I recently asked a friend, physical therapist and fellow PKBer, John Tuitele, to offer his thoughts on performing movements with the PKBs at the end of a bar, as in a barbell. Why do this, you might be wondering, well, I might answer, why not!? It was a-w-e-some!... but before I get carried away with how far myself and a fellow athlete felt we could challenge the physics behind long levers and unstable loads - allow me to introduce John Tuitele:
"Unstable loads at the end of a long lever can be a novel and effective mix to create gains if carefully and thoughtfully applied"
Mathematician Archimedes is cited as stating that a long enough lever could move the world. The same principle of leveraged load works well with resistance training, including kettle bell/bag workouts. With Olympic lifts, just the opposite is encouraged when we keep heavy loads close to center line of the body to minimize the lever arm.
Kettlebell swings deliberately utilize a long lever with straight arms throughout the movement, deliberately and to good effect, particularly in the eccentric phase of the exercise. Turkish get-ups "leverage" straight arm and an actively locked shoulder to make the movement more difficult to control - again to good effect. Consider the levers involved and amount of load tolerated with back squats vs. overhead squats. Overhead squats require a scaling of the load because the lever arm from the hips and across the trunk is much longer compared to a back squat (or front squat, too).
Why all this obscure rumination? I'll offer it is important to remember the effect of levers, labeling a lever as a significant compounding force. Whatever load is placed at the end of a lever is much more difficult to manage than loads kept close to the body. I recently viewed an overhead snatch with PKB Sandbags hanging from the barbell. The physical therapist in me squirmed more than a little bit as I viewed it and thought about an unstable load at the end of a long lever arm with amplified force moments across the hip, low back and especially the shallow joint of the shoulder.
As in all exercise programming, the principles of modification and scaling are essential. If those two foundational and vital elements of training are ignored, the risk of injury increases. Unstable loads at the end of a long lever can be a novel and effective mix to create gains if carefully and thoughtfully applied.
The thoughtful application of variation is paramount in all training, especially with increased or unstable loads at the end of a long lever arm. Put another way, one of my favorite quotes by Kelly Starrett is "Intensity is a brutal mistress." I'll add that you gotta keep a close eye on that evil wench: she'll turn on you in a heartbeat.
John Tuitele, PT, DPT is a physical therapist and gym owner who has coached hundreds of athletes in strength and conditioning programs including CrossFit. He is currently based out of Phoenix, Arizona.