Physical activity, body composition and bone density in ballet dancers

Abstract

The main purpose of the present study was to examine factors that d e c t bone mineral density (BMD) in female ballet dancers. Training history, Ca intake, body composition, total body BMD (TBMD) and site-specific BMD, and bone mineral content were described in twenty-four female ballet dancers (mean age 22.6 (SD 4.5) years). Training history was determined by questionnaires, Ca intake by 7 d dietary record, BMD and bone mineral content by dual-energy X-ray absorptiometry (DXA), total body water by 'H dilution, extracellular water by bromide dilution, body fat by underwater weighing ( W W ; twocomponent model), DXA, and the four-component (4C) model. Dancers had a significantly lower body mass index (BMI 18.9 (SD 1.0) kg/m2) than controls (21.3 (SD 1.9) kg/m2), with significantly lower percentage body fat (17.4 (SD 3.9) v. 244 (SD 5.1)) but comparable fat-free mass. Mean TBMD (1,147 (SD 0.069) g/cm2) was significantly higher (6 %) compared with that of a reference population. These high values could be attributed to the high BMD of legs and pelvis, the weight-bearing sites of the dancer's body. No relationship was found between age, start of ballet classes, period (years) of dancing, Ca intake, and BMD (total and site-specific). However, TBMD was positively related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to daily period (h) of training. Depending on the method used the percentage body fat ranged from 16.4 (by DXA) to 18.3 by the 4C model. These differences were significantly related to the TBMD. Percentage body fat by the different methods was not significantly different, except for DXA and 4C model. The present study showed that, despite the factors that have a negative effect on BMD, such as low body mass and late menarche, BMD in female ballet dancers was relatively high. These high values were probably caused by high levels of weight-bearing physical activity.Bone mineral density: Dual-energy X-ray absorptiometry : Underwater weighing

Influence of dietetic and anthropometric factors and of the type of sport practised on bone density in different groups of women

“…Significant correlations were seen between different dietetic and anthropometric parameters and both the BMD and BMC for the different areas studied (Table 3). The association between low body weight and poorer bone mineralisation has been reported by several authors (Van Marken Lichtenbelt et al, 1995;Wynn & Wynn, 1995;Young et al, 1995). In agreement, the dancers showed the lowest bodyweights and poorest bone densities.…”

Bone mineral density in young female Chinese dancers

“…Several cross-sectional studies have implied that regular weight-bearing exercise has beneficial effects on bone mass in premenopausal women [1,4,6,8,14]. Heinonen et al [6] reported that athletes -squash players, aerobic dancers, and speed skaters -have significantly higher weight-adjusted BMD values at the loaded sites than sedentary controls.…”

“…Van-Marken-Lichtenbelt et al [14] reported that mean total BMD of ballet dancers is significantly higher (6%) than that of a reference population. These high values 284 could be attributed to the high BMD of legs and pelvis, the weight-bearing sites of the dancer's body.…”

“…The results support the concept that training involving high strain rates from versatile movements and high peak forces is more effective for bone formation than training involving a large number of low-force repetitions. Alekel et al suggest that walking and aerobic dance provide physically active premenopausal women with greater lumbar and femoral BMD than premenopausal sedentary women [14].…”

Bone Quality in Female Ballet Dancers: A Possible Determinant of Bone Health

“…There have been several reports regarding BMD in ballet dancers. Lichtenbelt et al reported that the BMD in ballet dancers (n = 24) was significantly higher than that of a reference population [19]. On the other hand, Lucas reported that the BMD of ballet dancers (n = 15) was not significantly different from the control subjects [20].…”