Project Title:
An investigation of the impact of hydration status on cognitive performance of karateka
(athletes who practice karate)
Supervisors: Dr Liz Simpson, Professor Jacqueline McCormack
Contact Details: [email protected]; [email protected]
Level: PhD
Background
Hydration and exercise: Dehydration has a detrimental impact on exercise
performance potentially via increasing core body temperature, cardiovascular strain
and glycogen utilisation, altering metabolic function and impairing cognitive
performance (Sawka et al., 2007; Ganio et al., 2011). It is, therefore, critical that
athletes are adequately hydrated when exercising. Owing to variation in sweat rate
and composition between athletes (Sawka et al., 2007; Maughan et al., 2007;
Osterberg et al., 2009; Baker et al., 2015), it is not possible to provide one fluid
recommendation for all. ‘Salty sweaters’ may be particularly susceptible to heat
cramping (Eichner, 2007) and, therefore, may have higher needs for sodium
replacement. As the fluid requirements of athletes vary depending on individual
characteristics and the type/intensity of athletic activtiy in which they participate,
individualized fluid replacement strategies are needed. The American College of
Sports Medicine (ACSM) recommend that fluid intake during exercise should be
sufficient to limit body weight (BW) loss to <2% from baseline (Sawka et al., 2007).
However, this recommendation has been criticised as it may be inappropriate for
athletes that commence exercise in a severely dehydrated state.
Dehydration of ≥2% BW has consistently been shown to impair endurance
performance, particularly in warm weather conditions (Sawka et al., 2007; Chevront &
Kenefick, 2014). Furthermore, exercise-induced dehydration may have an adverse
effect on salivary antimicrobial proteins and immunoglobulins associated with mucosal
immunity (Fortes et al., 2012), thereby possibly resulting in increased susceptibility to
infection. Additionally pre-exercise dehydration of 3% BW impairs anaerobic
performance (Kraft et al., 2012, Davis et al., 2015) and even mild dehydration (~1-2%
BW loss) has been shown to negatively impact sport-specific cognitive-motor task
performance (Smith et al., 2012). Therefore, when providing nutritional advice to
athletes, an area in which many athletes appear to be lacking in knowledge (Heaney
et al., 2011; Walsh et al., 2011; Torres-McGhee et al., 2012), it is critical that individual
fluid requirements are specifically considered. Despite the obvious benefit of starting
exercise in a euhydrated state, many athletes begin exercise already dehydrated
(Osterberg et al., 2009; Volpe et al., 2009; Gibson et al., 2012; Rivera-Brown & De
Felix-Davila, 2012; Arnaoutis et al., 2014; Pettersson & Berg, 2014; Thigpen et al.,
2014; Magal et al., 2015). In addition many athletes do not drink sufficiently to replace
their fluid losses during exercise, with a high proportion being dehydrated posttraining/competition (Osterberg et al., 2009; Gibson et al., 2012; Rivera-Brown & De
Felix-Davila, 2012; Arnaoutis et al., 2014;
A recently published study within NICHE investigated the hydration status of
individuals participating in a variety of sports/activities pre- and posttraining/competition and to determine their sports nutrition knowledge, with a focus on
fluid knowledge (Magee et al. 2016). Urine specific gravity (USG) was measured
immediately before and after exercise and BW loss during exercise was assessed.
Nutritional knowledge was assessed using a validated questionnaire. 31.9% of
athletes commenced exercise in a dehydrated state (USG >1.020) with 43.6% of
participants dehydrated post-training/competition. Dehydration was particularly
prevalent (>40% of cohort) among karateka, female netball players, army officer
cadets, and golfers. Golfers that commenced a competitive 18 hole round dehydrated
took a significantly higher number of strokes to complete the round in comparison to
their euhydrated (properly hydrated) counterparts (79.5 ± 2.1 vs. 75.7 ± 3.9 strokes, p
= .049). Nutritional knowledge was poor among participants (median total score [IQR];
52.9% [46.0, 59.8]), albeit athletes who were euhydrated at the start of exercise had
a higher overall score in comparison to dehydrated athletes (55.2% vs. 50.6%, p =
.001). Findings from the study recently published by researchers in NICHE, therefore,
have significant implications for the education of athletes in relation to their individual
fluid requirements around exercise. Specifically in relation to karate more than 60%
were dehydrated following the training session. Karateka had the highest change in
Urine Specific Gravity (a measure of hydration) during training compared to the other
athletes and the highest median level of body weight loss during their training session
compared to other athletes. In all the types of athletes poorer hydration was associated
with poorer nutritional knowledge.
Hydration and karate: The practice of karate involves three aspects: Kihon (basic
movements such as punches, kicks and blocks); Kata (karateka must memorise, learn
and be to perform a large number of Kata which each are a very highly specific series
of attacks and blocks which are carried out in sequence) and Kumite (sparring with a
partner). During regular training sessions karateka usually train intensively for 90
minutes to 2 hours, traditionally with no break for hydration. In addition asking to go to
the toilet is disapproved, therefore, many karateka do not hydrate in the hour or two
before training. Whilst allowance is of course made for anyone with medical issues,
this may be a particular concern for any karateka with continence issues (such as
women who have difficulties related to pregnancy and childbirth) and given that kumite
in particular is doing in a loose, bouncing stance. In addition senior karateka also wear
heavy cotton outfits (Gi’s) which may increase sweating and may absorb sweat.
Compared to many other athletic activities, karate is quite unique in that, as well as
requiring flexibility, strength and endurance, it also necessitates memory, spatial
awareness and speed of reaction but is often undertaken in a dehydrated status and
with no opportunities to hydrate – which may adversely affect the cognitive
performance of the karateka. It is important also to note that for the first time karate
will be included in the Olympics in 2020 so this is critical time for the UK national team
in beginning their focused preparation towards this event. The team are working
closely with the Karate Union of Great Britain on this project.
PhD proposal:
This sports nutrition and psychology project aims to:
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Determine the impact of hydration status of (senior grade) karateka on
performance and cognitive function in a UK wide study.
Determine the nutritional and hydration knowledge of karateka across the UK.
Investigate the impact of the implementation of a nutrition and hydration
intervention programme on the performance and cognitive function of the UK
national karate squad.
Determine the views of karateka across the UK towards traditional hydration
practices, at both training and competition sessions.
Methods
Pilot work is currently underway with the Northern Ireland Shotokan Karate squad to
determine the most appropriate cognitive tests in the CANTAB system for the
assessment of cognitive performance in karate. These will include assessment of
memory, spatial awareness and speed of reaction.
Part 1
The first part of the project will be a UK wide study involving assessment of the impact
of hydration status on cognitive performance of senior grade adult karateka and will
take place at the UK national Easter and summer training schools. Hydration status
will be assessed by measuring urine specific gravity and urine colour pre- and postexercise. Karateka will be asked to provide a urine sample immediately before training.
Height will be measured using a stadiometer and weights will be recorded before and
after training. Kareteka will also be asked to complete a validated questionnaire in
order to assess their knowledge of sports nutrition and hydration. Following an
intensive 90 minute training session hydration status and weight will be reassessed
and karateka will undertake a series of cognitive function tests via the CANTAB
system. The PhD student, assisted by a placement student, and will test approximately
5 karateka per session with three sessions per day for a week at each of the training
schools.
Part 2
The PhD student will also undertake a more focused intervention with the UK National
Squad (who are now focusing on their preparations for Olympics 2020, as well as the
other European and World competitions that they participate in regularly). For the
squad members, baseline assessment of their usual hydration status and cognitive
function following an intensive training session will be undertaken. In addition their
nutrition and hydration knowledge at baseline will be assessed. Detailed dietary
assessment of each competitor will be undertaken using the diet history method and
employing the Nutritics software to enable an estimation of the levels of individual
nutrient intakes as well calorie intake and hydration. The competitors will be given
focused and individual dietary and hydration advice to follow for a period of 6 months.
Then their hydration status, cognitive performance and nutrition/hydration knowledge
will be reassessed. In addition individual interviews will be conducted with competitors
and their coaches to assess the perceived impact on their performance and well-being.
Part 3
Quantitative and qualitative research will be undertaken to determine the attitudes of
UK karateka towards hydration practices in karate. This work will take place via focus
groups, questionnaires and individual interviews.
Part 4
Starting towards the beginning of their project, the student will also undertake a
systematic review analysing the impact of hydration status on cognitive function and
performance in athletes.
Resources
The student will have access to the School of Psychology Psychology Test library
where we hold measures of health and lifestyle, cognitive function and psychological
well-being. They will have access to CANTAB a computerised cognitive test battery,
and training on how to select, administer and interpret tests. They will also have access
to the Human Intervention Studies Unit in NICHE and training on how to take diet
histories and analysis reported intakes using the Nutritics software undertake urine
specific gravity and anthropometric measures. They will also be given training in how
to undertake a systematic review.
Skills required of applicant:
Ability to perform scientific literature searches.
Good communication skills.
Good report writing skills.
Ability to work independently and as part of a team.
Experience of databases and SPSS.
Experience of carrying out research projects. Preferably some experience of memory
testing but not essential as training will be given for CANTAB testing.
Undertaking the project will necessitate travelling to various locations around the UK
and Ireland (with overnight stays) in order to undertake testing, therefore, the applicant
would need to be able and willing to travel.
As significant numbers of karateka under the age of 18 will also be present at the
training sessions (although not taking part in the study) the Karate Union of Great
Britain will likely expect that the applicant will undertake a criminal record check.
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