This exercise helps strengthen the back and core.
1 Begin on your hands and knees with knee directly under your hips and your hands directly under your shoulders.
2 Lift one arm and the opposite leg out straight in front of you, keeping your stomach tight and your hips still.
3 Slowly return to the starting position and switch sides.
4 Perform 10 to 15 repetitions on each side.
Once you've finished the exercise, click to see what percentage you have completed.