A, et al. mentioned a hypothesis of relaxing effect of B on muscle. They referred to the involvement of reuptake of calcium, reducing edema, neurological factors (e.g., Ib or γ fibers and α motor neurons) and inhibition of pain. It is probable that these factors involve in the effect of B on improving flexibility observed in this study.
 

C was used to assess complex joint motion related to BADLs in this study. However, to assess the effects of B on active and passive ROM could provide more information for considering the mechanism of improving flexibility.