Max speed and early acceleration are very polar, but eventually mid range will be something that needs to be discussed like the 40-50m zone. The purpose of the study is to see the effects on sprinting, not necessarily the adaptions.
I’m not sure why anyone is really interested in the effects on sprinting while your pulling the sled, I would think you would be interested in the whether or not there is a benefit that shows up in unresisted sprinting, which they didn’t measure. As I mentioned, I could have saved them the time and money because all of their results were obviously predictable. If they want to do a study on the effects of jumping with a heavy vest, I can tell them that the heavier the vest, the lower you jump. Its not rocket science.
Long term studies show
I’ve never seen a long term study covering this issue. This study tested immediately after training ceased at week 7. What about the long term effects, say 6 weeks later?
I[i]n fact, for the loads used by WS and WV in this study, UR training may actually be superior for improving sprint performance in the 18.3- to 54.9-m interval.[/i]
Again, badly designed study in that they are studying the transistion zone and Max V (remember these are lacrosse players) but using loads characteristic of acceleration training. Secondly, it appears this training was not part of an overall sprint training program. Who does heavy sled towing only and expects to improve Max V? What if sleds of various weights were towed as part of a well planned sprint training program? Again, not a well designed study.
So heavy sled (50% BW) max sprinting would be an unlikely method of developing max velocity.
I, like just about everyone else, doubts 50%bw sleds will do anything for Max V, with the remotely possible exception of an athlete who has no weight room training (or other resistance training for strength), who may lack general strength, and does the work as part of a well designed sprint program. This study was not designed in manner that would allow it to answer any of these questions.