Spatial Distribution And Activity Of The Erector Spinae Muscles In Cyclists With Recent History Of Low Back Pain

Overactivation of erector spinae (ES) muscles has been identified as one of the potential major causes of low back pain (LBP) in cyclists. However, less is known about cyclists’ lumbar region activation patterns. Accordingly, in this cross-sectional study, we compared the activation and spatial distribution of ES muscles in cyclists with and without a recent history of LBP. Based on Oswestry Disability Index (ODI-I), participants were assigned to either an LBP or to an asymptomatic group (CG). They performed an incremental cycling test characterized by 4 bouts of 3 min at 70, 80, 90, and 100% of their FTP. Concurrently, the ES activity was recorded bilaterally through HDsEMG and synchronized at source with an electro-goniometer to characterize the pedal strokes. The average normalized RMS amplitude, the entropy, and the y-axis barycenter (y-bar) of the RMS maps were extracted. RESULTS: Statistical analyses revealed differences in RMS amplitude between 70-100% (+19%, p=.010), 80-100% FTP (+21%, p=.004) in the LBP group, and between LBP and CG at 100% FTP (9.6%, p=.049). Similarly, entropy differed significantly between 70-100% FTP (-8.4%, p=.002) and 80-100% FTP (-8.5%, p=.002) in the LBP only. Our results suggest that greater magnitude and reduced homogeneity of ES activity during an incremental cycling test may reflect an inefficient recruitment strategy of ES in cyclists with a recent history of LBP.