Analysis of fatigue development during elite male handball matches.

This study aimed at describing the physiological demands and fatigue development during elite male handball matches. Our hypothesis was that players perform multiple high-intensity activities during periods of the game and develop temporary and end-match neuromuscular fatigue. Time-motion analyses and heart rate (HR) recordings were performed in 40 players during 12 competitive matches. Blood samples were collected, and sprint, jump, and intermittent exercise performance (Yo-Yo Intermittent Endurance level 2 test [YYIE2]) was assessed for 18 players at baseline conditions and after 2 competitive matches, and additional blood sampling and testing were performed for 12 of these players during a friendly match. The time spent with high-intensity running (4.4 ± 2.0 to 3.1 ± 1.7%), the frequency of demanding actions (61 ± 5 to 54 ± 6), and the time with HR above 80% HRmax (62 ± 21 to 41 ± 17%) were lowered from the first to the second half. Average blood lactate during the match was 3.6 ± 2.1 (1.3-8.6) mM. Plasma free fatty acids (FFA), glycerol, glucose, and uric acid increased (p ≤ 0.05) during the first half and plasma FFA and glycerol increased further (p ≤ 0.05) during the second half. After an intense period in the second half, sprint performance was decreased by 3.9 ± 4.9%. After the match, YYIE2 (33.4 ± 8.7%), vertical jump (7.4 ± 6.5%), and 20-m sprint performance (1.6 ± 2.6%) was lower (p ≤ 0.05) than at baseline. This study showed that the intensity is high in certain periods during elite male handball games and that physical performance is impaired both temporarily during and toward the end of games confirming our hypothesis. These findings enables physical trainers and coaches to plan and design proper game-specific training exercises aiming at delaying both temporary and end-game fatigue and strengthen the physiological rationale for the need for substitutions in various stages of match-play.

Physiological demands of elite team handball with special reference to playing position.

This study aimed to analyze the physiological demands of match play for different playing positions in elite male team handball. Time motion (N = 30) and heart rate (HR; N = 70) data were recorded throughout 10 official matches. The mean distance covered by backcourt players (4.96 ± 0.64 km) was greater (p ≤ 0.02) than for wings and pivots (4.23 ± 0.52 and 3.91 ± 0.51 km, respectively). Backcourt players spent less time standing still and walking (∼76%) than wings and pivots (∼80%) (p ≤ 0.03), and wings spent more time sprinting than the other playing positions. Backcourt players (122.9 ± 17.0) and pivots (126.8 ± 33.0) performed more high-demanding actions per game than wings (54.6 ± 15.6) (p = 0.01). The time spent by pivots in high-intensity activities decreased from the first to the second half (4.1 ± 2.4 to 2.7 ± 0.9%; p ≤ 0.01), while backcourt players showed a decrease in high-demanding playing actions (p ≤ 0.05). Backcourt players and pivots had higher mean (84 ± 9 and 83 ± 9% vs. 79 ± 10%; p ≤ 0.03) and peak effective HR, and percentage of total time at intensities >80% maximal HR (HRmax) than wings. The fraction of total time spent at intensities >80% HRmax decreased for all outfield playing positions in the second half (from 39-76 to 30-46%). Competitive team handball involves position-specific differences in the physiological demands. Furthermore, exercise intensity decreases from the first to the second half for all outfield playing positions suggesting that these players experience neuromuscular fatigue. Training of elite handball players should comprise high-intensity position-specific exercises aiming at improving the ability to maintain a high exercise intensity throughout the game.

Training status and match activity of professional soccer players throughout a season.

The purpose of this study was to examine match activity (MA) and fatigue development (FD) during official soccer games in different moments of a season and the influence of training status (TS) on MA and FD. Match activity of 13 professional players was examined by time-motion analysis at 4 time points of a competitive season. In addition, per time point within the 2-week period between the 2 games video-filmed, players performed the following physical tests: countermovement jump, 5- and 30-m sprints, change of direction, knee extensor and flexor isokinetic strength, and Yo-Yo intermittent endurance test-level 2. The players covered a greater high-intensity distance running (HI; p < 0.05) in the last quarter of the season (E4) than in the second (E2) and the third (E3) quarters. Within each assessment period, a greater distance was covered in HI during the peak 5-minute period of the match (P5-min) than in the 5-minute period after P5-min (Next5-min) and the remaining 5-minute periods (Av5-min; p < 0.05) of the match. Also, P5-min was higher in E4 than in the beginning of the season (E1, E2, and E3; p < 0.05). The physical fitness variables, composites scores of power-related and isokinetic strength tests were correlated (r ranging between 0.59 and 0.73, p < 0.05) with game physical parameters (GPPs) analyzed by time motion. Soccer players were found to cover more HI during the game and in the P5-min toward end of season. The players with greater muscle strength and power expressed lower performance decrements in the GPPs. In conclusion, the results highlight the relevance of players' neuromuscular function on game physical performance.

Physical and physiological demands of elite team handball.

This study aimed to analyze elite team handball physical and physiological demands during match play. Time-motion (N = 30) and heart rate (HR; N = 60) analyses were performed throughout 10 official matches. The defined locomotor categories were standing still, walking, jogging, fast running, sprinting, backwards movement, sideways medium-intensity movement, and sideways high-intensity movement, and playing actions studied were jumps, shots, stops when preceded by high-intensity activities, changes of direction and one-on-one situations. During matches, the mean distances covered were 4,370 ± 702.0 m. Around 80% of the total time was spent standing still (43.0 ± 9.27%) and walking (35.0 ± 6.94%) and only 0.4 ± 0.31% with sprinting. The most frequent high-intensity actions were stops, changes of direction, and one-on-one situations. Effective mean HR was 157 ± 18.0 b·min(-1) (82 ± 9.3% of HRmax), and total HR was 139 ± 31.9 b·min(-1) (72 ± 16.7% of HRmax). The HR, time spent in high-intensity activities, frequency of stops, changes of direction, one-on-one situations, and most intense periods of the game were higher during the first half than during the second half (p ≤ 0.05). The opposite was observed for the number of time outs and the time between each change of activity (p = 0.00). Handball is an intermittent exercise that primarily uses aerobic metabolism, interspersed by high-intensity actions that greatly tax anaerobic metabolism. Additionally, exercise intensity decreases from the first to the second half of the match, suggesting that neuromuscular fatigue may occur during the game. The training of elite handball players should comprise exercises targeting the ability to perform specific high-intensity actions throughout the game and to rapidly recover during the less intense periods.

Effects of cold water immersion on the recovery of physical performance and muscle damage following a one-off soccer match.

The aim of this study was to assess the effects of a single session of cold or thermoneutral water immersion after a one-off match on muscular dysfunction and damage in soccer players. Twenty-male soccer players completed one match and were randomly divided into cryotherapy (10 min cold water immersion, 10°C, n = 10) and thermoneutral (10 min thermoneutral water immersion, 35°C, n = 10) groups. Muscle damage (creatine kinase, myoglobin), inflammation (C-reactive protein), neuromuscular function (jump and sprint abilities and maximal isometric quadriceps strength), and delayed-onset muscle soreness were evaluated before, within 30 min of the end, and 24 and 48 h after the match. After the match, the players in both groups showed increased plasma creatine kinase activity (30 min, 24 h, 48 h), myoglobin (30 min) and C-reactive protein (30 min, 24 h) concentrations. Peak jump ability and maximal strength were decreased and delayed-onset muscle soreness increased in both groups. However, differential alterations were observed between thermoneutral water and cold water immersion groups in creatine kinase (30 min, 24 h, 48 h), myoglobin (30 min), C-reactive protein (30 min, 24 h, 48 h), quadriceps strength (24 h), and quadriceps (24 h), calf (24 h) and adductor (30 min) delayed-onset muscle soreness. The results suggest that cold water immersion immediately after a one-off soccer match reduces muscle damage and discomfort, possibly contributing to a faster recovery of neuromuscular function.

Elite futsal refereeing: activity profile and physiological demands.

The purpose of this study was to determine the physiological demands and to establish the relationship between activity profile and endurance capacity of futsal referees. Eighteen elite futsal referees (33.0 ± 5.1 years, 173 ± 5 cm, and 73.2 ± 8.4 kg) were studied. Video filming (n = 18) and heart rate (HR) recordings were performed throughout games. Blood lactate (n = 14) was determined at rest and after the game. Endurance capacity was determined with the Yo-Yo IE2. The number of activity changes was as high as 1,395 ± 218 (± SD). Total distance covered, high-intensity running (HIR), sprinting (SPR), and sideways running were 5.89 ± 0.56, 0.96 ± 0.29, 0.09 ± 0.07, and 0.91 ± 0.46 km, respectively. The number of HIR and SPR bouts was 129 ± 41 and 9 ± 8, respectively, with a mean duration of ∼1.4 seconds. Blood lactate content was 1.0 ± 0.3 and 1.5 ± 0.5 mM before and after the game. The amount of HIR performed during the match correlated significantly (r = 0.77; p < 0.05) with the Yo-Yo IE2 performance. Considering the data obtained in the present study, the use of match-specific intermittent fitness tests to evaluate futsal referees seems to be required.

Individual match playing time during the season affects fitness-related parameters of male professional soccer players.

The purpose of this study was to analyze the effects of an entire season on physical fitness parameters (PFPs) in male professional soccer players (N = 18). Performance in 5- and 30-m sprint (T5 and T30), countermovement jump (CMJ), agility (T-test), knee extensor (KE) and knee flexor (KF) isokinetic strength, hamstrings/quadriceps strength ratio (H/Q) and bilateral differences (BDs), and Yo-Yo intermittent endurance test 2 (YYIE2) was evaluated in 4 moments (E1-E4) throughout the season. Individual match playing time was quantified. Significant improvements in CMJ and YYIE2 from E1 to E2 were observed (p < 0.05-0.01). The T30 improved from E2 to E3 (p < 0.01). The CMJ decreased from E2 to E3 and E4, and YYIE2 from E2 to E4 (p < 0.05). There were increments in the H/Q ratio and Agility from E1 and E2 to E3 and E4 (p < 0.05-0.01). Significant correlations were found in all evaluation points between different PFPs and between changes in strength parameters and agility, T5 and T30, CMJ, and YYIE2 (p < 0.05-0.001). Influence of individual match playing time was correlated to changes in T5 (E1 to E3; r = -0.705), KE nondominant leg (KEND; E2 to E3; r = 0.786), and KF (E3 to E4; r = 0.575-0.590). The interrelationship between muscle strength (e.g., KE), sprint (e.g., T5), and jump abilities (CMJ) suggests the importance of muscle strength and power training for soccer. This study suggests that the systematic participation of the players in soccer matches favors the increase and maintenance of soccer players KE and KF muscle strength and sprint ability (T5). Thus, given the unique demands of actual match play, coaches should try to incorporate a competitive friendly match in the weekly training cycle of nonstarter players.

Variability of activity profile during medium-sided games in professional soccer.

BACKGROUND: In Southern European countries it is very frequent to perform medium-sized games (MSG) as last training drill. We analyzed the individual variability and changes in activity patterns during MSG throughout the preseason. METHODS: Activity profile during MSGs (10v10+goalkeepers, duration: 10-min, field length: 50 m, width: 90 m, area per player: 204.5 m2) was quantified using a GPS in 14 professional male players (6 defenders, 5 midfielders 5 and attackers). RESULTS: Inter-individual variability was higher for high-intensity (HIR), very-high speed (VHS), maximum acceleration (Accmax) and maximum deceleration (Decmax) distance (CV=25.2 to 43.3%), compared to total distance (TD), total acceleration (Acctot) and total deceleration (Dectot) distance (CV= 8.3 to 18.3%). Defenders showed higher variability in TD, HIR, VHS, Acctot and Dectot (ES= 1.30 to 11.28) compared to the other field positions, whereas attackers showed higher variability in HIR, VHS Accmax and Decmax (ES=-4.92 to 2.07) than other the field positions. Variability in TD regularly increased (ES= -2.13 to -0.91) towards the end of the preseason, while HIR and VHS variability tended to increase over the 3rd and the 4th preseason week (ES=-0.94 to -3.05). However, the behavior of variability across the preseason period was more unpredictable for Acctot and Dectot, both decreasing in the 3rd week (ES= 0.70 to 1.20), while Decmax increased in the 4th week (ES=-0.91±0.59). CONCLUSIONS: During MSGs, individual variability of activity differs among field positions, and tends to increase with either speed or acceleration intensity, underlining the need of an individualized approach for training load monitoring.

Switching between pitch surfaces: practical applications and future perspectives for soccer training.

INTRODUCTION: Soccer training and completion is conventionally practiced on natural grass (NG) or artificial turf (AT). Recently, AT pitches for training/competition, and of unstable surfaces for injury prevention training has increased. Therefore, soccer players are frequently exposed to variations in pitch surface during either training or competition. These ground changes may impact physical and physiological responses, adaptations as well as the injury. The aim of this review was to summarize the acute physical and physiological responses, chronic adaptations, and injury risk associated with exercising on different pitch surfaces in soccer. EVIDENCE ACQUISITION: Eligible studies were published in English, had pitch surface as an independent variable, and had physical, physiological or epidemiological information as outcome variables. Specific data extracted from the articles included the training response, training adaptations or injury outcomes according to different pitch surfaces. A total of 224 studies were retrieved from a literature search. EVIDENCE SYNTHESIS: Twenty articles met the inclusion criteria: 9 for acute physical and physiological responses, 2 for training adaptations and 9 for injury assessment. The literature lacks consistent evidence regarding the effects of pitch surface on performance and health outcomes in soccer players. However, it seems that occasionally switching training surfaces seems a valuable strategy for focusing on specific musculoskeletal queries and enhancing players' fitness. For instance, sand training may be occasionally proposed as complementary training strategy, given the recruitment of additional musculature probably not involved on firmer surfaces, but the possible training-induced adaptations of non-conventional soccer surfaces (e.g., sand) might potentially result into a negative transfer on AT or NG. CONCLUSIONS: Since the specific physical demands of soccer can differ between surfaces, coaches should resort to the use of non-traditional surfaces with parsimony, emphasizing the specific surface-related motor tasks, normally observed on natural grass or artificial turf. Further studies are required to better understand the physiological effects induced by systematic surface-specific training, or switching between pitch surfaces.

Does Night Training Load Affect Sleep Patterns and Nocturnal Cardiac Autonomic Activity in High-Level Female Soccer Players?

Purpose: To analyze whether exercise training conducted at night disturbs sleep and affects nocturnal cardiac autonomic control in high-level female athletes. Methods: A total of 18 high-level female soccer players (mean [SD] age 20.4 [2.1] y) wore actigraphs and heart-rate (HR) monitors during night sleep throughout night training days (n = 8) and resting days (n = 8), for 3 consecutive weeks. This was a longitudinal study that measured internal training load, sleep, nocturnal cardiac autonomic activity, and well-being ratings prior to training sessions. Results: Training load varied across training days (eg, training impulse range, mean [SD]; effect size, ES [95% confidence interval]: 72.9 [18.8] to 138.4 [29.6] a.u.; F4,62 = 32.331; ηp2=.673 [.001-.16], large effect; P < .001). However, no differences in subjective well-being ratings were observed, although ES was large. Total sleep time (training days vs resting days: 07:17 [00:47] h vs 07:51 [00:42] h; ES = 0.742 [0.59-0.92], P = .005; moderate effect) and sleep-onset time (00:58 [00:19] h vs 00:44 [00:16] h; ES = 0.802 [0.68-0.94], P = .001; moderate effect) were negatively affected after night training. In addition, small effects were detected for wake-up time, time in bed, and sleep latency (P > .05). No differences were detected in HR variability during sleep (range of lnRMSSD: 4.3 [0.4] to 4.5 [0.4] ln[ms] vs 4.6 [0.3] to 4.5 [0.4] ln[ms]; F3,52 = 2.148; P > .05; ηp2=.112 [.01-.25], medium effect), but HR during sleep was significantly higher after training days (range of HR: 56 [4] to 63 [7] beats/min vs 54 [4] to 57 [6] beats/min; F2,32 = 15.956; P < .001; ηp2=.484 [.20-.63], large effect). Conclusion: Overall, the results indicate that exercise training conducted at night may disturb sleep and affect HR, whereas limited effects can be expected in HR variability assessed during sleep in high-level female soccer players.

Small-sided soccer games on sand are more physically demanding but less technically specific compared to games on artificial turf.

BACKGROUND: The use of sand has been suggested as fitness-enhancing surface in field-based team sports. However, concerns have arisen in regard whether physical responses associated to sand training are sport-specific. We compared physical and technical demands during small-sided soccer games (4 vs. 4 + goalkeeper; SSGs) played on artificial turf and on sand. METHODS: Movement patterns, rating of perceived exertion (RPE) and technical parameters were obtained from eight adult male soccerers (20.1±1.0 years, 176±4 cm and 70.1±2.0 kg) using Global Positioning Systems, Visual Analogue Scale questionnaires, and notational analysis. RESULTS: High-intensity actions (high intensity running, high intensity activities), low changes of speed, as well as peak and average speed were higher on artificial turf (P<0.05; effect sizes (ES) 0.41 to 0.82). In contrast, time spent by jogging as well as high and maximum changes of speed was higher on sand (P<0.05; ES: 0.59 to 0.82). Moreover, players perceived more demanding to play on sand (P<0.05; ES=0.72). Rating of successful actions was higher during turf SSGs than sand SSGs (P<0.05; ES: 0.44 to 0.73), whereas actions requiring lifting the ball were higher on sand (P<0.05; ES: 0.47 to 0.50). CONCLUSIONS: The use of sand can be considered as complemental to on-turf soccer training, when the training goal is to tax lower limb muscle strength or to require high-ball situations. Nonetheless, sand training is not appropriate when the achievement of maximal speed is desired. Further research should clarify the suitability of sand training within soccer conditioning programs.

Effects of Late-Night Training on "Slow-Wave Sleep Episode" and Hour-by-Hour-Derived Nocturnal Cardiac Autonomic Activity in Female Soccer Players.

PURPOSE: To assess the sensitivity of nocturnal heart-rate-variability-monitoring methods to the effects of late-night soccer training sessions in female athletes. METHODS: Eleven female soccer players competing in the first division of the Portuguese soccer league wore heart-rate monitors during sleep at night throughout a 1-wk competitive in-season microcycle, after late-night training sessions (n = 3) and rest days (n = 3). Heart rate variability was analyzed through "slow-wave sleep episode" (10-min duration) and "hour by hour" (all the RR intervals recorded throughout the hours of sleep). Training load was quantified by session rating of perceived exertion (281.8 [117.9] to 369.0 [111.7] arbitrary units [a.u.]) and training impulse (77.5 [36.5] to 110.8 [31.6] a.u.), added to subjective well-being ratings (Hopper index = 11.6 [4.4] to 12.8 [3.2] a.u.). These variables were compared between training and rest days using repeated-measures analysis of variance. RESULTS: The log-transformed slow-wave sleep-episode cardiac autonomic activity (lnRMSSD [natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal RR intervals] varying between 3.92 [0.57] and 4.20 [0.60] ms; [Formula: see text]; 95% confidence interval, .01-.26), lnHF (natural logarithm of high frequency), lnLF (natural logarithm of low frequency), lnSD1 (natural logarithm of short-term beat-to-beat variability), and lnSD2 (natural logarithm of long-term beat-to-beat variability), and the nontransformed LF/HF were not different among night-training session days and rest days (P > .05). Considering the hour-by-hour method (lnRMSSD varying between 4.05 [0.35] and 4.33 [0.32] ms; [Formula: see text]; 95% confidence interval, .26-.52), lnHF, lnLF, lnSD1, and lnSD2 and the nontransformed LF/HF were not different among night-training session days and rest days (P > .05). CONCLUSION: Late-night soccer training does not seem to affect nocturnal slow-wave sleep-episode and hour-by-hour heart-rate-variability indices in highly trained athletes.