Body composition changes in female bodybuilders during preparation for competition

Objective: To determine anthropometric and body composition changes in fema le bodybuilders during preparation for competition. Design: There was an attempt to match subjects in the control and experimen tal groups for height and percentage body fat (%BF for the initial test of this longitudinal study. Subjects: Five competitive bodybuilders ((X) over bar +/- s.d.: 35.3 +/- 5. 7 y; 167.3 +/- 3.7 cm; 66.38 +/- 6.30 kg; 18.3 +/- 3.5 %BF) and five athlet ic females ((X) over bar +/- s.d.: 30.9 +/- 13.0 y; 166.9 +/- 3.9 cm; 55.94 +/- 3.59 kg; 19.1 +/- 3.3 %BF) were recruited from advertisements in a bod ybuilding newsletter and placed on sports centre noticeboards. Interventions: The following measurements were conducted 12 weeks, 6 weeks and 3-5 d before the bodybuilders' competitions: anthropometric profile, bo dy density by underwater weighing, total body water via deuterium dilution and bone mineral mass from a dual-energy X-ray absorptiometry scan. A combi nation of the last three measurements enabled the %BF to the determined by a four compartment model. Results: A significant (P less than or equal to 0.001) 5.80 kg body mass lo ss by the bodybuilders as they prepared for competition was primarily due t o a reduction in fat mass (FM; -4.42 kg; 76.2%) as opposed to fat-free mass (FFM; -1.38kg; 23.8%). The decreases in body mass and FM over the final 6 weeks were greater than those over the first 6 weeks. Their %BF decreased ( P < 0.001) from 18.3 to 12.7, whereas the values for the control group rema ined essentially unchanged at 19.1-19.6 %BF. These body composition changes by the bodybuilders were accompanied by a significant decline (P < 0.001) of 25.5 mm (76.3-50.8 mm) in the sum of eight skinfold thicknesses (triceps + subscapular + biceps + iliac crest C supraspinale + abdominal + front th igh + medial calf). Conclusions: Although the bodybuilders presented with low %BFs at the start of the experiment, they still significantly decreased their body mass duri ng the 12 week preparation for competition and most of this loss was due to a reduction in FM as opposed to FFM. Sponsorship: Australian Research Council (small grants scheme).