Maybe because when manual stretching, you apply a greater force than with a hanger(especially for begginer-intermediate levels) ?
I agree and also believe that to get the benefit from hanging, you have to reach fatigue and ride the fatigue. For thus reason, I think more sets at moderate weight is the best approach. Those using excessive weight hang for shorter periods which some argue is equally or more effective. Maybe 40 minutes of hanging with stretching also thrown in will work. But I’m not sure 40 minutes daily of only hanging at light or moderate weight will yield much results.
Current (Sept 15, 2011) BPEL - 7.6 MSEG - 5.8
Goal 8 x 6 (preferably NBPEL)