The aim of this study was to assess physical fitness, match performance and development of fatigue during competitive matches at two high standards of professional soccer. Computerized time-motion analyses were performed 2-7 times during the competitive season on 18 top-class and 24 moderate professional soccer players. In addition, the players performed the Yo-Yo intermittent recovery test. The top-class players performed 28 and 58% more (P < 0.05) high-intensity running and sprinting, respectively, than the moderate players (2.43 ± 0.14 vs 1.90 ± 0.12 km and 0.65 ± 0.06 vs 0.41 ± 0.03 km, respectively). The top-class players were better (11%; P < 0.05) on the Yo-Yo intermittent recovery test than the moderate players (2.26 ± 0.08 vs 2.04 ± 0.06 km, respectively). The amount of high-intensity running, independent of competitive standard and playing position, was lower (35-45%; P < 0.05) in the last than in the first 15 min of the game. After the 5-min period during which the amount of high-intensity running peaked, performance was reduced (P < 0.05) by 12% in the following 5 min compared with the game average. Substitute players (n = 13) covered 25% more (P < 0.05) ground during the final 15 min of high-intensity running than the other players. The coefficient of variation in high-intensity running was 9.2% between successive matches, whereas it was 24.8% between different stages of the season. Total distance covered and the distance covered in high-intensity running were higher (P < 0.05) for midfield players, full-backs and attackers than for defenders. Attackers and full-backs covered a greater (P < 0.05) distance in sprinting than midfield players and defenders. The midfield players and full-backs covered a greater (P < 0.05) distance than attackers and defenders in the Yo-Yo intermittent recovery test (2.23 ± 0.10 and 2.21 ± 0.04 vs 1.99 ± 0.11 and 1.91 ± 0.12 km, respectively). The results show that: (1) top-class soccer players performed more high-intensity running during a game and were better at the Yo-Yo test than moderate professional players; (2) fatigue occurred towards the end of matches as well as temporarily during the game, independently of competitive standard and of team position; (3) defenders covered a shorter distance in high-intensity running than players in other playing positions; (4) defenders and attackers had a poorer Yo-Yo intermittent recovery test performance than midfielders and full-backs; and (5) large seasonal changes were observed in physical performance during matches.

To examine the physiological response and reproducibility of the Yo-Yo intermittent recovery test and its application to elite soccer. Heart rate was measured, and metabolites were determined in blood and muscle biopsies obtained before, during, and after the Yo-Yo test in 17 males. Physiological measurements were also performed during a Yo-Yo retest and an exhaustive incremental treadmill test (ITT). Additionally, 37 male elite soccer players performed two to four seasonal tests, and the results were related to physical performance in matches. The test-retest CV for the Yo-Yo test was 4.9%. Peak heart rate was similar in ITT and Yo-Yo test (189 ± 2 vs 187 ± 2 bpm), whereas peak blood lactate was higher (P < 0.05) in the Yo-Yo test. During the Yo-Yo test, muscle lactate increased eightfold (P < 0.05) and muscle creatine phosphate (CP) and glycogen decreased (P < 0.05) by 51% and 23%, respectively. No significant differences were observed in muscle CP, lactate, pH, or glycogen between 90 and 100% of exhaustion time. During the precompetition period, elite soccer players improved (P < 0.05) Yo-Yo test performance and maximum oxygen uptake (V̇O2max) by 25 ± 6 and 7 ± 1%, respectively. High-intensity running covered by the players during games was correlated to Yo-Yo test performance (r = 0.71, P < 0.05) but not to V̇O2max and ITT performance. The test had a high reproducibility and sensitivity, allowing for detailed analysis of the physical capacity of athletes in intermittent sports. Specifically, the Yo-Yo intermittent recovery test was a valid measure of fitness performance in soccer. During the test, the aerobic loading approached maximal values, and the anaerobic energy system was highly taxed. Additionally, the study suggests that fatigue during intense intermittent short-term exercise was unrelated to muscle CP, lactate, pH, and glycogen.

In soccer, the players perform intermittent work. Despite the players performing low-intensity activities for more than 70% of the game, heart rate and body temperature measurements suggest that the average oxygen uptake for elite soccer players is around 70% of maximum ([Vdot]O_2max). This may be partly explained by the 150 – 250 brief intense actions a top-class player performs during a game, which also indicates that the rates of creatine phosphate (CP) utilization and glycolysis are frequently high during a game. Muscle glycogen is probably the most important substrate for energy production, and fatigue towards the end of a game may be related to depletion of glycogen in some muscle fibres. Blood free-fatty acids (FFAs) increase progressively during a game, partly compensating for the progressive lowering of muscle glycogen. Fatigue also occurs temporarily during matches, but it is still unclear what causes the reduced ability to perform maximally. There are major individual differences in the physical demands of players during a game related to physical capacity and tactical role in the team. These differences should be taken into account when planning the training and nutritional strategies of top-class players, who require a significant energy intake during a week.

The aims of this study were to (1) determine the activity profiles of a large sample of English FA Premier League soccer players and (2) examine high-intensity running during elite-standard soccer matches for players in various playing positions. Twenty-eight English FA Premier League games were analysed during the 2005–2006 competitive season (n = 370), using a multi-camera computerised tracking system. During a typical match, wide midfielders (3138 m, s = 565) covered a greater distance in high-intensity running than central midfielders (2825 m, s = 473, P = 0.04), full-backs (2605 m, s = 387, P < 0.01), attackers (2341 m, s = 575, P < 0.01), and central defenders (1834 m, s = 256, P < 0.01). In the last 15 min of a game, high-intensity running distance was ∼20% less than in the first 15-min period for wide midfielders (467 m, s = 104 vs. 589 m, s = 134, P < 0.01), central midfielders (429 m, s = 106 vs. 534 m, s = 99, P < 0.01), full-backs (389 m, s = 95 vs. 481 m, s = 114, P < 0.01), attackers (348 m, s = 105 vs. 438 m, s = 129, P < 0.01), and central defenders (276 m, s = 93 vs. 344 m, s = 80, P < 0.01). There was a similar distance deficit for high-intensity running with (148 m, s = 78 vs. 193 m, s = 96, P < 0.01) and without ball possession (229 m, s = 85 vs. 278 m, s = 97, P < 0.01) between the last 15-min and first 15-min period of the game. Mean recovery time between very high-intensity running bouts was 72 s (s = 28), with a 28% longer recovery time during the last 15 min than the first 15 min of the game (83 s, s = 26 vs. 65 s, s = 20, P < 0.01). The decline in high-intensity running immediately after the most intense 5-min period was more evident in attackers (216 m, s = 50 vs. 113 m, s = 47, P < 0.01) and central defenders (182 m, s = 26 vs. 96 m, s = 39, P < 0.01). The results suggest that high-intensity running with and without ball possession is reduced during various phases of elite-standard soccer matches and the activity profiles and fatigue patterns vary among playing positions. The current findings provide valuable information about the high-intensity running patterns of a large sample of elite-standard soccer players, which could be useful in the development and prescription of specific training regimes.

Sies were taken before and after the game as well as immediately after an intense period in each half. The players performed five 30-m sprints interspersed by 25-s recovery periods before the game and immediately after each half (N = 11) or after an intense exercise period in each half (N = 20). Results: Muscle lactate was 15.9 ± 1.9 and 16.9 ± 2.3 mmol·kg−1 d.w. during the first and second halves, respectively, with blood lactate being 6.0 ± 0.4 and 5.0 ± 0.4 mM, respectively. Muscle lactate was not correlated with blood lactate (r2 = 0.06-0.25, P >0.05). Muscle glycogen decreased (P < 0.05) from 449 ± 23 to 255 ± 22 mmol·kg−1 d.w. during the game, with 47 ± 7% of the muscle fibers being completely or almost empty of glycogen after the game. Blood glucose remained elevated during the game, whereas plasma FFA increased (P < 0.05) from 0.45 ± 0.05 to 1.37 ± 0.23 mM. Mean sprint time was unaltered after the first half, but longer (P < 0.05) after the game (2.8 ± 0.7%) as well as after intense periods in the first (1.6 ± 0.6%) and second halves (3.6 ± 0.5%). The decline in sprint performance during the game was not correlated with muscle lactate, muscle pH, or total glycogen content. Conclusion: Sprint performance is reduced both temporarily during a game and at the end of a soccer game. The latter finding may be explained by low glycogen levels in individual muscle fibers. Blood lactate is a poor indicator of muscle lactate during soccer match play....