Assessing Nutritional Knowledge in Elite Badminton Players: Study Results

By Freddy Brown, and Prof Cathy Speed

ABSTRACT

smash-in-badmintonBackground: Badminton is an “intermittent” racquet sport, requiring technical skill and sport-specific-fitness. This study aimed to assess the nutritional knowledge of badminton players to shape the delivery of future support, and to facilitate fuelling and recovery strategies.

Methods: The General Nutrition Knowledge Questionnaire was administered online to 26 players on the GB Badminton Squad. The questionnaire was comprised of the following sections:

1) awareness of dietary recommendations;

2) knowledge of food sources of nutrients;

3) making practical food choices;

4) awareness of diet-disease associations; and

(5) knowledge of antioxidant vitamins.

Results: Players scored 70.8% on awareness of dietary recommendations, 62.3% on knowledge of food sources of nutrients, and 67.7% on using knowledge to make food choices. The group scored significantly lower than the highest scoring section on the technical questions regarding disease-associations and antioxidants (47.9% and 17.9%, respectively). The group scored highest on questions mentioning sugar, but significantly lower for questions mentioning fat (73.1% vs. 55.2%, p= 0.01).

Conclusions: Future interventions should use this knowledge of healthy eating and nutrients to shape education for fuelling and recovery. Education should also focus on increasing athletes’ knowledge of fats, particularly those suggested by the literature to impact positively on performance, wellness, and rehabilitation.

What are the new findings?

  • Badminton players on the GB Performance Programme showed favourable scores compared to previously studied athletic populations, scoring particularly well on awareness of dietary recommendations, knowledge of food sources of nutrients, and food choices.
  • Poorer knowledge was shown in the subjects of disease-associations and antioxidants.
  • The group scored but significantly lower for questions mentioning fat compared other macronutrients.

How might it impact on clinical practice in the near future?

  • Future interventions should use this knowledge of healthy eating and nutrients to shape education for fuelling and recovery.
  • Education should also focus on increasing athletes’ knowledge of fats, particularly those suggested by the literature to impact positively on performance, wellness, and rehabilitation.

BACKGROUND

Badminton is a racquet sport of an intermittent nature, requiring repeated bouts of high-intensity effort in between periods of recovery. Badminton requires a blend of technical skills, tactics and concentration, sport-specific-fitness, and psychological strength (1) whilst peak aerobic capacity (represented by RER values approaching 1) may be reached frequently throughout match-play and training, emphasising the importance of obtaining an adequate carbohydrate intake (2). The updated scoring system (best of 3 games of 21 points) introduced in 2006 increased average rally times (3), with training strategies adapted to allow players to cope with greater physiological demands. Elite players participate in a busy tournament schedule, necessitating frequent foreign travel. Aspects of this lifestyle may therefore compromise making appropriate food choices, as well as sleep and immune-function. These varied demands place a great deal of importance on training-adaptation and supportive nutritional strategies for fuelling and recovery, as well as health and wellness during competition and travel.   

AIMS

The purpose of this study was to assess the nutritional knowledge of badminton players in order to shape the delivery of future education and support strategies. This could help facilitate fuelling and recovery strategies in such a demanding environment, and help tailor interventions to deliver maximum impact in a sport where nutritional support is relatively new to the culture.

METHODS

Ethical approval was requested from the UK Health Departments Research Ethics Service. An email was sent to all GB Badminton players residing at the National Badminton Centre, Milton Keynes, inviting them to participate. The possible benefits of the study, and requirements in terms of time and divulging personal information, were detailed in a participant information sheet, and informed consent voluntarily obtained from all participants.

The General Nutrition Knowledge Questionnaire (GNKQ), focusing on good dietary choices and the knowledge of nutritional contents of foods (4), was slightly adapted to make the wording relevant to athletes. These minor alterations essentially consisted of replacing the words “starchy foods” with “carbohydrate dense foods” and replacing the word “healthier”, with the phrase “more suited to fuelling/recovering from training”. This was done to reflect vocabulary more usually found in the culture of sports nutrition, as well as to coincide with the messages provided at the National Badminton Centre which emphasised training-specific nutritional strategies, instead of classifying foods as always either “healthy” or “unhealthy”. Messages on sugar particularly could have caused confusion from the idea of health, rather than requirement. This questionnaire was deemed particularly appropriate for the aims of the study, having been constructed to “identify areas of weakness in people’s understanding of healthy eating” and to examine the “relationship between nutrition knowledge and dietary behaviour”. This instrument has been used to compare the knowledge of athletic and non-athletic populations, allowing multiple comparisons (5, 6). The questionnaire was comprised of four main sections, being designed to test 1) awareness of dietary recommendations; 2) knowledge of food sources related to the advice, that is, which foods contain which nutrients; 3) ability to use knowledge to make practical food choices; and 4) awareness of diet-disease associations. In addition there was a final subsection (5) testing knowledge of antioxidant vitamins. As part of post-hoc analysis, questions were also categorised into those explicitly mentioning specific macronutrients; carbohydrate, sugar, protein and fat. One mark was awarded for each correct answer. Multiple choice questions with multiple correct answers were allocated additional marks for avoiding incorrect answers (e.g. a question requiring the identification of carbohydrate-rich foods from 6 choices would have a total of 6 marks available).

The questionnaire was administered on-line using an internet-based survey programme, and completed by badminton players residing in the National Badminton Centre.

All data were analyzed using the SPSS for Windows (Release 19.0) statistical software package (SPSS, Chicago, Ill., USA). Differences in mean scores between various groupings were analysed with parametric ANOVAs   (one-way/between measures), whilst within-individual differences between questionnaire subsections were also assessed (one-way/within measures). The accepted level of significance was set at P=0.05 for all statistical tests.

RESULTS

Population Demographics

Elite Badminton Players (26 in total; 14 men and 12 women), training full time at the National Badminton centre, Milton Keynes, completed the questionnaire. Their details are summarised in Table 1. Despite the young age of the cohort, they exhibited a high average level of education with 7 of 26 (27%) having a degree, and 22 athletes (85%) having been educated to at least an A-level standard. All were in full time training, completing 21-25hr per week.

Table 1: Population Demographics

 Age (± SD) Education: Highest level Most frequent competition level
Secondary/GCSE A-levels Diploma Degree European International
Male 22.4 (2.4) 2(14%) 8 (57%) 1 (7%) 3 (21%) 4 (71%) 10 (29%)
Female 22.7 (3.8) 2(17%) 6 (50%) 4 (33%) 7(58%) 5(42%)

Dietary Knowledge

The mean score for the whole cohort was 65.3 (from 111 available marks; 58.9 %). Women tended to score higher on average than men with a score of 63.4% Vs 55.0%, although this difference did not reach significance (P=0.1).

Scores were no different between singles players and those that did not play singles when considering either the whole cohort, or when assessing the different disciplines within sexes (results not shown). There was also no difference in total scores between those educated to degree standard and above, and those educated to a lower level.

Table 2: Scores on the questionnaire of dietary knowledge

SCORE (%)
Total Score (% ± SD) Subsection Score   (% ± SD) Macronutrient Score (% ± SD)
Total scorePercentage Recommendations nutrients choices disease antioxidants protein sugar carbohydrate fat
All Players 58.9 (13.1) 70.8 (10) 62.0 (15.1) 67.7 (18.6) 47.9 (20.4) 17.9 (32.0) 71.6 (18.5) 73.1 (15.1) 72.6 (21.3) 55.2 (16.8)
men 55.0 (13.4) 70.7 (9.2) 57.9 (16.1) 64.3 (17.4) 43.3 (21.4) 13.1 (33.4) 64.3 (14.6) 72.9 (13.3) 71.4 (18.0) 51.1 (17.5)
women 63.4 (11.6) 70.8 (10.8) 66.8 (12.2) 71.7 (19.5) 53.3 (19.3) 23.6 (29.7) 80.2 (18.8) 73.3 (17.2) 74.0 (24.7) 59.9 (14.4)

 

Players scored on average above 60% in the sections focused on awareness of dietary recommendations (70.8%), knowledge of food sources of nutrients (62.0%) and using knowledge to make food choices (67.7%). Players scored significantly lower in comparison to the most highly scored section for awareness of diet-disease associations (47.9%) and for knowledge of antioxidants (17.9%).

Subdividing the questions into those on specific macronutrients, the group scored averages of 71.6% on questions explicitly mentioning protein, 73.1% for those mentioning sugar and 72.6% for carbohydrate rich foods. They scored significantly lower compared to the highest scoring section (on sugar) for questions mentioning fat (55.2%; p=0.001).

Most frequently correctly/incorrectly answered questions

Of the 10 questions most frequently answered correctly, 5 were on the nutrient content of food, 4 were on dietary recommendations, and 1 was on dietary choices. Of the 5 questions on nutrient content, 3 were on carbohydrate rich foods, 2 on sugar and one each on protein and fat (Table 3).

Table 3: 10 most frequently correctly answered questions

Question Section Macronutrients Mentioned Frequency of Correct Answers Percentage of Athletes with Correct answer
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods? Vegetables Recommendations 25 96
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods? Fruit? Recommendations 25 96
Do you think these are high or low in added sugar? Ice-cream? Nutrients Sugar 25 96
Do you think these foods are high or low protein? Chicken? Nutrients Protein 25 96
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods? sugar? Recommendations Sugar 24 92
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods? Fat? Recommendations 24 92
Do you think experts would group any of the following as carbohydrate-rich foods? Pasta? Nutrients Carbohydrate-dense foods 23 88
Do you think experts would group any of the following as carbohydrate-rich foods? Rice? Nutrients Carbohydrate-dense foods 23 88
Do you think experts would group any of the following as carbohydrate-rich foods? Porridge? Nutrients Carbohydrate-dense foods 23 88
Which would be the best choice for a low fat, high fibre light meal? (Tick one). Baked Beans? Choices Fat 22 85

 

The questions with the lowest average scores are recorded below, alongside the number of athletes who answered each question correctly (Table 4). These consist of the 10 most frequently incorrectly answered questions, and the 10 most frequently incorrectly answered questions after the disease-risk and antioxidant questions are ignored (15 in total).

Table 4: Most frequently incorrectly answered questions

Question Section Macronutrients Mentioned Frequency of Correct Answers Percentage of Athletes with Correct answer
Do you think these help prevent heart disease?- Eating fewer preservatives (y/n)? Disease 1 4
Have you heard of antioxidant vitamins? Which of these is an antioxidant vitamin? Vitamin k (y/n)? Anti-oxidants 2 8
Do you think these help prevent cancer?- Eating fewer preservatives (y/n)? Disease 2 8
Polyunsaturated margarine contains less fat than butter- y/n? Nutrients Fat 2 8
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods? Meat? Recommendations 2 8
Do you think health experts recommend that people should be eating more, the same amount, or less of these foods?   Carbohydrate-dense foods such as Whole-grains, Pasta and Rice? Recommendations Carbohydrate-dense foods 3 12
Have you heard of antioxidant vitamins? Which of these is an antioxidant vitamin? B Complex Vitamins Anti-oxidants 4 15
Have you heard of antioxidant vitamins? Which of these is an antioxidant vitamin? Vitamin e Anti-oxidants 4 15
Do you think these fatty foods are high or low in saturated fat? Margarine? Nutrients 4 15
Do you think these fatty foods are high or low in polyunsaturates? Vegetable oil? Nutrients Fat 4 15
Do you think these are high or low in fat? Low Fat Spread Nutrients Fat 5 19
Do you think these fatty foods are high or low in saturated fat? (tick one box per food); Red Meat Nutrients 6 23
Some foods contain a lot of fat but no cholesterol (agree/disagree)? Nutrients Fat 6 23
A type of oil which contains mostly monounsaturated fat is: (tick one); Olive Oil Nutrients Fat 6 23
Which cheese would be the best choice as a lower fat option? (Tick one); Edam? Choices Fat 6 23

 

This table displays the 15 most frequent incorrect answers. These comprise of the 10 most frequent wrong answers, alongside the 10 most frequent wrong answers that remain after questions regarding disease-risk-associations and knowledge of antioxidants are removed

DISCUSSION

Elite GB badminton players showed a good level of knowledge, with their total scores comparing favourably with those in other young athletic populations, including Elite Australian age-group athletes in national level competition (5), and American university athletes (6). These findings may be due in part to the slightly greater average age of our participants. These badminton players were also mostly competing at an international level as opposed to a national or varsity standard. The elite development pathway of GB Badminton would have exposed these athletes to sport-science support throughout their careers.

Themes in correct vs. incorrect answers

When subdividing the questions into those on specific macronutrients, the group scored highest on questions regarding sugar, and significantly lower for questions mentioning fat (73.1% vs. 55.2%, p= 0.01). When subdividing on areas of knowledge, an awareness of making suitable food-choices is demonstrated by the fact that players scored on average above 60% in the sections focused on awareness of dietary recommendations (70.8%), knowledge of food sources of nutrients (62.3%) and using knowledge to make food choices (67.7%). These Badminton players scored far lower on the more technical questions regarding disease-associations and antioxidants (47.9% and 17.9%, respectively). This initial finding would suggest a good awareness of healthy food choices, specifically those regarding sugar; a recurring theme throughout these athletes’ answers. Area of technical knowledge were far weaker. This trend is relatively consistent amongst young athletes, with other researchers proposing that younger athletes are less concerned with disease at this early stage of their careers (5, 6). Whilst this is not unlikely, similar trends were seen in the initial validation of the GNKQ in an older population.

Although the most poorly answered sections were on technical knowledge, and could be argued to be less impactful on performance than health guidelines, there is a lot of existing research on the potential benefits of antioxidant intake (dietary and supplementary) for athletic recovery and injury rehabilitation (7). Therefore a greater understanding of the roles, functions and sources of antioxidants could impact on performance. In contrast, although athletes showed good knowledge of dietary choices and recommendations, this is only one of a myriad of factors influencing behaviour (8). Food diaries and information on common obstacles to healthy eating behaviours would need to be obtained before making recommendations on dietary interventions.

Questions on carbohydrate-dense foods

Questions specifically mentioning “carbohydrate” or “starch” were answered most accurately compared to those on the other macronutrients. Being in the Elite Performance Programme throughout their careers, it is likely athletes will have been exposed to a great deal of information on the importance of carbohydrate for fuelling and recovery. However, this knowledge seemed to be coupled with an air of caution concerning sugar consumption. Despite the fact 23 from 26 athletes identified pasta, rice and porridge as carbohydrate rich foods, 20 athletes also successfully identified an adverse health condition associated with high sugar intakes. In contrast, only 3 athletes knew that current dietary advice for the general population was to consume more carbohydrate. This same question was also highlighted as particularly low scoring in American university athletes, with 53% answering this question incorrectly, compared to 88% in our sample. There is currently a great deal of controversy over optimal carbohydrate intakes for sport, with many weight-loss diets advocating a reduction in carbohydrate intake, and evidence emerging that has led some to advocate carbohydrate-depletion as a strategy for enhancing endurance adaptations (9). Carbohydrate recommendations consider training volume, body weight and specific sports (10), possibly leading to confusion with the more general healthy-eating advice in the public domain. Our players may have been overly sensitive to the possibilities of increasing caloric intake with a high carbohydrate diet.

Fat

Once questions regarding disease-risk-associations and knowledge of antioxidants are removed, then 6 of the 10 most frequently incorrectly answered questions involved fat. All of these questions were categorised as pertaining to “knowledge of nutrient-content” of foods, with a great deal of confusion over different forms of fat. A common theme was regarding perceived “healthier options” as lower in absolute levels of fat. For example, only 5 athletes managed to identify the fact that low-fat spreads are not low in fat in absolute terms, whilst only 2 athletes identified the fact that polyunsaturated margarine did not contain less fat than butter. A possible explanation for many of the incorrect results may be in confusing dietary choices deemed to be “healthy” or “unhealthy” with absolute macronutrient contents. Accordingly, only one athlete identified cottage cheese as a low fat food, cheeses generally being high in fat.

A great deal of research has also strongly advocated the use of polyunsaturated fatty acids for mediating the inflammatory effects of exercise (11), which could be pertinent for recovery and immune health. Such dietary strategies depend on the different properties of fatty acids, meaning that the lack of ability to differentiate between fats may potentially impact on performance.

Protein

The second most frequently incorrectly answered question, pertained to the recommendations that we consume less meat (only one athlete answered this correctly). This particular question was also poorly answered amongst young Australian and American athletes (5, 6). These badminton players habitually consumed protein around training (a total of 18 athletes took some kind of protein supplement – results not shown), and possibly emphasised protein to the point of contradicting public health advice on meat. These recommendations are based on reducing saturated fat intake. Accordingly, only 6 of 26 athletes recognised red meat as being a food high in saturated fat, although this answer may not be wholly incorrect as lean cuts of red meat are widely available that approach the European Commission’s definition of a food low in saturates (containing less than the 1.5% saturated fat by weight). Such ambiguity has been previously highlighted as a limitation of the questionnaire (5). Furthermore, both the team physician and former nutritionist had previously emphasised nutritional strategies for iron repletion, with 2 of the female athletes surveyed identified as having iron insufficiencies. This may have reinforced the image of red meat as a “healthy” option.

CONCLUSIONS AND FUTURE DIRECTIONS

Elite GB badminton players have a sound knowledge of dietary recommendations and making healthy dietary choices, with a good grasp of the protein, carbohydrate and sugar content of food. Knowledge of fat wasn’t as comprehensive, whilst technical knowledge of antioxidants and disease associations was lower than more practical knowledge of dietary recommendations and food choices. These athletes’ knowledge was particularly focused towards macronutrients and behaviours pertinent to athletic fuelling and recovery. However, this may have manifested in attitudes that were particularly cautious towards sugar, and potentially overemphasised the importance of meat in the diet. Future educational delivery should use this knowledge of macronutrients to shape educational strategies. Further food diary analysis is needed, as well as information on obstacles to appropriate eating behaviours. Education strategies should emphasise the role of fats and dietary antioxidants for energy balance, recovery and immune function, as well as highlight disease risk-factors. Initial presentations should be followed up with individual consultations in accordance with players’ preferences.

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  8. Mickleborough TD, Murray RL, Ionescu AA, Lindley MR. Fish oil supplementation reduces severity of exercise-induced bronchoconstriction in elite athletes. Am J Respir Crit Care Med. 2003 Nov 15;168(10):1181-9.

……….

Freddy Brown, MSc, MBioch (Oxon) is a Performance Nutritionist – GB Badminton, National Badminton Centre, Milton Keynes: Freddy.brown@eis2win.co.uk. He collected all information, and conducted all analyses and wrote up the study.

Professor Cathy Speed Is a Sports Physician at the English Institute of Sport, National Badminton Centre, Milton Keynes. Prof Cathy Speed over saw and supervised Mr. Brown’s data collection and article authorship.

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