The Olympic lifts are extensively used in the conditioning of athletes. They help to teach athletes how to apply force quickly. For these lifts, this is done while standing up and involves most of the muscles of the body. Having said this, these lifts have limitations in that their resemblance to sporting activities is occasionally oversold.
Moolyk et al, in the December issue of the Journal of Strength and Conditioning Research, had a study comparing the lower extremities during the impact phases of jump landing and weightlifting. To study this, the authors had ten female athlete subjects, volleyball players and weightlifters. The athletes had a mean clean 1-RM that was a little over 85% of bodyweight. In the study, the subjects performed four reps each of block jumps and drop jumps as well as three sets of two reps each of 80% for both the clean and the power clean.
The results are interesting. When reading, keep in mind that these are studies of the impact phase of landing:
· The knees are the primary contributors to the impact phase of the exercises studied. The exact contribution ranged from ~46% (for the jump task) to ~63% (the clean). With the drop jump and the power clean being very similar at 57% and 58%.
· From there, the results are a little different. For some exercises the hip contributed more to the impact than the ankle (drop jumps and the clean), for others the hip contributed less than the ankle (jumping conditioning), and for the power clean the hip and ankle contributed equally.
· At initial contact of the landing, the hip angle was very similar for the drop jump, power clean, and full clean. It was lower for the jumping conditioning. At initial contact, the knee and ankle angles were similar between the power clean and full clean. However, the jumping conditions had lower knee angles and greater ankle angles than the clean conditions at initial contact.
· A peak knee flexion, all four exercises had similar ankle angles. However, the knee and hip angles were very different. Clearly the full clean had the greatest knee angle and hip angle. This was followed by the drop jump, jumping conditioning, then the power clean.
· In terms of joint moments at peak knee flexion during impact, the knee provides the most across all exercises, followed by the hip, followed by the ankle. The greatest joint moments is for the clean, followed by the power clean, with both jumps being very similar to each other.
What does all this mean? One way to look at this (and the way the authors looked at this) is that all exercises are knee extensor dominant. This suggests that the full clean especially is a great exercise for training this and enhancing jumping performance. Another way of looking at this is that all four exercises are different from each other – at least during the impact phase. This is largely true in terms of joint contribution, joint angles, and joint moments. For example, while all four exercises primarily involve knee joint contribution; for the full clean it’s almost 63%, for the power clean it’s almost 58%, for the drop jump it’s almost 56%, and for the jumping conditioning it’s almost 46%. So, when looking at the knee joint, the drop jump and power clean are similar in terms of joint contribution, but none of them are similar in terms of joint angles or moments. For me, this study reinforces the fact that the Olympic lifts are general training tools for most sporting activities. In other words, they help to provide a physical foundation and train the athlete to apply force quickly, but they don’t replicate the sporting activity.
Moolyk, A.N., Carey, J.P., and Chiu, L.Z.F. (2013). Characteristics of lower extremity work during the impact phase of jumping and weightlifting. Journal of Strength and Conditioning Research, 27(12): 3225-3232.