The Physiological Demands of Football

Aims of Presentation : Describe what actions are typical of a football match. Explain how positional differences effect physiological demands. Explain how Aerobic and Anaerobic power is needed by footballers. Explain the fatigue footballers experience and what effect it has on the overall game. Discuss previous research concerning Energy consumption in a football match.

Physiological demands The physiological demands of soccer play are indicated by the exercise intensities at which the many different activities during match play are performed. Reilly. T, 1996

Work Rate Profile Reilly. T, 1996

Positional Differences The physiological demands and work rate of footballers are largely determined by the positional role they play in a team. The largest distances are covered by midfield players who have to act as links between defence and attack. In studies of English league players (Reilly, 1976) full backs showed the greatest versatility. However although they covered more overall distance than centre backs, they covered less distance sprinting. The greatest distances covered sprinting were found in strikers and midfielders.

Positional Differences

Aerobic Power Football calls for an oxygen uptake roughly corresponding to 75% of the VO 2 max (Reilly. T, 1990), a value likely to be close to the anaerobic threshold of most players. VO 2 max was found to be correlated significantly with the distance covered in a game, underlining the need for a high work-rate and high aerobic fitness, particularly for midfield players Smaros (1990) also showed that V0 2 max influenced the number of sprints players attempted

Anaerobic Power Centre-backs and strikers have to jump more frequently than full backs or midfield players. The frequency of once every 5-6 mins denotes that whilst jumping ability may not be as important in football as in basketball and volleyball, anaerobic power output and the ability to jump well vertically are requirements for centre backs and strikers (particularly target men)

Fatigue Bangsbo (1991) reported total distance covered in the first half was 5% (around 300m) greater than in the second. Van Gool et al (1988) found Belgium university players covered an average of 444 metres more in the 1 st half than the 2 nd. Reilly and Thomas (1976) found an inverse relationship between aerobic fitness (V02 max) and decrement in work- rate

Distances covered over 90 minutes split into 15 minute intervals

Importance of Glycogen Swedish club players with low glycogen content in the vastus lateralis muscles were found to cover 25% less overall distance than the other players(Saltin, 1973) Also those with low muscle glycogen stores pre match covered 50% of the total distance walking and 15% at top speed, compared to 27% walking and 24% sprinting for players who started with high muscle glycogen concentrations.

Energy Expenditure Energy expenditures have been estimated from both work rate profiles and heart rate values. Heart rate averaged throughout the game are related to heart – rate oxygen consumption relationships determined for individuals in laboratory conditions. Estimates are in general agreement that soccer competition at the top level entails an average energy expenditure of 4000 to 6000 KJ (for a 70kg player) (Bangsbo 2000). Chemical techniques such as the doubly – labelled water method may prove useful in the future.

Energy Expenditure Comparisons