Soccer 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 10 km 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.

http://carlocapelli.it/ftp/didattica/master calcio/bibliografia_essenziale/stolen_et_al_2005.pdf

Physiology of Soccer: An Update

The present study aimed to analyse the influence of speed and power abilities in goal situations in professional football. During the second half of the season 2007/08, videos of 360 goals in the first German national league were analysed by visual inspection. For the assisting and the scoring player the situations immediately preceding the goal were evaluated. The observed actions were categorised as: no powerful action, rotation (around the body's centre-line), straight sprint, change-in-direction sprint, jump, or a combination of those categories. Two hundred and ninety-eight (83%) goals were preceded by at least one powerful action of the scoring or the assisting player. Most actions for the scoring player were straight sprints (n = 161, 45% of all analysed goals, P < 0.001) followed by jumps (n = 57, 16%), rotations and change-in-direction sprints (n = 22, 6% each). Most sprints were conducted without an opponent (n = 109, P < 0.001) and without the ball (n = 121, P < 0.001). Similarly, for ...

Straight sprinting is the most frequent action in goal situations in professional football

/pdf/2020-esc-guidelines-on-sports-cardiology-and-exercise-in-4he1udph9m.pdf

2020 ESC Guidelines on sports cardiology and exercise in patients with cardiovascular disease.

The purpose of this study was to evaluate the physical demands of English Football Association (FA) Premier League soccer of three different positional classifications (defender, midfielder and striker). Computerised time-motion video-analysis using the Bloomfield Movement Classification was undertaken on the purposeful movement (PM) performed by 55 players. Recognition of PM had a good inter-tester reliability strength of agreement (κ = 0.7277). Players spent 40.6 ± 10.0% of the match performing PM. Position had a significant influence on %PM time spent sprinting, running, shuffling, skipping and standing still (p 0.05). Players spent 48.7 ± 9.2% of PM time moving in a directly forward direction, 20.6 ± 6.8% not moving in any direction and the remainder of PM time moving backward, lateral, diagonal and arced directions. The players performed the equivalent of 726 ± 203 turns during the match; 609 ± 193 of these being of 0° to 90° to the left or right. Players were involved in the equivalent of 111 ± 77 on the ball movement activities per match with no significant differences between the positions for total involvement in on the ball activity (p > 0.05). This study has provided an indication of the different physical demands of different playing positions in FA Premier League match-play through assessment of movements performed by players.

Physical demands of different positions in FA Premier League soccer

Field-based team sports, such as soccer, rugby and hockey are popular worldwide. There have been many studies that have investigated the physiology of these sports, especially soccer. However, some fitness components of these field-based team sports are poorly understood. In particular, repeated-sprint ability (RSA) is one area that has received relatively little research attention until recent times. Historically, it has been difficult to investigate the nature of RSA, because of the unpredictability of player movements performed during field-based team sports. However, with improvements in technology, time-motion analysis has allowed researchers to document the detailed movement patterns of team-sport athletes. Studies that have published time-motion analysis during competition, in general, have reported the mean distance and duration of sprints during field-based team sports to be between 10-20m and 2-3 seconds, respectively. Unfortunately, the vast majority of these studies have not reported the specific movement patterns of RSA, which is proposed as an important fitness component of team sports. Furthermore, there have been few studies that have investigated the physiological requirements of one-off, short-duration sprinting and repeated sprints (<10 seconds duration) that is specific to field-based team sports. This review examines the limited data concerning the metabolic changes occurring during this type of exercise, such as energy system contribution, adenosine triphosphate depletion and resynthesis, phosphocreatine degradation and resynthesis, glycolysis and glycogenolysis, and purine nucleotide loss. Assessment of RSA, as a training and research tool, is also discussed.

/pdf/physiological-and-metabolic-responses-of-repeated-sprint-4kvn16w16o.pdf

Physiological and Metabolic Responses of Repeated-Sprint Activities Specific to Field-Based Team Sports

The reliability and validity of a soccer-specific field test of repeated sprint ability was assessed. Seven male games players performed the repeated sprint test on six separate occasions. The temporal pattern of the mean sprint time was analysed by using coefficient of variation with confidence intervals (CI), and repeated measures ANOVA. A within subject mean coefficient of variation of 1.8% (95% CI, 1.5–2.4) was found for performance in the repeated sprint test across all six trials. The mean coefficient of variation across trials 2–4 was found to be 1.9% (95% CI, 1.3–3.1), compared to trials 4–6, where it was 1.4% (95% CI, 1.0–2.3). The ANOVA showed that a significant difference was present between the trials (F6,30 9.8, P < 0.001). A Tukey post-hoc test showed that significant differences were present between trial 1 and trials 3–6, and trial 2 and trial 5. The learning effect was complete by trial 3. Performance in the repeated sprint test was compared to total running time averaged from two repeats of the maximal anaerobic running test laboratory protocol. Mean sprint time in the repeated sprint test and total running time in the laboratory protocol had a correlation coefficient of r=−0.298 (P=0.516, n=7), suggesting that the energetics of the two tests are not closely related. In conclusion, this soccer-specific field test demonstrated high reliability.

Evaluation of the reliability and validity of a soccer-specific field test of repeated sprint ability

We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P < 0.01), but it was similar to Vest. Packs and Water blunted the rise of Tmu until minute 16 and for the duration of the CISP (40 min), respectively (P < 0.01). Reductions in PPO occurred from minute 32 onward in Control, and an increase in PPO by approximately 4% due to Packs was observed (main effect; P < 0.05). The method of precooling determined the extent to which heat strain was reduced during intermittent sprint cycling, with leg precooling offering the greater ergogenic effect on PPO than either upper body or whole body cooling.

https://www.physiology.org/doi/pdf/10.1152/japplphysiol.00822.2005

Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

Purpose:This study investigated the effects of precooling on performance and pacing during self-paced endurance cycling in the heat and, further, the effects of cooling on contractile function as a mechanism for performance changes.Methods:After familiarization, eight male cyclists performed

Precooling can prevent the reduction of self-paced exercise intensity in the heat.

https://bura.brunel.ac.uk/bitstream/2438/20036/2/FullText.pdf

Isothermic and fixed intensity heat acclimation methods induce similar heat adaptation following short and long-term timescales.

Background :
Hypoxia has been shown to increase glucose uptake in skeletal muscle using the contraction-stimulated pathway, independent of the actions of insulin. Yet, the same stress has also been linked with causing insulin resistance and hyperglycaemia. The aim of this study was to examine the effects of acute hypoxia with and without exercise on insulin sensitivity () in individuals with type 2 diabetes.
Methods :
Eight type 2 diabetic patients completed 60 min of the following: (1) normoxic rest; (2) hypoxic rest [O2 = 14.6 (0.4)%]; (3) normoxic exercise and (4) hypoxic exercise [O2 = 14.6 (0.4)%]. Exercise trials were set at 90% of lactate threshold. Each condition was followed by a labelled intravenous glucose tolerance test to provide estimations of insulin sensitivity () and ?-cell function.
Results :
Two-compartmental analysis showed that insulin sensitivity () was higher following hypoxic rest compared with normoxic rest (p = 0.047). Insulin sensitivity () was also higher following hypoxic exercise [4.37 (0.48) × 10?4/min (µU/mL)] compared with normoxic exercise [3.24 (0.51) × 10?4/min (µU/mL)] (p = 0.048). Acute insulin response to glucose was reduced following hypoxic rest versus normoxic rest (p = 0.014).
Conclusions :
This study demonstrated that (1) hypoxic-induced improvements in glucose tolerance in the 4 h following exposure can be attributed to improvements in peripheral insulin sensitivity () and (2) exercise and hypoxia have an additive effect on insulin sensitivity () in type 2 diabetic patients. Acute hypoxia may therefore improve short-term glycaemic control in individuals with type 2 diabetes. The application of these findings in the clinic will require further investigation.

/pdf/acute-hypoxia-and-exercise-improve-insulin-sensitivity-si2-50m6him2ih.pdf

Neil Maxwell

Papers

Evaluation of the reliability and validity of a soccer-specific field test of repeated sprint ability

Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

Precooling can prevent the reduction of self-paced exercise intensity in the heat.

Isothermic and fixed intensity heat acclimation methods induce similar heat adaptation following short and long-term timescales.

Acute hypoxia and exercise improve insulin sensitivity (SI2*) in individuals with type 2 diabetes