A positive trend was seen for patients with a longer duration of complaints ( greater than 6 months ) ; they were more likely to report higher function scores and to have less pain on activity with exercise therapy than with usual care compared to those with a shorter duration of complaints ( = 12.3 ; 95 % confidence interval : -0.08 , 24.7 ; P = .05 and = -1.74 ; 95 % confidence interval : -3.90 , 0.43 ; P = .12 , respectively ) .