• Acute effects of Vitamin D3 supplementation on muscle strength in Judoka athletes: a randomized placebo-controlled, double-blind trial

      Wyon, Matthew; Wolman, Roger; Nevill, Alan M; Cloak, Ross; Metsios, George S; Gould, Douglas; Ingham, Andrew; Koutedakis, Yiannis (Wolters Kluwer Health, 2016-07-01)
      Objective: Indoor athletes have been shown to be prone to vitamin D3 deficiency. The aim of the study was to examine the acute effects of vitamin D supplementation on muscle function using isokinetic dynamometry. Design: Randomized placebo-controlled, double-blind study. Setting: Institutional. Participants: Adult male white national level judoka athletes (n = 22) who were involved in full-time training. Exclusion criteria were vitamin supplementation, overseas travel to sunny climes, and/or an injury incurred during the last 3 months before testing. Interventions: Subjects were randomly allocated to the treatment (150 000IU vitamin D3) or placebo and given blinded supplements by an independent researcher. Participants were tested twice, 8 days apart, on a Monday morning before the start of judo training and after 2 days of rest. A 5 to 7 mL of blood sample was collected followed by isokinetic concentric quadriceps and hamstring muscle function assessments on the right leg at 30 and 200°·s. Main outcome measures: Repeated-measures analysis of variance was used to analyze isokinetic muscle force and serum 25(OH)D3. Regression to the mean was used to examine changes in 25(OH)D3 levels over the study period. Results: The treatment group demonstrated a significant increase in serum 25(OH)D levels (34%, P ≤ 0.001) and muscle strength (13%, P = 0.01) between days 1 and 8. No significant differences were found for the placebo group for the same period. Conclusions: A single bolus of 150 000IU vitamin D3 had a significant positive effect on serum 25(OH)D levels and muscle function in vitamin D insufficient elite indoor athletes. Clinical relevance: Serum 25(OH)D3 levels of indoor athletes should be monitored throughout the year and especially during winter months. Beneficial responses, in muscle strength and serum 25(OH)D3, to 1 dose of vitamin D3 supplementation can be observed within 1 week of ingestion. Muscle strength is linked to serum 25(OH)D levels. Acute Effects of Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial (PDF Download Available). Available from: https://www.researchgate.net/publication/283499805_Acute_Effects_of_Vitamin_D3_Supplementation_on_Muscle_Strength_in_Judoka_Athletes_A_Randomized_Placebo-Controlled_Double-Blind_Trial [accessed May 10, 2016].
    • Body mass index, nutritional knowledge, and eating behaviors in elite student and professional ballet dancers.

      Wyon, Matthew; Hutchings, Kate M; Wells, Abigail; Nevill, Alan M (Wolters Kluwer Health, 2014-09)
      Objective: It is recognized that there is a high esthetic demand in ballet, and this has implications on dancers' body mass index (BMI) and eating behaviors. The objective of this study was to examine the association between BMI, eating attitudes, and nutritional knowledge of elite student and professional ballet dancers. Design: Observational design. Setting: Institutional. Participants: One hundred eighty-nine participants from an elite full-time dance school (M = 53, F = 86) and from an elite ballet company (M = 16, F = 25) volunteered for the study. There were no exclusion criteria. Interventions: Anthropometric data (height and mass), General Nutrition Knowledge Questionnaire (GNKQ), and the Eating Attitude Test—26 (EAT-26) were collected from each participant. Main Outcome Measures: Univariate analysis of variance was used to examine differences in gender and group for BMI, GNKQ, and EAT-26. Regression analyses were applied to examine interactions between BMI, GNKQ, and EAT-26. Results: Professional dancers had significantly greater BMI than student dancers (P < 0.001), and males had significantly higher BMI scores than females (P < 0.05). Food knowledge increased with age (P < 0.001) with no gender difference. Student dancers had a significant interaction between year group and gender because of significantly higher EAT-26 scores for females in years 10 and 12. Regression analysis of the subcategories (gender and group) reported a number of significant relationships between BMI, GNKQ, and EAT-26. Conclusions: The findings suggest that dancers with disordered eating also display lower levels of nutritional knowledge, and this may have an impact on BMI. Female students' eating attitudes and BMI should especially be monitored during periods of adolescent development.
    • Implications for Research Methods When Conducting Studies With the Users of Online Health Communities

      Bond, Carol; AHMED, OSMAN HASSAN; HIND, MARTIN (Wolters Kluwer Health, 2014-03)