Straighten your spine, load both heels back against the blocks, don’t lean forward in the set position because you’ll increase the load over your hands and may struggle with a fast (right) hand response to the gun (because your hands are pinned down on the track). Elevate your hips high enough so that you can drive your left knee through from the rear to around the starting line or over it without jamming. Remember in the early acceleration phase you need the foot to strike behind the pelvis to drive your body forward. If your foot strikes ahead of the pelvis you need to wait until the body rolls ahead of the foot again before you can push effectively. Angles behind the knees in the set position are usually around 90 degrees (your right knee) and 120 on the rear leg.