The automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without low back pain- A cross-sectional study

TL;DR

This study examines how older adults with and without back pain use their abdominal muscles during stable and unstable standing tasks.

Contribution

It explores automatic abdominal muscle activity in older adults with low back pain during dynamic standing postural tasks.

Findings

Task dynamicity significantly affected thickness change only in the TrA muscle in participants without LBP.

Standing on a dynamic surface increased TrA muscle activity in the control group compared to static standing.

No significant effects were found for the IO and EO muscles in either group.

Abstract

The postural control and abdominal muscles’ automatic activity were found to be impaired in subjects with low back pain (LBP) during static activities. However, the studies are predominantly conducted on younger adults and a limited number of studies have evaluated abdominal muscles’ automatic activity during dynamic standing activities in subjects with LBP. The present study investigated the automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without LBP.

Twenty subjects with and 20 subjects without LBP were included. The thickness of the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles was measured during rest (in supine), static, and dynamic standing postural tasks. To estimate automatic muscle activity, each muscle’s thickness during a standing task was normalized to its thickness during the rest. Standing postural tasks were performed using the Biodex Balance System.

The mixed-model analysis of variance revealed that task dynamicity significantly affected thickness change only in the TrA muscle (P = 0.02), but the main effect for the group and the interaction were not significantly different (P > 0.05). There were no significant main effects of the group, task dynamicity, or their interaction for the IO and EO muscles (P > 0.05). During dynamic standing, only the TrA muscle in the control group showed greater thickness changes than during the static standing task (P < 0.05).

Standing on a dynamic level increased the automatic activity of the TrA muscle in participants without LBP compared to standing on a static level. Further research is required to investigate the effects of TrA muscle training during standing on dynamic surfaces for the treatment of older adults with LBP.

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