Developing Nutritional Considerations for Elite Squash Players Through a Performance Problems Lens

This PhD programme was a match funded PhD between Sheffield Hallam University, England Squash and the UK Sports Institute. The researcher worked as a performance nutrition practitioner, delivering consultancy services to England Squash while conducting impactful research to create new knowledge and change practice. In collaboration with the coaches and players at England Squash, the researcher undertook a needs analysis to identify four ‘performance problems’: (1) what are players understanding of nutrition; (2) do players have an awareness of their energy expenditure and know how to appropriately fuel and recover effectively from session to session to optimise their health, physical performance and training adaptations?; (3) players generally train twice per day from the hours of 09:30 to 11:30 and 14:00 to 16:00. Does this give players enough opportunity to optimally recover and rehydrate from one session to the next?; (4) some players have high sweat rates. Are players optimally rehydrated post session when they have limited time in-between training sessions? Consequently, the PhD aimed to answer these ‘performance problems’. Study one systematically reviewed all the physiological and nutritional literature conducted in squash to ascertain whether any of the ‘performance problems’ identified by the researcher had previously been answered. None of the ‘performance problems’ had been answered and the researcher also found that much of the physiological and nutritional literature is of a low quality and outdated. Thirty-five studies were included in the review. The study utilised the PEDro scale to quantify the methodological quality of the studies with many of the studies conducted in squash shown to have poor (10) or fair (19) methodological quality, and only four conveying good and two conveying excellent methodological quality. This is due to many of the studies conducted in squash being observational in design (32), rather than rather than double blinded crossover design studies.; Only 14/35 studies were conducted using elite or world class players, so it was difficult to translate much of the literature to elite players, due to a lack of validity. Much of the literature may be outdated as the World Squash Federation and Professional Squash Association changed the rules of squash in 2009 and therefore may not be valid due to these rule changes altering the in playing dynamics of squash (Murray et al., 2016). The review also presented some future directions for research to be conducted within squash. Study two quantified the nutrition knowledge of squash players through the Nutrition for Sport Knowledge Questionnaire (NSKQ) (Trakman et al., 2017). Many of the elite squash players who were funded by England Squash didn’t engage with performance nutrition consultancy services and felt that their knowledge and habits were appropriate. Consequently, the study aimed to screen players to determine whether they could benefit from nutrition support. A greater nutrition knowledge has been shown to lead to superior dietary behaviours (Valliant et al., 2012). Players were shown to have ‘average’ nutrition knowledge, and this led to conversations regarding nutrition support for many players, as well as whether the non-specific guidelines utilised in the NSKQ were relevant. Players questioned the relevance of the NSKQ and therefore the following two studies aimed to quantify the energetic demands, and hydration demands of elite squash players to critique whether non-specific guidelines were appropriate. Study three calculated the energy balance of a cohort of elite male squash players throughout a seven-day training microcycle. The study originally aimed to also quantify the energy balance of elite female squash players as well, however due to the cost implications of the methodology utilised, the reference standard doubly labelled water, there wasn’t enough funding available. Male players were chosen as that is where the ‘performance problem’ was perceived to be experienced. Mean daily EE was 4,210 ± 1,017 Kcals throughout the 7-day microcycle, with mean daily EI being 3,389 ± 981 Kcals. This equated to a mean daily negative energy balance of 821 Kcals, with mean EA over the microcycle was 31.68 ± 17.91 Kcal⋅kg-1 FFM⋅d-1 , indicating reduced EA. Player one was reported to have a mean energy balance of -2,392 Kcals⋅d-1 and mean energy availability of 11 Kcal⋅kg-1 FFM⋅d-1 . The study highlighted that elite male squash players exhibited a high energy expenditure throughout a training microcycle and may follow poor nutrition strategies such as severe energy restriction, leading to low energy availability and sub optimal carbohydrate intake. These sub optimal nutritional practices may lead to reduced training performance and symptoms of relative energy deficiency in sport. Nutrition support was provided to the cohort of players to optimise their nutrition strategies. Study four quantified the sweat rates and sweat [Na+ ] of elite squash players throughout a training session alongside their hydration practices. The study also aimed to determine whether two hours and thirty minutes was enough time to optimally rehydrate from one training session to the next, as many players would have limited time in-between training sessions. Players were shown to have a mean fluid balance of −1.22 ± 1.22% throughout the training session with a mean sweat rate of 1.11 ± 0.56 L·h-1 and a mean sweat [Na+ ] of 46 ± 12 mmol·L-1 . Two hours and thirty minutes was not shown to be enough time to replace the fluid and Na+ losses experienced from the previous session. Individualised hydration strategies were provided to each player who took part in the study to optimise their hydration strategies, as well as generating conversations with players and coaches regarding the training culture of England Squash and whether two hours and thirty minutes is enough time to optimally refuel and rehydrate from training sessions. Consequently, this PhD has created new knowledge and changed practices of elite squash players by: (1) systematically reviewing all of the available physiological and nutritional literature conducted within squash, having a positive impact on applied practice by presenting guidance for scientists, coaches, and players, whilst identifying gaps in knowledge to guide researchers on the future directions of research within squash; (2) quantifying the nutrition knowledge of elite squash players, identifying that it may be appropriate for players to consult with a sports nutritionist to increase their sport nutrition knowledge and nutrition habits; (3) calculating the energy balance of elite male squash players throughout a seven-day microcycle, providing the data to inform sport-specific nutritional guidelines while critiquing whether players current nutritional habits are optimal and subsequently providing bespoke nutritional support based on the data; (4) measuring the sweat rates and sweat [Na+] of players throughout a training session to provide players with individualised hydration strategies to optimise their physical performance.