The main aim of this study was to assess the nutrition knowledge of elite squash players. This study also aimed to quantify the association between age and world ranking on players nutrition knowledge. Thirdly, the study aimed to quantify the effects of standard of relevant education and where players obtained their main source of nutrition information from on players nutrition knowledge. The final aim of the study was to survey what contemporary sports nutrition research elite squash players would like to see being conducted in the future.
The main findings of this study were (1) elite squash players have average nutrition knowledge, (2) there were no differences in nutrition knowledge between male and female players, (3) age and world ranking had a small positive association with nutrition knowledge, (4) players who had a relevant undergraduate degree were found to have better nutrition knowledge than those who had not relevant qualification, (5) players who obtained their main source of nutrition knowledge from a sports nutritionist were shown to have better nutrition knowledge than players who obtained from a sports scientist or the internet, (6) players valued quantifying the energetic demands throughout a training period as the research they would like to see undertaken in the future.
Sports Nutrition Knowledge and Influencing Factors
Overall, players sport nutrition knowledge was average (56%). Evaluations of players nutrition knowledge in comparison to other athletes is difficult due to the heterogeneity of tools and standard of athlete used to assess sports nutrition knowledge . The RNSKQ was devised as a universal tool to quantify athlete’s nutrition knowledge and make comparisons among different sports . To date, three previous studies [19, 20, 21] have used the NSKQ to assess sports nutrition knowledge with no previous study using the RNSKQ. All three studies found athletes sports nutrition knowledge to be poor (Jenner et al., 2018 = 46% ; Trakman et al., 2018 = 46% ; McCrink et al., 2020 = 40% ) in contrast to the present findings. Elite squash players should aim to increase their nutrition knowledge as this may optimise their dietary practices  which have been reported to be sub-optimal [9, 22]. Nutritional education interventions have been effective at increasing nutrition knowledge in athletes . Future research should aim to quantify the effectiveness of a nutritional educational intervention at increasing nutrition knowledge in elite squash players.
Sex was shown to have no significant differences on overall nutrition knowledge or any subsections (Fig. 3). Assuming appropriate energy availability , aside from iron intake in regularly menstruating females , the main determinants of a player’s nutritional requirements are based on their training load, regardless of sex . Therefore, sex shouldn’t influence nutrition knowledge and is consistent with findings from Trakman et al. (2016) . Future research should aim to quantify the training loads and energy expenditures of male and female elite squash players to determine whether there are any differences in relative energetic demands between sexes. This would convey whether any differences in nutrition education are required between sexes among elite squash players. It would also provide specific nutritional recommendations for elite squash players to follow as reported in other racket  and high intensity intermittent sports . 55 players (71%) surveyed in the present study conveyed that they would like to see this research undertaken. Players dietary intakes should also be quantified alongside training loads, as reported in other high intensity intermittent sports (26, 27). This would give an insight into whether players dietary intake is optimal in relation to their training load . Players in the present study had poor knowledge of the contemporary carbohydrate and protein guidelines (see supplementary tables 13 and 33 [10, 29]). This is consistent with findings from Ventura-Comes et al., (2019)  that elite Spanish squash players under consume carbohydrate in comparison to contemporary guidelines , with players rarely consuming foods which have a high carbohydrate content such as bread, potatoes, pasta and rice. Despite having poor knowledge of contemporary guidelines, players in the present study were able to identify the carbohydrate (see supplementary tables 14–18) and protein (see supplementary tables 32 and 42) content of foods, as well as appropriate protein sources to promote muscle growth post resistance training (see supplementary tables 34–37). Players were also aware of what macronutrients to consume pre (see supplementary table 59), during (see supplementary table 64) and post exercise (see supplementary table 66), as well as a suitable fuelling strategy (see supplementary table 61) and snack during a 60-90-minute session (see supplementary table 65). This suggests that although players are unaware of contemporary guidelines, they may still follow optimal fuelling and recovery strategies. Many of the carbohydrate sources Ventura-Comes et al., (2019)  were reporting players to under consume were low glycemic index carbohydrates. It could be possible that squash players have a higher intake of high glycemic index carbohydrates. These are recommended around training sessions . Food consumption frequency questionnaires have been shown to display poor validity and reliability  in comparison to other methods such as weighed food diaries, snap ‘N’ send and 24-hour dietary recall [31, 32]. Subsequently, more valid and reliable methods need to be employed to assess the energy intake and nutritional habits of elite squash players to obtain a better understanding of their dietary practices.
Players were shown to have poor supplementation knowledge in the present study (45%). This is consistent with findings from Venutra-Comes et al., (2018)  who reported that elite Spanish squash players consumed ergogenic aids which had a lower efficacy such as glutamine, branch chain amino acids and flaxseed oil, rather than ones which had higher efficacy such as beta-alanine, creatine and sodium bicarbonate . Players in the present study were unable to identify the rationale for use of beta-alanine (see supplementary table 77) supplementation. Beta-Alanine could enhance squash performance by increasing muscle carnosine stores and the subsequent buffering capacity of the muscle . Tam et al., (2019)  reported that supplementation was the least frequent topic of nutrition education interventions (34%). This may explain why supplementation knowledge is poor in players. Players should aim to increase their supplementation knowledge to optimise their supplementation strategy. Future research should quantify the effectiveness of a nutritional education programme in elite squash players which includes supplementation information. Future research should also aim to quantify the efficacy of ergogenic aids (e.g. beta-alanine, sodium bicarbonate, creatine, caffeine and nitrates) in elite squash to establish a supplementation strategy specific to the sport.
Age was shown to have a small positive effect on nutrition knowledge (r = .281), which is in contrast to previous findings . Players may not have support to a nutritionist in their early years, as national governing bodies prioritise senior players who have a greater likelihood of achieving success. Nutritional education interventions have been shown to increase nutrition knowledge in adolescent athletes . Future research should aim to quantify the effectiveness of a nutritional education intervention to increase nutrition knowledge in adolescent athletes and determine whether this translates into practice.
World ranking was also shown to have a small positive effect on nutrition knowledge (r = .208). Players with better nutrition knowledge have been shown to have more optimal dietary practices . This may increase athletic performance and consequently increase a player’s world ranking.
A relevant undergraduate degree was shown to significantly increase nutrition knowledge in players in comparison to players with no relevant qualification (Fig. 4). This is to be expected given that undergraduate degrees (e.g. BSc Sport & Exercise Science) are designed to increase knowledge in a subject specific area, and many players cited that they had completed a nutrition module as part of their course.
Players who received their main source of nutrition information from a sport nutritionist were shown to score significantly higher than players who received their main source of nutrition information from a sport scientist, or the internet / social media (Fig. 5). Consequently, players should look to consult with a sports nutritionist to obtain nutrition information and be discouraged from using the internet / social media to increase their nutrition knowledge. Surprisingly, players who obtained their main source of nutrition information were shown to have poor nutrition knowledge (44%). Sport scientists might be able to understand and communicate mechanistic underpinning. However, they may lack the ability to translate this into practical nutrition recommendations and coherent strategies for athletes.
Conclusions and Future Directions
This was the first study to quantify the nutrition knowledge of elite squash players. Players were found to have average nutrition knowledge (56%). Sex was shown to have no effect on players nutrition knowledge. Age and world ranking were shown to have a small positive effect on nutrition knowledge. Players who had a relevant undergraduate degree had better nutrition knowledge than those who had no relevant education. Players who consulted with a sports nutritionist were shown to have better nutrition knowledge than those who obtained nutrition information from the internet or a sport scientist. Consequently, based on data from this study, elite squash players should aim to increase their nutrition knowledge by consulting with a sports nutritionist. Future research should aim to quantify the effectiveness of a nutrition education intervention at increasing the nutrition knowledge of elite squash players.
Players had poor knowledge of contemporary carbohydrate and protein guidelines with previous research reporting mismatches between guidelines and dietary intakes . However, it is possible that these guidelines and not specific to elite squash players and does not translate into poor dietary practices. Future research should quantify the training load and dietary practices of elite squash players to create specific nutritional recommendations for the sport. This will provide information on whether players dietary practices are optimal and will create specific nutrition recommendations for elite squash players as exhibited in other racket  and high intensity intermittent sports .