Carlo Castagna

Physiology of soccer : An update

AbstractSoccer is the most popular sport in the world and is performed by men and women, children and adults with different levels of expertise. Soccer performance depends upon a myriad of factors such as technical/biomechanical, tactical, mental and physiological areas. One of the reasons that soccer is so popular worldwide is that players may not need to have an extraordinary capacity within any of these performance areas, but possess a reasonable level within all areas. However, there are trends towards more systematic training and selection influencing the anthropometric profiles of players who compete at the highest level. As with other activities, soccer is not a science, but science may help improve performance. Efforts to improve soccer performance often focus on technique and tactics at the expense of physical fitness.During a 90-minute game, elite-level players run about 10km at an average intensity close to the anaerobic threshold (80–90% of maximal heart rate). Within this endurance context, numerous explosive bursts of activity are required, including jumping, kicking, tackling, turning, sprinting, changing pace, and sustaining forceful contractions to maintain balance and control of the ball against defensive pressure. The best teams continue to increase their physical capacities, whilst the less well ranked have similar values as reported 30 years ago. Whether this is a result of fewer assessments and training resources, selling the best players, and/or knowledge of how to perform effective exercise training regimens in less well ranked teams, is not known. As there do exist teams from lower divisions with as high aerobic capacity as professional teams, the latter factor probably plays an important role.This article provides an update on the physiology of soccer players and referees, and relevant physiological tests. It also gives examples of effective strength- and endurance-training programmes to improve on-field performance. The cited literature has been accumulated by computer searching of relevant databases and a review of the authors’ extensive files. From a total of 9893 papers covering topics discussed in this article, 843 were selected for closer scrutiny, excluding studies where information was redundant, insufficient or the experimental design was inadequate. In this article, 181 were selected and discussed. The information may have important implications for the safety and success of soccer players and hopefully it should be understood and acted upon by coaches and individual soccer players.

Factors influencing physiological responses to small-sided soccer games

Abstract The aim of this study was to examine the effects of exercise type, field dimensions, and coach encouragement on the intensity and reproducibility of small-sided games. Data were collected on 20 amateur soccer players (body mass 73.1 ± 8.6 kg, stature 1.79 ± 0.05 m, age 24.5 ± 4.1 years, [Vdot]O2max 56.3 ± 4.8 ml · kg−1 · min−1). Aerobic interval training was performed during three-, four-, five- and six-a-side games on three differently sized pitches, with and without coach encouragement. Heart rate, rating of perceived exertion (RPE) on the CR10-scale, and blood lactate concentration were measured. Main effects were found for exercise type, field dimensions, and coach encouragement (P < 0.05), but there were no interactions between any of the variables (P > 0.15). During a six-a-side game on a small pitch without coach encouragement, exercise intensity was 84 ± 5% of maximal heart rate, blood lactate concentration was 3.4 ± 1.0 mmol · l−1, and the RPE was 4.8. During a three-a-side game on a larger pitch with coach encouragement, exercise intensity was 91 ± 2% of maximal heart rate, blood lactate concentration was 6.5 ± 1.5 mmol · l−1, and the RPE was 7.2. Typical error expressed as a coefficient of variation ranged from 2.0 to 5.4% for percent maximal heart rate, from 10.4 to 43.7% for blood lactate concentration, and from 5.5 to 31.9% for RPE. The results demonstrate that exercise intensity during small-sided soccer games can be manipulated by varying the exercise type, the field dimensions, and whether there is any coach encouragement. By using different combinations of these factors, coaches can modulate exercise intensity within the high-intensity zone and control the aerobic training stimulus.

Validity of a repeated-sprint test for football.

Three studies involving 108 football players were conducted to examine the reliability of a repeated-shuttle-sprint ability (RSSA) test and its ability to differentiate between players of various competitive levels and playing positions. Study 1: Short-term reliability was determined in 22 professional players completing the RSSA test (6 x 40-m sprints with 20 s of recovery between sprints) on two separate occasions. Study 2: Long-term reliability (seasonal changes) was examined in 31 professional players completing the RSSA test four times (during the preseason period, at the start, middle and end of the competitive season). Study 3: 108 players were divided and compared according to competitive level or playing position. Standard error of measurement values expressed as coefficient of variation for RSSA mean time and best time were 0.8 and 1.3 % (short-term reliability) and 0.9 and 1.2 % (long-term reliability), respectively. The smallest worthwhile changes were 0.5 % for both mean and best time. Professional players showed better RSSA performance than amateur players, and defenders displayed the lowest RSSA performance. In conclusion, the RSSA test showed adequate construct validity but only RSSA mean time showed sufficient reliability to detect large training-induced changes but not small important differences.

The validity and reliability of a global positioning satellite system device to assess speed and repeated sprint ability (RSA) in athletes.

There is a limited understanding of the validity and reliability of commercially available global positioning satellite (GPS) devices for assessing repeated sprint performance in athletes. The aims of this study were to assess the convergent validity and the test-retest reliability of a GPS device for measuring repeated sprint ability test (RSAT) variables. Two groups participated in this study, a group of 21 physical education students (age: 20.2+/-2.3 years, stature: 1.75+/-0.42 m, body mass: 68.0+/-6.8kg) and a second group 14 elite junior soccer players (age: 14.5+/-1.2 years, stature: 1.60+/-0.09 m, body mass: 57.7+/-3.8kg) volunteered to participate in this study. Convergent validity was assessed as the correlation between sprint performance (15 and 30-m) using both timing lights and a portable GPS device during a RSAT (7 x 30-m sprints with 30-s of active recovery). The 7 x 30-m RSAT test-retest reliability using GPS device was assessed in elite junior soccer players repeating the test 1 week apart and expressing reliability as a coefficient of variation. Results showed a strong correlation between peak speed measures with the GPS device and RSAT performance measured with timing lights for the 15-m (r(2)=0.87, p<0.001, N=147) and 30-m (r(2)=0.94, p<0.001, N=147) splits, respectively. There was a low coefficient of variation for summated maximal speed (1.7%) and peak speed (1.2%) during the 7 x 30-m RSAT, but high variation for the percentage decrement score (36.2%). These results provide evidence to support the use of the GPS device as an alternative measure to assess repeated sprint performance but suggest a percentage decrement score is not a reliable measure of RSAT performance.

Match demands of professional Futsal: A case study

Despite its popularity and competitive status there have been only few scientific studies that have examined Futsal in professional players. Consequently the aim of this study was to examine the physiological responses and activity pattern to Futsal simulated game-play in professional players. Eight full-time professional outfield Futsal players volunteered for this study: age 22.4 (95% CI 18.8-25.3) years, body mass 75.4 (60-91) kg, height 1.77 (1.59-1.95) m and VO2max 64.8 (53.8-75.8) ml kg(-1) min(-1). Physiological measurements were assessed during highly competitive training games (4x10-min quarters) and consisted of game VO2, game blood-lactate concentration ([la](b)) and game heart rates (HRs). Game activities were assessed using a computerised video-analysis system. During simulated game-play players attained 75% (59-92) and 90% (84-96) of VO2max and HR(max), respectively. Mean game VO2 was 48.6 (40.1-57.1) ml kg(-1) min(-1). Peak game VO2 and HRs were 99% (88-109) and 98% [90-106] of laboratory maximal values, respectively. Players spent 46 and 52% of the playing time at exercise intensities higher than 80 and 90% of VO2max and HR(max), respectively. Mean [la](b) was 5.3 (1.1-10.4) mmol l(-1). Players covered 121 (105-137) m min(-1) and 5% (1-11) and 12% (3.8-19.5) of playing time spent performing sprinting and high-intensity running, respectively. On average players performed a sprint every approximately 79 s during play. These results show that Futsal played at professional level is a high-intensity exercise heavily taxing the aerobic and anaerobic pathways.

Fitness determinants of success in men's and women's football

Abstract In this study, we examined gender and age differences in physical performance in football. Thirty-four elite female and 34 elite male players (age 17 ± 1.6 to 24 ± 3.4 years) from a professional football club were divided into four groups (n = 17 each) according to gender and competitive level (senior males, senior females, junior males, and junior females). Players were tested for specific endurance (Yo-YoIR1), sprint over 15 m (Sprint-15m), vertical jump without (CMJ) or with (ACMJ) arm swing, agility (Agility-15m), and ball dribbling over 15 m (Ball-15m). The Yo-YoIR1 and Agility-15m performances showed both a gender and competitive level difference (P < 0.001). Senior and junior males covered 97 and 153% more distance during the Yo-YoIR1 than senior and junior females, respectively (P < 0.001). Gender but not age differences were found for Sprint-15m performance (P < 0.001). No difference in vertical jump and Ball-15m performances were found between senior and junior males (P > 0.05). More marked gender differences were evident in endurance than in anaerobic performance in female players. These results show major fitness differences by gender for a given competitive level in football players. It is suggested that training and talent identification should focus on football-specific endurance and agility as fitness traits in post-adolescent players of both sexes.

Match running performance in elite Australian Rules Football

There is little information describing the match running demands of elite-level Australian Rules Football (AF). The aims of this study were to examine: (1) match running demands; and (2) the influence of periods of increased physical activity on subsequent running performance in the Australian Football League. Time-motion analyses were performed 1-9 times per player from 16 professional AF players from the same club during games in 2005-2007, using portable global positioning systems during 65 matches. Game movements (standing, walking, jogging, running, higher-speed running, and sprinting) and distances (total distance covered [TD]; low-intensity activity [LIA, distance <14.4kmh(-1)]; and, high-intensity running distance [HIR, distance>14.4kmh(-1)]) were collected. The influence of the first half physical activities on second half activities, and each quarter on the subsequent quarter were analysed. The mean (+/-SD) TD and HIR distance covered during the games were 12,939+/-1145m and 3880+/-663m respectively. There were reductions in TD in the second (-7.3%), third (-5.5%) and fourth (-10.7%) quarters compared to the first quarter (p<0.01). The HIR was reduced after the first quarter (p<0.001). Players that covered larger TD or HIR during the first half or quarter decreased distance in the next half and quarter, respectively (p<0.001). These results show that a reduction in exercise intensity is inevitable during an AF match and that higher intensity activities reduce towards the end of games. High average speed during each half or quarter also affects subsequent running performance in elite-level AF.

Physiological Aspects of Soccer Refereeing Performance and Training

The role of the referee is far from minimal in the economy of soccer, as very often, particularly in professional soccer, a wrong judgment may have profound implications on the outcome of the game. In this regard, a better knowledge of soccer refereeing can obviously benefit the game. Recent studies have shown that during a competitive match, an elite soccer referee may cover 9–13km attaining approximately 85–90% and approximately 70–80% of maximal heart rate and maximal oxygen uptake (V̇O2max), respectively. Of the total distance covered about 4–18% is covered at high intensity. Blood lactate concentration has been reported to be in the range of 4–5 mmol/L; however, during competitive matches, blood lactate concentrations as high as 14 mmol/L have been observed. This figure is similar to that extensively reported for soccer players, specifically paralleling that observed in midfield players. However, compared with players, referees are 15–20 years older, often have a non-professional status and cannot be substituted during the game. Furthermore, this important physical stress superimposes onto a high perceptual-cognitive workload throughout the entire game. In relation to fitness status, referees possess V̇O2max values somewhat lower than the players they officiate, with mean values in the range of 44–50 mL/kg/min. However, the methods used by the Federation Internationale de Football Association and the Union of European Football Associations to test referee fitness need to be changed as the current fitness tests do not relate to match performance. More task-specific tests such as the Yo-Yo Intermittent Recovery Test (YYIRT) have been devised and validated for use with referees. Given that aerobic performance is positively correlated with match performance, it is important that referees are trained to improve their ability to cover large distances during a match and also to repeat high-intensity efforts. A number of studies have shown large improvements in YYIRT performance following both short-term (12 weeks) and long-term (16 months) high-intensity interval training. Future research needs to focus on a number of important areas including the decision-making ability of referees when officiating under different conditions, such as high thermal strain, and the impact of age on both physical and mental performance.

Effects of intermittent-endurance fitness on match performance in young male soccer players.

Castagna, C, Impellizzeri, F, Cecchini, E, Rampinini, E, and Barbero Alvarez, JC. Effects of intermittent-endurance fitness on match performance in young male soccer players. J Strength Cond Res 23(7): 1954-1959, 2009-The purpose of this study was to examine the effect of specific endurance (Yo-Yo Intermittent recovery test level 1, Yo-Yo IR1) on match performance in male youth soccer. Twenty-one young, male soccer players (age 14.1 ± 0.2 years) were involved in the study. Players were observed during international championship games of corresponding age categories and completed the Yo-Yo IR1 on a separate occasion. Physical (distance coverage) and physiological match demands were assessed using Global Positioning System technology and heart rate (HR) short-range telemetry, respectively. During the match (two 30-minutes halves), players covered 6,204 ± 731 m, of which 985 ± 362 m (16%) were performed at high intensities (speed >13 km·h−1, HIA). A significant decrement (3.8%, p = 0.003) in match coverage was evident during the second half. No significant (p = 0.07) difference between halves was observed for HIA (p = 0.56) and sprint (speed >18 km·h−1, SPR) distances. During the first and second halves, players attained the 86 ± 5.5 and 85 ± 6.0% of HRmax (p = 0.17), respectively. Peak HR during the first and second halves were 100 ± 4 and 99.4 ± 4.7% of HRmax, respectively. Yo-Yo IR1 performance (842 ± 352 m) was significantly related to match HIA (r = 0.77, p < 0.001) and total distance (r = 0.65, p = 0.002). This studys results showed that specific endurance, as determined by Yo-Yo IR1 performance, positively affects physical match performance in male young soccer players. Consequently, the Yo-Yo IR1 test may be regarded as a valid test to assess game readiness and guide training prescription in male youth soccer players.

Effect of match-related fatigue on short-passing ability in young soccer players.

PURPOSE To examine whether the fatigue accumulated during match play or determined by short bouts of high-intensity intermittent activities affect short-passing ability in junior soccer players. A further aim was to examine the influence of physical fitness as measured using the Yo-Yo Intermittent Recovery Test (YYIRT) on the changes in short-passing ability after a 5-min simulation of high-intensity activities (HIS). METHODS Sixteen players (mean +/- SD: age 17.6 +/- 0.5 yr, height 174 +/- 7 cm, body mass 68 +/- 6 kg) participated in the study. A quasi-experimental control-period design was used for the study. Short-passing ability was measured using the Loughborough Soccer Passing Test (LSPT). Players completed the LSPT in two sessions during the 1-wk control period, followed by two unofficial matches during which the LSPT was performed during and after the first and the second halves of the game. Furthermore, the change in LSPT performance was determined after 5 min of HIS. RESULTS A decline in LSPT performance was found during and after the game (P < 0.01). The accuracy of the LSPT decreased after the HIS. A significant correlation was found between the YYIRT scores and the decline in LSPT performance (accuracy, total time, total time with penalties) after HIS (r = -0.51 to -0.65; P < 0.05). CONCLUSIONS This study showed that the fatigue developed during a match and after relatively short bouts of high-intensity intermittent activities has a detrimental effect on short-passing ability, and that the fatigue-related decline in technical proficiency for a given intensity is associated with the fitness level of the players.