Purpose Strength of the core muscles and the transversus abdominis (TrA) play an important role in the functional mobility and lumbar stability. Quantification of TrA thickness using ultrasound is used as an indirect index of muscle recruitment. The aim of this study was to determine if, and to what extent the thickness of TrA is affected in different Pilates training positions, and which position causes the greater increase in TrA thickness.
Methods Forty-four healthy women were divided into a young (25 - 35 years old) and middle-aged (age 36 - 55 years old) group. TrA thickness was quantified using ultrasound whilst the participants performed the basic position, the hundred, bridge, side plank and the dead bug exercise.
Results Analysis of variance showed that dead bug exercise showed greater TrA thickness (relative to rest) than the remainder exercises (p < 0.05) while the younger group had greater overall TrA thickness than the middle-aged group (p < 0.05).
Conclusions Based on these results, it is concluded that the most preferable exercise for greater TrA thickness increase is the dead bug exercise. Pilates exercises such as the basic position and the hundred exercises, can precede the exercises that present a larger TrA thickness, such as the bridge, the side plank and the dead bug. The order of exercises can be similar for both young and middle-aged women.