Association between Head Motion Measured by Wearable Earbuds during Indoor Cycling and Lower Back and Lower Limb Pain in Soccer Players

Background: Indoor cycling exercise is commonly utilized for warm-ups and rehabilitation among soccer players. Individuals with lower back pain exhibit increased trunk motions, such as flexion, lateral leaning, and rotation, while cycling, which can elevate spinal loading. Trunk motion can be estimated using the head motion data measured by wireless earbud sensor. Purpose: The purpose of this study was to compare the range of three-dimensional head motions in soccer players with and without lower back and lower limb (LB & LL) pain, and to assess the correlation between pain intensity and head motion during indoor cycling. Study design: Cross-sectional study Methods: Thirty-one high school soccer players took part in the study, with 16 experiencing LB & LL pain, and 15 without such pain. Pain intensity after the soccer game was evaluated using a visual analogue scale. Wireless earbud sensor was used to measure maximal range of head motion in three-dimensional planes during indoor cycling. The Mann-Whitney U test was utilized to compare head motions between groups. In addition, Spearman correlation coefficients were employed to assess the relationship between pain intensity and head motion. Results: Pain group significantly showed greater range of head motions than the non-pain group in sagittal, frontal and transverse planes (p<0.05). Pain intensity was significantly correlated with head motions in each sagittal, frontal and transverse plane (ρ=0.75, 0.56 and 0.46, respectively). Conclusions: We found significant differences in the range of 3D head angles during cycling between soccer players with and without pain, as well as a correlation between pain intensity and 3D head angles. These findings highlight the applicability of head angle data, acquired via wireless earbuds, during warm-up cycling for soccer players experiencing LB & LL pain.