Use standard 3ds Max Design scale transforms to adjust a biped's posture by scaling the size of its links. You must be in Figure mode to scale the biped links. If you try to scale a biped without going into Figure mode, nothing happens.
As with rotation, when you scale biped links, Biped constrains the transform to use the link's Local coordinate system. The position of other biped links can change so they remain attached to the resized link. If you shorten the thigh, the calf and ankle will maintain their size, but change their position.
Use Scale and the Transform gizmo to scale links.
Scaling the biped limbs to fit snugly to the mesh will help when Physique is used to associate the mesh with the biped. The Bounding Box option uses biped limb dimensions to size the envelopes. This saves time when you adjust envelopes in Physique.