An investigation of the impact of hydration status on cognitive performance in martial artists and the use of the theory of planned behaviour to determine their attitudes and beliefs in hydration prior to training

Abstract

Background:
Martial arts are a group of combat sports which include striking sports such as Karate and Taekwondo and grappling sports including Judo and Brazilian Jiu Jitsu. They have become increasingly popular in the UK and Ireland over recent years. There is a propensity to restrict fluid prior to competition and a high prevalence of dehydration has also been observed prior to training in martial artists. The aim of this research is to examine the impact of hydration status on cognitive function and to investigate the attitudes and beliefs of martial artists prior to a 90-minute training session using the theoretical framework of the theory of planned behaviour (TPB).

Methods:
There were two different types of study design employed in this research. A cross sectional between-subject design explored the impact of hydration on cognitive function in Judo, Brazilian Jiu Jitsu (BJJ) and Karate athletes after a martial arts training session (Study one). Participants undertook baseline measurements of height, weight and urine specific gravity (USG) pre and post exercise. In addition, martial artist performed 5 cognitive tests(simple reaction time, 5-choice reaction time, rapid visual information processing, spatial span, spatial working memory) from four cognitive domains post-exercise using The Cambridge Automated Neuropsychological Test Battery (CANTAB).

The second study design was a sequential exploratory design with mixed methods used in two different research studies. Firstly, a cohort of Judo and BJJ athletes (Study two) and secondly included participants from Karate (Study 3). Both studies had two phases i) an elicitation study examining the salient beliefs of the participants to hydration prior to a 90-minute training session with the results being used in phase two. ii) a TPB questionnaire was constructed using the salient beliefs from phase one, exploring the attitudes and beliefs of martial artists to hydration in the form of the direct and indirect TPB constructs of attitudes(ATT), subjective norms (SN) and perceived behavioural control (PBC). These three constructs were used to predict behavioural intentions via regression analyses in an extended TPB model along with socio-demographic information.

Results:
In study one no significant differences were observed in four cognitive tests using a computerised test battery called CANTAB (simple reaction time, rapid visual information processing, spatial span, spatial working memory) between dehydrated and euhydrated participants. For 5-choice reaction time the dehydrated participants were significantly faster. Only spatial working memory was significant between Judo / BJJ athletes and Karateka with athletes from Karate performing less errors. For study one, subject norms and perceive behavioural control significantly predicted intentions to hydrate prior to a 90-minute training session in Judo and BJJ athletes. When indirect TPB measures were analysed five indirect ATT (feel nauseous, feel better, boost energy levels, better brain function, aids recovery) and two indirect PBC (carrying a water bottle, being too busy) predicted behavioural intentions. Similar findings were observed in study 3 on Karate, with ATT, SN and PBC all predicting intentions to hydrate prior to a 90-minute training session. For indirect constructs, four ATT(bloating, improved performance, maintain stamina, prevent fatigue), one SN (coaches) and three PBC (having access to fluid, being properly prepared, drinking prior to training)predicted intentions to hydrate.

Conclusions: In the research presented in this thesis dehydration did not negatively affect cognitive function after a martial arts training session except in the case of 5-choice reaction time which improved reaction time. It is unclear why this occurred, it may be due to increased brain activity or there is a possibility that with faster reaction time there is a speed/accuracy trade-off when DEH. When considering the two TPB studies, SN and PBC significantly predicted behavioural intentions to hydrate prior to 90-minute training session when examining Judo and BJJ athletes, with ATT, SN and PBC predicting intentions in Karateka. This suggests that social influence and control factors are potential factors in iimproving hydration practices in martial arts. The indirect TPB predictors are useful in identifying factors that could inform a potential behaviour change intervention. Before any firm conclusions can be drawn on hydration in martial arts, more RCT are needed on the impact of hydration on performance and cognition over a longer time period. Future research should focus on developing a behavioural change intervention for those that are in need of improving hydration habits.

Date of Award	May 2025
Original language	English
Supervisor	Liz Simpson (Supervisor) & Pamela Magee (Supervisor)