Comparison of lumbar spinal angle between normal body mass index and overweight young adults

[Purpose] This study compared the upper and lower lumbar angles of normal body mass index and overweight young adults, and examined the relationships among body mass index, waist circumferences, and lumbar angles. [Subjects and Methods] Sixty participants aged 18-25 years were recruited and allocated to 2 groups (n=30 per group): normal body mass index (18.5-24.9 kg/m(2)) and overweight group (body mass index, ≥ 25.0 kg/m(2)). During lumbar angle measurement, the participants stood in a relaxed position with bare feet. The upper and lower lumbar angles of each participant were measured using a flexible ruler, and the angle calculated by the tangent method. The waist circumference was also measured. [Results] The mean lower lumbar angle in the overweight group was significantly greater than that of the normal body weight group. Moreover, only the lower lumbar angle was associated with a significant increase in the body mass index (r=0.28). Waist circumference showed no association with the lumbar angles. [Conclusion] This is the first study to suggest that increased body weight could cause lower lumbar angle deviation in young adults. Further studies should investigate individuals with symptomatic back pain or back dysfunction and the impact of body weight on lumbar spinal angles.