Problem 14

Given information

Given: Touching your toes while you are seated on the floor with outstretched legs. Touching your toes from a standing position.

Step-by-step explanation

Take the pivot at waist height for a person sitting with legs extended (shown in the figure). Consider the weight of the upper half of the body doing torque clockwise, for this force the lever arm is relatively small as is the torque made by the arms, therefore the muscles of the back do not do much tension due to the small total torque performed.