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FLUCTUATIONS IN BODY COMPOSITION INDICES   [read the french version]

Author :   Louise Segui and Willy Pieter

FLUCTUATIONS IN BODY COMPOSITION INDICES
IN DANCERS DURING TRAINING

Louise Segui* and Willy Pieter**
*Middlesex University, London, UK
**University of Asia and the Pacific, Pasig City, MM, Philippines

The purpose of this study was to monitor body composition fluctuations in dancers during dance training to assess fluid loss both daily and over one week. Twenty-six female ballet dancers aged 16-20 years, in their first (n=12) or second year (n=14) of three-year full-time dance education, were weighed before the first dance class on Monday, Tuesday, Friday and Saturday and after dance classes on Monday and Friday of the same week. All first year students attended approximately twenty, 30-120-minute dance classes a week. Second year students attended approximately twenty-four, 45-120- minute dance classes each week. In addition to height and weight, BMI and percent relative total body fat were derived. MANOVA procedures were used for comparisons between and within Year groups. LSD post-hoc analyses were employed to determine the exact location of any differences.

Collapsed over Year, body weight decreased significantly during Monday (from 51.10 + 3.72 kg to 50.73 + 3.72 kg, p < 0.001) and Friday (from 51.03 + 3.78 kg to 50.49 + 3.75 kg, p < 0.001) and was significantly lower (p = 0.017) on Saturday before class (50.84 + 3.74 kg) than Monday before class. Between Monday before class and the last measurement on Friday, a loss of 1.21 ± 1.14% (range -1.21 - 3.83%) body weight occurred. BMI was higher Monday before class (19.33 + 1.27 kg/m2) than Monday after class (19.19 + 1.24 kg/m2) (p < 0.001) and Friday after class (19.10 + 1.26 kg/m2) (p < 0.001). Percent body fat on Monday before class (13.79 + 2.29%) was higher than on Friday after class (13.35 + 2.33%) (p < 0.001).


Within Year 1, body weight decreased from 51.62 + 3.11 kg on Monday before class to 51.13 + 3.14 kg on Friday after class (p = 0.001). Percent fat decreased significantly on Monday (from 13.79 + 2.29% to 13.53 + 2.29%, p = 0.002) and Friday (from 13.73 + 2.31% to 13.35 + 2.33%, p = 0.001). Within Year 2, BMI was significantly lower on Tuesday before class (19.30 + 1.40 kg/m2, p = 0.016) and Saturday before class (19.30 + 1.32 kg/m2, p = 0.014) than on Monday before class (19.44 + 1.39 kg/m2). Percent fat decreased from 14.03 + 2.49 on Monday before class to 13.47 + 2.50 on Friday after class (p < 0.001). The findings indicate inadequate fluid replacement by Year 1 and Year 2 dancers during and after classes in school hours. A BMI of around 19 kg/m2 for Year 1 dancers is classed underweight, but an even greater concern lies at the low end of the range with some of the students having a BMI of 17 kg/m2. Classical Ballet classes may be the greatest threat to fluid balance maintenance in Year 1 students. Year 2 students suffered a 1.54 ± 1.25% (range -0.93 - 4.01%) loss in body weight from Monday before class to Friday after the last class.

A body weight deficit of 1% can produce performance decrements, but in addition, some of the students at the top end of the range were demonstrating fluid deficits as high as 4%. A 4% loss in weight in one exercise bout has been linked to a performance deterioration of 20-30% as well as leading to nausea, vomiting and diarrhea. The low body fat of Year 2 dancers (13-14%) is well below the underweight cut-off point of 17% suggested in the literature. Low percent fat has been linked to hormone imbalances; however, low body weight has also been suggested as a cause of menstrual abnormalities, which would put Year 2 dancers at further risk. It is pertinent to recognize that the Classical Ballet and Pointe Work classes produced the greatest weight loss in second year students. Dancers should be given ample time during training to drink fluids, which will allow them to balance fluid intake and losses more closely.

This is an abstract from the Helsinki Symposium (3-4 June 2001) All rights reserved by the authors.