Pseudocode:
...
ent_animate(stand);
my.pose=2;
ent_animate(crouch);

my.pose=3;
ent_animate(crouch);
ent_animate(walk,ANM_ADD);

if(my.skill1>0)
ent_blendpose(1,2,my.skill1);

my.skill1=100*key_w;
smooth(my.skill1,0.99);