written by Dave Lipson
Midline stability is a common theme taught in crossfit. Simply put it refers to a fixed and braced position of a nuetral spine wedded to the pelvis. If you stand up straight and put one finger on the sternum and another on the top of the pelvic bone, this distance would represent your midline. If the distance between those two points changes at any time while moving, you have compromised your midline stability. Midline stability and bracing the spine are things we do during almost all activities that move a large load, a long distance quickly. (See kenetic chain part 1 for why.)
The yoke is a fairly simple implement that involves a long straight base that is loaded in front and behind the lifter with a large thick crossbar that is picked up out of the quarter squat. Picture a loaded barbell welded to the wrack with an even load infront and behind the bar. A makeshift (chain yoke) model can be made with 4′ chains hooked on to the ends of the bar, with the weight hanging at the botton of the chains. The weight is picked up out of the quarter squat and carried for a distance.
Why is the yoke king when it comes to training the midline? The word yoke refers to the area of the body around the rear delts and lower traps. This is where the weight baring occurs during a yoke carry. You will not find another implement that can load and apply force through the axial skeleton more than the yoke. A 400lb male back squatter can typically carry a 600-700lb yoke. The skeleton operates at it’s strongest through neutral joint positions. The yoke requires very little flexion or extension of at any joints. You are merely performing a very hard isometric hold at the core while allowing your feet to move in quick little steps underneath you. It is an unbelievable tool when it comes to bracing the spine.
The opportunity to load that skeleton with that much weight is a huge stimulus for core strength, which is the limiting factor for most lifts ie. People that can leg press 800 lbs and back squat 225lb. The weak link in the chain is the core. The lower body can produce far more force than the axial skeleton can translate. The body will only produce as much force as can safely be translated. It is part of our brains involuntary survival mechanism. Training this weak link has transferability to all activities of power.
For these reasons the yoke is a good tool to warm up with prior to any heavy days or days with a concentration on the midline. By waking up and getting a huge motor unit recruitment around the core, you can develop the kinesthetic awareness to engage the supporting musculature in bracing the spine during more dynamic movements of lesser load.