Centre of Mass


In our Olympic Lifting classes (Tuesdays and Thursdays, 5:30 p.m.), conversations about “centre of mass” are not unusual. Sometimes it’s direct: “You’re stronger nearer to your centre of mass,” I’ll say. Other times, the cues are different, but the reason for them is much the same. For example, doubtless at some point, athletes at Crux have heard the trainer say something like: “try to ensure the bar path is as vertical as possible”; or “don’t move the bar around yourself; move yourself around the bar”; or “keep the bar close to your body.” All of these are related in that these are all cues to keep the weight close to the athlete’s centre of mass. This is because, as I wrote above, we are strongest when the weight is closest to our centre of mass. Really, this is true regardless of the lift: Olympic lift, power lift, whatever!

But sometimes that weight can get away from us. In weightlifting, one spot where it’s easy to let the weight move away from our centre of mass is during the end of the second pull. (The second pull is when the weight passes approximately mid-thigh to the point where the athlete is in full hip extension.). This happens most often because the athlete, in anticipation of having to get under the bar quickly, doesn’t come to full hip and knee extension at the point of initiating the shrug, so the bar stays low and slightly away from the thighs, never rising to waist level. If the athlete has a strong shrug, the bar may reach waist level and higher, but, because the hips aren’t fully extended, there will be a gap of some 3 or 4 inches perhaps between the bar and the hips--that is, 3 or 4 inches away from our centre of mass. That’s lost strength.

As we all recognize, achieving full extension is critical to an efficient Olympic lift; this is something all athletes should continuously work to improve technique in order to use their strength efficiently. Don’t waste the added strength that complete hip and knee extension provides. Be patient to complete the second pull and keep the bar in close; you’ll surprise yourself with just how much more upward momentum you add to the lift, and therefore, how much more space is created in order to get under and receive the bar.

If any of this sounds familiar or even if it just sounded confusing, come see us at the Olympic lifting class on Tuesdays and Thursdays at 5:30. See you there!'

Coach Kris