Asanas for strength
Strength in the muscles is developed by the regular practice ot these asanas.
Asanas work not only on the major muscles, but also on the minor ones so that they can assist the former.
Asanas teach us to use our physical strength in an intelligent and elegant way, and not exerting brute force.
What is important is the dexterity with which the movements are made.
Isometric exercises are performed to develop a specific muscle, while isotonic exercises generate strength.
Asanas are more holistic in their approach. Isometric movements occur simultaneously on multiple muscles while doing a particular asana.
For example, adjusting the arms and fixing the shoulder blades while slowly going up or down in Urdhva Dhanurasana exercises the back, deltoids and arm muscles simultaneously. Once you are in Urdhva Dhanurasana, the weight of one`s body helps in bringing about an isotonic effect and generate strength in arms and legs.
From the book “Yoga for sports” by B.K.S. Iyengar.