RESUMEN
BACKGROUND: Previous literature suggests that transversus abdominis (TrA) activation is diminished in chronic low back pain (cLBP) subjects compared to healthy subjects in less-functional positions. However, few studies have investigated the effects of upright functional movement on TrA activation in cLBP individuals. OBJECTIVE: This pilot study aimed to compare TrA activation characteristics in healthy and cLBP subjects during the movement of double leg standing (DLS) to single leg standing (SLS) and to a 30∘ single leg quarter squat (QSLS). METHODS: TrA activation was determined by the percentage change in TrA thickness from DLS to SLS and DLS to QSLS. TrA thickness was measured in 14 healthy and 14 cLBP participants using ultrasound imaging with a probe holder at 20 mm and 30 mm from the fascia conjunction point. RESULTS: At both measurement points (20 and 30 mm), there were no significant main effects of body sides, lower limb movements and the interactions between them on TrA activations between the healthy and cLBP participants even after covariates were adjusted for (all p> 0.05). CONCLUSIONS: Results from this study suggest the evaluation of TrA activation during upright functional movements as part of an assessment for cLBP management may not be suggested.