Avoid wrist strain by making sure wrists are in proper alignment when holding high plank. In proper alignment wrists should be directly under your shoulders with soft elbows. Align your wrists so the middle and index fingers point forward. You want to ground your fingers into the mat, particularly the index fingers, by putting pressure into them. By putting pressure into your fingers, you spread the weight from the wrist joint out over the entire hand. Thus, rather than the weight going into a small portion of the hands (high pressure), the weight is fanned out over a greater area (less pressure).