A Systematic Review of Athletes' and Coaches' Nutrition Knowledge and Reflections on the Quality of Current Nutrition Knowledge Measures

Jumping and throwing performance in the World Masters' Athletic Championships 1975-2016

Participation and performance of elite age group athletes from 35-39 to 95-99 years competing in World Masters Athletics (WMA) Championships 1975-2016 were examined for throwing (discus, hammer, javelin and shot put) and jumping (high jump, long jump, pole vault and triple jump) events. Overall, 21,723 observations from 8,974 master athletes were analysed. A mixed regression model with sex, age group, calendar year and interactions terms (sex-age group; sex-year) defined as fixed effects was performed for each event separately. Performances over time were increasing overall for each event, with a cubic trend. Compared with women, men had better performances (e.g. in triple jump the estimated difference was 3.378 meters, p < 0.001). However, women improved their performance more than men across calendar years. Performances declined with age for each event (e.g. in triple jump, compared with age group 45-49 years, performance in age group 35-39 years was 1.041 meter better and in age group 85-89 years was 5.342 meter worse). In summary, performance in jumping and throwing events of WMA Championships improved across calendar years, whereas the decline of performance with age was dependent on sex and event.

Dietary intake of professional Australian football athletes surrounding body composition assessment

BACKGROUND

Sports Dietitians aim to assist in improving performance by developing nutrition knowledge (NK), enhancing dietary intake and optimising body composition of athletes. In a high-pressure environment, it is important to identify factors that may compromise an athlete's nutrition status. Body composition assessments are regularly undertaken in sport to provide feedback on training adaptions; however, no research has explored the impact of these assessments on the dietary intake of professional athletes.

METHODS

This cross-sectional study assessed dietary intake (7-day food diary), nutrition knowledge (Nutrition for Sport Knowledge Questionnaire) and body composition (Dual-energy X-ray absorptiometry) of 46 professional male Australian football (AFL) athletes during a 2017 pre-season training week (7 days) where body composition assessments were undertaken. Dietary intake was assessed against International Olympic Committee recommendations for professional athletes.

RESULTS

Overall, no athlete met dietary their recommended energy intake (15 ± 1.1 vs. 9.1 ± 1.8 MJ, respectively) or carbohydrate recommendations (6-10 vs. 2.4 ± 0.9 g·kg-1·day-1). Only 54% met protein recommendations. Secondary analyses demonstrated significant associations between education status and energy intake (P < 0.04) and vegetable intake (P < 0.03), with higher levels of education being associated with higher intakes. A moderately positive association was observed between NK scores and meeting estimated energy requirements (r = 0.33, P = 0.03). NK scores were also positively associated with protein (r = 0.35, P = 0.02), fibre (r = 0.51, P = 0.001) and calcium intakes (r = 0.43, P = 0.004).

CONCLUSIONS

This research identified that the dietary intake of professional AFL athletes during a pre-season training week where body composition assessments were undertaken did not meet current recommendations. Several factors may influence the dietary intake of AFL athletes, including lower education levels, poor NK and dietary intake restriction surrounding body composition assessment. Athletes may require support to continue with performance-based nutrition plans in periods surrounding body composition assessment.

Australian Football Athletes Lack Awareness of Current Sport Nutrition Guidelines

Sports nutrition is an evolving field, but there is a lack of data on Australian athletes' knowledge of current sports nutrition guidelines. Additionally, several tools used to assess nutrition knowledge (NK) have not undergone adequate validation. The purpose of this study was to assess and compare the sports NK of elite and nonelite Australian football (AF) athletes using a newly validated questionnaire-The Nutrition for Sport Knowledge Questionnaire. Elite AF players (n = 46) were recruited directly from their club dietitian and nonelite AF players (n = 53) were invited to participate via e-mail from their club president or secretary. The mean NK score of elite and nonelite AF players was 46 ± 16% and 51 ± 11%, respectively (p = .041). In both groups, knowledge of macronutrients, weight management, and alcohol was better than knowledge of supplements, micronutrients, and sports nutrition. Nonelite athletes achieved statistically significantly higher scores on the questionnaire subsections testing weight management (elite: 48 ± 18; nonelite: 57 ± 19, p = .019), micronutrients (elite: 39 ± 19; nonelite: 50 ± 16, p = .004), and alcohol (elite: 52 ± 13; nonelite: 71 ± 17, p = .002). While overall NK of Australian athletes was poor, scores varied greatly among individuals (range: 10-70%) and across the six subsections (topics) being assessed. Professionals working with athletes should undertake an assessment of the athletes' NK so that they can provide targeted education programs.

Nutrition Knowledge Among Young Finnish Endurance Athletes and Their Coaches

The nutrition knowledge of athletes and coaches is often inadequate. However, athletes need sufficient knowledge of this subject to understand the importance of food choices for their athletic performance, recovery, and overall health. Adequate nutrition knowledge and skills are important for coaches because they are often the most significant source of nutrition knowledge for their athletes. Most previous nutrition knowledge studies have been carried out in team sports and outside Scandinavia. The aim of this study, therefore, was to evaluate the nutrition knowledge of Finnish endurance athletes (156 males and 156 females; age = 17.9 ± 1.2 years) and their coaches (69 males and 25 females; age = 44.3 ± 12.3 years). The three main sports among the participants were cross-country skiing (n = 53 coaches and n = 111 athletes), orienteering (n = 13 and n = 110), and biathlon (n = 6 and n = 38). On average, the coaches (N = 94) answered 81% ± 9% of the 79 nutrition questionnaire items correctly, whereas the respective result was 73% ± 9% among the athletes (N = 312). The coaches had significantly (p < .001) better nutrition knowledge of all the five subcategories of the questionnaire, whereas the "dietary supplements" and "nutrition recommendations for endurance athletes" subcategories appeared particularly difficult for the athletes. The average nutrition knowledge score of athletes was relatively low. As nutrition knowledge may have a positive association with athletes' food choices and subsequent dietary intake, Finnish endurance athletes and coaches would benefit from enhanced nutrition education.

Brief Education Intervention Increases Nutrition Knowledge and Confidence of Coaches of Junior Australian Football Teams

This study evaluated the impact of a brief (20-min) nutrition education intervention embedded in an existing mandatory coach education course for coaches of junior (8–12 years old) Australian football teams. A total of 284 coaches (68% of 415 coaching course participants) completed a presession questionnaire, and 110 coaches (27% of coaching course participants) completed an identical postsession questionnaire. The responses to the pre- and postsession surveys were matched for 78 coaches. Coaches’ ratings of their own understanding of the nutritional needs of young athletes (6.81, 8.95; p < .001), the importance of young athletes adhering to a healthy diet (9.09, 9.67; p = .001), their confidence in their own nutrition knowledge (7.24, 8.64; p < .001), and their confidence in advising young athletes on nutrition and hydration practices (6.85, 8.62; p < .001), all significantly improved following the education session. Nearly all coaches (>95%) provided a correct response to six of the 15 nutrition and hydration knowledge questions included in the presession questionnaire. Even with this high level of presession knowledge, there was a significant improvement in the coaches’ nutrition and hydration knowledge after the education session across five of the 15 items, compared with before the education session. The results of this study suggest that a simple, short nutrition education intervention, embedded in an existing coach education course, can positively influence the nutrition knowledge and self-efficacy of community-level, volunteer coaches of junior sports participants.

Development and validation of a brief general and sports nutrition knowledge questionnaire and assessment of athletes' nutrition knowledge

Background

The Nutrition for Sport Knowledge Questionnaire (NSKQ) is an 89-item, valid and reliable measure of sports nutrition knowledge (SNK). It takes 25 min to complete and has been subject to low completion and response rates. The aim of this study was to develop an abridged version of the NSKQ (A-NSKQ) and compare response rates, completion rates and NK scores of the NSKQ and A-NSKQ.

Methods

Rasch analysis was used for the questionnaire validation. The sample (n = 181) was the same sample that was used in the validation of the full-length NSKQ. Construct validity was assessed using the known-group comparisons method. Temporal stability was assessed using the test-retest reliability method. NK assessment was cross-sectional; responses were collected electronically from members of one non-elite Australian football (AF) and netball club, using Qualtrics Software (Qualtrics, Provo, UT).

Results

Validation - The A-NSKQ has 37 items that assess general (n = 17) and sports (n = 20) nutrition knowledge (NK). Both sections are unidimensional (Perc5% = 2.84% [general] and 3.41% [sport]). Both sections fit the Rasch Model (overall-interaction statistic mean (SD) = − 0.15 ± 0.96 [general] and 0.22 ± 1.11 [sport]; overall-person interaction statistic mean (SD) = − 0.11 ± 0.61 [general] and 0.08 ± 0.73 [sport]; Chi-Square probability = 0.308 [general] and 0.283 [sport]). Test-retest reliability was confirmed (r = 0.8, P < 0.001 [general] and r = 0.7, P < 0.001 [sport]). Construct validity was demonstrated (nutrition students = 77% versus non-nutrition students = 60%, P < 0.001 [general] and nutrition students = 60% versus non-nutrition students = 40%, P < 0.001 [sport]. Assessment of NK - 177 usable survey responses from were returned. Response rates were low (7%) but completion rates were high (85%). NK scores on the A-NSKQ (46%) are comparable to results obtained in similar cohorts on the NSKQ (49%). The A-NSKQ took on average 12 min to complete, which is around half the time taken to complete the NSKQ (25 min).

Conclusions

The A-NSKQ is a valid and reliable, brief questionnaire designed to assess general NK (GNK) and SNK.

Electronic supplementary material

The online version of this article (10.1186/s12970-018-0223-1) contains supplementary material, which is available to authorized users.

Fundamentals of glycogen metabolism for coaches and athletes

The ability of athletes to train day after day depends in large part on adequate restoration of muscle glycogen stores, a process that requires the consumption of sufficient dietary carbohydrates and ample time. Providing effective guidance to athletes and others wishing to enhance training adaptations and improve performance requires an understanding of the normal variations in muscle glycogen content in response to training and diet; the time required for adequate restoration of glycogen stores; the influence of the amount, type, and timing of carbohydrate intake on glycogen resynthesis; and the impact of other nutrients on glycogenesis. This review highlights the practical implications of the latest research related to glycogen metabolism in physically active individuals to help sports dietitians, coaches, personal trainers, and other sports health professionals gain a fundamental understanding of glycogen metabolism, as well as related practical applications for enhancing training adaptations and preparing for competition.

Athletes and Supplements: Prevalence and Perspectives

In elite sport, where opponents are evenly matched, small factors can determine the outcome of sporting contests. Not all athletes know the value of making wise nutrition choices, but anything that might give a competitive edge, including dietary supplements, can seem attractive. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, unless the athlete has a nutrient deficiency, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy, nor obtain approval from regulatory bodies before marketing supplements. This creates the potential for health risks, and serious adverse effects have been reported from the use of some dietary supplements. Athletes who compete in sports under an anti-doping code must also realize that supplement use exposes them to a risk of ingesting banned substances or precursors of prohibited substances. Government systems of regulations do not include specific laboratory testing for banned substances according to the WADA list, so a separate regulatory framework to evaluate supplements for their risk of provoking a failed doping test is needed. In the high-performance culture typical of elite sport, athletes may use supplements regardless of possible risks. A discussion around medical, physiological, cultural, and ethical questions may be warranted to ensure that the athlete has the information needed to make an informed choice.

Development of a nutrition knowledge questionnaire for young endurance athletes and their coaches

Both athletes and coaches should have adequate nutrition knowledge to understand the importance of diet on athletic performance, recovery, and health. Nutrition knowledge can be assessed reliably only by validated knowledge questionnaires. The aim of this study was to develop a reliable and valid questionnaire for assessing the nutrition knowledge of young endurance athletes and their coaches. The questionnaire was developed with an expert panel and pilot tested by athletes, coaches, and students. Content, face, and construct validities both as test-retest reliability and internal consistency reliability were ensured when the current questionnaire was developed. Athletes (n = 16) and coaches (n = 13) pilot tested the 127-item questionnaire. After item analysis and proposals from the expert panel, 41 items were removed. Internal consistency of the 86-item questionnaire in the pilot study was 0.87, measured using Cronbach's α. Construct validity was evaluated by the difference in knowledge between nutrition (n = 20) and humanities students (n = 22). Nutrition students had significantly higher knowledge scores (P < .001). Test-retest reliability for all knowledge sections between those groups was 0.85 measured using Pearson's r. Final adjustments to the questionnaire were made on the grounds of feedback from the respondents and proposals from the experts (n = 6). These adjustments resulted in minor changes in the construct of the items, the layout of the questionnaire, and the removal of 7 items. The final questionnaire had 79 items. The questionnaire can be used to measure the overall nutrition knowledge of endurance athletes and their coaches and to find potential gaps in nutrition knowledge.

The nutrition for sport knowledge questionnaire (NSKQ): development and validation using classical test theory and Rasch analysis

BACKGROUND

Appropriate dietary intake can have a significant influence on athletic performance. There is a growing consensus on sports nutrition and professionals working with athletes often provide dietary education. However, due to the limitations of existing sports nutrition knowledge questionnaires, previous reports of athletes' nutrition knowledge may be inaccurate.

METHODS

An updated questionnaire has been developed based on a recent review of sports nutrition guidelines. The tool has been validated using a robust methodology that incorporates relevant techniques from classical test theory (CTT) and Item response theory (IRT), namely, Rasch analysis.

RESULTS

The final questionnaire has 89 questions and six sub-sections (weight management, macronutrients, micronutrients, sports nutrition, supplements, and alcohol). The content and face validity of the tool have been confirmed based on feedback from expert sports dietitians and university sports students, respectively. The internal reliability of the questionnaire as a whole is high (KR = 0.88), and most sub-sections achieved an acceptable internal reliability. Construct validity has been confirmed, with an independent T-test revealing a significant (p < 0.001) difference in knowledge scores of nutrition (64 ± 16%) and non-nutrition students (51 ± 19%). Test-retest reliability has been assured, with a strong correlation (r = 0.92, p < 0.001) between individuals' scores on two attempts of the test, 10 days to 2 weeks apart. Three of the sub-sections fit the Rasch Unidimensional Model.

CONCLUSIONS

The final version of the questionnaire represents a significant improvement over previous tools. Each nutrition sub-section is unidimensional, and therefore researchers and practitioners can use these individually, as required. Use of the questionnaire will allow researchers to draw conclusions about the effectiveness of nutrition education programs, and differences in knowledge across athletes of varying ages, genders, and athletic calibres.

Developing and validating a nutrition knowledge questionnaire: key methods and considerations

Objective

To outline key statistical considerations and detailed methodologies for the development and evaluation of a valid and reliable nutrition knowledge questionnaire.

Design

Literature on questionnaire development in a range of fields was reviewed and a set of evidence-based guidelines specific to the creation of a nutrition knowledge questionnaire have been developed. The recommendations describe key qualitative methods and statistical considerations, and include relevant examples from previous papers and existing nutrition knowledge questionnaires. Where details have been omitted for the sake of brevity, the reader has been directed to suitable references.

Results

We recommend an eight-step methodology for nutrition knowledge questionnaire development as follows: (i) definition of the construct and development of a test plan; (ii) generation of the item pool; (iii) choice of the scoring system and response format; (iv) assessment of content validity; (v) assessment of face validity; (vi) purification of the scale using item analysis, including item characteristics, difficulty and discrimination; (vii) evaluation of the scale including its factor structure and internal reliability, or Rasch analysis, including assessment of dimensionality and internal reliability; and (viii) gathering of data to re-examine the questionnaire’s properties, assess temporal stability and confirm construct validity. Several of these methods have previously been overlooked.

Conclusions

The measurement of nutrition knowledge is an important consideration for individuals working in the nutrition field. Improved methods in the development of nutrition knowledge questionnaires, such as the use of factor analysis or Rasch analysis, will enable more confidence in reported measures of nutrition knowledge.

Validation of a General and Sport Nutrition Knowledge Questionnaire in Adolescents and Young Adults: GeSNK

Good knowledge of nutrition is widely thought to be an important aspect to maintaining a balanced and healthy diet. The aim of this study was to develop and validate a new reliable tool to measure the general and the sport nutrition knowledge (GeSNK) in people who used to practice sports at different levels. The development of (GeSNK) was carried out in six phases as follows: (1) item development and selection by a panel of experts; (2) pilot study in order to assess item difficulty and item discrimination; (3) measurement of the internal consistency; (4) reliability assessment with a 2-week test-retest analysis; (5) concurrent validity was tested by administering the questionnaire along with other two similar tools; (6) construct validity by administering the questionnaire to three groups of young adults with different general nutrition and sport nutrition knowledge. The final questionnaire, consisted of 62 items of the original 183 questions. It is a consistent, valid, and suitable instrument that can be applied over time, making it a promising tool to look at the relationship between nutrition knowledge, demographic characteristics, and dietary behavior in adolescents and young adults.

A valid and reliable nutrition knowledge questionnaire for track and field athletes

Background

Establishing an understanding of an athlete’s nutrition knowledge can inform the coach/practitioner and support the development of the athlete. Thus the purpose of the study was to develop a psychometrically valid and reliable tool to assess general and sport nutrition knowledge.

Methods

An 85 question questionnaire was developed in consultation with a panel of experts. Ninety-eight participants from the UK completed the questionnaire, and again 3 weeks later. The participants were classified into two groups: those with nutrition (NUT, n = 53) training (sport nutritionists and dietitians who were either practicing or undertaking a postgraduate qualification in the field), and those without (NONUT, n = 48) training (professionals and postgraduate students with no exposure to any form of nutrition training). The questionnaire was then administered to a pilot cohort of UK based track and field athletes (n = 59) who were requested to time how long it took to complete the questionnaire.

Results

Psychometric statistical analysis of the results was completed, resulting in the removal of 23 questions for a total of 62 questions in the final questionnaire. The validated questionnaire was then administered to 58 track and field athletes. Internal consistency was assessed using Chronbach’s alpha (α > 0.7), Pearson’s correlation (p < 0.05) was used to assess reliability. Construct validity was evaluated using a t-test (p < 0.05). A total test retest correlation of 0.95 was achieved (sub-section range: 0.87–0.97). Internal consistency was accepted in each sub-section (α = 0.78–0.92) and the nutrition-trained group scored significantly higher on the overall questionnaire (80.4 vs 49.6%). The overall score for the athletic group was 61.0%.

Conclusion

The questionnaire satisfied all psychometric measures and provides a new valid and reliable tool to assess general and sport nutrition knowledge of track and field athlete.

Electronic supplementary material

The online version of this article (doi:10.1186/s40795-017-0156-0) contains supplementary material, which is available to authorized users.

Sport Nutrition Knowledge, Behaviors and Beliefs of High School Soccer Players

For adolescent athletes (14–18 years), data on sport nutrition knowledge, behaviors and beliefs are limited, especially based on sex, race/ethnicity and socioeconomic status. High school soccer players (n = 535; 55% female; 51% White, 41% Latino; 41% National School Lunch Program (NSLP) participants (80% Latino)) completed two questionnaires (demographic/health history and sport nutrition). The sport nutrition knowledge score was 45.6% with higher scores in NSLP-Whites vs. NSLP-Latinos (p < 0.01). Supplement knowledge differed by sex (16% lower in females; p = 0.047) and race/ethnicity (33% lower in Latinos; p < 0.001). Breakfast consumption was 57%; females ate breakfast less (50%) than males (60%; p < 0.001); NSLP-participants ate breakfast less (47%) than non-NSLP (62%; p < 0.001). Supplement use was 46%, with Latinos using more supplements than Whites do (p = 0.016). Overall, 30% used protein shakes, with females using less than males (p = 0.02), while use was twice as likely in Latino vs. White (p = 0.03). Overall, 45% reported their nutrient requirements were different from non-athlete peers. Latinos were less likely (p = 0.03) to report that their diet met nutritional requirements, but more than twice as likely to report that nutritional supplements were necessary for training (p < 0.001). Adolescent athletes, especially females and Latinos, would benefit from sport nutrition education that enhances food selection skills for health and sport performance.

Sports Nutrition Knowledge, Perceptions, Resources, and Advice Given by Certified CrossFit Trainers

Background: CrossFit is a large, growing force in the fitness community. Currently, Level 1 and 2 CrossFit certification classes do not include nutrition education. The purpose of this study was to identify sports nutrition knowledge, perceptions, resources, and advice given by Certified CrossFit Trainers. Methods: An online questionnaire that measured these four constructs was placed on a private Facebook community, open only to certified CrossFit trainers, for 10 days. Results: Complete surveys were obtained from 289 CrossFit trainers. The mean Sport Nutrition Knowledge (SNK) score was 11.1 ± 2.1, equivalent to 65.3% ± 12.4% correct. The trainers perceived nutrition to be extremely important to athletic performance (9.4 ± 0.9 on a 10 point scale). Overall, the trainers graded their SNK higher than that of their CrossFit peers. The internet and CrossFit peers were the most frequently reported sources for nutrition information; Registered Dietitians were the least reported source. The Paleo and Zone diets were the most common dietary regimens recommended by CrossFit trainers. Results indicated a positive correlation between a CrossFit trainer’s self-reported hours of nutrition education and their SNK score (r = 0.17; p < 0.01). Conclusion: Nutrition education modules for Level 1 and 2 CrossFit trainers, developed with input from Board Certified Specialists in Sports Dietetics, are recommended.

Metabolic Phenotyping of Diet and Dietary Intake

Nutrition provides the building blocks for growth, repair, and maintenance of the body and is key to maintaining health. Exposure to fast foods, mass production of dietary components, and wider importation of goods have challenged the balance between diet and health in recent decades, and both scientists and clinicians struggle to characterize the relationship between this changing dietary landscape and human metabolism with its consequent impact on health. Metabolic phenotyping of foods, using high-density data-generating technologies to profile the biochemical composition of foods, meals, and human samples (pre- and postfood intake), can be used to map the complex interaction between the diet and human metabolism and also to assess food quality and safety. Here, we outline some of the techniques currently used for metabolic phenotyping and describe key applications in the food sciences, ending with a broad outlook at some of the newer technologies in the field with a view to exploring their potential to address some of the critical challenges in nutritional science.