Abstract
Endleman I, Critchley DJ. Transversus abdominis and obliquus internus activity during Pilates exercises: measurement with
ultrasound scanning.
Objective
To assess activity of transversus abdominis (TrA) and obliquus internus abdominis (OI) muscles during classical Pilates
exercises performed correctly and incorrectly, and with or without equipment.
Design
Repeated-measures descriptive study.
Setting
Pilates studio.
Participants
A volunteer sample of women (n=18) and men (n=8), mean age ± SD (43±14y), with more than 6 months classical Pilates
training and no back pain or other condition likely to influence abdominal muscle activity.
Interventions
Participants performed Pilates imprint, hundreds A and B, roll-up, and leg-circle exercises on a mat. The hundreds exercise was
also performed on a reformer (sliding platform). Mat imprint and hundreds exercises were instructed to be performed correctly
(with abdominal drawing-in) or incorrectly (without drawing-in).
Main Outcome Measure
Thickness of TrA and OI middle fibers measured with ultrasound imaging.
Results
TrA thickness increased during the mat imprint, hundreds A, hundreds B, leg-circle, and roll-up exercises (all P=.001) compared
with resting. OI thickness increased during the mat imprint, hundreds A, hundreds B, leg-circle (all P=.001), and roll-up
exercises (P=.002) compared with resting. TrA thickness during reformer hundreds B was greater than during mat hundreds B
(P=.011); OI thicknesses were not different for this comparison. During incorrect imprint, neither TrA or OI thicknesses were
different to resting. TrA and OI muscle thicknesses were moderately correlated (R=.410; P=.001).
Conclusions
This study provides the first evidence that a selection of classic Pilates exercises activates TrA and OI. Use of the reformer
exercise machine can result in greater TrA activation in some exercises. TrA and OI did not function independently during these
exercises. Research into the training effects of Pilates or in patient populations can be undertaken using ultrasonography in
submaximal exercises.