Fig 1 -

The comparison of mean velocity (A), sway area (B), medio-lateral path length (C) and antero-posterior path length (D) for the effect of trimester of pregnancy and for the effect of PPGP. FO–standing on firm surface with eyes open; FC–standing on firm surface with eyes closed; CO–standing on compliant surface with eyes open; CC–standing on compliant surface with eyes closed; 2NP–second trimester, no-pain group (white); 2PPGP–second-trimester pregnancy-related pelvic girdle pain group (orange); 3NP–third-trimester no-pain group (blue); 3PPGP–third-trimester pregnancy-related pelvic girdle pain group (yellow); * indicates a significant difference between the two groups p<0,05.</p

Demographic characteristics of participants with and without PPGP across 2nd and 3rd trimesters.

Demographic characteristics of participants with and without PPGP across 2nd and 3rd trimesters.</p

Postural sway assessment.

FO–standing on firm surface, eyes open; FC–standing on firm surface, eyes closed; CO–standing on complian surface, eyes open; CC–standing on compliant surface, eyes closed; NP–no pain; PPGP–pregnancy related pelvic girdle pain; SD–standard deviation; p–p value; p 2NP– 3NP–p value between second trimester no pain group and third trimester no pain group; ML–medio lateral; AP–antero posterior; * indicates a significant difference. (PDF)</p

Typical CoP movement recordings.

<p>Typical CoP movement recordings from a young and an elderly participant under the four experimental conditions. The CoP path is indicated by the black dotted line, the CoP outline is indicated in blue, and the elliptic PCA region with 95% points along each axis is delineated by the red line.</p

Descriptive data for the participants in the study.

<p>Descriptive data for the participants in the study.</p

Fractal dimensions of the medio-lateral (D_ML) and antero-posterior (D_AP) CoP time series over short (0 s to 0.3 s) and long (0.8 s to 12 s) time intervals for the 18 young and 26 elderly participants.

<p>*p<0.05.</p

Gains in postural sway.

<p>Gains in postural sway expressed as the quotients between the normal light eyes opened conditions to the (1) very low illumination, (2) eyes closed and (3) total darkness conditions for the young participants (dark green) and the elderly participants (light grey). * indicates a significant difference between the two age groups at p<0.05, and # indicates marginal significance at 0.05</p

Mean forward displacement of the COP and dominant hand on level ground.

<p>(a) Mean forward movement of the COP on a level ground in no touch (white) and touch (black) conditions for variables: Max - forward displacement of the CoP, Hold – average position of the COP in the end position that lasted 2 seconds; Sway - of the COP during a 2 second hold of the reach expressed as path length, Initial back - initial backward displacement of the COP during reach).(b) Mean movement of the hand during the reaching movement in the no touch (white) and touch (black) conditions. The significant differences are marked as **p<0.01; ***p<0.001.</p

Mean forward displacement of the COP and dominant hand on elevated surface.

<p>(a) Mean forward movement of the COP on a 1 m elevated surface in no touch (white) and touch (black) conditions for variables: Max - forward displacement of the CoP, Hold – average position of the COP in the end position that lasted 2 seconds; Sway - of the COP during a 2 second hold of the reach expressed as path length, Initial back - initial backward displacement of the COP during reach).(b) Mean movement of the hand during the reaching movement in the no touch (white) and touch (black) conditions. The significant differences are marked as **p<0.01; ***p<0.001.</p

Traces of the anterior displacement of the COP and dominant hand.

<p>Traces of the anterior displacement of the COP (a) in no touch (solid line) and light touch conditions and traces of foreword movements of the dominant hand. (b) Trace of hand anterior displacement during reaching movement in no touch (solid line) and light touch conditions (dotted line).</p