“…Previous researches suggested that traction forces of 11-16 kg were necessary to elicit a measurable change in cervical spine structures [3,32,36,37]. The sustained traction was usually applied to the disc herniation patients with a time period from 2 to 20 min depending on their conditions, and the 3-5 min was often suggested for the first treatment [22,32,34]. Therefore, the cervical traction force was adjusted to 25% of individual body weight for a 5 min continuous traction in our experiments.…”