Edinburgh Napier University

  Posterior pelvic tilt (PPT) exercises are frequently used in back rehabilitation, although the immediate effect of PPT in people not educated in this exercise is unknown. This study evaluated the effect of PPT in healthy participants on pelvic angle and muscle activity compared to normal standing. Reflective markers were attached to the left and right Anterior Superior Iliac Spine (ASIS) and Posterior Superior Iliac Spine (PSIS) in ten healthy participants without back pain. Kinematic data were collected using 10 high speed cameras. Surface electromyography (EMG) electrodes were attached to rectus abdominis (RA), gluteus maximus (GM), erector spinae (ES), external oblique (EO) and internal oblique (IO) muscles (left and right sides). EMG signals were transmitted via telemetry and synchronised with the kinematic data collected during stance and PPT (3 trials, 10s). PPT was achieved by verbal and manual facilitation at the start of each PPT trial. EMG data were full-wave rectified and the integrated EMG (iEMG) calculated. The angle between the left PSIS, ASIS and vertical, significant angle and iEMG differences between stance and PPT, and correlations between angle and iEMG were calculated. There was a significant angle reduction from stance (102°) to PPT (93°) and a significant iEMG increase for GM left, RA left, OE left and OI right. Angle or change in angle was not correlated to any muscle or change in muscle activity. Therefore PPT causes a significant increase in muscle activation, but is independent of the magnitude of the position change.