Bikram Yoga

As a Bikram yoga junkie, I wanted to examine the amount of force exerted on a person’s leg in the “standing head to knee” posture (Dandayamana Janusirasana); pictured below is the 2010 Bikram Yoga World Champion, Kasper van den Wijngaard, performing the posture. In competitive yoga, an individual is required to hold the posture for a period of time without moving. Therefore, I will treat this problem as an equilibrium problem. 

I simplified the posture by representing it with the following free body diagram:

I aim to calculate the amount of force required to hold up the horizontal leg so as to remain in equilibrium

Assumptions:

·      Mass of van den Wijngaard’s is 57 kg (125 lbs)

·      Length of his leg is 1.0 m

·      Equilibrium

·      Standing leg is vertical axis of rotation

·      Counterclockwise is positive

Calculations:

Στ = F_h (1.0m) – mg (0.5m) = 0

F_h = mg (0.5m) = (57kg)(9.8 m/s²)(0.5m) = 279.3 N

The force required to hold the posture in equilibrium is 297.3 N