Muscles Involved
Primary: Rectus abdominis, external oblique, internal oblique Secondary: Gluteus maximus, serratus anterior
Exercise Notes
The RKC plank is an intermediate plank variation that requires considerable muscle skill and endurance. Many people lack the abdominal and gluteal motor skills and stamina to produce a pelvic tuck (posterior tilt) and hold it for time. It is important to be able to dissociate the pelvis from the spine and to possess strong glutes because they help prevent excessive anterior (forward) tilt or overarching. This variation builds gluteal endurance as well as lower abdominal and oblique endurance. The key is to hold the pelvic tilt while driving the elbows toward the feet and the feet toward the elbows, making the isohold considerably more challenging. It takes time to master this movement, so make sure you're proficient in simpler plank variations before attempting the RKC plank.
Side Plank