Critical Instant

The Biomechanics

The critical instant is a very crucial phase in the backtuck. This is the point when the feet leave the ground. At this point in the skill, the arms should be straight and extended as high as possible, ideally covering the ears. This provides backward momentum. The legs should be almost fully extended and the feet should be entirely in plantar flexion. This provides the force required to stay in the air for the full rotation. The athletes should be jumping almost vertically, only leaning back slightly. The optimum angle of take off is between 100°-120°. Jumping too vertically can result in a slower rotation which could cause the athlete to under rotate. Taking off at a greater angle than 120° can cause the skill to be too low to the ground and also cause under rotation.

120°

My body is at a 120° angle as my feet leave the ground

Plantar Flexion

Legs extending but not completely straight

Arms should be straighter at this point