Jia S, et al. - Researchers examined how vibration of differing sinusoidal axial cyclic loading frequencies affects different forms of scoliosis in the lumbar spine. They developed four finite element models, comprising a healthy spine, Lenke-A, Lenke-B and Lenke-C scoliosis of the lumbar S1-L1 region. Resonant frequencies of the finite element models were extracted with modal analysis with an upper-body mass of 40 kg and 400 N preload. The response to vibration of models under a sinusoidal axial loading of ± 40N at frequencies of 3, 5, 7, 9, 11 and 13 Hz using an upper body mass of 40 kg and 400 N preload was obtained via performing a transient dynamic analysis. Findings suggest different vibrational characteristics of different forms of scoliosis; the first-order resonant frequencies of healthy, Lenke-A, Lenke-B and Lenke-C spines were 9.2, 3.9, 4.6 and 5.7 Hz, respectively. Deformation of a Lenke-A lumbar spine was more frequent at a lower vibration frequency and of a Lenke-C lumbar spine was more frequent at a higher vibration frequency. Under loading condition of whole body vibration, they identified the scoliotic vertebrae as the weak link in scoliosis. Higher sensitivity of scoliosis was observed to this form of vibration. Where the frequency of axial cyclic vibrational loading of the lumbar spine was closer to its resonant frequency, the vibrational amplitude was larger.