Does kick-off time affect performance in football?
As well as being the first ever winter World Cup, the format of fixtures in Qatar is also different to previous tournaments. There are four group games being played every day (instead of two), with kick off times staggered throughout the day at 1pm, 4pm, 7pm and 10pm (Qatar local time). Although these kick off times are great for fans in the UK, the 10pm kick off time is not ideal for players.
Are there advantages to a late kick off in Qatar?
In hot conditions, players body temperature and dehydration risk increases, both of which compromises performance. For example, players cover less distance as temperature increases. One of the pros of a 10pm kick off in Qatar is that temperature will be lower (around 24 °C) than the earlier games, where temperatures could exceed 32 °C! However, the benefit of the cooler temperature at 10pm also comes with some disadvantages. England’s second group game against the USA kicks off at 10pm, which means the game will finish around midnight (probably much later based on the added times we’ve seen so far). In this article, I will briefly explain why playing football at 10pm is sub-optimal for performance and post-match recovery.
Out of synch
Circadian rhythms are physical, mental, and behavioral changes that follow a cycle of approximately 24-hours. Time of day and circadian physiology have substantial effects on physical and cognitive performance, as our circadian rhythm influences the time of day when peak performance is likely to occur (Reilly & Waterhouse, 2009). Many aspects of sporting performance (e.g., reaction time and speed) display a diurnal rhythm, where better performances are typically achieved in the late afternoon/early evening compared to the morning or late evening. Research suggests that peaks in actions requiring speed, strength and power occur between 15:30 to 20:30 hours, which means the 10pm kick off will be sub-optimal for most players from a physiological perspective.
Humans typically have an interindividual preference for the timing of waking behaviours (e.g., social activities and exercise habits) and sleep, which is referred to as ‘chronotype’. People who prefer to wake and perform activities in the early morning are classified as ‘early chronotypes’ and individuals who prefer to function later in the day are classified as ‘late chronotypes’, and those in between are ‘intermediate chronotypes’. Therefore, players who are early or intermediate chronotypes may find the 10pm game more physically and mentally challenging than players who are late chronotypes (Thun et al., 2016).
Elite athletes have identified sleep as being one of the most beneficial recovery strategies. However, athletes often experience poor sleep after an evening competition.
The reasons why players can’t sleep well after an evening game will be familiar to most of us. When you do a stressful activity (be it mental or physical), your body produces the hormone cortisol (often known as the stress hormone), which influences our alertness and circadian rhythm (see above). Cortisol production has a diurnal rhythm where it peaks in the morning and gradually decreases throughout the day, which is partly why we begin to feel sleepy in the evening. However, a stressful activity performed in the late evening, such as playing in front of 60,000 spectators, causes cortisol to increase. This rise in cortisol and other hormones in the late evening hinders our ability to fall asleep. Other factors also prevent players from sleeping after a game, such as the exposure to bright light and caffeine, both of which promote wakefulness. Hence why players have been reported to do recovery sessions at 1:30am after an evening game rather than lying in bed awake.
In addition to sleeping less, players sleep quality is also likely to suffer (Nadelec et al., 2015). Several physiological processes occur during sleep that promote muscle recovery. For example, growth hormone, which influences repair, is produced during non-rapid eye movement sleep. Sleep deprivation has also been shown to impair muscle glycogen repletion, delay the repair of damaged muscle, and increase the perception of pain and fatigue (Nadelec et al., 2015). Players perceived recovery ratings are also worse after night games. Taken together, the reduced quality and quantity of sleep players experience after an evening game increases the time they need to recover.
What can be done to minimise the negative effects of late-night football?
All the teams at the World Cup will have arrived in Qatar at least a week before their first game to allow players and staff to adapt to the new time zone. However, the approaches that teams use to prepare for night matches will be different. Most teams will adapt their schedules to match the next kick-off time. For a game at 10pm, this might involve players waking later in the morning and training later in the evening than usual. The purpose of this is schedule change is to shift/delay the players circadian rhythms to the later time of day. With only a few days between games, this change in training time is unlikely to have a significant physiological effect but could be useful psychologically. With game times changing throughout the tournament, it is unclear if it is better for teams to adopt a constant or adapting schedule.
All professional teams implement post-game recovery strategies that include methods to enhance physiological recovery. Commonly used methods include bespoke nutrition practices (e.g., recovery shakes), active recovery, cold water immersion, compression garments, and massage. The purpose of most recovery methods is to aid the repair of damaged muscles and replenish glycogen (stored carbohydrate) in the muscles and liver. Most teams will also ensure the players sleep hygiene is optimal, which involves creating an environment and recommending behaviours that are conducive to achieving quality sleep. For example, ensuring the beds are comfortable and the bedrooms are cool and dark. One study reported that a sleep hygiene strategy improved players sleep quantity after a late-night match, although there were no improvements in physical performance, perceptual recovery, or markers of muscle damage.
The 10pm kick off time should be the coolest time to play in the Qatar World Cup, which theoretically means the players performances are less likely to suffer because of the heat. However, playing football at 10pm is sub-optimal from a physiological perspective and will likely impede the players post-match recovery. Various strategies will be implemented to reduce the negative effects associated with the games at 10pm, such as training at a similar time in the days before the game and implementing post-game recovery strategies and sleep hygiene practices.