Fluids and electrolytes in football
This process of losing body water is called dehydration, due to which acute or chronic dehydration, called hypohydration, occurs.
Most team sports matches include two time periods (usually 30 or 45 minutes long) separated by a break in the middle of the game (10-20 minutes). During this half-time break, players try to rest mentally and physically, rehydrate, use ergogenic aids, listen to their coach’s technical instructions and receive medical treatment or change their equipment1. However, this protocol, so widely accepted by players and coaches, may not be the best to follow. Some studies have shown that in football, there is a decrease in physical2 and cognitive3 performance and an increase in injury risk4 at the beginning of the second half. It appears that the decrease in body temperature due to excessive passive recovery in the changing room may be behind this decline in the player’s performance.
A recent study5 suggests the use of a different intervention model during half-time in order to reduce the possible negative effects of the break in the match. It proposes the following actions(assuming the rest period lasts for 15 minutes):
The decrease in body temperature seen during the half-time break could be avoided with two strategies6:
1. Warm clothing, outdoor survival jackets or thermal blankets can be used with little inconvenience for players. This has proven to be beneficial to fight the decrease in body temperature.
2. The room temperature of the changing room could be a bit higher.
The re-warm-up proposed at the end of the break could improve the players’ physical and technical performance in comparison with passive recovery practices7. Performing high intensity exercises and/or post-activation potentiation may be a good strategy. The presence of caffeine and carbohydrates in the mouth may facilitate performance immediately afterwards8,9. However, if the time between taking them and the exercise that follows is too long, the ergogenic effects of these substances could be lost. The recommendation is to chew caffeine gum and take carbohydrate solutions in the final moments of the break. The positive reinforcement of viewing video sequences of successful actions taken by the players could increase the positive messages from the coach10. Likewise, images of the opposing team that generate negative reactions in the players must be presented cautiously.
However, this theoretical intervention model for half-time in matches should never be a rigid protocol. It is meant to complement rather than replace the practices that the players find beneficial and that is part of their individual activation strategies.
Carlos Lago Peñas
1Towlson, C.; Midgley, A.W. & Lovell, R. (2013). Warm-up strategies of professional soccer players: practitioners’ perspectives. J Sports Sci. 31(13):1393-401.
2 Mohr, M.; Krustrup, P. &Bangsbo J. (2005). Fatigue in soccer: a brief review. J Sports Sci. 23(6):593-9.
3 Greig, M.; Marchant, D.; Lovell, R.; et al. (2007). A continuous mental task decreases the physiological response to soccer-specific intermittent exercise. Br J Sports Med. 41(12):908-13.
4 Hawkins, R.D. & Fuller CW. (1996). Risk assessment in professional football: an examination of accidents and incidents in the 1994 World Cup finals. Br J Sports Med. 30(2):165-70
5 Russell, M.; West, D.; Harper, L.D.; Cook, C. & Kilduff, L.P. (2015). Half-time strategies to enhance second-half performance in team-sports players: A review and recommendations. Sports Medicine. 45(3):353-364.
6 Kilduff, L.P.; West, D.J.; Williams, N.; et al. (2013). The influence of passive heat maintenance on lower body power output and repeated sprint performance in professional rugby league players. J Sci Med Sport. 16(5):482-6.
7 Mohr, M.; Krustrup, P.; Nybo, L.; et al. (2004). Muscle temperature and sprint performance during soccer matches: beneficial effect of rewarm-up at half-time. Scand J Med Sci Sports. 14(3): 156–62.
8Beaven, C.M.; Maulder, P.; Pooley, A.; et al. (2013). Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance.ApplPhysiolNutrMetab. 38(6):633-7
9 Ryan, E.J.; Kim, C.H.; Fickes, E.J.; et al. (2013). Caffeine gum and cycling performance: a timing study. J Strength Cond Res. 27(1):259-64.
10 Cook, C.J. &Crewther, B,T. (2012). The effects of different pre-game motivational interventions on athlete free hormonal state and subsequent performance in professional rugby union matches. PhysiolBehav. 106(5):683-8.
An article published in The Orthopaedic Journal of Sports Medicine —in which members of the club’s medical services participated— now suggests to consider the detailed structure of the area affected, and treating the extracellular matrix as an essential player in the prognosis of the injury.