Student Scholar Symposium Abstracts and Posters

Document Type


Publication Date

Spring 5-1-2024

Faculty Advisor(s)

Dr. Jo Armour Smith


Many individuals with low back pain (LBP) experience episodic symptoms. During symptomatic episodes, individuals with LBP have delayed trunk muscle activation during anticipated postural perturbations, though it's unclear if these postural control changes persist between symptomatic episodes. This study examined anticipatory postural muscle activation in adults with and without recurrent LBP to determine the influence of muscle fatigue and typical symptom characteristics on trunk muscle activation. 55 young adults with a greater than one-year history of recurrent LBP and 30 young adults with no history of LBP were recruited. Electromyography electrodes were placed on their thoracic and lumbar paraspinals, external obliques, internal obliques, and left deltoid. While standing, participants rapidly raised their left (non-dominant) arm as quickly as possible in response to an auditory cue. Ten repetitions were performed before and after paraspinal fatigue was induced using the Sorensen test. Timing and amplitude of anticipatory trunk muscle activation, and abdominal/paraspinal co-contraction were calculated. Effects of fatigue and LBP status were investigated, as well as associations between pain characteristics and postural control. The results found that speed of arm motion did not change post-fatigue nor between groups. Timing, amplitude, and co-contraction did not differ between groups. In adults with and without LBP, adaptations in the timing and amplitude of postural muscle activation occurred in fatigued and non-fatigued muscles in response to fatiguing exercise. In individuals with a history of recurrent LBP, greater pain severity and impact during painful episodes were associated with delayed onset and reduced co-contraction of the trunk musculature during anticipated postural challenges. Due to the heterogeneity and symptom-dependence of postural control impairments in individuals with LBP, the prescription of rehabilitation exercises for the trunk musculature should be tailored for each individual based on their unique symptom-associated motor patterns.


Presented at the Spring 2024 Student Scholar Symposium at Chapman University.