Vinyasa, arm balances and handstands often leave yoga practitioners complaining of wrist pain, especially at the Ulnar side of the hand, that is, the base of the palm furthest from the thumb. To combat this, the focus is on various hand positions, pushing down with the base of the thumb, rising up onto the fingers when jumping through, Pada Hastasasna or wrist guards.
An analysis of body mechanics provides another alternative: we are designed to be able to make both pushing and pulling movements that utilise opposite, or antagonistic, muscle pathways. In other words, pulling is the opposite of pushing.
If you analyse the hand movements of yoga, they are pushing movements – there is no scope for pulling movements, unless you work with a partner or adjust students as a teacher. The fact that yoga involves mostly pushing movements means that wrist and finger extensor muscles tend to shorten, because the hand is held perpendicular to the forearm, while the finger and wrist flexors are constantly being stretched.
Pada Hastasana helps to stretch the extensor muscles but strengthening the wrist flexors can be much more helpful. Wrist curls can be used, but since you are pushing your entire body weight onto your hands in many asanas, pulling your bodyweight is more effective. These kinds of exercises are usually chin-ups, pull-ups or horizontal rows.
Although most women and many men struggle with these movements it is not necessary to learn to do full movements, hanging from your hands and pulling yourself upwards, even a few centimetres and holding that position for 5-10 seconds is sufficient, with as many repetitions as you can manage. Gym equipment is also not necessary, any place you can hang from your hands will do.
Reading sources: Boyle, 2004, Functional Training for Sports