I've tried your suggestion but didn't fix it.

Actually, they are of different frame animation.
Here's my animation sequence:
SlowPedal: index 2-48 -> model is on pedal slowly the bike
TurnRight: index 154-177
TurnLeft: index 181-204

So, in MED playing the animation, this how it looks
TurnRight (front):


TurnRight (back):


What I want to do is that, when the model turns right, I'll be playing the SlowPedal+TurnRight animation.
But when I run my code I didn't get the desired output?

It seems it's not playing the TurnRight animation..
Sample output:


I just follow the lite-c workshop on bone animation but it didn't work for me well.

At first, moving forward I play the SlowPedal animation
Code:
ent_animate(my,"SlowPedal",anim_percent,ANM_CYCLE)


Then, when player turns right (key_d is pressed)
Code:
ent_animate(my,"TurnRight",anim_percent,ANM_ADD);


Is there something wrong with the code?

Hope you could advise. Thanks