This is a great side ab exercise. By keeping your knees straight and lowering them from side to side, you exercise and strengthen your obliques as well as your abs. Sometimes, people find it difficult to exercise the side muscles around their core region. Yet this exercise is perfect for targeting not only your sides but also your fronts abs.
How to do the Grand Father Clock Exercise:
Lay on the ground with your arms out wide. This is to help with balance. Keep your knees straight while lifting them high into the air. Slowly lower your legs to one side until they are a few inches off the ground. Lift them back to starting position and repeat on the other side.
Muscle group worked:
Obliques, Front abs
Target Repetitions for Muscle Growth: 6-8
Target Repetitions for Muscle Tone/Endurance: 8-12
Why the Grand Father Clock Exercise works:
Since you are lowering your legs to one side, it engages the obliques in a unique way. When your legs are close to the ground, your side muscles have to contract tremendously in order to prevent them from falling to the ground.
Keep your knees as straight as you can. The straighter your knees are, the more difficult this exercise will be.
Breathe out as your legs move toward the ground and breathe in as your legs come back up into the air.
Disclaimer: Talk to your primary care physician before beginning any exercise regimen.