Wikipedia info on the plank.
The plank (also called a front hold, hover, or abdominal bridge) is an isometric core strength exercise that involves maintaining a position similar to a push-up for the maximum possible time.
The most common plank is the forearm plank which is held in a push-up-like position, with the body’s weight borne on forearms, elbows, and toes. Many variations exist such as the side plank and the reverse plank. The plank is commonly practiced in Pilates and yoga, and by those training for boxing and other sports.
The “extended plank” adds substantial difficulty to the standard plank exercise. To perform the extended plank, a person begins in the push-up position and reaches their arms/hands as far forward as possible.
The plank strengthens the abdominals, back and shoulders. Muscles involved in the front plank include[7]:
- Primary muscles: erector spinae, rectus abdominis (abs), and transverse abdominis.
- Secondary muscles (synergists/segmental stabilizers): trapezius (traps), rhomboids, rotator cuff, the anterior, medial, and posterior deltoid muscles (delts), pectorals (pecs), serratus anterior, gluteus maximus (glutes), quadriceps (quads), and gastrocnemius.
Muscles involved in the side plank include:
- Primary: transversus abdominis muscle, gluteus medius and gluteus minimus muscles (abductors), the adductor muscles of the hip, and the external, and internal obliques.
- Secondary: gluteus maximus (glutes), quadriceps (quads), and hamstrings.
