Table S1. Changes in the neck disability index from baseline (per protocol set)

SCM (n=161) / Traction (n=161) / p
NDI at baseline / 22.72±6.23 / 22.71±6.16 / 0.909
Week 2
NDI / 18.16±4.79 / 19.48±5.43 / 0.018*
Change from baseline / -4.67±5.245 / -3.23±4.46 / 0.015*
p / <0.001* / <0.001*
Week 4
NDI / 17.58±4.76 / 18.93±5.58 / 0.025*
Change from baseline / -5.25±5.73 / -3.89±4.88 / 0.019*
p / <0.001* / <0.001*
Week 12
NDI / 17.23±4.65 / 18.52±5.51 / 0.041*
Change from baseline / -5.60±6.09 / -4.19±4.78 / 0.047*
p / <0.001* / <0.001*
Week 24
NDI / 17.06±4.78 / 18.03±5.25 / 0.073
Change from baseline / -5.87±6.49 / -4.79±5.55 / 0.079
p / <0.001* / <0.001*

SCM: Shi-style cervical manipulations; NDI: neck disability index

*p<0.05

Table S2. Changes in participant-rated pain from baseline (per protocol set)

SCM (n=161) / Traction (n=161) / p
Pain score at baseline / 58.17±12.94 / 57.77±12.36 / 0.894
Week 2
Pain score / 34.48±14.67 / 37.65±14.16 / 0.026*
Change from baseline / -23.91±15.67 / -20.12±13.96 / 0.015*
p / <0.001* / <0.001*
Week 4
Pain score / 32.23±14.62 / 35.53±13.59 / 0.037*
Change from baseline / -26.14±16.84 / -22.24±13.18 / 0.021*
p / <0.001* / <0.001*
Week12
Pain score / 30.89±14.65 / 33.96±15.34 / 0.068
Change from baseline / -27.28±16.34 / -23.81±15.67 / 0.075
p / <0.001* / <0.001*
Week24
Pain score / 29.27±14.81 / 31.49±14.66 / 0.078
Change from baseline / -28.91±16.43 / -26.28±15.47 / 0.141
p / <0.001* / <0.001*

SCM: Shi-style cervical manipulations

*p<0.05

Table S3. Changes in participant-rated quality of life from baseline (per protocol set)

SCM (n=161) / Traction (n=161) / p
SF-36 at baseline / 59.86±15.34 / 59.64±15.96 / 0.979
Week 2
SF-36 / 66.59±15.14 / 63.75±16.16 / 0.108
Change from baseline / 6.81±11.92 / 4.10±10.98 / 0.056
p / <0.001* / <0.001*

SCM: Shi-style cervical manipulations

*p<0.05