Abdominal exercises affect inter-rectus distance in postpartum women: a two-dimensional ultrasound study.

OBJECTIVES: To compare inter-rectus distance (IRD) at rest between women who had a vaginal delivery with women who had a caesarean section, and to describe the effect of different abdominal exercises on IRD. SETTING: Physiotherapy practice. DESIGN: Cross-sectional experimental study. PARTICIPANTS: Thirty-eight postpartum primiparous mothers with a singleton baby (vaginal delivery: n=23; caesarean section: n=15). INTERVENTIONS: Two-dimensional ultrasound images from the abdominal wall were recorded at rest and at the end position of abdominal crunch, drawing-in and drawing-in+abdominal crunch exercises. IRD measurements at rest, above and below the umbilicus, were compared between the two groups (vaginal delivery and caesarean section). IRD was also measured above and below the umbilicus during three abdominal exercises in both groups. MAIN OUTCOME MEASURES: IRD 2 cm above and below the umbilicus. RESULTS: No significant differences in IRD, either above or below the umbilicus, were found between the vaginal delivery and caesarean section groups. IRD above the umbilicus was significantly reduced during abdominal crunch exercises compared with at rest {mean 21.7 [standard deviation (SD) 7.6]mm vs 25.9 (SD 9.0) mm; mean difference 4.2 mm; 95% confidence interval (CI) 0.5 to 7.9}. IRD below the umbilicus was significantly greater during drawing-in exercises compared with at rest [16.0 (SD 8.1) mm vs 11.4 (SD 4.9) mm; mean difference 4.5 mm; 95% CI 1.6 to 7.4]. CONCLUSION: In contrast to existing recommendations for abdominal strength training among postpartum women, this study found that abdominal crunch exercises reduced IRD, and drawing-in exercises were ineffective for reducing IRD. Further basic studies and randomised controlled trials are warranted to explore the effect of abdominal training on IRD.

Inter-rectus distance in postpartum women can be reduced by isometric contraction of the abdominal muscles: a preliminary case-control study.

OBJECTIVES: To determine the effect of isometric contraction of the abdominal muscles on inter-rectus distance in postpartum women. DESIGN: Preliminary case-control study. SETTING: Research laboratory. PARTICIPANTS: Ten postpartum women {mean age 30 [standard deviation (SD) 4] years; mean weight 58 (SD 7) kg; mean height 159 (SD 4) cm} and 10 nulliparous (control) women [mean age 28 (SD 2) years; mean weight 56 (SD 6) kg; mean height 160 (SD 6) cm]. INTERVENTIONS: Ultrasound images from the anterior abdominal wall were recorded at rest (supine position) and during an abdominal isometric contraction, with the subject actively performing an abdominal crunch (crook lying position). Two-way analysis of variance was used to compare the inter-rectus distance between groups (postpartum vs control) and between levels of abdominal muscle activation (rest vs isometric contraction). MAIN OUTCOME MEASURES: Inter-rectus distance 2cm above the level of the umbilicus. RESULTS: The inter-rectus distance was significantly greater in the postpartum group compared with the control group [14.7 (SD 3.1) mm vs 9.6 (SD 2.8) mm; mean difference 5.1mm; 95% confidence interval (CI) 3.4 to 6.8]. The inter-rectus distance was significantly lower during isometric contraction compared with rest [10.7 (SD 3.1) mm vs 13.4 (SD 3.1) mm; mean difference 2.8mm; 95% CI 1.2 to 4.5]. No interaction was found between group and muscle contraction. CONCLUSIONS: The inter-rectus distance was significantly higher in postpartum women compared with controls, and significantly lower during isometric contraction of the abdominal muscles (abdominal crunch) compared with rest.

Effects of different arm external loads on the scapulo-humeral rhythm.

OBJECTIVE: To investigate the effects of the magnitude of the external load, applied on the hand, on the orientation of the shoulder girdle (scapulo-humeral rhythm). DESIGN: Thirty subjects performed both arms' elevation in three planes of elevation: sagittal (anteflexion), frontal (abduction), and scapular (scaption). Measurements were performed against five levels of external load (0-4 kg), on each plane of elevation. BACKGROUND: Some controversy exists whether additional load influences the SHR. Moreover, no data are available on the SHR during arm abduction and anteflexion. METHODS: The SHR was recorded by means of a six degree of freedom electromagnetic tracking device. RESULTS: The external load applied on the hand affects scapular three-dimensional position: scapular protraction is particularly affected on abduction and scaption; scapular latero-rotation on anteflexion and abduction; and scapular spinal tilt on anteflexion. CONCLUSIONS: The magnitude of the external load, applied on the hand, influences the scapular position and the scapulo-humeral rhythm, particularly on abduction. Those effects are visible on scapular latero-rotation and spinal tilt, during anteflexion, and on scapular protraction during scaption. Additionally, the initial position of the shoulder girdle seems to play an important role on the definition of the individual SHR pattern. RelevanceThis study can provide a basis for evaluation of shoulder pathology associated with abnormal scapular kinematics.