AmaZulu High Performance Column – March 2023

Welcome back to our monthly performance column, over the months of January and February we discussed cold water immersion and contrast water therapy, this month, we are going to look at one of the most underappreciated recovery tools available, sleep.


So, why is sleep such a valuable recovery tool, well, it’s been found to provide important psychological and physiological functions that are fundamental to the recovery process (Silva et al., 2021). Without drilling down into these functions, as that is not the theme of this article, when someone sleeps, various hormones are released that allow for physiological recovery, whilst sleep is also associated with improved learning and motor memory, as well as cognitive recovery and decision-making capacity (Nedelec et al., 2015a; Silva et al., 2021). This is reinforced by several studies that have shown that a loss in sleep has negative consequences both physically and cognitively (Bonnar et al., 2018).

There are several variables that can interfere with sleep onset and quality, such as, playing in night matches, napping during the day, caffeine consumption and alcohol consumption, resulting in sleep deprived players and have a reduced capacity to perform (Nedelec et al., 2015a; Nedelec et al., 2015b). Considering the interplay between performance and sleep, and how footballers are regularly exposed to situations that limit their sleep quality and/or quantity, it’s important to try and mitigate that, and ensure peak athletic performance.

Sleep and performance:

In conducting a basic review of the literature, it has been suggested that sleep is “the best recovery strategy available to an athlete” (Bonnar et al., 2018). With this in mind, there are 3 categories of methods that are available for athletes and coaches to explore that maximize sleep-ability. We will focus on “sleep extension” and “sleep hygiene” in this article.

Table 1: Sleep intervention categories (Sourced from Bonnar et al., 2018).

Sleep extension:

Bonnar and colleagues (2018) conducted a systematic review on athlete sleep interventions, where they reviewed two papers that investigated total sleep duration interventions – i.e., increase the total sleep time of the athletes to see if it had an affect on performance. It was found in both studies that an increase in total sleep duration per day, including naps, was led to a range of improvements, both physical and technical. Both sets of studies indicated that athletes were getting on average 8.4-8.85 hours of sleep per day, and that a total period of 1 week following this protocol is required to see the benefits associated.

Sleep hygiene:

There are a number of sleep hygiene strategies that can be implemented to improve sleeping conditions of players, this is particularly important when players are involved in late night fixtures. Fullagar and colleagues (2016) investigated the use of a sleep hygiene strategy (SHS) versus allowing players to proceed with their normal post-game routine (NSHS). The SHS players were in their bedrooms as soon as possible after dinner, with the bedrooms dimmed and ear plugs and eyes masks provide, and the rooms at an average temperature of 17 degrees Celsius. No technological stimulation was allowed 15-30 minutes before bed, and lights were turned off at 00:00. It was found that the SHS group had a greater sleep duration, however, there was no improvement in physical performance measures. It can be argued that lack of an extended intervention and implementation of SHS in this study is the reason for the lack of performance related benefits.

The concept of an extended SHS intervention was investigated by Harada et al., (2015), with it being found that over a 1-month period, there was a greater subjective improvement in soccer performance, whilst at the 3-month follow-up period, it was found that the players had better sleep quality, had shifted to being a “morning person” and reported significant improvement in soccer performance.

Figure 1: Sleep hygiene considerations (Adapated from YLMSportScience).


As we can see, sleep certainly has a pivotal role to play in the recovery of players and their ability to perform. This means that various considerations should be made when it comes to the scheduling of training and travelling after late-night fixtures. Athlete education is also incredibly important in this, as players need to be taught good sleep hygiene and how the use of their phone, or the consumption of alcohol may in fact have an affect on their sleep quality – this is something we will go into further detail in next months column.

I hope this has highlighted the importance of sleep with regards to recovery and performance, and, at the same time provided you with some new tools to use to improve your very own sleep hygiene.

If you are interested and would like to take the next step in your soccer science career, take a look at the courses offered by our Official Education Partner, the International Soccer Science and Performance Federation on

Joshua Smith; MSc., PGDip, BSc (HONS)

High Performance Manager

AmaZulu FC


Bonnar, D. et al. (2018) “Sleep interventions designed to improve athletic performance and recovery: A systematic review of current approaches,” Sports Medicine, 48(3), pp. 683–703. Available at:

Fullagar, H. et al. (2016) “The effect of an acute sleep hygiene strategy following a late-night soccer match on recovery of players,” Chronobiology International, 33(5), pp. 490–505. Available at:

Harada, T. et al. (2015) “Intervention study using a leaflet entitled ‘three benefits of ‘go to bed early! get up early! and intake nutritionally Rich Breakfast!’ A message for athletes’ to improve the soccer performance of University Soccer Team,” Sleep and Biological Rhythms, 14(S1), pp. 65–74. Available at:

Nédélec, M. et al. (2015a) “Sleep hygiene and recovery strategies in elite soccer players,” Sports Medicine, 45(11), pp. 1547–1559. Available at:

Nédélec, M. et al. (2015b) “Stress, sleep and recovery in Elite Soccer: A critical review of the literature,” Sports Medicine, 45(10), pp. 1387–1400. Available at:

Silva, A.C. et al. (2021) “Sleep extension in athletes: What we know so far – a systematic review,” Sleep Medicine, 77, pp. 128–135. Available at:

Sleep – page 7 (2017) YLMSportScience. Available at: (Accessed: March 28, 2023).