Knowledge and perceptions of North-West University rugby players on timing of protein ingestion
Abstract
Introduction :
In South Africa rugby is regarded as a national sport that is being developed from a young age. In universities, rugby players are further being moulded, developed and prepared for the professional league and they often experience pressure to compete at top level (Hale, 2013:3). Training and competition in addition to academic commitments provide unique challenges to university rugby players (Simiyu, 2010:17), not only in terms of optimal time management, but also in terms of optimal nutrition.
The importance of protein for athletes has long been recognized (Tipton & Wolfe, 2004:65) and more recently the correct timing of protein intake has been identified as an important component to optimize the adaptive response to both resistance and endurance exercise. Research conducted by Cermak et al. (2014:1454) and McLain et al. (2013:68) indicated that timely consumption of protein before, during and after exercise also has the ability to increase muscle protein synthesis, muscle glycogen restoration, muscle damage repair, muscle size, muscle strength and potentially performance. The International Olympic Committee recommends that 20-25g of high quality protein should be ingested 30 minutes following resistance exercise to restore muscle glycogen and promote protein synthesis (Slater & Phillips, 2011:71). Not all rugby players are necessarily familiar with these guidelines and since nutrition knowledge (and perceptions) has been shown to influence what and when athletes eat, (Walsh et al., 2013:371; Strachan et al., 2009:51) information on the knowledge and perceptions of timing of protein intake of university rugby players can be useful to improve nutritional practices via for instance education. Although data is available on nutritional knowledge of rugby players (Alaunyte et al., 2015, Hale, 2013, Walsh et al., 2011) very little is known about university rugby players‟ knowledge and perceptions specifically regarding the timing of protein intake. Accurate knowledge assessment in a specific population requires a valid and reliable tool to collect knowledge data (Whati et al., 2005:77). To our knowledge, a valid and reliable questionnaire to specifically determine the knowledge of protein timing in university athletes is also not available from the literature. The aim of the dissertation was to therefore determine the knowledge and perceptions of North-West University rugby players on timing of protein intake through a questionnaire that was developed, validated and tested for reliability.
Methods :
A descriptive, cross-sectional study with a quantitative and qualitative component was conducted. The study consisted of two main parts including the development and validation of a knowledge questionnaire and a cross-sectional study to determine knowledge and perceptions of university athletes on timing of protein intake. The knowledge questionnaire was developed by means of a literature review and tested for content validity by experts in the field of sports nutrition. Face validity was determined in a group of students and lectures before the knowledge questionnaire was tested for construct validity (including item difficulty internal consistency and item discrimination) and reliability. The test–retest method was used to test the same questionnaire in 70 hockey and cricket players from North-West University on two separate occasions 15 days apart. Various statistical tests were performed to assess the different aspects of validity including item difficulty index and Cronbach‟s alpha, and reliability including Cronbach‟s alpha, t test, percentage difference, correlation coefficients, Kappa statistics and Bland-Altman analysis.
In the second part of the study 103 male rugby players from the North-West University in South-Africa volunteered to complete the knowledge questionnaire on the timing of protein intake. Participants were included if they were between the ages of 18 - 24 years, enrolled in a degree or diploma at the university, and playing for the universities 1st, u/21A or u/19A team or student provincial 1st, u/21A or u/19A team (e.g. these were students from the university who represented the student provincial team or played for the student provincial team). A sub-sample of players per team was also randomly selected to participate in semi-structured focus-group discussions to gain more insight into the perceptions of university rugby players regarding timing of protein intake.
Main Findings :
A 12-item knowledge questionnaire was developed. Item difficulty of 11 questions was good (>10%), strength of consistency was good (Cronbach‟s alpha (CA) = 0.31), but internal consistency was poor (CA = 0.31). The questionnaire is reliable at group level for agreement (t test P = 0.078) and association (Bland-Altman indicated 95.7% within limits of agreement). On individual level the questionnaire showed limited bias (P = 0.072), limited error (CA = 0.64), limited agreement (Kappa = 0.13), but strong association (Interclass correlation was 0.64). After this newly developed and validated knowledge questionnaire was completed by the rugby players, the overall mean percentage knowledge score on timing of protein intake was 39.8±13.9% and only 29% of the players scored ≥50%. Although the majority of participants (87.5%) correctly identified the optimal time to consume protein after training, and 81.6% knew which athletes will benefit from applying protein timing strategies correctly, knowledge regarding the role and benefits, as well as the optimal source and amount of protein to consume when was poor (ranged from 11.7 - 35.5%). The first and u/21 teams tended to score higher on the knowledge questionnaire compared to the u/19 teams (42.0 [33.0 - 50.0] vs. 42.0 [33.0 - 42.0] vs. 33.0 [25.0 - 42.0], P = 0.06), however knowledge was not significant different between the forwards and the backs. A spearman rank correlation demonstrated an overall weak positive correlation (r = 0.24, P<0.05) between weight and knowledge score. The participants in the present study perceived the timing of protein intake to be important, but perhaps not as important as the source of protein. The most common perception specifically with regards to timing of protein intake was that the best time to consume protein is after training. The 30-minute period following exercise was perceived as an important period to replenish protein and avoid muscle breakdown. Inter- and intra-reliability of coded focus group discussion data were determined as ĸ = 0.74 and ĸ =0.81, respectively.
Conclusion :
Although North-West University rugby players perceived protein timing to be important, they have poor knowledge regarding protein timing specifically with regards to the type and amount of protein to be consumed. The fact that they knew when to ingest protein (i.e. after exercise/training) and the perception that protein ingestion is important after exercise could be due to the influence of the coaches instructing them to consume protein after exercise and making protein shakes available to them after exercise. These players should therefore be educated on the timing of protein intake.
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- Health Sciences [2060]