Objective: To assess claims regarding the effects of Pilates training on flexibility, body composition, and health status.

Design: An observational prospective study.

Setting: A community athletic club.

Participants: A sample of 47 adults (45 women, 2 men) who presented for Pilates training.

Interventions: Not applicable.

Main outcome measures: Fingertip-to-floor distance, truncal lean body mass by bioelectric impedance, health status by questionnaire and visual analog scale were assessed at baseline, 2, 4, and 6 months (+/-1 wk).

Results: Thirty-two of 47 enrolled subjects met the protocol requirements of missing no more than 1 weekly 1-hour session Pilates mat class during each 2-month period. Investigators were blinded to measurements from previous time points. Median (interquartile range [IQR]) fingertip-to-floor distance improved from baseline by 3.4 cm (1.3-5.7 cm), 3.3 cm (0.3- 7.8 cm), and 4.3 cm (1.5-7.6 cm) at 2, 4, and 6 months, respectively (paired nonparametric analysis, all P<.01). There were no statistically significant changes in truncal lean body mass, height, weight, or other body composition parameters. Self-assessment of health also did not change in a statistically significant manner from its baseline median (IQR) value of 77 mm (69-85 mm).

Conclusions: Pilates training may result in improved flexibility. However, its effects on body composition, health status, and posture are more limited and may be difficult to establish. Further study might involve larger sample sizes, comparison with an appropriate control group, and assessment of motor unit recruitment as well as strength of truncal stabilizers.