@steven-miller
I just happen to harbor the belief that olympic lifts are not as specific as simple weighted jumps, and not as good for power development compared to weighted jumps. Joe Defranco holds this same opinion, commenting on how the most explosive movement in oly lifts comes form the bar, and the spine (and the study I am about to share shows that jump squats produce a more explosive barbell movement than power cleans).
http://www.defrancostraining.com/ask-joe-test/41-strength-training/180-hang-cleans-vs-weighted-jumps-for-explosive-hip-extension.htmlPeople like power cleans because they're called "POWER" cleans, as if they develop power. Of course they do, but so do jump squats, and the barbell jumps Daniel demonstrates. I think the jumps Daniel demonstrates, trap bar jumps, and high bar squat jumps, innervate the muscles used in vertical jumping more specifically, and more so in general, than oly lifting exercises but I cannot find EMG studies demonstrating this. Using kinesthetic senses, it is clear though that you "feel it" more in your quads in jump squats than hang snatches..
In this study here,
http://www.ncbi.nlm.nih.gov/pubmed/21777152, the researchers measured the power of the whole system (bar +body, using a force plate), of the bar only, and the body only, utilizing a single sacral optimal marker (results may have been different if utilizing a single cervical optical marker since the oly lifts require so much spinal extension), in the squat, squat jump, and power clean in 9 male college students with 2+ years of oly lifting.
It was found that BAR peak power was higher in a jump squat than in a powerclean in all the loads used, from 30-90%1RM. Body peak power was significantly lower in the power clean compared to jump squat again in all the loads used. The maximum body power during the jump squat occurred at 0%1RM and was triple that of the maximum power produced during the power clen at 90%1RM. Same story for system peak power (measured using the force plate). Greatest system power was achieved at 0%1RM and was more than double that of the maximum from the power clean.
I have the fulltext access and just read through all of it. I can't find any studies looking at the effects of jump squats versus hang snatches though, or barbell Daniel jumps.
THis does not mean that power cleans won't incrase your vertical jump. This study here (
http://people.stfx.ca/x2006/x2006nsx/Challis-2004-EXAMINATION%20OF%20THE%20SCALING%20OF%20HUMAN%20JUMPING.pdf) found that oly lifting improved sprint speed and vert more than complex training of heavy squatting and jumping. However, only the oly training group improved in the squat jump, so this does not prove anything about the topic at hand, whether or not squat jumps are better than oly lifts. In fact this raises the notion that squat jumps are better, since practising them would improve them more than oly lifting and since JS performance improved, as well as vertical, we could expect better sprint times and counter movement jumps in a jump squat program.
Other ways of analyzing this are using the tendo. But I will stop here
Edit: oh yeah, what does this bar power versus body power mean?
From the article:
"Throwers or competitive
weightlifters, for example, may be more concerned
with bar velocity and power and not necessarily body
power, whereas jumpers and sprinters may be more
concerned with body or system velocity and power."
Again, body power was triple in the jump squat versus power clean. The fact that max power occurred at 0% jump squat 1RM though is weird, i don't know if that shows us that training jumps without weight is the best strategy therefore.
This study,(
http://www.ncbi.nlm.nih.gov/pubmed?term=Comparison%20of%20four%20different%20methods%20to%20measure%20power%20output%20during%20the%20hang%20power%20clean%20and%20the%20weighted%20jump%20squat.%20) which only looked at bar power and system power, found that bar power was higher in a hang power clean versus a weighted jump squat. Results: system power was slightly higher in the jump squat, but the hang powwerclean was close, variations where huge. Without EMG though it doesn't mean much, we don't know which muscles are invovled and it doesn't answer the specificity question.