The SUP technique basics
We stand with our feet hip-width apart and parallel on the board at the height of the strap or the grip. The knees are slightly bent. This way you can easily compensate for small waves. Try to loosen up. The feeling of standing on raw eggs will pass after about 10 minutes.
The push arm (upper arm on the handle, opposite paddle side) is leading the whole paddling movement and ideally stands vertically above the paddle blade.
The pull arm (paddle side) grips the spar about shoulder width below the handle. It is the fulcrum of the paddling motion and remains almost extended throughout.
The resulting triangle of forces between the pull arm, push arm and upper body leads to a stable posture on the one hand and promotes an effective paddle stroke on the other. A triangle of forces is also created by the upper body, water surface and paddle, which gives you a lot of stability while paddling.