Fig. 2

Study schedule showing time points for enrollment and assessment. NDI Neck Disability Index, NPQ Northwick Park Neck Pain Questionnaire, SF-36 36-item Short-Form Health Survey, VAS visual analogue scale, W-1 screening before enrollment, W0 baseline assessment, W2 assessment after the sixth treatment, which is in the second week, W4 assessment after the 12th treatment, which is in the fourth week, W10 assessment 10 weeks after the first treatment, W16 assessment 16 weeks after the first treatment