated with velocity, the Borg 6-20 Scale RPE, blood lactate, and heart rate for both load-incremented test (rs = .87-.96), and estimation trials (rs = .75-.90). There were no significant differences among velocities, heart rate and blood lactate concentration between estimation and production trials. The OMNI-Kayak RPE Scale showed concurrent and construct validity in assessing perception of effort in flatwater kayaking and is a valid tool for self-regulation of exercise intensity.

BACKGROUND: Prolonged fatigue effects may be a concern after futsal matches mainly because of the actions performed by futsal players (e.g., sprinting, jumping) that usually involve the stretch-shortening cycle (SSC). However, there no studies analyzed the prolonged effects of futsal-specific fatigue and how futsal players can recover from performance tasks. OBJECTIVE: To analyze the acute and prolonged effects of a protocol that simulates specific physical demands of futsal on countermovement-jump, sprint performance, muscle strength and muscle soreness. METHODS: Fifteen amateur futsal male athletes (18.3 ± 3.8 years) performed a futsal intermittent running protocol (FIRP) and were assessed for (moment production, sprint and jumping performance and muscle soreness) at pre, during half-time, immediately after, post 24 and 48 hours after the FIRP. Analysis of variance (repeated measures) was used to compare variable means over time. RESULTS: The main results indicated a decrement in the CMJ height (p = 0.03) and an increase of 10 m and 20 m sprint times (p = 0.01– p < 0.01, respectively) during half-time and the post FIRP. There was a decrement in eccentric peak moment of the knee extensors (p = 0.02) and flexors (p < 0.01) until 48h post protocol and a decrement in concentric peak moment of the flexors (p < 0.01) post protocol. Athletes reported muscle soreness in the hamstrings (p = 0.03) post and 24 h after the FIRP. CONCLUSION: FIRP induced acute effects in the jump and sprint performances only. On the other hand, the knee moment production capability (mainly eccentric) suffered acute and also prolonged effects of the FIRP accompanied by delayed muscle soreness in the hamstring muscles. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate a novel procedure, based on the perceived exertion threshold (PET) concept, involving non-exhaustive tests ([PET.sub.14-17]) to estimate critical power (CP), as well as to examine the reproducibility of these indices. Twenty young men performed 2 trials (Trial 1 and Trial 2) of 4 exhaustive predictive tests to estimate CP, PET, and [PET.sub.14 17]. The slope coefficients of the regression lines corresponding to the ratings of perceived exertion (RPE) versus time relationship (y axis) obtained during the predictive tests were plotted against the power outputs (x axis) to estimate PET. PET was calculated as the intersection point of the regression line in the power axis. The 14-1 7 RPE range of each predictive test was modeled using the same mathematical procedures used to estimate [PET.sub.14 17]. CP was derived from the power-time hyperbolic equation. Analysis of variance revealed no significant differences among CP (189-194 W), PET (190-191 W) and [PET.sub.14 17], (191-195 W). The correlations between CP and PET (r = 0.87), CP and [PET.sub.14 17] (r = 0.89), and PET and [PET.sub.14 17] (r = 0.88) were all strong. Additionally, the bias [+ or -] limits of agreement when plotting CP and PET was -2.16 [+ or -] 31.60 W, and -5.70 [+ or -] 31.21 W when comparing CP and [PET.sub.14 17]. Relatively high reproducibility levels of CP (ICC = 0.96), PET (ICC = 0.85) and [PET.sub.14 17] (ICC = 0.83) were recorded in the test-retest fashion. It can be concluded that the [PET.sub.14 17] can be utilized with relatively high accuracy and reproducibility to estimate CP without causing exhaustion in the subjects. KEY WORDS critical power, rating of perceived exertion, cycle ergometer

Older women participated in a 12-week high-speed resistance training program under two supervisor-to-subject ratio methods (i.e., high versus low supervision) to assess its effects on muscle strength, power, functional performance, and quality of life assessed before (T1) and after (T2) intervention. Women were divided into either the control group (CG, n = 15), high supervision group (HSG, n = 30), or low supervision group (LSG, n = 28). The training program included exercises requiring high-speed concentric muscle actions. No differences were observed among groups at T1. Between T1 and T2, the HSG showed a higher (p < .05) improvement in muscle strength (ES = 0.36–1.26), power (ES = 0.5–0.88), functional performance (ES = 0.52–0.78), and quality of life (ES = 0.44–0.82) compared with LSG and CG. High-speed resistance training under closer supervision is more effective for improving muscle strength, power, functional performance, and quality of life in older women. [ABSTRACT FROM AUTHOR]

Furthermore, in the present study, the sprint test was better linked to traditional COD tests (i.e., 505) than to the On-Court COD test, suggesting than the inclusion of specific lower-limb movements along with badminton mock shots makes the On-Court COD test a very specific COD measurement. Keywords: racket sports; specific movement; neuromuscular performance; testing EN racket sports specific movement neuromuscular performance testing 155 164 10 04/29/22 20220415 NES 220415 Introduction As an intermittent sport, badminton is characterized by repetitive short periods of exercise (i.e., 1-9 s) and recovery (i.e., low intensity activities such as standing and walking for 6-15s) interspersed with longer breaks in play (i.e., "time outs" of 120s between games) ([33]). The excellent reliability of the On-Court COD test agrees with previous research revealing that certain specific badminton COD tests are highly reproducible ([6]; [32]), supporting its use in badminton fitness testing batteries. [Extracted from the article]

Sanchez-Sanchez, J, Raya-Gonzalez, J, Ramirez-Campillo, R, Chaabene, H, Petisco, C, and Nakamura, FY. The increased effectiveness of resistance training on unstable vs. stable surfaces on selected measures of physical performance in young male soccer players. J Strength Cond Res 36(4): 888-894, 2022-To examine the effects of 10-week (2/wk) resistance training on stable vs. unstable surfaces on selected measures of physical performance in young male soccer players, national-level U19 players participated in this study. They were randomly allocated to an unstable resistance training group (uRT, n = 27) or a stable resistance training group (sRT, n = 28). Before and after the training, horizontal jumping with dominant (Hop D) and nondominant leg (Hop non-D), repeated sprint ability (RSA best time [RSAbest] and RSA mean time [RSAmean]), change-of-direction (COD) speed (Illinois COD test), and aerobic endurance (YoYo Intermittent Recovery Test Level 1 [YoYo IR1]) were assessed. To establish the effects of the interventions on the dependent variables, a 2 (group: uRT and sRT) x 2 (time: pre, post) analysis of variance with repeated measures on time was computed. A significant main effect of time was observed for Hop non-D, RSAbest, and RSAmean (p = 0.003-0.06, effect size [ES] = 0.06-0.15). Furthermore, significant group x time interactions were shown for RSAbest (p = 0.007, ES = 0.13) and RSAmean (p = 0.002, ES = 0.2). Post hoc analysis revealed significant pre- to post-training improvements for RSAbest (p = 0.002, ES = 0.35) and RSAmean (p = 0.0002, ES = 0.36) in the uRT. In the sRT, however, no significant pre-post performance changes were observed in RSAbest and RSAmean. In conclusion, 10 weeks of an in-season resistance training on unstable conditions in addition to regular soccer training was effective in improving repeated-sprint ability performance in youth male elite soccer players including maximal linear sprinting and the ability to perform repeated sprint. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the repeated effect of social media on smartphones immediately before training sessions on inhibitory control (Stroop task), endurance (tethered swimming), countermovement jump (CMJ), and swimming performance (50, 100, and 400-m freestyle) in high-level female swimmers. Methods: It is a randomized and experimental investigation with parallel groups. Twenty-two participants underwent the eight weeks of the experiment. The swimmers (eight to twelve sessions per week with 15.9 ± 1.6 hours/week, and training experience of ~ 5.6 years) were randomized in two groups: control (CON, n = 11) and smartphone (SMA, n = 11). Immediately before each training session, the CON group watched videos about Olympic Games for 30-min. The SMA group used social network smartphone apps during 30-min. The inhibitory control, endurance, CMJ, and swimming performance were measured before and after the eight weeks of intervention. Results: No group x time interaction for 50-m freestyle (F(4, 18) = 1.04; p =.33; η2 = 0.09) and CMJ performance (F(4, 18) = 0.31; p =.58; η2 = 0.03) was found. Both experimental groups improved CMJ (F(2, 20) = 8.71; p =.01; η2 = 0.46). Only the CON group improved the 100-m (p =.02), 400-m freestyle (p =.01), and endurance performance (p =.01). The CON group improved the inhibitory control response (p =.01). Conclusion: It is concluded that the repeated effect of social media on smartphones immediately before swimming training sessions might reduce or nullify training gains on swimming and endurance performance. [ABSTRACT FROM AUTHOR]

Research has shown that soccer players regularly execute curved sprints during matches. The purpose of this study was to determine the age-related effects on curve sprint (CS) performance to both sides, asymmetry, and association with linear sprint (LS). Eighty-four soccer players (aged 16.1 ± 1.6 categorized in U15, U17, and U20) were recruited, who performed CS and LS tests. One-way analysis of variance (ANOVA) and effect size (ES) were used to compare CS performance between age categories, and relationships between physical performance measures were calculated using Pearson's correlation coefficient. The main findings of this study were that: 1) there were significant differences in the "good" side CS among age groups (p < 0.001; ES from moderate to large), but not in the "weak" side CS, 2) curve asymmetry was significantly higher in U20 than U15 (p < 0.05; ES large) and U17 players (p < 0.05; ES moderate), and 3) relationships between CS and LS times decreased with age (from significant and very large [p < 0.001] to non-significant and small-moderate [p > 0.05]). This study highlights the importance of assessing and training CS in different age categories, an action that becomes less correlated with LS as age increases, with the aim of mitigating the increase in asymmetries as a result of the specialization process, focusing interventions mainly on improving the CS "weak" side. [ABSTRACT FROM AUTHOR]

We studied the effects of repeated inducements of mental fatigue (MF) from using social media on smartphones immediately before training sessions by young male volleyball athletes, focusing specifically on their decision-making, endurance, and countermovement jump performance (CMJ). We pair-matched 24 participants according to their decision-making abilities and then, randomly assigned them to one of two 4-week block training groups: control (CON) and smartphone use (SMA). For a 30-minute period before each training session, the CON group watched TV and the SMA group used social media apps on smartphones. We found a significant group x time interaction effect for decision making (attack, p = 0.03; passing, p = 0.02) during training blocks. More specifically, only the CON group improved their decision making (attack, p = 0.03; passing, p = 0.02). Both groups significantly improved their CMJ performance (p =.01), with no significant group x time interaction effect for CMJ (p = 0.91). Neither group significantly improved their endurance (p = 0.56). We concluded that 30-minutes of repetitive social media app use on a smartphone immediately before 4-weeks of volleyball training sessions negatively affected decision-making in young male volleyball athletes. [ABSTRACT FROM AUTHOR]

This study compared the physical performance of Paralympic sprinters with visual impairments (PSVI) and their guides in jump and sprint tests. Ten PSVI and guides executed squat jumps (SJ), countermovement jumps (CMJ), horizontal quintuple right/left-leg jumps (QR/QL), decuple jumps (DEC), and 50-m-sprint tests. The guides were superior to the PSVI in SJ (35.9 ± 6.3 vs 45.6 ± 3.2 cm), CMJ (38.5 ± 6.2 vs 46.7 ±4.0 cm), QR (9.2 ± 1.9 vs 12.7 ± 1.0 m), QL (9.4 ± 1.9 vs 13.1 ± 0.8 m), DEC (21.0 ± 3.3 vs. 27.2 ± 1.7 m), and 50-m sprints (8.4 ± 0.4 vs 7.6 ± 0.5 m/s). The average differences between the PSVI and guides in the sprint tests was 10%, range 1-24%. Therefore, substantial differences in sprinting speed (in favor of the guides) between the peers were observed. Coaches should develop strategies to train the guides to improve their muscle-power performance. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the training loads reported by karate athletes of the Brazilian national team in the week immediately before their participation in the 2015 Pan American Games. Methods: Eleven elite karate athletes (7 men and 4 women, 24.42 ± 3.75 y, 1.70 ± 0.09 m, 69.6 ± 13.2 kg) from the Brazilian national team took part in this study. Session rating of perceived exertion (s-RPE) was quantified in all training sessions. Moreover, resting heart-rate variability (HRV), as analyzed through the natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD), and countermovement-jump (CMJ) performance before and after 8 training sessions were assessed throughout the week. The differences based on magnitudes were calculated comparing pre- and posttraining session, as well as measures performed every morning during the week. Results: The weekly s-RPE was 2608.5 ± 431.2 a.u. The lnRMSSD was very likely higher on Monday than on the following days of the week, remaining stable during this period. CMJ height did not change during the week. Almost certain differences were observed in lnRMSSD pre- and posttraining session, while CMJ height did not change. Conclusions: The national karate-team athletes did not present signs of fatigue accumulation, as indicated by relatively steady HRV and unchanged CMJ during the week, as planned by the coaches for precompetition technical and tactical refinement. [ABSTRACT FROM AUTHOR]

Purpose: To compare the LnRMSSD and the LnRMSSD:RR values obtained during a 5-min stabilization period with the subsequent 5-min criterion period and to determine the time course for LnRMSSD and LnRMSSD:RR stabilization at l-min analysis in elite team-sport athletes. Participants: 35 elite futsal players (23.9 ± 4.5 y, 174.2 ± 4.0 cm. 74.0 ± 7.5 kg, 1576.2 ± 396.3 m in the Yo-Yo test level 1). Methods: The RR-interval recordings were obtained using a portable heart-rate monitor continuously for 10 min in the seated position. The 2 dependent variables analyzed were LnRMSSD and LnRMSSD:RR. To calculate the magnitude of the differences between time periods, effect-size (ES) analysis was conducted. To assess the levels of agieement, intraclass correlation coefficients (ICC) and Bland-Altman plots were used. Results: The LnRMSSD and LnRMSSD:RR values obtained during the stabilization period (0-5 min) presented very large to nearly perfect ICCs with the values obtained duting the criterion period (5-10 min), with trivial ESs. In the ultra-short-term analysis (ie, l-min segments) the data showed slightly less accurate results, but only trivial to small differences with very large to nearly perfect ICCs were found. Conclusion: LnRMSSD and LnRMSSD.RR can be recorded in 5 min without traditional stabilization periods under resting conditions in team-sport athletes. The ultra-short-term analysis (1 min) also revealed acceptable levels of agreement with the criterion. [ABSTRACT FROM AUTHOR]

This systematic review and meta-analysis aimed to analyse the technologies and main training variables used in the literature to monitor flywheel training devices in real time. In addition, as the main research question, we investigated how eccentric overload can be effectively monitored in relation to the training variable, flywheel shaft type device and the moment of inertia selected. The initial search resulted in 11,621 articles that were filtered to twenty-eight and seventeen articles that met the inclusion criteria for the systematic review and meta-analysis, respectively. The main technologies used included force sensors and rotary/linear encoders, mainly to monitor peak or mean force, power or speed. An eccentric overload was not always achieved using flywheel devices. The eccentric overload measurement was related to the main outcome selected. While mean force (p = 0.011, ES = -0.84) and mean power (p < 0.001, ES = -0.30) favoured the concentric phase, peak power (p < 0.001, ES = 0.78) and peak speed (p < 0.001, ES = 0.37) favoured the eccentric phase. In addition, the lower moments of inertia (i.e., from 0.01 to 0.2 kg⋅m²) and a cylindrical shaft type (i.e., vs conical pulley) showed higher possibilities to achieve eccentric overload. A wide variety of technologies can be used to monitor flywheel devices, but to achieve eccentric overload, a flywheel cylindrical shaft type with low moments of inertia is advised to be used. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the sensitivity of maximal (Yo-Yo Intermittent Recovery [IR] 1 and 2) and submaximal (5'-5') tests to identify training adaptations in futsal players along with the suitability of heart-rate (HR) and HR-variability (HRV) measures to identify these adaptations. Methods: Eleven male professional futsal players were assessed before (pretraining) and alter (posttraining) a 5-wk period. Assessments included 5'-5' and Yo-Yo IR1 and IR2 performances and HR and HRV at rest and during the IR and 5'-5' tests. Magnitude-based-inference analyses examined the differences between pre- and posttraining, while relationships between changes in variables were determined via correlation. Results: Posttraining, Yo-Yo IR1 performance likely increased while Yo-Yo IR2 performance almost certainly increased. Submaximal HR during the Yo-Yo IR1 and Yo-Yo IR2 almost certainly and likely, respectively, decreased with training. HR during the 5'-5' was very likely decreased, while HRV at icst and during the 5-5 was likely increased alter training. Changes in both Yo-Yo IR performances were negatively correlated with changes in HR during the Yo-Yo IR1 test and positively correlated with the change in HRV during the 5'-5'. Conclusions: The current study has identified the Yo-Yo IR2 as more responsive for monitoring training-induced changes of futsal players than the Yo-Yo IR1. Changes in submaximal HR during the Yo-Yo IR and HRV during the 5'-5' were highly sensitive to changes in maximal performance and are recommended for monitoring training. The 5'-5' was recommended as a time-efficient method to assess training adaptations for futsal players. [ABSTRACT FROM AUTHOR]

This study aimed to compare anthropometric and physical fitness of Brazilian female national team soccer players from the U15 to senior categories, and to compare the physical performance between selected and nonselected players. Subjects included 231 athletes (U15, n = 46, U17, n = 49, U20, n = 98, and Senior, n = 38). Body mass, height, sum of skinfolds, squat jump (SJ), countermovement jump (CMJ), 20-m linear sprint, and Yo-Yo IR1 were assessed. The U15 players were shorter than all other groups (p < 0.01) and lighter than U20 players (p < 0.01). Regarding physical tests, Senior athletes presented higher SJ compared with U20, and both showed higher CMJ and SJ compared with the U15 and U17 (p < 0.05). Senior athletes were also faster than players of all other categories in 20-m sprint (p < 0.01) and covered the greatest distance in the Yo-Yo IR1 (p < 0.05). U20 were better in the Yo-Yo IR1 than the younger groups (p < 0.05). When comparing selected and nonselected players, no differences were identified in anthropometric measures (p > 0.05). However, selected players from U17, U20, and Senior teams showed better performance in Yo-Yo IR1 than nonselected ones (p < 0.05). Finally, selected senior athletes also presented higher CMJ and SJ than nonselected players (p < 0.05). These results suggest that, although there is a tendency for maintenance in anthropometric measures from the age of 15 years, there are substantial improvements in speed, lower-body power, and aerobic capacity from U20 age group. In addition, it seems that intermittent aerobic fitness contributes to the selection of players to international tournaments in national teams. [ABSTRACT FROM AUTHOR]

Cold water immersion (CWI) is a recovery method in sports, acting through a reduction in body temperature and improvement of muscular function by limiting post-exercise inflammation processes. Purpose: To analyze the effectiveness of intermittent and continuous cold-water immersion (CWI) on skin temperature recovery throughout the days after the strenuous exercise protocol. An independent group trial was performed using a randomized 3x3 repeated measures ANOVA model. The sample consisted of 40 male physically active adults who were divided into three groups: Control Group, 12 min sitting in a 23 °C ± 0.5°C room; Intermittent CWI, 12 min intermittent immersions 2 min inside (12 ± 0.4°C) and 1 min outside (23 °C ± 0.5°C); Continuous CWI, 12 min continuous immersion at 12 ± 0.4 °C. After an exhaustion jumping fatigue protocol, participants performed the correspondent recovery protocol. Skin temperature of hamstrings and quadriceps of both lower limbs were assessed pre, post 24 hours, and post 48 hours using a thermal camera. No significant effects (p> 0.05) on the skin temperature in response to the immersion protocols, both in the average temperature or in the maximum temperature in quadriceps or hamstrings. CWI recovery protocols did not report significant effects on the skin temperature, both in the average temperature or in the maximum temperature in quadriceps or hamstrings. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Small-sided games (SSGs) are a useful strategy to optimize the training process in soccer. The modification of some variables simultaneously implies several physical adaptations in soccer players. Thus, the aim of this study was to analyze the differences in the physical demands encountered by soccer players in different SSGs formats focusing on the scoring methods (i.e., mini-goals and regular goals with goalkeepers) and to the numerical superiority situations (i.e., no superiority, variable superiority, and fixed superiority). Eight elite young soccer players from the same team (age: 17.9 ± 1.1 years) randomly completed six SSG formats. Physical parameters (i.e., total distance [TD], distance covered at different speeds [D1, D2, D3, D4, D5 and D6], and distance covered accelerating [ACC] and decelerating [DEC]) were collected. The main results showed that the variable superiority (i.e., 4vs4+1) situation is more demanding, in terms of TD and distance covered at D3 and D4, in comparison to no superiority (i.e., 4vs4) and fixed superiority (i.e., 5vs4) situations both SSGs played with mini-goals and regular goals with goalkeepers. Besides, higher physical demands were registered in fixed superiority (i.e., 5vs4) than in no superiority (i.e., 4vs4) situation. Finally, only in a no superiority (i.e., 4vs4) situation higher distances at D1 and D5 were registered during the SSG played with mini-goals but higher distance at D3 was covered in the SSG format with regular goals and goalkeepers. Playing SSGs in variable superiority situation is more demanding in comparison to no superiority (i.e., 4vs4) and fixed superiority situations both during those SSGs played with mini-goals and/or regular goals and goalkeepers. In addition, SSGs played with mini-goals induced higher physical demands than playing with regular goals and goalkeepers during no superiority games. These findings could be useful for coaches in order to periodize the training drills within the microcycle to modulate the training session intensity. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the agreement of the data on the kinematic demands and collective tactical variables during a professional soccer match between GPS and UWB sensors. The data were extracted from a professional soccer match played in "the regular season" during 2019-2020. The analysis indicated a high-degree of agreement between UWB and GPS sensors to measure the total distance covered (ICC>0.94). In addition, Bland-Altman plots showed a low average difference for the total distance covered between the devices (mean difference = -0.011 to -0.017 m). Although the collective tactical variable (i.e. surface area) showed a high-degree of agreement between both devices (i.e. ICC>0.84), a significant main effect was found for the average difference between the UWB sensor and GPS sensor (mean difference = -9.25 to 57.41 m2). In addition, Bland-Altman plots showed a slight systematic bias for lower surface area measured by the GPS sensor in comparison to the UWB sensor. Researchers and technical staff should consider that the data provided by the GPS and UWB can be interchangeable in the analysed kinematic variables. However, the data provided by the devices cannot be compared in the analysed collective variables due to the differences found. [ABSTRACT FROM AUTHOR]