Single Arm Kickback
For this exercise, you will be holding a pushup position with one hand, while the other hand is completing a triceps extension. The focus here is going to be on core stabilization and upper body strength. With the one being elevated, you are going to have to engage your core even more than normal to keep from moving. With the opposite hand, you are working on the triceps, focusing on strength
As you can see here, just like all other pushup variations, you want to keep the torso tight and in a straight line. Try to squeeze your abs into your stomach/spine. With you elevated arm, focus on keeping the upper arm (biceps/triceps area) even with your torso, or as close as it can get. You want your only arm movement to be the rotation at the elbow. Do no drop the elbow below the level of your torso. This movement should be done in a slow and controlled manner to maximize its efficiency.