Available cases Imputed analyses Outcome Estimated difference (95% Cl) P value* Estimated difference (% Cl) P value* Oswestry disability index -4.1 (-8.1 to -0.1) 0.04 -4.5 (-8.2 to -0.8) 0.02 Shuttle walking test 34 (-8 to 77) 0.12 25 (-16 to 66) 0.23 SF-36 (physical component score) 2.0 (-1.2 to 5.3) 0.21 2.5 (-0.4 to 5.5) 0.09 SF-36 (mental component score) -0.2 (-2.9 to 2.6) 0.90 0.4 (-2.0 to 2.9) 0.73

^* Analysis of covariance adjusted for baseline measure.