If this is done correctly, the center of gravity of the lifter-barbell complex will be over the foot of the lifter during the pull and later on, towards the back of the foot when the bar is received. During the execution, the lifter moves around the barbell in a way that favor mechanical advantages in an effort to lift the barbell as ”easily” as possible. It also means that the barbell trajectory is dependent on the favored positions by the lifters. This is what I call seizing the moment of least resistance.
The biomechanics of the lifters are as interesting – or even more -as the trajectory of the barbell. How the lifter moves around the bar as he pulls, meaning the positions he adopts (angles) as well as how he makes it happen, and the morphology of the lifter – especially in regard to the length of the limbs (arms and leg) as well as the torso/legs ratio- are of incredible importance in understanding technique and refining it.
More over, other factors are quite important too. I am referring to the neuro-motor qualities of the lifters such as his ability to recruit the right muscles to do the task, his ability to reduce or limit co-contractions of muscles or to inhibit to some extents antagonists muscles, his ability to time correctly the uses of muscles and, to push it even further, his ability to recruit the right muscles fibers to get the right result. Thus, the bar path is not enough to access what is really happening during the lift.
Here is the bar trajectory of Suleymanoglu and Krostev as illustrated in Bartonletz (1996) paper ”biomechanics of the snatch: towards a higher training efficiency”. For both lifters, the bar travels towards the lifter reaching the hips, before travelling forward (as in more forward than it was at the hip). Althought one could argue that Suleymanoglu’s trajectory is ”straight”, it is not. For one, the bar starts around the beginning of the foot. The bar never ever cross that starting position vertical line: It is travelling behind it (more towards the lifter). Krastev does that as well.
Here, Bartonletz compares two lifts with different first pull velocity. I have written before about speed and mechanical considerations of the first pull and this should not come as a surprise to the reader of First Pull. Anyhow, in both cases, the bar is not travelling straight up, it is being kept close -especially in the case of a slower first pull. Please look at the maximal velocity reached by the lifter who pulled slower off the ground.
My point, with this article, is not to say that bar paths don’t matter. They do matter as long as they are considered along other things – such as morphology of the lifter, biomechanics, and neuro-motor aspects. These studies show that there is a very high variance in bar paths among the best lifters of the world. More importantly, it shows that there are many types of pull that can be used with great success (read elite level success) and that the trajectory of the bar – although different from the normalized text book model- as to be the result of the lifter using all the mechanical advantages he can get. In other words, if the bar path is not straight on your bar path application (Bar sense) or software (Kinovea), but the lifters keeps the bar close to his body as well as uses positions in which he is strong (read : at mechanical advantages), then success of the lift is possible. If this is true, then flattening the curve of the trajectory might not be necessary or recommended. Ultimately, it stresses that individualization of technique is a must. The bar has to be close to the body, but not necessarily travel in a straight fashion.