Location and sequence of muscle onset in deep abdominal muscles measured by different modes of ultrasound imaging

Spine stabilisation exercises in the treatment of chronic low back pain: a good clinical outcome is not associated with improved abdominal muscle function

“…Whilst ultrasound recordings have been shown to be reliable and valid for assessing the ''earliest onset of activity'' within deeplying the lateral abdominal muscle group [37,62,67] they cannot be used to identify with any certainty which of the lateral abdominal muscles (TrA, OI or OE) is activated first. Possible reasons for this have been discussed in detail before [37,60,62,67]. Nonetheless, the latter authors maintain that the ''earliest muscle active'' gives an adequate measure for clinical studies in this area, delivering a valid representation of the phenomenon under investigation.…”

“…Nonetheless, the latter authors maintain that the ''earliest muscle active'' gives an adequate measure for clinical studies in this area, delivering a valid representation of the phenomenon under investigation. Indeed, due to the wide intraindividual and interindividual variabilities in the onset responses of the three muscles, some authors consider that examination of the ''earliest onset of activity'' may even convey certain advantages, by taking account of individual activation strategies that can otherwise be obscured by averaging group data for any given muscle [37,62,67]. This, coupled with the obvious benefit of using a non-invasive procedure in the assessment of patients, appears to make it a feasible approach for studies of deep muscle activation in connection with cLBP.…”

Is activation of transversus abdominis and obliquus internus abdominis associated with long-term changes in chronic low back pain? A prospective study with 1-year follow-up

“…However, location of onset cannot be distinguished by M-mode. By ultrasound strain rate recordings in the present material, which may distinguish onset location in the abdominal muscles or muscles layers separately, 65% of abdominal contractions were found to start in the deep part of obliquus internus, 25% in transversus abdominis and 10% simultaneously in the deep part of obliquus internus and transversus abdominis, but with considerable intrasubject variability 13. Negative sign before onset mean that the abdominal muscles were activated before deltoid in anticipation of arm flexion.…”

“…In terms of onset, the validity of separating the deep abdominal muscles may not be equally appropriate as first onset may vary between transversus and deep fibres in obliquus internus, both between and within individuals 13. The results for M-mode recordings suggest that 100 ms delayed onset after intervention was associated with two points higher pain on the numeric rating scale 1 year after intervention (table 2, last row), but CIs were again broad.…”

“…Motion (M)-mode was used to record first onset of abdominals relative to deltoid during the rapid arm flexion test 13. The unilateral rapid arm flexion test creates forces upon which the abdominal muscles have to react in an anticipatory manner to support the spine.…”