Abstract
The aim of the present study is to analyse nutritional supplements (NS) consumption by squash players of different levels (international vs. national). A total of 14 international players and 28 national ones answered a NS consumption frequency questionnaire that had been previously validated. A T-Student test was used for independent samples and a χ² test was used in the comparative analysis among athletes of different levels. International level players consume NS in greater proportion vs. national level players (100% vs. 67.9% p = 0.017), with differences in the consumption of bicarbonate of soda, glutamine, branched-chain amino acids, and flaxseed oil (p < 0.05). Even though international level athletes show a greater total number of NS, as well as of the total of NS of each of the categories based on scientific evidence level (sports food, medical supplements, and ergogenic aids of groups A, B, C, and D) in relation to the national level athletes, no statistically significant differences were detected (p > 0.05). With regard to nutritional advice, there are also differences among performance levels (p = 0.003), being personal trainers (28.6%) and dietitians-nutritionists (21.4%) the greatest prescribers when it comes to international-level players, whereas 55.6% of the national-level players do not receive nutritional advice. The pattern of NS consumption, based on evidence level, is unbalanced and its performance could be favored if the dietitian-nutritionist were included as a nutritional advisor for these athletes.
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Key Findings
Metabolic demands in the sport squash translate to high resistance requirements, both aerobic and anaerobic, muscular strength and manual grip strength, movement speed, change of direction and reaction, agility, acceleration, and flexibility. When the performance level increases considerably, adequate intake of energy and nutrients becomes even more critical as any small benefit acquired can provide an advantage during the competition. The possibility of improving performance often encourages athletes to consider nutritional supplements (NS) consumption. In 2000, the Australian Institute of Sport (AIS) created a NS classification system for athletes (known as ABCD system), in which NS are differentiated according to the existent level of scientific evidence, as well as to other parameters that are related to security, legality, and effectiveness to improve sports performance. NS belonging to group A constitute NS that show a high level of scientific evidence for performance improvement, distinguishing among sports food (it provides a source of nutrients when it is not practical to consume everyday food, such as sports drinks, bars and gels, or milk whey protein), medical supplements (effective when treating clinical alterations such as nutritional deficiency) and performance supplements (they improve sports performance: caffeine, B-alanine, creatine, sodium bicarbonate, and nitrate or beetroot juice). Group B comprises NS that might have a positive effect on certain conditions, although a higher number of investigations is required, whereas group C comprises NS with no ergogenic effects and group D comprises NS of which use is not allowed due to being included in the list of substances and methods forbidden in sports. The aim of the current paper is to analyse the pattern of NS consumption and choice by squash players who compete at a national and international level.
Flaxseed oil was one NS described in the paper. The authors noted its impact on sports performance is still to be defined, although some point out a possible protection against bone mass loss and the capacity of mobilising and using the fat as fuel during long training sessions. International-level squash players show a higher NS consumption when compared to national-level players, 100% of the international-level squash players consume NS. In addition, the low consumption of NS with a potential ergogenic effect, such as creatine, sodium bicarbonate, caffeine, β-alanine, and nitrate/beetroot juice, which have been proven to have effects on sports performance, makes the NS consumption pattern to be imbalanced based on the level of scientific evidence.