The physical aspects of elite soccer players have been studied extensively in men (1,2,10,12,14-18,22,25). Less information exists regarding the physical demands in women soccer players (5,6,7,11,19,24). Body dimensions (8) and maximum aerobic power (6,8,11,23) of women players have been determined in several studies. In addition, some studies have examined the activity profile during match play (2,24). However, the main focus has been on total distance covered, which is believed to be a poor indicator of physical match performance, since most of the game is covered by low-intensity activities such as walking and jogging, which hardly can be considered physically demanding (1,2,15).
Mohr et al. (15) studied work profiles of international top-class male soccer players and the development of fatigue during a soccer game. They found that top-class male soccer players experience fatigue both temporarily during a game and towards the end of a game. Additionally, it was demonstrated that international top-class players exercise at a greater intensity during a game than professional players at a moderate competition level. Recently, Krustrup et al. (11) showed that for women players, the amount of high-intensity running in a game was related to the training status of the players. Whether the work rate profiles of women soccer players are dependent on the standard of play has not previously been examined. Thus, the aim of the present study was to study the activity profiles of elite women soccer players at different levels during a soccer match.
Experimental Approach to the Problem
To study the activity profiles and physical match performance of women soccer players in relation to standard of play, elite players representing 2 different competition levels were individually videotaped in competitive matches and computerized time-motion analysis was applied to determine the work profiles.
Nineteen women national team soccer players, classified as top-class players, participated in the study. They represented 9 different national teams from 5 different continents and were all employed as professional soccer players in the U.S. top league. Moreover, 15 elite players from the best Danish and Swedish league, deemed high-level players, took part in the study. None of these players were representing their respective national teams. The 34 participants included 10 central defenders, 14 midfield players, and 10 attackers. The players were fully informed of all experimental procedures before giving their informed consent to participate.
Each player was observed by individual videotaping in 1 or 2 competitive matches. The top-class players were observed in international matches or the U.S. top league, whereas the high-level players were investigated in Danish or Swedish league matches. The players were videotaped close up during the entire match. The VHS movie cameras (NV-M50, Panasonic, Germany) were positioned at the side of the pitch, at the level of the midfield line, at a height of about 15 m and at a distance of 30-40 m from the touchline. The videotapes were later replayed on a monitor for computerized coding of the activity pattern (1,2,11,15). The following locomotor categories were used: standing (0 km·h−1), walking (6 km·h−1), jogging (8 km·h−1), low-speed running (12 km·h−1), moderate-speed running (15 km·h−1), high-speed running (18 km·h−1), sprinting (25 km·h−1), and backward running (10 km·h−1).
The locomotor categories were chosen in accordance with Bangsbo et al. (1) and Mohr et al. (15). However, sprinting speed was adapted to female players after detailed studies of the videotapes. Thus, the time it took for a player to pass pre-markers in the grass, for example, distance of the center circle and other known distances were used to calculate the speed for each activity of locomotion. The aforementioned activities were later divided into 4 locomotor categories: (1) standing; (2) walking; (3) low-intensity running, encompassing jogging, low-speed running, and backward running; and (4) high-intensity running, consisting of moderate-speed running, high-speed running, and sprinting. The frequency and duration of each activity were recorded and the data are presented in 5-, 15-, 45-, and 90-minute periods. The distance covered for each activity within each interval was determined as the product of the total time and mean speed for that activity. The total distance covered during a match was calculated as the sum of the distances covered during each type of activity. The peak distance covered by high intensity running represents the 5-minute period with highest distance of high-intensity running in a game for an individual.
Reproducibility of the results obtained by the time-motion analysis has previously been determined. In a study by Krustrup and Bangsbo (9), no systematic differences were observed in test-retest analysis of the same match and the mean intra-individual differences in total distance covered was less than 0.2 km (coefficient of variation; CV = 1%). The intraindividual variations in walking, low-intensity running, high-intensity running, and backward running were 2, 5, 3, and 3%, respectively. These values are in the same range as observed by Bangsbo et al. (1991). The 37 matches analyzed in the present study were all analyzed by the same experienced observer, who has analyzed more than 350 soccer matches. The first and the second half of each match were analyzed in a random order. Before the analysis of each player was initiated, the player's style of locomotion was studied intensively and several validation tests were performed for the individual players according to the predetermined categories of locomotion.
Values are presented as means ± SEM. Differences between the first and second half were determined using the Student's paired t-test. Differences between the 2 levels of competition were tested with a Student's unpaired t-test. Differences between team positions were tested by a one-way analysis of variance. Differences between 5- or 15-minute periods within the match were determined using an analysis of variance test with one way repeated measurement. In case of a significant difference between treatments, a Tukey post-hoc test was used to identify the points of difference. Significance level was set as P ≤ 0.05.
The number of change in activity was not different between the top-class and high-level players (1379 ± 34 and 1326 ± 24, respectively) corresponding to an activity change every ~4 seconds. The number of high-intensity runs and sprinting bouts was greater (P < 0.05) for top-class than high-level players (154 ± 7 vs. 125 ± 7 and 30 ± 2 vs. 26 ± 1, respectively; Figure 1). There was no difference in the mean duration of any of the activities between the two groups (Figure 1).
The top-class players spent 19.4 ± 1.0%, 42.8 ± 1.1%, and 27.7 ± 1.2% of the total time during a game standing, walking, and performing low-intensity running, respectively, which was not different from high-level players. The top-class players performed (P < 0.05) high-intensity running and sprinting more than the high-level players (6.0 ± 0.3% vs. 4.4 ± 0.5% and 1.2 ± 0.1% vs. 0.9 ± 0.1%, respectively; Figure 1). No differences were observed in the time spent running backwards between the 2 groups (3.9 ± 0.3% vs. 3.6 ± 0.2%, respectively).
The top-class players ran more (P < 0.05) at both low and high-intensity during the first compared to the second half (29.0 ± 1.1% vs. 26.5 ± 1.3% and 6.5 ± 0.4% vs. 5.4 ± 0.3%, respectively; Figure 2). Moreover, they sprinted more often (P < 0.05) in the first compared with the second half (1.2 ± 0.1% vs. 1.0 ± 0.1%; Figure 2). Similar differences (P < 0.05) were observed for the high-level players when comparing low- and high-intensity running as well as sprinting in the 2 halves (29.7 ± 2.8% vs. 27.9 ± 2.9%, 4.5 ± 0.6 vs. 4.3 ± 0.5%, and 1.0 ± 0.1 vs. 0.9 ± 0.1%, respectively.
The total distance covered during a match was 10.33 ± 0.15 km for the top-class players, which was similar to the high-level players (10.44 ± 0.15 km). The distance covered with high-intensity running during a match was 28% greater (P < 0.05) for top-class than for high-level players (1.68 ± 0.09 vs. 1.30 ± 0.10 km). The distance covered by sprinting was 0.46 ± 0.02 km for top-class players, which was 24% longer (P < 0.05) than for high-level players (0.38 ± 0.05 km). The distance covered during the first half was longer (P < 0.05) than in the second half for top-class players (5.28 ± 0.09 km vs. 5.05 ± 0.08 km), whereas no difference was observed for high-level players (5.22 ± 0.09 km vs. 5.21 ± 0.08 km).
Both top-class and high-level players covered more (P < 0.05) distance by high-intensity running in the first than in the second half of the match (0.91 ± 0.05 km vs. 0.70 ± 0.04 km and 0.68 ± 0.06 km vs. 0.62 ± 0.04 km, respectively). Moreover, the distance covered by sprinting was longer (P < 0.05) in the first than in the second half for both top-class (0.25 ± 0.02 km vs. 0.21 ± 0.01 km) and high-level players (0.20 ± 0.03 km vs. 0.17 ± 0.02 km).
Change in Performance During a Match
The distance covered by high-intensity running by top-class players in the final 15-minute period of the game was 27-57% lower (P < 0.05) than in the first four 15-minute periods (0.21 ± 0.01 km vs. 0.27 ± 0.02 km to 0.33 ± 0.02 km). The high-level players covered a 16-41% shorter (P < 0.05) distance by high-intensity running in the five last 15-minute periods than during the first 15-minute period (0.16 ± 0.01 km to 0.23 ± 0.01 km vs. 0.28 ± 0.03 km; Figure 2). Moreover, in both halves the amount of high intensity running was lower (P < 0.05) in the final 15 minutes than in the first and the second 15-minute interval for the high-level players.
The sprinting distance covered by the top-class players was shorter (P < 0.05) in the last compared with the first four 15-minute periods (0.05 ± 0.01 km vs. 0.07 ± 0.01 km to 0.08 ± 0.01 km, respectively). The high-level players sprinted more in the first 15 minutes than in the last 15-minute interval of both the first (0.09 ± 0.01 km vs. 0.05 ± 0.01 km) and second (0.07 ± 0.01 km vs. 0.04 ± 0.01 km) half (Figure 2).
The peak distance covered by high intensity running in a 5-minute period was 183 ± 9 m for top-class players, which was 33% longer (P < 0.05) than for the high-level players (138 ± 8 m; Figure 3). In the following 5-minute period, the amount of high intensity running was 77 ± 6 m for top-class players, which was 17% lower (P < 0.05) than the average distance covered during all 5-min intervals not including the peak distance (93 ± 5 m). No significant decline in high intensity running immediately after the peak 5-min interval was observed for the high-level players (Figure 3).
Both the top-class and the high-level players performed more (P < 0.05) high-intensity running in the initial 5 minutes of the first half compared with the second half (135 ± 9 m vs. 96 ± 7 m and 106 ± 15 m vs. 76 ± 13 m, respectively). In addition, the amount of sprinting was 22% and 38% greater (P < 0.05) in the first 5 minutes of the first half than in the corresponding period in the second half for the top-class and the high-level players, respectively.
The total number of headers performed during a game was 11 ± 1 and 8 ± 1 for the top-class and high-level players, respectively (NS). In addition, they carried out 16 ± 1 and 14 ± 1 tackles, respectively (NS). For all players the number of headers was the same in the first and second half (6 ± 1 vs. 5 ± 1), whereas they performed more (P < 0.05) tackles during the first than second half (8 ± 1 vs. 7 ± 1).
No difference was observed in total distance covered between playing position, but the defenders ran less (P < 0.05) high intensity running (1.26 ± 0.11 km) than both midfield players and attackers (1.65 ± 0.11 and 1.63 ± 0.10 km, respectively), with no difference between midfielders and attackers (Figure 4). The attackers sprinted 0.52 ± 0.03 km, which was longer (P < 0.05) than the defenders (0.33 ± 0.05 km), with the midfield players being in between 0.43 ± 0.04 km having intermediate values. Players within each position ran less high intensity running and sprinted less (P < 0.05) in the second half compared with the first. The defenders performed more (P < 0.05) headers than the midfield players (11 ± 2 vs. 7 ± 2, respectively), whilst was not different from the attackers (9 ± 2). No significant difference was observed in the amount of tackles performed between playing positions.
The major findings of the present study were that the top-class women players ran significantly longer at high intensities and sprinted more compared to high-level women players competing at a lower, but still elite standard. Furthermore, the top-class players performed approximately 40% less high intensity running in the last 15 minutes of a game compared to previously in the game, whereas the high-level players showed a decrease in high intensity running at the end of both the first and second half. Also for the top-class players the amount of high intensity running was significantly lowered in a period following the most intense period of a game. Altogether, these findings indicate that women players at a high-level of competition are fatiguing both towards the end of a game and temporarily during a game. Finally, when looking at each playing position, the midfielders and attackers performed more high intensity running than defenders, and attackers sprinted more than defenders.
The observation that the top-class women players were performing more intense running than high-level players is in accordance with the observation made with male players where Italian top-class players were compared with professional Danish players (15). The top-class women players in the present study were at the time of collection playing in the U.S. top-league, which was considered the best in the world and held a significant number of the players of the top three national teams in the world. The high-level players played in the Danish and Swedish league, which are also regarded among the best in the world with the Danish and Swedish ranked 8th and 4th, respectively, on the FIFA list. Because both groups of players had a decrease in the amount of high intensity running towards the end of a game, it could be concluded that the players' abilities were restricted and the results suggest that the endurance capacity of the players was insufficient. Thus, it appears that the higher the standard of women soccer the more high intensity running is performed. In agreement, Swedish players from the 3rd best national league performed ~40% less high intensity running than the high-level players in the present study (Andersson et al. unpublished data). The respective sub-elite players also had significantly lower maximal oxygen uptake, as well as a worse performance in both vertical jump and 30-meter sprint tests compared to players in the best league in Sweden (Andersson et al. unpublished data). Moreover, a close correlation has been observed between Yo-Yo intermittent recovery test performance and the amount of high intensity running in games in women soccer (11) and it has been observed that Yo-Yo intermittent endurance test performance is significantly higher for national team players than domestic players in the best Danish league (13). When comparing the performance of the women players in the present study with elite men players, it is clear that there are no differences in the total distance covered in a game (15) but the women players are covering less distance at a high intensity compared to men (Figure 5). However, the difference between the top-class women players and elite male soccer players is not great. Together, the findings illustrate that it is important for a soccer player to be able to repeatedly and regularly perform exercises at a high intensity.
Within each group of elite players marked individual differences in the high intensity running distance were observed. It was to some extent related to the position in the team. The central defenders were running less than the midfield players and attackers, and this difference seems not to be related to tactical limitations of the defenders because they also had a lowering of high intensity running towards the end of a game. In accordance, midfielders have a significantly higher Yo-Yo intermittent recovery test performance than defenders, with full-backs and attackers having intermediate test scores (3). Moreover, it has been observed that midfielders have a higher maximal oxygen uptake than defenders and attackers (8,11).
The reduction in high intense running towards the end of a game is in agreement with findings for male players (12,15-17,20,21) and could be a result of fatigue. It has been speculated that that this type of fatigue may be related to reduced muscle glycogen levels (3,4,12), but such measurements were not obtained in the present study. For the top-class women players a lowering of high intense running was seen after a period with intense running (Figure 4), which is similar to observations for men elite players (15) and may indicate that fatigue also occurs temporarily for women players at the highest level. It has been observed within men soccer players that the ability to perform repeated sprints is reduced after an intense period of a game (12) and based on the present results it is likely also to occur for women. This means that in training there ought to be a specific emphasis on improving the women players´ ability to recover from intense exercise.
In summary, the present results suggest that the greater the standard of women soccer the greater the running intensity during the match. Independent of the level of competition the amount of high intensity running is lowered towards the end of a match, suggesting that fatigues occur at the end of a game. Similarly, the decrease in high intensity running for top-class players after a period with intense exercise indicates that fatigue may also occur temporarily during a game. The amount of high intensity running is related to the position of the players, thus defenders were performing significantly less than midfield players and attackers.
Valid information regarding the intermittent activity pattern of women soccer is fundamental for understanding the physical demands of the game, which is essential for planning fitness training in detail. The present investigations revealed that there seems to be relatively small difference in physical match performance between international top-class women players and men elite players at a moderate international standard of play, high-lighting the importance of the physical dimension in women elite soccer. Moreover, the relatively large difference in high intensity running between the two levels of women soccer clearly shows the importance of being able to perform high intense running bouts repeatedly and to recover from these actions throughout the game. Thus, fitness training for women soccer players should aim at improving these qualities, meaning that aerobic high intensity training, as well as speed endurance training should be given a high priority. Finally, the large individual variations in activity pattern demonstrates the importance of aspects such as tactical role and playing position, which should be taken seriously into account and included into the fitness training sessions.
We thank the soccer players who participated in this study. The technical assistance from the camera crew (Per Hansen, Jan-Malm Hansen, Christoffer Krustrup, Jens Jung Nielsen, Mette Zebis, and Helga Ellingsgaard) is greatly appreciated. The study was supported by Team Denmark, the Danish Natural Science Research Council, the Swedish FA, and the Sports Research Council (Idrættens Forskningsråd).
1. Bangsbo, J, Nørregaard, L, and Thorsøe, F. Activity profile of competition soccer. Can J Sports Sci
16: 110-116, 1991.
2. Bangsbo, J. The physiology of soccer-with special references to intense intermittent exercise. Acta Physiol Scand
619S: 1-155, 1994.
3. Bangsbo, J, Mohr, M, and Krustrup, P. Physical and metabolic demands of training and match-play in the elite football player. J Sport Sci
24: 665-674, 2006.
4. Balsom, PD, Wood, K, Olsson, P, and Ekblom, B. Carbohydrate intake and multiple sprint sports: with special reference to football (soccer). Int J Sports Med
20: 48-52, 1999.
5. Brewer, J and Davies, JA. The female player. In: Football (Soccer)
. B. Ekblom, ed. Oxford: Blackwell, 1994. pp. 95-99.
6. Davies, JA, and Brewer, J. Physiological characteristics of an international female soccer squad. J Sports Sci
10: 142-143, 1992.
7. Davies, JA and Brewer, J. Applied physiology of female soccer players. Sports Med
16: 180-189, 1993.
8. Jensen, K and Larsson, B. Variations in physical capacity among the Danish national soccer team for women during a period of supplemental training. J Sports Sci
9. Krustrup, P and Bangsbo, J. Physiological demands of top-class soccer refereeing in relation to physical capacity: effect of intense intermittent exercise training. J Sports Sci
10. Krustrup, P, Mohr, M. Amstrup, T, Rysgaard, T, Johansen, J, Steensberg, A, Pedersen, PK, and Bangsbo, J. The yo-yo intermittent recovery test: physiological response, reliability and validity. Med Sci Sports Exerc
35: 695-705, 2003.
11. Krustrup, P, Mohr, M, Ellingsgaard, H, and Bangsbo, J. Physical demands during an elite female soccer game: importance training status. Med Sci Sport Exerc
37: 1242-1208, 2005.
12. Krustrup, P, Mohr, M, Steensberg, A, Bencke, J, Kjær, M, and Bangsbo, J. Muscle and blood metabolites during a soccer game: implications for sprint performance. Med Sci Sport Exerc
. 38: 1165-1171, 2006.
13. Krustrup, P, Mohr, M, Heiner-Møller, A, Krustrup, B, Poulsen, A, and Bangsbo, J. The use of sub-maximal and maximal yo-yo intermittent endurance testing in soccer. In: ECSS 2006, Book of Abstracts, 2006
. pp. 155.
14. Mayhew, SR and Wenger, HA. Time-motion analysis of professional soccer. J Hum Mov Stud
11: 49-52. 1985.
15. Mohr, M, Krustrup, P, and Bangsbo, J. Match performance of high-standard soccer players with special reference to development of fatigue. J Sports Sci
21: 439-449, 2003.
16. Mohr, M, Krustrup, P, Nybo, L, Nielsen, JJ, and Bangsbo, J. Muscle temperature and sprint performance during soccer matches-beneficial effects of re-warm up at half-time. Scand J Med Sci Sports
14: 156-162, 2004.
17. Mohr, M, Krustrup, P, and Bangsbo, J. Fatigue in soccer-a brief review. J Sports Sci
. 23: 593-599, 2005.
18. Ohashi, J, Togari, H, Isokawa, M, and Sukuzi, S. Measuring movement speeds and distance covered during soccer match-play. In: Science and Football
. Reilly T, Lees A, Davids K, and Murphy WJ, eds. London/New York: E & FN Spon, 1988. pp. 434-440.
19. Polman, R, Walsh, D, Bloomfield, J, and Nesti, M. Effective conditioning of female soccer players. J Sports Sci
22: 191-203, 2004.
20. Rebelo, N, Krustrup, P, Soares, J, and Bangsbo, J. Reduction in intermittent exercise performance during a soccer match. J Sports Sci
16: 482-483, 1998.
21. Reilly, T and Thomas, V. A motion analysis of work-rate in different positional roles in different positional roles in professional football match-play. J Hum Mov Stud
2: 87-97, 1976.
22. Reilly, T. Energetics of high-intensity exercise (soccer) with particular reference to fatigue. J Sports Sci
15: 257-263, 1997.
23. Rhodes, EC and Mosher, RE. Aerobic and anaerobic characteristics of elite female university players. J Sports Sci
10: 143-144, 1992.
24. Shepard, RJ. Biology and medicine of soccer: an update. J Sports Sci
17: 757-786, 1999.
25. Van Gool, D, Van Gerven, D, and Boutmans, J. The physiological load imposed on soccer players during real match-play. In: Science and Football
. Reilly T, Lees A, Davids K, and Murphy WJ, eds. London/ New York: E & FN Spon, 1988. pp. 51-59.