The influence of soccer playing actions on the recovery kinetics after a soccer match

Association between Concentric and Eccentric Isokinetic Torque and Unilateral Countermovement Jump Variables in Professional Soccer Players

Isokinetic tests have been highly valuable to athletic analysis, but their cost and technical operation turn them inaccessible. The purpose of this study was to verify the correlation between unilateral countermovement jump variables and isokinetic data. Thirty-two male professional soccer players were subjected to the isokinetic testing of both knee extensors and flexors in concentric and eccentric muscle contractions. They also executed unilateral countermovement vertical jumps (UCMJ) to compare maximum height, ground reaction force, and impulse power with isokinetic peak torque. Data analysis was conducted through Pearson correlation and linear regression. A high correlation was found between dominant unilateral extensor concentric peak torque and the UCMJ maximum height of the dominant leg. The non-dominant leg jump showed a moderate correlation. No other variable showed statistical significance. Linear regression allowed the generation of two formulae to estimate the peak torque from UCMJ for dominant and non-dominant legs. Although few studies were found to compare our results, leading to more studies being needed, a better understanding of the unilateral countermovement jump may be used in the future as a substitute to the expensive and technically demanding isokinetic testing when it is unavailable, allowing the assessment of lower limb physical asymmetries in athletic or rehabilitation environments.

Playing Position is Associated with Injury Incidence Rate in Male Academy Soccer Players

CONTEXT

It is unclear whether playing position influences injury in male academy soccer players (ASP).

OBJECTIVE

To determine if playing position is associated with injury in ASP.

DESIGN

Descriptive Epidemiology Study.

SETTING

English, Spanish, Uruguayan and Brazilian soccer academies.

PARTICIPANTS

369 ASP from Under 14 (U14) to U23 age groups, classified as 'post-peak height velocity' using maturity offset, and grouped as goalkeepers (GK), lateral defenders (LD), central defenders (CD), lateral midfielders (LM), central midfielders (CM) and forwards (FWD). Additional analysis compared central (CENT) with lateral/forward (LAT/FWD) positions.

MAIN OUTCOME MEASURES

Injuries were recorded prospectively over one season. Injury prevalence proportion (IPP), days missed and injury incidence rate (IIR, injuries per 1000 training/match hours, n=116) were analysed according to playing position.

RESULTS

No association with playing position was observed for any injury type/location regarding IPP (P≥0.089) or days missed (P≥0.235). The IIR was higher in CD than LD for general (9.30 vs. 4.18 injuries/1000h, P=0.009), soft-tissue (5.14 vs. 1.95 injuries/1000h, P=0.026) and ligament/tendon injuries (2.69 vs. 0.56 injuries/1000h, P=0.040). Regarding CENT vs. LAT/FWD, there were no associations with IPP (P≥0.051) or days missed (P≥0.083), but general IIR was greater in CENT than LAT/FWD (8.67 vs. 6.12 injuries/1000h, P=0.047).

CONCLUSIONS

ASP playing position was not associated with IPP or days missed but the higher general, soft-tissue and ligament/tendon IIR in CD suggests this position warrants specific attention regarding injury prevention strategies. These novel findings highlight the importance of including training/match exposure when investigating the influence of playing position on injury in ASP.

Monitoring Postmatch Fatigue During a Competitive Season in Elite Youth Soccer Players

CONTEXT

Countermovement jump (CMJ) and perceived wellness measures are useful for monitoring fatigue. Fatigue indicators should simultaneously show sensitivity to previous load and demonstrate influence on subsequent physical output; however, these factors have not been examined.

OBJECTIVE

To explore the efficacy of CMJ and wellness measures to both detect postmatch fatigue and predict subsequent physical match output in elite youth soccer players.

DESIGN

Cross-sectional study.

PATIENTS OR OTHER PARTICIPANTS

Sixteen soccer players (18 ± 1 years) from 36 English Football League Youth Alliance League fixtures.

MAIN OUTCOME MEASURE(S)

Physical match outputs (total distance, high-speed running, very high-speed running, and accelerations and decelerations [AD]) were recorded using a 10-Hz global positioning system and 200-Hz accelerometer device during competitive match play. The CMJ height and perceived wellness were assessed weekly and daily, respectively, as indirect indicators of fatigue. Four subunits of wellness (perceived soreness, energy, general stress, and sleep) were measured using customized psychometric questionnaires.

RESULTS

Simple linear regression showed that match AD predicted energy (R2 = 0.08, P = .001), stress (R2 = 0.09, P < .001), and total wellness (R2 = 0.06, P = .002) at 2 days postmatch. The CMJ (R2 = 0.05, P = .002), stress (R2 = 0.08, P < .001), sleep (R2 = 0.03, P = .034), and total wellness (R2 = 0.05, P = .006) measures at 5 days prematch predicted AD during the subsequent match.

CONCLUSIONS

The CMJ and wellness measures may be useful for detecting postmatch fatigue. Wellness scores, but not CMJ, at 5 days prematch influenced subsequent match output and therefore may be used to plan and periodize training for the upcoming microcycle.

Test-Retest Reliability of the Isometric Soleus Strength Test in Elite Male Academy Footballers

BACKGROUND

Currently there is no reliability data available for the isometric soleus strength test (ISST), commonly used as a monitoring tool in elite football settings. Isometric strength testing for other muscle groups, most notably the hamstrings, is utilized to identify injury risk and readiness to train/play. To profile athletes efficiently, performance practitioners require optimal measures that are reliable. The aim of this study was to investigate the test-retest reliability of the isometric strength test of the soleus and propose a standardized protocol for its use within an elite male football population.

STUDY DESIGN

Test-retest reliability single cohort study.

METHODS

Thirty elite male footballers (age = 22.8±5.0 years, height = 180.0±0.08 cm, weight = 70.57±4.0 kg) performed the ISST, through three maximum 3-second hold efforts with one minute rest between repetitions and 48 hours between tests, in each test. The test was performed mid-competitive season. All data bilaterally were checked for normality using the Shapiro-Wilk test before a Pearson's Correlations and Bland-Altman's analyses were performed.

RESULTS

Test-retest reliability demonstrated high reliability for ISST bilaterally (Right: r = 0.89; Left: r = 0.79, p<0.05). The standard error of measurement (SEM) (%) was 9.09 - 12.47% and minimal detectable change (MDC) was 25.19 - 34.56 (N) for Peak Force (PF) measures of the ISST. Bilateral levels of agreement were found to be +/- 2 standard deviations (SD) of the interval of agreement bilaterally for ISST (Levels of agreement (LOA): Right: Upper 352.49 - Lower -494.76; Left: Upper 523.82 - Lower -591.30. Bilaterally no significant difference was detected between values (Right: p=0.09, CI: -153.21-10.95; Left: p=0.52, CI: -139.81-72.33).

CONCLUSION

The results of this study demonstrate high reliability for the ISST. The ISST displays a high test-retest reliability for assessing PF characteristics of the soleus in elite male academy footballers. This test may be beneficial for performance practitioners for profiling soleus function of athletes.

Individual-based Creatine Kinase Reference Values in Response to Soccer Match-play

The aim of the present study was to determine the creatine kinase reference limits for professional soccer players based on their own normal post-match response. The creatine kinase concentration was analyzed in response to official matches in 25 players throughout a 3-year period. Samples were obtained between 36-43 hours following 70 professional soccer matches and corresponded to 19.1±12.1 [range: 6-49] samples per player. Absolute reference limits were calculated as 2.5^th and 97.5^th percentile of the samples collected. Creatine kinase values were also represented as a percentage change from the individual's season mean and represented by 90^th, 95^th and 97.5^th percentiles. The absolute reference limits for creatine kinase concentration calculated as 97.5^th and 2.5^th percentiles were 1480 U.L^-1 and 115.8 U.L^-1, respectively. The percentage change from the individual's season mean was 97.45±35.92% and players were in the 90^th, 95^th and 97.5^th percentiles when the percentages of these differences were 50.01, 66.7, and 71.34% higher than player's season mean response, respectively. The data allowed us to determine whether the creatine kinase response is typical or if it is indicative of a higher than normal creatine kinase elevation and could be used as a practical guide for detection of muscle overload, following professional soccer match-play.

Variation in Physical Performance of Futsal Players During Congested Fixtures

PURPOSE

To investigate the match-to-match variation of physical performance during official congested fixtures in elite futsal players.

METHODS

Physical performance was measured by external and internal load metrics in 12 elite male futsal players. Two periods with 3 matches within 4 days were analyzed. The variation in physical performance of the players during matches was analyzed using the latent growth curve modeling that estimated interindividual and intraindividual growth paths.

RESULTS

Playing time had a significant effect on physical performance growth with significant paths of interindividual and intraindividual variability. Players who competed for more time revealed lower initial levels (ie, first match) of total distance covered (β = -0.62), high-speed running (β = -0.18), accelerations (β = -0.31), decelerations (β = -0.44), and session rate of perceived exertion (β = 0.81) than players who competed for less time (P < .05). In addition, players who competed for more time revealed higher increases in total distance covered (β = 0.47), high-speed running (β = 0.16), and session rate of perceived exertion (β = 0.66) and lower increases in accelerations (β = -0.21) and decelerations (β = -0.58) than players who competed for less time from the first to the third match (P < .05).

CONCLUSIONS

Congested fixtures did not affect physical performance in elite futsal players. Playing time showed to be a key performance factor. There was a considerable heterogeneity in the responsiveness to physical performance over congested fixtures, suggesting an analysis of individual variability to evaluate real changes in match performance, training intensity, and workload.

Running Performance and Hormonal, Maturity and Physical Variables in Starting and Non-Starting Elite U14 Soccer Players During a Congested Match Schedule

This study examined changes in match running performance (MRP) in Under-14 soccer players (13.5 ± 0.7 yrs) during a congested match schedule (CMS) (4 matches played within a 5-day period). It also examined the difference in salivary testosterone (sT) concentration, somatic maturation, jumping tests, and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) between the players selected to play (SLG; group who participated in all matches) and players non-selected to play (NSG). A significant difference was observed for the frequency of decelerations (DEC) across matches (match 4 vs. matches 1, 2 and 3; p = 0.05; partial ƞ² = 0.20). No difference between matches was observed for total running distance (TRD), high-speed running distance (HSRD), and frequency of accelerations (ACC) (p > 0.05). A wide range for within-player coefficient of variation (CV) values was observed for all MRP variables (range: 10.5 = TRD to 30.6 = HSRD). No difference between SLG and NSG for any of the assessed variables was observed (p > 0.05). The findings suggest that DEC was the most pertinent variable for monitoring changes in MRP during the CMS. In addition, at an elite youth soccer level, the biological maturity and fitness might not influence selection to play.

Seasonal Changes and Relationships in Training Loads, Neuromuscular Performance, and Recovery and Stress State in Competitive Female Soccer Players

Background: The purpose of this study was to examine seasonal changes in training load (TL), neuromuscular performance, subjective recovery, and stress state, and to investigate the relationships between acute and chronic TL and neuromuscular performance in competitive female soccer players.

Methods: Nine competitive female soccer players (20.0 ± 1.7 years; 60.3 ± 6.3 kg; 164.0 ± 5.8 cm) completed the Short Recovery and Stress Scale and the countermovement jump (CMJ) with polyvinyl chloride pipe (CMJ0) and 20 kg barbell (CMJ20) at 2–3 h before 1st match (NC₁), 6th match (NC₂), 9th match (C₁), and 15th match (C₂) of the competitive season. TL included total distance, high-speed running, and PlayerLoad. Acute and chronic TL was calculated by using the average of 2 days (D₂), 7 days (D₇), and 21 days (D₂₁) prior to four different match play.

Results: Significant decreases were found from NC₁ to C₁ in D₇ total distance [p = 0.03, Cohen's effect size (d_z) = 1.40]. D₇ total distance and PlayerLoad significantly decreased from NC to C₁ and C₂ (p = 0.001–0.01, d_z = 1.40–1.72). Significant increases were observed from NC₁ to C₁ in CMJ0 jump height (p = 0.03, d_z = 1.40), (p = 0.021, d_z = 1.44), and peak power (p = 0.03, d_z = 1.32). Significant negative correlations were observed for D₇ total distance and CMJ0 jump height (p = 0.02, r = 0.79) and peak power (p = 0.03, r = 0.71) at C₂, while significant positive correlations were observed at C₁ for D₇ PlayerLoad and CMJ0 jump height (p = 0.02, r = 0.80).

Conclusion: Polyvinyl chloride pipe (CMJ0) jump height and peak power may increase from preseason to the midcompetitive season. Seasonal variations may affect the relationships between D₇ TL and CMJ0 performance.

Influence of Well-Being Indices and Recovery State on the Technical and Physiological Aspects of Play During Small-Sided Games

ABSTRACT

Selmi, O, Gonçalves, B, Levitt, DE, Ouergui, I, Sampaio, J, and Bouassida, A. Influence of well-being indices and recovery state on the technical and physiological aspects of play during small-sided games. J Strength Cond Res 35(10): 2802-2809, 2021-Soccer players performing at high level are frequently exposed to periods of intense training, which can induce substantial stress and fatigue. These high-intensity stimuli likely lead to a lower state of well-being and poor recovery and, consequently, may affect players' performance. This study aimed to assess the influence of well-being indices (i.e., self-ratings of sleep, stress, fatigue, and delayed onset muscle soreness [DOMS]) and the total quality of recovery (TQR) on technical and physiological measures during soccer small-sided games (SSGs). Twenty male professional soccer players (age: 25.1 ± 1.0 years) performed four 25-minute SSG sessions. Well-being indices were collected before each SSG-session. Heart rate was continuously measured throughout each session, and the ratings of perceived exertion and blood lactate concentration were collected after each SSG. A hierarchical cluster analysis was performed across variables and cases to identify associations between variables and variability in players' responses between sessions. No significant correlations were found between well-being indices, TQR and physiological parameters. Total quality recovery was positively correlated with successful pass % (r = 0.27) and interceptions (r = 0.25) and negatively correlated with lost balls (r = -0.25). Fatigue and DOMS were negatively correlated with tackles (r = -0.29, r = -0.28, respectively), successful pass % (r = -0.58, r = -0.55, respectively) and interceptions (r = -0.25, r = -0.27, respectively), and positively correlated with lost balls (r = 0.32, r = 0.28, respectively). Results provide an alternative and complementary method to understand training responses and can be an objective tool to help create subgroups in training for optimizing performance. This study demonstrates the efficacy and utility of using simple well-being and recovery measures to help coaches monitor athlete readiness.

Weekly Variations of Short-Duration Maximal Jumping Performance in Soccer Players: Exploring Relationships With Accumulated Training Load and Match Demands

Purpose: The aim of this study was 2-fold: (1) to analyze variations of short-duration maximal jumping performance in players exposed to a match and those who were not and (2) to analyze the relationships between changes in the short-duration maximal jumping performance and different accumulated training load and match demands measures.

Methods: Twenty-four professional soccer players (age: 20.3 ± 1.7 years) were monitored daily for their training load and match demands over 6 weeks. In addition, they performed a weekly short-duration maximal jumping performance test (72 h after the last match).

Results: Negative moderate correlations were found between percentage of change of countermovement jump (CMJ) height and Acummulated training load (ATL) of total distance (TD), high metabolic load (HML), accelerations (ACC), and decelerations (DEC) (r = −0.38, p = 0.004; r = −0.33, p = 0.013; r = −0.39, p = 0.003; and r = −0.30, p = 0.026). No correlations were found for match load (ML). TD, HML, ACC, and DCC (r = 0.27, r = 0.25, r = 0.31, and r = 0.22, respectively) were used to predict the percentage of change of CMJ height.

Conclusion: Match participation has negative effects on CMJ performance. The ATL of HML, ACC, DCC, and TD have a significant influence on both CMJ measures changes. Also, the ATL values of those metrics are the best predictors of the percentage changes of CMJ performance.

Effects of Interlimb Asymmetries on Acceleration and Change of Direction Speed: A Between-Sport Comparison of Professional Soccer and Cricket Athletes

ABSTRACT

Bishop, C, Read, P, Brazier, J, Jarvis, P, Chavda, S, Bromley, T, and Turner, A. Effects of interlimb asymmetries on acceleration and change of direction speed: a between-sport comparison of professional soccer and cricket athletes. J Strength Cond Res 35(8): 2095-2101, 2021-The first aim of this study was to quantify and compare asymmetries among professional soccer and cricket athletes. The second aim was to examine the association between asymmetries and performance within both groups. Professional soccer (n = 18) and cricket (n = 23) athletes performed single-leg countermovement jumps, single-leg drop jumps (SLDJs), a 10-m sprint, and 505 change of direction speed (CODS) tests. Interlimb asymmetries were calculated as a standard percentage difference, Mann-Whitney U tests conducted to establish systematic bias between groups, and Spearman's r correlations used to establish the relationship between asymmetry scores and speed and CODS performance. Soccer athletes sprinted faster, jumped higher, and had a greater reactive strength index (RSI) score than cricket athletes (p < 0.05). However, cricketers showed reduced ground contact times compared with footballers during the SLDJ (p < 0.05). The cricket group showed significantly greater jump height (asymmetry = 11.49 vs. 6.51%; p = 0.015) and RSI (asymmetry = 10.37 vs. 5.95%; p = 0.014) asymmetries compared with soccer players. These metrics were also associated with slower 505 times in the cricket group only (r = 0.56 -0.74; p < 0.01). These results show that between-limb asymmetries exhibit no association with speed and CODS in elite soccer players but are associated with reduced CODS in elite cricketers. Thus, the reduction of interlimb asymmetries may be of greater consideration when working with cricket vs. soccer athletes.

Motion Analysis of Match Play in U14 Male Soccer Players and the Influence of Position, Competitive Level and Contextual Variables

This study aimed to investigate match running performance in U14 male soccer players in Norway, and the influence of position, competitive level and contextual factors on running performance. Locomotion was monitored in 64 different U14 players during 23 official matches. Matches were played at two different competitive levels: U14 elite level (n = 7) and U14 sub-elite level (n = 16). The inclusion criterion was completed match halves played in the same playing position. The variables’ influence on match running performance was assessed using mixed-effect models, pairwise comparisons with Bonferroni correction, and effect size. The results showed that the U14 players, on average, moved 7645 ± 840 m during a match, of which 1730 ± 681 m (22.6%) included high-intensity running (HIR, 13.5–18.5 km·h⁻¹) and sprinting (>18.5 km·h⁻¹). Wide midfielders (WM) and fullbacks (FB) covered the greatest sprint distance (569 ± 40 m) and, in addition to the centre midfield position (CM), also covered the greatest total distance (TD) (8014 ± 140 m) and HIR distance (1446 ± 64 m). Centre forwards (CF) performed significantly more accelerations (49.5 ± 3.8) compared other positions. TD (7952 ± 120 m vs. 7590 ± 94 m) and HIR (1432 ± 57 m vs. 1236 ± 43 m) were greater in U14 elite-level matches compared with sub-elite matches. Greater TD and sprint distances were performed in home matches, but, on the other hand, more accelerations and decelerations were performed in matches played away or in neutral locations. Significantly higher TD, HIR and sprinting distances were also found in lost or drawn matches. In conclusion, physical performance during matches is highly related to playing position, and wide positions seem to be the most physically demanding. Further, competitive level and contextual match variables are associated with players’ running performance.

Automated Classification of Changes of Direction in Soccer Using Inertial Measurement Units

Changes of direction (COD) are an important aspect of soccer match play. Understanding the physiological and biomechanical demands on players in games allows sports scientists to effectively train and rehabilitate soccer players. COD are conventionally recorded using manually annotated time-motion video analysis which is highly time consuming, so more time-efficient approaches are required. The aim was to develop an automated classification model based on multi-sensor player tracking device data to detect COD > 45°. Video analysis data and individual multi-sensor player tracking data (GPS, accelerometer, gyroscopic) for 23 academy-level soccer players were used. A novel 'GPS-COD Angle' variable was developed and used in model training; along with 24 GPS-derived, gyroscope and accelerometer variables. Video annotation was the ground truth indicator of occurrence of COD > 45°. The random forest classifier using the full set of features demonstrated the highest accuracy (AUROC = 0.957, 95% CI = 0.956-0.958, Sensitivity = 0.941, Specificity = 0.772. To balance sensitivity and specificity, model parameters were optimised resulting in a value of 0.889 for both metrics. Similarly high levels of accuracy were observed for random forest models trained using a reduced set of features, accelerometer-derived variables only, and gyroscope-derived variables only. These results point to the potential effectiveness of the novel methodology implemented in automatically identifying COD in soccer players.

Jumping Asymmetries Are Associated With Speed, Change of Direction Speed, and Jump Performance in Elite Academy Soccer Players

ABSTRACT

Bishop, C, Brashill, C, Abbott, W, Read, P, Lake, J, and Turner, A. Jumping asymmetries are associated with speed, change of direction speed, and jump performance in elite academy soccer players. J Strength Cond Res 35(7): 1841-1847, 2021-The aim of this study was to establish interlimb asymmetries across different age groups in elite academy male soccer players and to examine any relationships between asymmetry and measures of physical performance. Fifty-one players from an English Premier League soccer academy were split into under-23 (n = 21), under-18 (n = 14), and under-16 (n = 16) groups and performed bilateral and unilateral countermovement jumps, 5-, 10-, and 20-m sprints, and a 505 change of direction speed tests. All tests showed low variability (coefficient of variation ≤ 2.5%) and good to excellent reliability (intraclass correlation coefficient = 0.80-0.99). A 1-way analysis of variance showed that the under-23 group was significantly faster than the under-16 group during the 20-m sprint (2.90 vs. 2.98 s; p = 0.02; effect size = 0.94). No other significant differences were present between groups. Interlimb asymmetry was quantified from the single-leg countermovement jump, and no significant differences in the magnitude of asymmetry were present between groups. However, multiple significant correlations were present in each age group between asymmetry and physical performance tests, all of which were indicative of reduced athletic performance. Results from this study show that although interlimb asymmetry scores are comparable across age groups in elite academy soccer players, differences as low as 5% are associated with reduced physical performance during jumping, sprinting, and change of direction speed tasks. This study suggests the importance of monitoring jump height asymmetries in elite academy soccer players.

The Quantification of Acceleration Events in Elite Team Sport: a Systematic Review

BACKGROUND

Wearable tracking devices are commonly utilised to quantify the external acceleration load of team sport athletes during training and competition. The ability to accelerate is an important attribute for athletes in many team sports. However, there are many different acceleration metrics that exist in team sport research. This review aimed to provide researchers and practitioners with a clear reporting framework on acceleration variables by outlining the different metrics and calculation processes that have been adopted to quantify acceleration loads in team sport research.

METHODS

A systematic review of three electronic databases (CINAHL, MEDLINE, SPORTDiscus), was performed to identify peer-reviewed studies that published external acceleration load in elite team sports during training and/or competition. Articles published between January 2010 and April 2020 were identified using Boolean search phrases in relation to team sports (population), acceleration/deceleration (comparators), and competition and/or training (outcome). The included studies were required to present external acceleration and/or deceleration load (of any magnitude) from able-bodied athletes (mean age ≥ 18 years) via wearable technologies.

RESULTS

A total of 124 research articles qualified for inclusion. In total, 113/124 studies utilised GPS/GNSS technology to outline the external acceleration load of athletes. Count-based metrics of acceleration were predominant of all metrics in this review (72%). There was a lack of information surrounding the calculation process of acceleration with 13% of studies specifying the filter used in the processing of athlete data, whilst 32% outlined the minimum effort duration (MED). Markers of GPS/GNSS data quality, including horizontal dilution of precision (HDOP) and the average number of satellites connected, were outlined in 24% and 27% of studies respectively.

CONCLUSIONS

Team sport research has predominantly quantified external acceleration load in training and competition with count-based metrics. Despite the influence of data filtering processes and MEDs upon acceleration, this information is largely omitted from team sport research. Future research that outlines acceleration load should present filtering processes, MEDs, HDOP, and the number of connected satellites. For GPS/GNSS systems, satellite planning tools should document evidence of available satellites for data collection to analyse tracking device performance. The development of a consistent acceleration filtering method should be established to promote consistency in the research of external athlete acceleration loads.

Perceptual and Biochemical Responses in Relation to Different Match-Day +2 Training Interventions in Soccer Players

The aim of this study was to examine the impact of two different post-match training interventions on the subsequent recovery of perceptual and biochemical parameters after the game. In a crossover design, eight sub-elite players underwent a soccer-specific training (SST) and an active recovery (AR) regimen on the second day after a match (+48 h). Muscle soreness as well as muscle damage (creatine kinase, CK), inflammatory (C-reactive protein and interleukin 6), immunological (e.g., lymphocytes, neutrophils, and monocytes), and endocrine (cortisol) markers were obtained at baseline (-72 h), immediately after (0 h), and 72 h post-match (+72 h). AR promoted a higher restoration of muscle soreness values (P = 0.004, η2 p = 0.49) together with a better restoration of CK within 72 h post-match compared with SST (P = 0.04, η2 p = 0.36). Conversely, no significant (P > 0.05, η2 p < 0.91) differences were observed in the recovery timeframe of inflammatory, immunological, and endocrine responses between SST and AR. Overall, AR elicited a quicker muscle soreness and CK restoration compared to SST intervention at 72 h post-match. Such information provides novel evidence-based findings on the appropriateness of different recovery strategies and may aid to improve the practitioners' decision-making process when two consecutive games are played within 3 days.

Does Eligibility Classification Matter? Tracking Cardiac Autonomic Function during a Collegiate Soccer Season

The current study examined differences in heart rate (HR) variability (HRV) across student-athlete eligibility classifications within a men’s soccer team. The study also aimed to identify any differences in HRV while competing at home or away. Data collection covered an entire collegiate season, commencing in the preseason and concluding upon elimination from the NCAA Soccer tournament. Comparisons of HR and HRV, paired with self-reported subjective measures, were documented between student-athlete eligibility classifications, home versus away games, and based on soccer position (forward, midfielder, defender, goalkeeper). HR and HRV were similar based on student-athlete eligibility. Heart rate exhibited a small, but statistically significant decrease (β = −1.7 bpm (95% CI: −2.9, 0.57), p = 0.003) for the away games relative to home. HRV showed a statistically significant increase in the away game setting (β = 2.1 (95% CI: 0.78, 3.38), p = 0.002). No difference in HRV was observed across eligibility classification. This lack of difference may be attributed to a different perception of stress amongst male athletes. Athletes also exhibited a reduced HRV at home, likely as an indication of their readiness to compete paired with an increased self-confidence, given there was no difference in any subjective measures of mood or stress or between games played away or at home.

Neuromuscular, Endocrine, and Perceptual Recovery After a Youth American Football Game

ABSTRACT

Davis, JK, Wolfe, AS, Basham, SA, Freese, EC, and De Chavez, PJD. Neuromuscular, endocrine, and perceptual recovery after a youth American football game. J Strength Cond Res 35(5): 1317-1325, 2021-American football is a high-intensity intermittent sport consisting of various movements and repeated collisions which highlights the importance of adequate recovery from a game to prepare for the next competition. Therefore, the purpose of this study was to determine the time course of recovery markers after a youth American football game. Thirteen male American football youth players were monitored for 7 days after a single football game. Baseline measures were taken 28 hours pregame for lower-body neuromuscular function by countermovement jumps (CMJs) to determine peak power (PP), jump height (JH), flight time (FT), and takeoff velocity (TOV). Saliva was analyzed for cortisol, testosterone, and C-reactive protein (CRP). Perceptual recovery was assessed by the modified profile of mood states (POMS), perceived recovery status (PRS), and a daily wellness questionnaire. These measures were repeated immediately postgame (30 minutes) and at 20, 44, 68, 92, 116, and 140 hours postgame. Compared with baseline values, there was a significant decrease (p < 0.05) in CMJ PP, JH, and TOV up to 68 hours postgame and FT 44 hours postgame. No significant difference existed among time points for salivary testosterone and CRP. Cortisol levels significantly increased postgame compared with baseline (p < 0.05). Total mood disturbance, assessed by POMS, and daily wellness markers for energy were significantly decreased (p < 0.05), whereas daily wellness markers for soreness were significantly increased (p < 0.05) immediately after the game. Players exhibited a significant decrease in PRS up to 44 hours postgame (p < 0.05), similar to the decrease in neuromuscular function. Neuromuscular function and PRS are impaired for up to 44-68 h postgame.

Biomechanical Determinants of Performance and Injury Risk During Cutting: A Performance-Injury Conflict?

BACKGROUND

Most cutting biomechanical studies investigate performance and knee joint load determinants independently. This is surprising because cutting is an important action linked to performance and non-contact anterior cruciate ligament (ACL) injuries. The aim of this study was to investigate the relationship between cutting biomechanics and cutting performance (completion time, ground contact time [GCT], exit velocity) and surrogates of non-contact ACL injury risk (knee abduction [KAM] and internal rotation [KIRM] moments) during 90° cutting.

DESIGN

Mixed, cross-sectional study following an associative design. 61 males from multidirectional sports performed six 90° pre-planned cutting trials, whereby lower-limb and trunk kinetics and kinematics were evaluated using three-dimensional (3D) motion and ground reaction force analysis over the penultimate (PFC) and final foot contact (FFC). Pearson's and Spearman's correlations were used to explore the relationships between biomechanical variables and cutting performance and injury risk variables. Stepwise regression analysis was also performed.

RESULTS

Faster cutting performance was associated (p ≤ 0.05) with greater centre of mass (COM) velocities at key instances of the cut (r or ρ = 0.533-0.752), greater peak and mean propulsive forces (r or ρ = 0.449-0.651), shorter FFC GCTs (r or ρ = 0.569-0.581), greater FFC and PFC braking forces (r = 0.430-0.551), smaller hip and knee flexion range of motion (r or ρ = 0.406-0.670), greater knee flexion moments (KFMs) (r = 0.482), and greater internal foot progression angles (r = - 0.411). Stepwise multiple regression analysis revealed that exit velocity, peak resultant propulsive force, PFC mean horizontal braking force, and initial foot progression angle together could explain 64% (r = 0.801, adjusted 61.6%, p = 0.048) of the variation in completion time. Greater peak KAMs were associated with greater COM velocities at key instances of the cut (r or ρ = - 0.491 to - 0.551), greater peak knee abduction angles (KAA) (r = - 0.468), and greater FFC braking forces (r = 0.434-0.497). Incidentally, faster completion times were associated with greater peak KAMs (r = - 0.412) and KIRMs (r = 0.539). Stepwise multiple regression analysis revealed that FFC mean vertical braking force and peak KAA together could explain 43% (r = 0.652, adjusted 40.6%, p < 0.001) of the variation peak KAM.

CONCLUSION

Techniques and mechanics associated with faster cutting (i.e. faster COM velocities, greater FFC braking forces in short GCTs, greater KFMs, smaller hip and knee flexion, and greater internal foot progression angles) are in direct conflict with safer cutting mechanics (i.e. reduced knee joint loading, thus ACL injury risk), and support the "performance-injury conflict" concept during cutting. Practitioners should be conscious of this conflict when instructing cutting techniques to optimise performance while minimising knee joint loading, and should, therefore, ensure that their athletes have the physical capacity (i.e. neuromuscular control, co-contraction, and rapid force production) to tolerate and support the knee joint loading during cutting.

Acute Effects of Match-Play on Neuromuscular and Subjective Recovery and Stress State in Division I Collegiate Female Soccer Players

ABSTRACT

Ishida, A, Bazyler, CD, Sayers, AL, Mizuguchi, S, and Gentles, JA. Acute effects of match-play on neuromuscular and subjective recovery and stress state in Division I collegiate female soccer players. J Strength Cond Res 35(4): 976-982, 2021-The purpose of this study was to investigate acute effects of match-play on neuromuscular performance and subjective recovery and stress state and the relationship between training load (TL) and changes in neuromuscular performance in female soccer players. Twelve National Collegiate Athlete Association Division I players participated (20.7 ± 2.3 years; 64.4 ± 7.2 kg; 164.5 ± 6.0 cm) and completed countermovement jump (CMJ) at 0 kg (CMJ0) and 20 kg (CMJ20) and the Short Recovery Stress Scale (SRSS) at 3 hours pre-match (Pre), 12 hours post-match (Post12), and 38 hours post-match (Post38). Countermovement jump variables included body mass, jump height (JH), modified reactive strength index (RSI), peak force (PF), relative PF, eccentric impulse, concentric impulse (CI), peak power (PP), relative PP (RPP), eccentric average PP, and concentric average power (CAP). The SRSS consists of 4 Stress Scales (SSs) and 4 Recovery Scales (RSs). Training loads included total distance, total PlayerLoad, high-speed running, and session ratings of perceived exertion. Significant moderate to large decreases were observed from Pre to Post12 in JH, RSI, CI, PP, RPP, and CAP in CMJ0 and CMJ20 (p < 0.05, effect size [ES] = 0.63-1.35). Significant changes were observed from Pre to Post12 in all RSs (p < 0.05, ES = 0.65-0.79) and 3 SSs (p < 0.05, ES = 0.71-0.77). Significant correlations were observed between CMJ20 PP from Pre to Post12 and all TLs (p < 0.05, r = -0.58 to -0.68). CMJ0 and CMJ20 JH and PP may indicate acute neuromuscular changes after match-play. The magnitude of CMJ20 PP decrements from Pre to Post12 may be affected by soccer match-play volumes.

Effect of a Shock Micro-Cycle on Biochemical Markers in University Soccer Players

This study aimed to examine various biochemical biomarkers changes during a shock micro-cycle in soccer players from a university team. The study had 22 players (age: 22 ± 3 years; body mass: 68.6 ± 7.1 kg; height: 1.73 ± 0.07 m). The study measured total cholesterol (TC), triglycerides (TG), cholesterol linked to high-density lipoproteins (HDL), low-density lipoproteins (LDL), very low density lipoproteins (VLDL), arterial index (AI), creatine kinase (CK), glutamate-oxalacetate-transaminase (GOT), glutamate-pyruvate-transaminase (GPT), creatinine (Cr), catalase (CAT), superoxide dismutase (SOD), cytokines IL6 and TNFα, total antioxidant capacity (Cap antiox tot), hemolysis percentage and glomerular filtration rate (GFR); measurements were conducted during a shock micro-cycle. The lipid profile variables had no statistical significance when compared on day 1 with day 14. Except for TNFα, the other biomarkers compared with day one had progressive increments until day seven, with a subsequent reduction on day 14; however, none of the biomarkers returned to baseline values despite this decrease. The data shown herein suggest the need to research these biomarkers in distinct types of mesocycles, exercise, intensity, load, and duration to diminish fatigue and improve athlete performance.

Urinary N-Terminal Fragment of Titin Reflects Muscle Damage After a Soccer Match in Male Collegiate Soccer Players

ABSTRACT

Tanabe, Y, Shimizu, K, Kondo, E, Yasumatsu, M, Nakamura, D, Sagayama, H, and Takahashi, H. Urinary N-terminal fragment of titin reflects muscle damage after a soccer match in male collegiate soccer players. J Strength Cond Res 35(2): 360-365, 2021-Previous studies have demonstrated that noninvasive urinary N-terminal fragment of titin (U-titin) concentration highly correlates with serum creatine kinase (CK) activity, a classic invasive muscle damage marker. This finding indicates that U-titin could be used to estimate muscle damage. However, these results were achieved using a laboratory-based eccentric exercise model. Therefore, it remains unclear whether U-titin is useful for evaluating muscle damage occurring in field sports events. As a result, we evaluated whether U-titin concentration closely relates to serum CK activity after a soccer match. Seventeen collegiate soccer players (age: 20 ± 1 year; height: 172 ± 6 cm; body mass: 65 ± 5 kg; Yo-Yo intermittent recovery test level 2, 1,135 ± 196 m) completed a test match (2 halves of 45 minutes separated by 15 minutes of normal half-time). U-titin concentration, serum CK activity, countermovement jump performance, and muscle soreness were assessed 2 hours before the match and 30 minutes, 24 hours, and 48 hours after the match. U-titin concentrations and CK activity similarly increased at 24 hours and returned to the baseline value at 48 hours after the match. Moreover, the percentage of changes in U-titin concentration from baseline after the match significantly and positively correlated with serum CK activity (r = 0.82, p < 0.05). These results suggest that the noninvasive marker U-titin can be used to assess muscle damage conditions in field sports events, such as soccer matches.

Are There Differences in Elite Youth Soccer Player Work Rate Profiles in Congested vs. Regular Match Schedules?

ABSTRACT

Zanetti, V, Carling, C, Aoki, MS, Bradley, PS, and Moreira, A. Are there differences in elite youth soccer player work rate profiles in congested vs. regular match schedules? J Strength Cond Res 35(2): 473-480, 2021-Official international tournaments in which youth soccer players participate can involve very congested schedules. Yet, no information regarding physical and technical match performance during congested vs. regular (noncongested) cycles is available. In this study, accelerations, decelerations, mean metabolic power (MP), and technical performance (offensive and defensive variables) were compared across very congested match (VCM; 10 international matches played over 3 successive days, including 2 days with 2 consecutive matches separated by a 4- to 5-hour interval) and 10 regular (noncongested match [NCM]) match periods in elite male Under 15 (U15, n = 11) and Under 17 (U17, n = 13) soccer players. Players wore a 15-Hz Global Positioning System unit with a 100-Hz triaxial accelerometer. The session rating of perceived exertion (RPE) were assessed 30 minutes after match. Results showed a higher number of accelerations per minute observed in VCM vs. NCM (U15; 2.27 ± 0.35 vs. 2.12 ± 0.23; effect size [ES] = 0.49; U17; 2.27 ± 0.41 vs. 2.01 ± 0.31; ES = 0.69). Decelerations per minute were higher during VCM (U15; 1.99 ± 0.27 vs. 1.84 ± 0.25; ES = 0.55; and U17; 1.98 ± 0.35 vs. 1.80 ± 0.27; ES = 0.56). Mean MP was higher in the VCM (U15; 0.42 ± 0.06 vs. 0.37 ± 0.02; ES = 1.08; U17; 0.46 ± 0.03 vs. 0.30 ± 0.03; ES = 1.94). Technical actions per minute were higher in the VCM for U17 (ES = 1.60 and 1.37, for offensive and defensive performance, respectively) but lower (during VCM) for U15 (ES = 3.59 and 0.28, for offensive and defensive performance). U15 reported a higher session RPE in the VCM (7.9 ± 0.5 AUs vs. 6.9 ± 0.5 AUs). The findings suggest that running activity in these youth players was unaffected overall in tournaments with congested schedules, and that the intensity of match-play was actually greater than in regular match schedules.

A New Foot-Mounted Inertial Measurement System in Soccer: Reliability and Comparison to Global Positioning Systems for Velocity Measurements During Team Sport Actions

The aims of this study were to i) compare a foot-mounted inertial system (PlayerMaker™) to three commercially available Global Positioning Systems (GPS) for measurement of velocity-based metrics during team sport movements and ii) evaluate the inter-unit reliability of the PlayerMaker™. Twelve soccer players completed a soccer simulation, whilst wearing a PlayerMaker™ and three GPS (GPS#1, #2 and #3). A sub-sample (n = 7) also wore two PlayerMaker™ systems concurrently. The PlayerMaker™ measured higher (p < 0.05) total distance (518 ± 15 m) compared to GPS#1 (488 ± 15 m), GPS#2 (486 ± 15 m), and GPS#3 (501 ± 14 m). This was explained by greater (p < 0.05) distances in the 1.5-3.5 m/s zone (356 ± 24 m vs. 326 ± 26 m vs. 324 ± 18 m vs. 335 ± 24 m) and the 3.51-5.5 m/s zone (64 ± 18 m vs. 35 ± 5 vs. 43 ± 8 m vs. 41 ± 8 m) between the PlayerMaker™, GPS#1, GPS#2 and GPS#3, respectively. The PlayerMaker™ recorded higher (p < 0.05) distances while changing speed. There were no systematic differences (p > 0.05) between the two PlayerMaker™ systems. The PlayerMaker™ is reliable and records higher velocity and distances compared to GPS.

Relationship Between the Session-RPE and External Measures of Training Load in Youth Soccer Training

Marynowicz, J, Kikut, K, Lango, M, Horna, D, and Andrzejewski, M. Relationship between the session-RPE and external measures of training load in youth soccer training. J Strength Cond Res 34(10): 2800-2804, 2020-The aim of this study was to identify the external training load (TL) markers (10 Hz Global Positioning System) that are most influential on the rating of perceived exertion (RPE) and session-RPE (sRPE) during youth soccer training. Data were collected from 18 youth soccer players during an 18-week in-season period. A total of 804 training observations were undertaken. We observed moderate to very large within-individual correlations between sRPE and measures of external load (r ranging from 0.36 to 0.76). Large, positive within-individual correlations were found between total covered distance, PlayerLoad, number of accelerations, and sRPE (r = 0.70, 0.64, and 0.62, respectively, p < 0.001). By contrast, small to moderate within-individual correlations were noted between RPE and measures of intensity (r ranging from 0.16 to 0.39). A moderate within-individual correlation was observed between high-speed running distance (HSR) per minute and RPE (r = 0.39, p < 0.001). The level of statistical significance was set at alpha = 0.05 for all tests. Two generalized estimating equation models were constructed, with RPE and sRPE as the response variables. The model identified by QIC for RPE contained 2 variables as follows: HSR per minute and distance in deceleration per minute, whereas sRPE was modeled with 3 predictors as follows: PlayerLoad, HSR, and distance in acceleration. The findings demonstrate that RPE does not reflect the intensity of a training session and that sRPE can be a useful, simple, and cost-effective tool for monitoring TL.

Effects of cumulative school soccer matches separated by 24-h or 48-h intervals on physical recovery status of U-19 players

Abstract This study aimed to evaluate the effects of cumulative school soccer matches separated by 24-h or 48-h intervals on the recovery status of U-19 players. Thirty-four school athletes (17.6 ± 1.1 years) who played in an U-19 school soccer competition (composed of one group with four teams and another group with three teams, followed by semifinals and final) were examined before three matches, which lasted 70 min. Seventeen athletes had a 24-h rest interval between each match (GGG group), while 18 athletes had a 48-h rest interval between the second and third matches (GG48hG group). Total Quality Recovery, countermovement jump, 10-m sprint, and maximum lumbar isometric strength were measured. The internal load of each match was calculated by the product of the session Rating of Perceived Exertion and match time. There was a 22% reduction in Total Quality Recovery (p< 0.001) and 12% in 10-m sprint performance (p< 0.001) before the third match in the GGG group, while the GG48hG group showed no changes for the same variables (p> 0.05). The countermovement jump decreased before the second match in both groups (GGG= 12% and GG48hG= 10%; p< 0.001), with no difference between groups (p> 0.05). In addition, both groups showed no changes in the isometric strength or the internal load match over the games (p> 0.05). Despite not providing complete muscle recovery, a 48-h interval between the second and third matches seems to have minimized the reduction of muscle performance due to consecutive matches.

Asymmetry Thresholds for Common Screening Tests and Their Effects on Jump Performance in Professional Soccer Players

CONTEXT

Arbitrary asymmetry thresholds are regularly used in professional soccer athletes, notwithstanding the sparse literature available to examine their prevalence.

OBJECTIVE

To establish normative and positional asymmetry values for commonly used screening tests and investigate their relationships with jumping performance.

DESIGN

Cross-sectional study.

SETTING

Elite soccer screening.

PATIENTS OR OTHER PARTICIPANTS

A total of 203 professional male soccer players.

MAIN OUTCOME MEASURE(S)

Bilateral and unilateral jumping; range of motion; and hamstrings (HAM), quadriceps (QUAD), and hip-adductor and -abductor strength tests were used to quantify asymmetry. Players were divided into 4 quartiles (Q1-Q4) based on the magnitude of their asymmetry for each test. Single composite scores were also developed to group tests by range of motion and HAM, QUAD, hip-adduction, and hip-abduction strength, and differences in jump performance were examined among players in each quartile.

RESULTS

Large variability (range = 5.2%-14.5%) was evident in asymmetry scores across the different tests and physical qualities. Forwards displayed greater asymmetry in concentric quadriceps and eccentric hip-abduction strength (P < .05). The HAM and QUAD composite scores indicated that Q4 players' jumps were shorter than those in other quartiles during a single-legged countermovement jump and 10-second hop (P < .05). No decrements in unilateral jump performance were shown among players in each quartile for range of motion or hip-adduction and -abduction strength, and no composite measures of asymmetry affected bilateral jump performance.

CONCLUSIONS

No single asymmetry threshold was present for all tests; the outcomes were task, variable, and population specific. Larger asymmetries in HAM and QUAD strength appeared to be detrimental to unilateral jump performance.

A Comparison of Bilateral vs. Unilateral-Biased Strength and Power Training Interventions on Measures of Physical Performance in Elite Youth Soccer Players

Stern, D, Gonzalo-Skok, O, Loturco, I, Turner, A, and Bishop, C. A comparison of bilateral vs. unilateral-biased strength and power training interventions on measures of physical performance in elite youth soccer players. J Strength Cond Res 34(8): 2105-2111, 2020-The aim of the present study was to compare the effects of bilateral and unilateral-biased strength and power training programs on measures of physical performance in male youth soccer players. Twenty-three elite youth players (age: 17.6 ± 1.2 years) were randomly assigned to either a unilateral (n = 11) or a bilateral (n = 12) group, who completed a strength and power intervention, twice per week for 6 weeks. The unilateral group completed rear foot elevated split squats (RFESS), single-leg countermovement jumps (SLCMJs), single-leg drop jumps (SLDJs), and single-leg broad jumps (SLBJs). The bilateral group intervention performed back squats, CMJs, drop jumps (DJ), and broad jumps (BJ). A 2 × 2 repeated measures analysis of variance showed no between-group differences. However, within-group differences were evident. The bilateral training group showed significant (p < 0.05) improvements in back squat strength (d = 1.27; %Δ = 26.01), RFESS strength (d = 1.64; %Δ = 23.34), BJ (d = 0.76; %Δ = 5.12), 10-m (d = -1.17; %Δ = 4.29), and 30-m (d = -0.88; %Δ = 2.10) performance. The unilateral group showed significant (p < 0.05) improvements in RFESS strength (d = 1.40; %Δ = 33.29), SLCMJ on the left leg (d = 0.76; %Δ = 9.84), SLBJ on the left leg (d = 0.97; %Δ = 6.50), 10 m (d = -1.50; %Δ = 5.20), and 505 on the right leg (d = -0.78; %Δ = 2.80). Standardized mean differences showed that bilateral training favored improvements in back squat strength and unilateral training favored improvements in RFESS strength, SLDJ on the right leg and 505 on the right leg. These results show that although both training interventions demonstrated trivial-to-large improvements in physical performance, the notion of training specificity was evident with unilateral training showing greater improvements in unilateral test measures.

Variability of professional soccer players' perceived match load after successive matches

This study analyses the differential perceived match load accumulated by professional soccer players depending on their: (a) participation in several consecutive official matches within the same week (Pre_Cup, Cup, and Post_Cup), and (b) total match participation time (i.e. 90 min, 70-90 min and < 70 min). Participants were 21 Spanish Second Division professional soccer players (M age = 27.1, SD = 3.3 years; M body height = 182.1, SD = 3.9 cm; M body mass = 75.8, SD = 5.14 kg). There were no significant differences (p > 0.05) in dRPE-ML among Pre_Cup, Cup and Post_Cup matches or in dRPE-ML between teams that took part in two or three official matches within the same week or three official matches in 2-4 consecutive weeks. The results suggest that participating in several matches in the same week does not increase accumulated perceived exertion for professional soccer players.

Post-match recovery of eccentric knee flexor strength in male professional football players

OBJECTIVES

This study aimed at verifying the effect of a football match on the eccentric knee flexor strength of male professional players along a 72-h period.

STUDY DESIGN

Quasi-experimental study.

SETTING

Football club facilities.

PARTICIPANTS

Fifteen players were assessed in four timepoints: 24 h before, immediately after, 48 h and 72 h after the match.

MAIN OUTCOME MEASURES

The eccentric knee flexor strength was assessed during the Nordic hamstring exercise execution.

RESULTS

Players presented a significant strength reduction immediately after match (Δ = 12%; p = 0.001; large effect size, d = 1.10), and did not recover their strength capacity within a 48 h-period (Δ = 6%; p = 0.011; moderate effect size, d = 0.57). At 72 h after the match, strength was similar to baseline levels (Δ = 3.5%; p = 0.122; small effect size, d = 0.34). Secondarily, individual response analysis considered a player 'fully recovered' when his strength deficit compared to the baseline measure was lower than the measurement coefficient of variation (i.e., <5%). Only 6 (40%) and 9 (60%) players were 'fully recovered' at 48 h and 72 h after the match, respectively.

CONCLUSION

Professional football players experienced an immediately post-match drop on the eccentric knee flexor strength, and significant strength deficits persisted for a 48-h period. Some players were not recovered at 72 h after the match.

Estudo prospectivo das lesões musculares em três temporadas consecutivas do Campeonato Brasileiro de Futebol

Objective  To perform a prospective evaluation of muscle injuries that occurred during the matches of series A and B of the Brazilian Men's Football Championship from 2016 to 2018.

Prospective  A prospective-cohort study with data collection regarding muscle injuries that occurred during the official matches of the first and second divisions of the Brazilian Men's Soccer Championship in the 2016, 2017 and 2018 seasons.

Results  The total number of muscle injuries was of 577 throughout the 3 seasons, with a gradual and annual reduction in the incidence of injuries (219 injuries in 2016, 195 in 2017, and 163 in 2018), with a statistically significant difference between the 2016 and 2018 seasons. Muscle injuries represented approximately 35% of the total lesions. The incidence of muscle injuries was of 7.66 per 1,000 hours of play. During the 3 seasons (2016 to 2018), the most common injury was of the hamstring muscle (41.1%, 40.5%, and 33.7% respectively). Wingers were the most affected players, and the most common injury severity scale was moderate (8 to 28 days). The moment of the match with the highest incidence of injuries was in the period between 61 and 75 minutes, with an index of 19.9%, with no statistical difference in relation to the other periods of the match.

Conclusion  There was an incidence of muscle injuries of 7.7 /1,000 h, and they occurred predominantly in home games, in defenders (wingers and centre-backs), with an average age of 28 years, mainly involving the hamstring muscles, with a moderate mean time of absence (8 to 28 days).

Relationship between Perceived Training Load, Well-Being Indices, Recovery State and Physical Enjoyment during Judo-Specific Training

This study investigated the relationship between well-being indices and the session rating of perceived exertion (session-RPE), recovery (TQR), and physical enjoyment (PE) during intensified, tapering phases of judo training. Sixty-one judo athletes (37 males, ranges 14-17 years, 159-172 cm, 51-67 kg) were randomly assigned to three experimental (i.e., randori, uchi-komi, running) and control groups (regular training). Experimental groups trained four times per week for 4 weeks of intensified training followed by 12 days of tapering. Session-RPE, well-being indices (i.e., sleep, stress, fatigue, delayed onset of muscle soreness (DOMS), Hooper index (HI)), and TQR were measured every session, whereas PE was recorded after intensified, tapering periods. Recovery (TQR) was negatively correlated with sleep, stress, fatigue, DOMS, HI, session-RPE in intensified period and was negatively correlated with sleep, stress, fatigue, DOMS, HI in tapering. Session-RPE was positively correlated with sleep, fatigue, DOMS, HI in intensified period and positively correlated with fatigue, DOMS in tapering. PE was negatively correlated with stress in intensified training. Enjoyment could be partially predicted by sleep only in intensified periods. Session-RPE could be partially predicted by TQR, fatigue during intensified periods and by sleep, and HI during tapering. Sleep, recovery state, pre-fatigue states, and HI are signals contributing to the enjoyment and internal intensity variability during training. Coaches can use these simple tools to monitor judo training.

Estimating Postmatch Fatigue in Soccer: The Effect of Individualization of Speed Thresholds on Perceived Recovery

PURPOSE

To investigate the effectiveness of different individualization methods of speed zones during match play to estimate postmatch perceptual recovery in soccer.

METHODS

Twelve players under the age of 19 y undertook field-based assessments to determine their maximal aerobic speed (MAS) and maximal sprint speed (MSS). External load (extracted from 10-Hz GPS over 10 official matches) was measured and classified into 4 categories as follows: low-speed running, moderate-speed running, high-speed running, and sprinting. Match running distribution into different speed zones was categorized using either MAS, MSS, MAS and MSS as measures of locomotor capacities, and absolute values. Players perceived recovery status was recorded immediately postmatch (Post) and 24 (G+24H) and 48 hours (G+48H) after each game.

RESULTS

Different individualization methods resulted in distinct match outputs in each locomotor category. Perceived recovery status was lower (P < .001) at Post (3.8 [1.32], 95% confidence interval [CI], 3.6 to 4.2), G+24H (5.2 [1.48], 95% CI, 4.9 to 5.6), and G+48H (6.0 [1.22], 95% CI, 5.7 to 6.3) compared with prematch values (7.1 [1.05], 95% CI, 6.8 to 7.3). The absolute perceived recovery-status score was better associated with high-speed running using the locomotor-capacities method at Post (β = -1.7, 95% CI, -3.2 to -0.22, P = .027), G+24H (β = -2.08, 95% CI, -3.22 to -0.95, P = .001), and G+48H (β = -1.32, 95% CI, -2.2 to -0.4, P = .004) compared with other individualization methods.

CONCLUSION

The authors' results suggest that locomotor capacities may better characterize the match intensity distribution (particularly for the high-speed running and sprinting categories) and should be preferred over MAS and MSS to estimate perceived recovery.

Changes in Perceived Exertion, Well-Being, and Recovery During Specific Judo Training: Impact of Training Period and Exercise Modality

The present study investigated the effect of intense and tapering training periods using different exercise modalities (i.e., Randori – grip dispute practice without throwing technique, Uchi-komi – technique repetition training, and sprinting) on rating of perceived exertion (RPE), well-being indices, recovery state, and physical enjoyment in judo athletes. Sixty-one adolescent male and female judo athletes (age: 15 ± 1 years) were randomly assigned to one of three experimental or one control groups. Experimental groups (Randori, Uchi-komi, and running) trained four times per week for 4 weeks of intense training (in addition to their usual technical-tactical judo training; control group underwent only such a training) followed by 12 days of tapering. RPE, well-being indices [i.e., sleep, stress, fatigue, and delayed onset muscle soreness (DOMS)], total quality of recovery (TQR), and physical enjoyment were measured every session. RPE, sleep, stress, fatigue, DOMS, Hooper index (HI; sum of wellbeing indices), and TQR were lower in the tapering compared with the intensified training period (P < 0.001). Moreover, the running group showed better values for sleep (P < 0.001), stress (P < 0.001), fatigue (P = 0.006), DOMS (P < 0.001), and HI (P < 0.001) in comparison with the other training groups, indicating a more negative state of wellbeing. The Randori and Uchi-komi groups showed higher values for TQR and physical enjoyment (both P < 0.001) than the running group, whereas RPE was lower in the control compared with all training groups (P < 0.001). Coaches should use more specific training modalities (i.e., Randori and Uchi-komi) during intensified training and should monitor well-being indices, RPE, and TQR during training periods. Moreover, for all variables, 12 days tapering period are beneficial for improving wellbeing and recovery after 4 weeks of intense training.

The effects of foam roll on perceptual and performance recovery during a futsal tournament

The present study investigated the efficacy of recovery by foam rolling (FR) on performance, psychological, and physiological parameters of futsal players in a simulated futsal tournament. In this randomized controlled trial design, four youth teams from Iran's national premier league participated in a simulated futsal tournament (five days, three matches). Sixteen youth futsal players from two teams (age: 19.1 ± 1.3 years old) were randomly distributed into two groups: (i) passive recovery (PR); and (ii) FR recovery. The FR recovery protocol consisted of five repetitions of 40 s separated by 20 s of rest on calf, quadriceps, hamstrings, and gluteus muscles 5 min after each match. The other group rested passively during the same period. The Yo-Yo intermittent recovery level 2, repeated sprint ability, vertical jump, and PRO agility tests were assessed pre- and post-tournament. Also, Hooper index (HI) and blood lactate concentrations were measured throughout matchdays. Data were analyzed by a repeated measure ANOVA and ANCOVA. Substantial improvements in HI on the second (ES:0.6) and third (ES:0.4) matchdays and faster lactate removal on the third (ES:0.3) matchday were observed in the FR group when compared to the PR group (p<0.05). Although FR recovery was slightly beneficial when compared to PR attenuated decrements in aerobic (-1.6%vs-9.7%) and anaerobic performance (-4.5%vs-1.3%), vertical jump (-1.6%vs-3.0%), and change of direction (-2.1%vs-4.3%), these effects were not statistically significant (p>0.05). The finding showed using FR during compact competitions expedites physical performance recovery, increases blood lactate clearance and leads to regenerate psychological characteristics. Therefore, along with other desirable recovery strategies, the use of FR could be recommended in short-term compacted futsal tournaments.

How did three consecutive matches with extra time affect physical performance? A case study of the 2018 football Men's World Cup

The purpose of this study was to ascertain the effect of playing three consecutive matches with extra time (ET) on the physical performance of selected Croatian players in their subsequent match, the final of the 2018 Men's World Cup in Russia. The case study consisted of 4 players on the Croatian national team (16 observations) who had played in all three matches up to 120 min. The consecutive full time matches (90 minutes) and extra time (30 minutes) were compared. The analysis was conducted using data collected by an advanced motion analysis system known as STATS and from interviews with the strength and conditioning coach of the Croatian national team. The recorded variables used were: total distance covered [m], distances covered [m] at intensity ranges of 20-25 km/h and above 25 km/h, and number of sprints performed. All the studied parameters systematically increased in each match up to 90 minutes of play, reached their maximum values in the semi-final and then decreased in the final match. Compared to the first extra time period, in the third extra time period the players covered twice as much distance with an intensity of 20-25 km/h and above 25 km/h, and recorded twice as many sprints. This investigation shows that players in central positions on the pitch are able to maintain or even increase high and very high intensity activity in three consecutive matches with extra time. These data complement the developing body of literature relating to the influence of accumulation of match play with extra time periods on high level players.

External Validity of the T-SAFT90: A Soccer Simulation Including Technical and Jumping Activities

PURPOSE

To examine the physiological, muscle-damage, endocrine, and immune responses to a modified soccer-simulation protocol to include technical and jumping activities characteristic of match play (the Technical Soccer-Specific Aerobic Field Test; T-SAFT90).

METHODS

Eighteen university players (age 23 [2] y, stature 175 [5] cm, body mass 74 [11] kg) performed the 90-minute protocol, with acute physiological responses monitored via heart rate, ratings of perceived exertion (6-20 scale), and body mass changes. Creatine kinase, myoglobin, cortisol, and leukocyte subset concentrations were measured at baseline, immediately (0 h), and 24 hours post T-SAFT90.

RESULTS

T-SAFT90 incurred an average heart rate equivalent to 87% (5%) of maximum, 16 (2) a.u. ratings of perceived exertion, and a 1.5% (1.0%) body mass deficit. Moderate to large proliferation of leukocyte subsets (P ≤ .01; leukocytes: 6.4-fold; neutrophils: 5.5-fold; lymphocytes: 2.0-fold) and increases in cortisol (2.3-fold) were observed at 0 hours (effect size = 1.13-3.52), each returning to baseline by 24 hours (P > .45; effect size = 0.05-0.50). Myoglobin peaked immediately post T-SAFT90 (4.8-fold), whereas creatine kinase (24 h: 6.0-fold) showed a delayed time course (both P ≤ .001; very large effects; effect size = 2.66 and 3.43, respectively).

CONCLUSIONS

The magnitude and time course of the physiological, immune, endocrine, and muscle-damage markers observed during and following T-SAFT90 are similar to values reported in match-play literature, demonstrating external validity of the simulation.

Muscle Damage During a Soccer World Cup Preparatory and Competition Period

PURPOSE

To report creatine kinase ([CK]) responses during a soccer World Cup preparatory and first-leg period and to determine the influence of aerobic fitness on postmatch [CK] responses.

METHODS

Eleven national-team players were analyzed in this study. A lactate threshold test was performed during the first 3 d, whereas fingertip blood was drawn most mornings (21 out of 30 d) for [CK] measurements. One-way repeated-measures analysis of variance was used for determining the effect of time on [CK] measurements, whereas Pearson correlation coefficient was used for assessing associations between the changes in [CK] and velocities associated with blood lactate concentrations of 2 (v2) and 4 mmol·L-1 (v4).

RESULTS

Peak [CK] concentrations were consistently reached on the first day after the match with values of 474 (261), 520 (419), and 460 (126) U·L-1 but with no significant differences between them. [CK] concentrations returned to prematch values (331 [201] U·L-1) on the second day after the match. The change in [CK] concentration between prematch and postmatch day was largely correlated (r = .614, P = .044) with v2.

CONCLUSIONS

Top-level soccer players display low levels of muscle damage during official tournaments, and they recover before the next match. Postmatch muscle damage is greater in players with higher aerobic endurance because this fitness quality enables them to execute high-intensity activities known to be a major contributor to muscle damage.

Field-based evaluation of hip adductor and abductor strength in professional male ice hockey players: Reference values and influencing factors

OBJECTIVES

To provide reference values and examine the influence of hip/groin pain on hip adductor and abductor strength in professional male ice hockey players, by using a straightforward 5-min procedure.

DESIGN

Cross-sectional study.

SETTING

On-field assessment of hip/groin muscle strength with dynamometry, together with the concomitant level of hip/groin pain with a visual analogue scale.

PARTICIPANTS

Professional male ice hockey players competing in the Swiss National League (n = 187).

MAIN OUTCOME MEASURES

Hip abductor strength, hip adductor strength and hip adductor:abductor ratio.

RESULTS

Reference values by playing position (goalkeepers, defenders and forwards) are provided for asymptomatic athletes. Players with hip/groin pain during adduction displayed lower hip adductor strength (p = 0.001) and hip adductor:abductor ratio (p = 0.012) than their symptom-free peers.

CONCLUSIONS

The presence of hip/groin pain during adductor testing may contribute to selective hip adductor weakness, whose cause-effect relation with possible groin problems remains to be demonstrated.

Deceleration, Acceleration, and Impacts Are Strong Contributors to Muscle Damage in Professional Australian Football

Gastin, PB, Hunkin, SL, Fahrner, B, and Robertson, S. Deceleration, acceleration, and impacts are strong contributors to muscle damage in professional Australian football. J Strength Cond Res 33(12): 3374-3383, 2019-The purpose of this study was to investigate the relationships between serum creatine kinase [CK], an indirect marker of muscle damage, and specific indices of match load in elite Australian football. Twenty-six professional players were assessed during a competitive Australian Football League (AFL) season. [CK] was collected 24-36 hours before match and 34-40 hours after match during 8 in-season rounds. An athlete-tracking technology was used to quantify match load. Generalized estimating equations and random forest models were constructed to determine the extent to which match-load indices and pre-match [CK] explained post-match [CK]. There was a 129 ± 152% increase in [CK] in response to AFL competition. Generalized estimating equations found that number of impacts >3g (p = 0.004) and game time (p = 0.016) were most strongly associated with post-match [CK]. Random forest, with considerably lower errors (130 vs. 316 U·L), found deceleration, acceleration, impacts >3g, and sprint distance to be the strongest predictors. Pre-match [CK] accounted for 11% of post-match [CK], and considerable interindividual and intraindividual variability existed in the data. Creatine kinase, an indicator of muscle damage, was considerably elevated as a result of AFL competition. Parametric and machine-learning analysis techniques found several indices of physical load associated with muscle damage during competition, with impacts >3g and high-intensity running variables as the strongest predictors. [CK] may be used as a global measure of muscle damage in field team sports such as AF, yet with some caution given cost, invasiveness, and inherent variability. Quantifying physical load and the responses to that load can guide athlete management decision-making and is best undertaken within a suite of practical, sport-specific measures, where data are interpreted individually and with an understanding of the limitations.

Effects of Soccer Match-Play on Unilateral Jumping and Interlimb Asymmetry: A Repeated-Measures Design

Bishop, C, Read, P, Stern, D, and Turner, A. Effects of soccer match-play on unilateral jumping and interlimb asymmetry: a repeated-measures design. J Strength Cond Res XX(X): 000-000, 2020-The aims of this study were two-fold: (a) determine the effects of repeated soccer match-play on unilateral jump performance and interlimb asymmetries and (b) examine associations between asymmetry and commonly reported external load variables collected during competition. Single-leg countermovement jumps and drop jumps were collected before and immediately after 5 soccer matches in elite academy soccer players. Global positioning system data were also collected during each match as part of the routine match-day procedures. Single-leg countermovement jump height and concentric impulse showed significant reductions after matches (p < 0.01; effect size [ES]: -0.67 to -0.69), but peak force did not (p > 0.05; ES: -0.05 to -0.13). Single-leg drop jump height and reactive strength also showed significant reductions after matches (p < 0.01; ES: -0.39 to -0.58). No meaningful reductions in asymmetry were present at the group level, but individual responses were highly variable. Significant associations between postmatch reactive strength asymmetry and explosive distance (r = 0.29; p < 0.05), relative explosive distance (r = 0.34; p < 0.05), high-speed running (r = 0.35; p < 0.05), and relative high-speed running (r = 0.44; p < 0.01) were observed. These findings show that unilateral jump tests are more appropriate than asymmetry to detect real change after soccer competition, and practitioners should be cautious about using asymmetry to inform decision-making during the temporal recovery period.

Can Milk Affect Recovery from Simulated Team-Sport Match Play?

This study investigated the effects of cow's milk on recovery from repeated simulated team games (STGs) in females. Twenty female team-sport athletes completed an STG circuit (2x ~ 30 min, with 10 min 'half-time'). Measures of muscle function, soreness and tiredness, symptoms of stress and serum markers of muscle damage and oxidative stress were determined pre- and 24 h, 48 h, 72 h and 96 h following the circuit. At 48 h, a second STG was completed. Sprint performance (5 m, 15 m), lap time, countermovement jump (CMJ), heart rate and RPE were recorded during each STG. Immediately following each STG, participants consumed either 500 mL of cow's milk (MILK) or 500 mL of an energy-matched carbohydrate (CHO) solution. Compared to CHO, MILK had a beneficial effect in attenuating losses in peak torque for knee extension (60°/s) (likely; effect size (ES) = 0.26 to 0.28) knee flexion (60°/s) (likely; ES = 0.45 to 0.61). A benefit for MILK was observed for 5 m sprint (possible-likely; ES = 0.40 to 0.58), 10 m sprint (likely; ES = 0.30 to 0.53) and symptoms of stress (likely-very likely, small). Mostly unclear outcomes for other variables were observed. For STG variables, trivial (HR, CMJ) and unclear (5 m sprint, 15 m sprint, lap-time, RPE) outcomes were recorded. In conclusion, the consumption of 500 mL of milk attenuated losses in muscle function and perceptions of stress following repeated simulated team-sports games. However, further investigation is warranted to determine whether MILK can influence subsequent team-sport performance.

Monitoring the Athlete Match Response: Can External Load Variables Predict Post-match Acute and Residual Fatigue in Soccer? A Systematic Review with Meta-analysis

BACKGROUND

Monitoring athletes' external load during a soccer match may be useful to predict post-match acute and residual fatigue. This estimation would allow individual adjustments to training programs to minimize injury risk, improve well-being, and restore players' physical performance and inform the recovery process.

METHODS

Using a systematic review and meta-analysis of the literature, the aim is to determine which monitoring variables would be the strongest predictors of acute (immediately) and residual (up to 72 h) fatigue states in soccer. PubMed, SPORTDiscus, and Web of Science databases were searched (until September 2018). Studies concurrently examining soccer match-related external load metrics and subjective and/or objective measures were selected to determine pooled correlations ([Formula: see text]) with confidence intervals (CI). The quality and strength of the findings of each study were evaluated to identify overall levels of evidence.

RESULTS

Eleven studies were included (n = 165 athletes). Acute ([Formula: see text] = 0.67; 95% CI = [0.40, 0.94]) and residual (24 h post-match, [Formula: see text] = 0.54; 95% CI = [0.35, 0.65]) changes in muscle damage markers and countermovement jump peak power output (CMJ_PPO) were, with moderate to strong evidence, largely correlated with running distance above 5.5 m s^-1. No other external load metric was largely correlated with both biochemical and neuromuscular markers. For every 100-m run above 5.5 m·s^-1, CK activity measured 24 h post-match increased by 30% and CMJ_PPO decreased by 0.5%. Conversely, the total distance covered did not present any evidence of a clear relationship with any fatigue-related marker at any time-point.

CONCLUSIONS

Running distance above 5.5 m·s^-1 represents the most sensitive monitoring variable characterizing biochemical and neuromuscular responses, at least when assessed during the initial 24 h (not at 48 h/72 h) post-match recovery period. In addition, total distance covered is not sensitive enough to inform decision-making during the fatigue monitoring process.

Effects of Foam Rolling as a Recovery Tool in Professional Soccer Players

Rey, E, Padrón-Cabo, A, Costa, PB, and Barcala-Furelos, R. Effects of foam rolling as a recovery tool in professional soccer players. J Strength Cond Res 33(8): 2194-2201, 2019-Foam rolling (FR) is a common strategy used after training and competition by players. However, no previous studies have assessed the effectiveness of FR as a recovery tool in sports populations. The aim of this study was to examine the effectiveness of FR (20 minutes of FR exercises on quadriceps, hamstrings, adductors, gluteals, and gastrocnemius) and passive recovery (20 minutes sit on a bench) interventions performed immediately after a training session on Total Quality Recovery (TQR), perceived muscle soreness, jump performance, agility, sprint, and flexibility 24 hours after the training. During 2 experimental sessions, 18 professional soccer players (age 26.6 ± 3.3 years; height: 180.2 ± 4.5 cm; body mass: 75.8 ± 4.7 kg) participated in a randomized fully controlled trial design. The first session was designed to collect the pretest values of each variable. After baseline measurements, the players performed a standardized soccer training. At the end of training unit, all the players were randomly assigned to the FR recovery group and the passive recovery group. A second experimental session was conducted to obtain the posttest values. Results from the between-group analyses showed that FR had a large effect on the recovery in agility (effect sizes [ES] = 1.06), TQR (ES = 1.08), and perceived muscle soreness (ES = 1.02) in comparison with the passive recovery group at 24 hours after training. Thus, it is recommended that soccer coaches and physical trainers working with high-level players use a structured recovery session lasting from 15 to 20 minutes based on FR exercises that could be implemented at the end of a training session to enhance recovery between training loads.

Intra- and Post-match Time-Course of Indicators Related to Perceived and Performance Fatigability and Recovery in Elite Youth Soccer Players

PURPOSE

Our aims were to examine (i) the internal load during simulated soccer match-play by elite youth players; and (ii) the time-course of subsequent recovery from perceived and performance fatigability.

METHODS

Eleven male youth players (16 ± 1 years, 178 ± 7 cm, 67 ± 7 kg) participated in a 2 × 40-min simulated soccer match, completing 30 rounds (160 s each) with every round including multidirectional and linear sprinting (LS20m), jumping (CMJ) and running at different intensities. During each round, LS20m, CMJ, agility, heart rate (HR), oxygen uptake (VO2), energy expenditure (EE), substrate utilization and perceived exertion RPE were assessed. In addition, the blood level of lactate (Lac) was obtained after each of the five rounds. Creatine kinase (CK) concentration, maximal voluntary isometric knee extension and flexion, CMJ, number of skippings in 30 s, and subjective ratings on the Acute Recovery and Stress Scale (ARSS) were examined before and immediately, 24 and 48 h after the simulation.

RESULTS

During the game %HRpeak (p < 0.05, d = 1.08), %VO2 peak (p < 0.05; d = 0.68), Lac (p < 0.05, d = 2.59), RPEtotal (p < 0.05, d = 4.59), and RPElegs (p < 0.05, d = 4.45) all increased with time during both halves (all p < 0.05). Agility improved (p < 0.05, d = 0.70) over the time-course of the game, with no changes in LS20m (p ≥ 0.05, d = 0.34) or CMJ (p ≥ 0.05, d = 0.27). EE was similar during both halves (528 ± 58 vs. 514 ± 61 kcal; p = 0.60; d = 0.23), with 62% (second half: 65%) carbohydrate, 9% (9%) protein and 26% (27%) fat utilization. With respect to recovery, maximal voluntary knee extension (p ≥ 0.05, d = 0.50) and flexion force (p ≥ 0.05, d = 0.19), CMJ (p ≥ 0.05, d = 0.13), number of ground contacts (p ≥ 0.05, d = 0.57) and average contact time (p ≥ 0.05, d = 0.39) during 30-s of skipping remained unaltered 24 and 48 h after the game. Most ARSS dimensions of load (p < 0.05, d = 3.79) and recovery (p < 0.05, d = 3.22) returned to baseline levels after 24 h of recovery. Relative to baseline values, CK was elevated immediately and 24 h after (p < 0.05, d = 2.03) and normalized 48 h later.

CONCLUSION

In youth soccer players the simulated match evoked considerable circulatory, metabolic and perceptual load, with an EE of 1042 ± 118 kcal. Among the indicators of perceived and performance fatigability examined, the level of CK and certain subjective ratings differed considerably immediately following or 24-48 h after a 2 × 40-min simulated soccer match in comparison to baseline. Accordingly, monitoring these variables may assist coaches in assessing a U17 player's perceived and performance fatigability in connection with scheduling training following a soccer match.

Effects of Two Competitive Soccer Matches on Landing Biomechanics in Female Division I Soccer Players

Fatigue has been proposed to increase the risk of knee injury. This study tracked countermovement jump, knee isometric strength, and kinetics and kinematics in 8 female soccer players (experimental group) during an anticipated sidestep maneuver before and after two matches played over a 43-h period. Time points were: Before and after match 1 (T0 and T1), 12 h after the first match (T2), and immediately after the second match (T3). A control group participated only in practice sessions. Isometric knee extension strength decreased by 14.8% at T2 (p = 0.003), but knee flexion was not affected until T3, declining by 12.6% (p = 0.018). During the sidestep maneuver, knee joint degrees of flexion at initial contact was increased by 17.1% at T3, but maximum knee and hip angle at initial contact were unchanged. Peak resultant ground reaction force (GRF) increased by 12.6% (p = 0.047) at T3 (3.03 xBW) from 2.69 xBW at T0, while posterior GRF was significantly higher than T0 at all three subsequent time points (T1 = 0.82 ± 0.23 xBW, T2 = 0.87 ± 0.22 xBW, T3 = 0.89 ± 0.22 xBW). Anterior tibial shear force increased significantly (p = 0.020) at T3 (1.24 ± 0.12 xBW) compared to T1 (1.15 ± 0.13 xBW), an 8.8% increase. Lateral tibial shear force was significantly higher at both T1 (0.95 ± 0.20 xBW) and T3 (1.15 ± 0.38 xBW) compared to T0 (0.67 ± 0.25 xBW). These findings suggest that participation in a soccer match has significant effects on both physical performance parameters and kinetics/kinematics during a sidestep cut, but these can be more pronounced after a second match with short rest.