Sylvi asked a really great question last Friday: “Why do we do exercises with only one dumbbell.” The answer fits right into this continuing thread regarding athleticism and fitness. I am going to re-answer the question here to practice being more concise with this information, but also to make sure everyone knows what we are doing and why we are doing it.
I don’t think it is overstating to say that you are successful (at least technically) in any sport to the extent that you are able to coordinate the movements of your upper and lower body in all three planes: the sagittal (in front, above, behind the body, like a good morning), frontal (out to the sides, like the arm movements in a jumping jack) and transverse plane (rotation around the center, like the upright torso twists we do in warm-up). Coordination means that we are able to move both upper and lower body through one or more planes, (e.g. squatting and deadlifting are moving both the upper and lower body in the sagittal plane), or prevent ourselves from moving through any planes (e.g. holding at the top of a ring dip) and, finally, and probably the most useful for most athletes, holding the upper body steady while the lower body is active (e.g. performing short turns while skiing or running) or moving the upper body as the lower body stays stable (e.g. hitting a tennis ball or baseball). CrossFit refers to this coordination of upper and lower body generically by the term midline stabilization or midline stability. Or as Kelly Starrett, KStar, of CrossFit San Francisco sums up so concisely in this video (CrossFit Journal Preview – video wmv mov): “The capacity to maintain neutral spine, under load, under tension, from head to the base of the sacrum.”
How do we both train and practice to keep our midline stabilized in all three planes? In a nutshell, we put weight as far as we can from our center of mass and move. The best example is the overhead squat. While it looks like we are just moving in the sagittal plane, anyone who has done an OHS that is heavy relative to their body weight knows the bar wants to move in every plane and keeping it in the sagittal plane can be very challenging. Another technique we use to both train and practice midline stability is use unilateral movements, i.e. weight bearing on only one side of the body, like pistols (single leg squats), single arm overhead lunges or, like last Friday, single arm waiter walk and the Turkish get-up. Unilateral movements have the added benefit of exposing any strength or mobility differences in either side while also adding more frontal and/or transverse plane training to a strictly sagittal plane movement like walking or squatting. Addressing these issues will help prevent injury and also increase performance.
In summary, one of the benefits of CrossFit training is that it explicitly targets building midline stability through a number of bilateral (e.g. overhead squat, kipping pull-ups, deadlift, etc.) and unilateral (e.g. overhead lunges, Turkish get-ups, kettlebell swings, etc.) functional movements. We use unilateral movements in particular For the following three reasons:
- Unilateral movements may be used in the sport or activity we are training for.
- Adds lateral and rotational components to primarily sagittal plane movements.
- Expose and address any strength/mobility issues on either side of the body.
References coming soon…