Changes in the Thickness of Trunk Stabilizer Muscles According to Increased Lifting Loads in Stoop Lifting

Altered Abdominal Muscle Recruitment and Declined Physical Function in Postpartum Individuals With Pregnancy-Related Pelvic Girdle Pain: A Matched Case-Control Study

INTRODUCTION

The influence of pregnancy-related pelvic girdle pain (PPGP) on lumbopelvic muscles has not been comprehensively examined in postpartum individuals. Previous research also presented self-reported activity limitations without objective measures.

METHODS

Thirty postpartum individuals with PPGP (PPGP group) and 30 age-, parity-, and postpartum duration-matched asymptomatic individuals (healthy group) were recruited. Transabdominal ultrasonography was used to measure muscle thickness or activation changes of the external oblique (EO), internal oblique (IO), transverse abdominals, lumbar multifidus, and pelvic floor muscles (PFMs) during rest and while performing the active straight leg raise (ASLR). Muscle changes were compared separately in the painful and nonpainful sides between the PPGP and health control group. Physical function was assessed using the ASLR fatigue (ASLRF), timed up-and-go, and 6-m walking (6MW) tests.

RESULTS

The PPGP group had greater thickening changes in the bilateral IO during ASLR compared with the healthy group (nonpainful side, 16.34 vs 3.52 mm; P = .010; painful side, 18.83 vs 6.60 mm; P = .02) but became thinner in the EO (nonpainful side, -2.19 vs 19.97 mm; P < .001; painful side, -5.97 vs 21.43 mm; P < .001). Thicker IO and EO on the nonpainful side (IO, 6.60 vs 5.78 mm; P = .004; EO, 5.37 vs 4.54 mm; P = .011) and a lower bladder base (indication of PFMs) (91.87 vs 78.61 mm; P = .002) during rest were also observed in the PPGP group. Furthermore, the performance of the ASLRF and 6MW tests was poorer in the PPGP than in the healthy group (ASLRF nonpainful side, 82.36 vs 59.09 sec; P = .01; painful side, 75.73 vs 59.26 sec; P = .04; 6MW, 3.48 vs 3.17 sec; P = .02).

DISCUSSION

Postpartum individuals with PPGP demonstrated altered abdominal muscle recruitment strategies during loading tasks, with objectively impaired physical functions. These findings are critical for developing effective muscle training interventions for PPGP.

Effect of evidence-based trunk stability exercises on the thickness of the trunk muscles

[Purpose] This study was conducted to investigate the effect of four spine stability exercises on the thickness of the internal and external oblique abdominal muscles, the transverses abdominis, and the multifidus muscles. [Subjects and Methods] Forty healthy adults were enrolled and randomly allocated to four groups. Ten participants performed bridge exercises (BE) while lying on their back; 10 others performed the same exercises with their right legs up (BERL); another 10 performed the same exercises on their side (SBE); and the remaining 10 performed them in a quadruped position with left arm and right leg lifts (QLARL). The participants performed the exercises three times a week for five weeks. The thicknesses of the muscles before and after the interventions were measured using ultrasound. [Results] The results show that the normal bridge exercise significantly thickened the TrA; BERL, the LM; QLARL, the IO; and SBE, the EO and the IO. [Conclusion] All four spine stability exercises were effective. The normal bridge exercise and BERL selectively strengthened the local muscles at the early stage of the treatment. We consider SBE and QLARL should be used in the later stages of treatments because they strengthen both the local and global muscles.