Research article - (2011)10, 478 - 482 |
Pre-Workout Carbohydrate Supplementation does not Affect Measures of Selfassessed Vitality and Affect in College Swimmers |
Kathleen M. Hill1,, James R. Whitehead1, Janice K. Goodwin2 |
Key words: Nutrition, swimmers, mood |
Key Points |
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Subjects |
Thirty-eight NCAA Division II men and women intercollegiate swimmers volunteered to participate in this study during a period of intensive training. Men and women swimmers trained together in one of three training groups: sprint, mid- distance, and distance. Average practice length was 90 minutes. The sprint group swam an average of 4400 yards/morning practice which consisted of three EN1 (minimum endurance pace) sets and one SP4 (spring level 4) set or one EN1, one EN2 (threshold endurance pace), and one SP4 set. The mid- distance group swam an average of 4800 yards/morning practice which consisted of three EN1 sets and one SP3 (sprint level 3) set or one EN1, one EN2, and one SP3 set. The distance group swam an average of 5400 yards/morning practice which consisted of three EN1 sets or one EN1 and one EN2 set. The swimmers did not change training groups during the course of the study, and practices were similar between the two weeks of the study. |
MeasuresVitality, athletic burnout, and affect measures |
Feelings of vitality were measured using the 6-item Vitality Scale which uses a 7-point Likert scale ranging from “not at all true” to “somewhat true” to “very true”(Bostic et al., |
Dietary information |
Dietary information was collected once at baseline prior to study interventions to describe normal dietary habits. A written, one-day 24-hour dietary recall was completed by each subject. Each dietary recall was reviewed by a registered dietitian or dietetics student under the supervision of a registered dietitian for clarification with each individual subject. Three-dimensional food models and measuring utensils were used to aid in this process. Diet Analysis Plus Version 5.0 for Windows® (Copyright 2001, Wadsworth Group and ESHA Research) was used to analyze the nutrient content from the 24-hour-dietary-recall. Subjects were also asked 10 written questions regarding certain nutrition habits, such as: “How many days per week do you eat or drink something (other than water) before morning swim practice? ”. For the purposes of this study, we defined ‘breakfast’ as any caloric food or beverage consumed before morning swim practice. |
Anthropometrics |
Weight (kg) and height (cm) were measured using a calibrated balance scale and stadiometer (Detecto®, Webb City, MO). Body mass index (BMI) (kg/m2) was calculated from these measurements. |
Procedure |
This study was conducted at the home training facility of the swim team. Subjects were instructed to continue their normal eating habits and to be consistent throughout the course of the study. This instruction was to reduce the effects that changes in routine may have on the subjective measures of the study or the upcoming championship competition, and to reduce the burden on the subjects. Approval to conduct this study was granted by the University of North Dakota Institutional Review Board, and all subjects gave informed consent prior to participation. Height, weight, 24-hour dietary recall, ABQ, and general vitality scale were obtained before a regularly scheduled Saturday morning swim practice (approximately 8AM). The swimmers were randomly assigned into two groups in a double- blind fashion to receive a CHO supplement or placebo before morning swim practice for two (week) days each in a cross-over design. A five-day washout period separated the cross-over conditions. The CHO supplement was 10 fluid ounces of commercially-available strawberry gelatin, which contained 45 g CHO (as sucrose), 5 g protein, and 200 total kcal. The placebo was 10 fluid ounces of commercially-available sugar-free strawberry-flavored gelatin (sweetened with aspartame and acesulfame potassium), which contained 4 g CHO, 2.5 g protein, and 25 total kcal. Subjects were not aware of the placebo condition until the completion of the study to minimize the possibility of detecting the slight taste variation due to the artificial sweetener in the placebo. Subjects swam their swim practices as normal during the study. Within five minutes following each of the two morning practice sessions each week, the subjects completed the current feelings of vitality scale and the AD ACL. |
Statistical analysis |
Pearson correlations were used to analyze the relationship between total kcal, total CHO, kcal/kg body weight and CHO/kg body weight from the 24-hour dietary recalls and general vitality scores and the three subscales of the ABQ. Independent t-tests were used to compare general vitality and each subscale of the ABQ between subjects in the highest and lowest tertile for breakfast consumption frequency. Paired t-tests were used to compare the differences between the supplement and placebo conditions on current feelings of vitality and affect (2-day average). All analyses were performed using Statistical Analysis Software (SAS 9.1.3, Cary, NC) and statistical significance was set at p = 0.05. |
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Height, weight, 24-hour dietary recall, and ABQ, and general vitality scale were completed by 37 swimmers, and 34 swimmers completed at least one day on each placebo and CHO supplement in the cross-over study. Subject characteristics and dietary intakes from 24h dietary recalls are shown in Swimmers reported varied reasons for forgoing breakfast in response to the question, “If you don’t eat before morning swim practice, what are the reasons? ” The responses followed several main themes and were therefore classified into one of five categories: ‘Avoidance of feeling nauseous/ill’ (f = 13), ‘Lack of time’ (f = 12), ‘Lack of access to food’ (f = 7), ‘Don’t like it/don’t feel like it’ (f = 6), and ‘Lack of hunger’ (f = 5). There were no significant effects of the CHO supplement on vitality (p = 0.22) or the four subscales (energetic, tiredness, tension, and calmness) of the AD ACL (all p ? 0.15) ( |
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The objectives of this study were to determine if relationships exist between breakfast and dietary habits and athlete burnout and vitality in swimmers, and to determine if CHO supplementation before morning practice would have a beneficial effect on post-practice subjective measures of affect and feelings of vitality. Previous research (Backhouse et al., We found a modest inverse relationship between total daily kcal and the reduced sense of accomplishment dimension of athlete burnout which may suggest that better nourished swimmers have less reduced sense of accomplishment. Conversely, it was unexpected that swimmers in the top tertile for breakfast consumption who ate breakfast most often had more sport devaluation compared to swimmers in the bottom tertile who never ate before swim practice. We propose one possible hypothesis based on the qualitative data collected. The most frequent response for why the swimmers did not eat breakfast before morning swim practice was ‘avoidance of feeling nauseous/ill’. Perhaps some swimmers with increased devaluation of the sport train less intensely and do not experience discomfort related to eating prior to practice, or don’t care if they experience discomfort. Indeed, fewer swimmers in the top tertile for breakfast consumption frequency reported ‘avoidance of feeling nauseous/ill’ (14 %) versus swimmers in the bottom tertile (53 %). It seems likely, however, that a complex array of factors is responsible for any associations between diet and athlete burnout. To our knowledge, this is the first exploration of diet and athlete burnout. Prospective studies of athlete burnout in swimmers using more rigorous dietary intake assessment methods would be useful in further establishing if relationships between diet and athlete burnout exist. Additionally, measuring athletic performance along with diet and athlete burnout would be valuable in assessing the importance these factors to athletic success. The reasons why swimmers reported not eating breakfast before morning practice may be useful to coaches, trainers, or sports nutritionists working with swimmers. Although our study showed no benefit of CHO supplementation on affect or vitality in our study, there is considerable evidence that consuming foods or beverages, particularly those high in CHO, before training is beneficial for physiological function and performance (Achten et al., This field-based study of the effect of CHO supplementation before morning swim practice on affect in swimmers failed to support previous findings from a laboratory-based study of CHO supplementation and affect in athletes (Backhouse et al., |
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Although we did not find an effect of CHO supplementation on affect or vitality in swimmers in this field-based experiment, there is evidence in the literature that CHO administration has beneficial effects on both physiological and psychological indices in athletes (Achten et al., |
ACKNOWLEDGEMENTS |
The authors would like to thank the swimmers who participated in the study and the coaches who made it possible, and the volunteer dietetics students who assisted with the study. This study was funded by departmental funds in the Department of Physical Education, Exercise Science, and Wellness, University of North Dakota, Grand Forks, ND 58201. |
AUTHOR BIOGRAPHY |
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REFERENCES |
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