y-balance

name	y-balance
description	Holds a single-leg Y-balance reach, hinging forward with the hands reaching ahead and one leg extended back. Use when a command mentions Y balance, single-leg reach, balance reach test, or reach forward on one leg.
category	locomotion
disable-model-invocation	true
subskills	["move-torso","move-leg","balance-and-posture"]

y-balance

Balance on one leg, hinge the torso forward, reach both hands ahead while the free leg extends back.

Composes: move-torso + move-leg + balance-and-posture

How

• Static pose. Hinge Spine+X35, free leg back (UpLeg-35), arms forward (UpperArm X~120); support knee soft.
• Hold ~1500 ms; counterbalance over the support foot.

Example

• "do a Y balance reach" -> {"durationMs":1500,"pose":{"Spine":[35,0,0],"LeftUpLeg":[-35,0,0],"LeftLeg":[10,0,0],"LeftFoot":[70,0,0],"RightLeg":[10,0,0],"LeftUpperArm":[120,0,90],"RightUpperArm":[120,0,-90]},"say":"Reach and balance."}

Limits & posture

Keep ≥1 foot grounded except at a jump's airborne apex; stay inside human joint ranges and keep weight over the support — see balance-and-posture.