Planks place a strong emphasis on the core muscles. The core muscles are those that make up the torso. They consist of the back musculature, abdominal muscles and hip musculature. The core is the foundation of the body. If proximal stability or core stability is not adequate, the muscles of the extremities will not function as effectively while running, cycling and swimming. Practical Benefits: Planks focus on the core as a whole. It is a great exercise to stimulate those muscles and to improve endurance. It improves core stabilization to enable cyclists to maintain up proper back position. Areas of Concern: Avoid this exercise if you experience shoulder pain and back pain while and/or after performing it.