Would programming high depth jumps with a long eccentric phase followed by a jump, be a good pre activation movement for squats? Or would they be better off placed on a separate day or at the end of a squat session?
Too much stress on the nervous system without being more effective than regular jumps as an activation tool.
Furthermore the long eccentric you mention (I assume that you mean waiting 2-3 seconds after you land before jumping) is only useful as a motor learning tool to learn to absorb force THEN jump. When using depth jumps to improve power the goal is to use the energy accumulation from the landing to produce MORE power in the jump. The result is that you should jump HIGHER when doing a depth jump vs, when you do a vertical jump.
If your depth jump is lower then the box is either too high for you or you are not yet efficient in that type of exercise (and the landing becomes inhibitory instead of potentiating). In both cases you need to drastically lower the height of the box.
SIDENOTE: I personally use a sensor called "BEAST" (thisisbeast.com) that measures velocity and power. So when doing depth jumps I start by establishing a power /speed baseline with a regular vertical jump then gradually increase the box height as long as I can produce AT LEAST as much power and ideally. I also stop the set when power drops down in a jump.
OK back to your question, a long eccentric/absorption phase will defeat the purpose of the depth jump, which is to produce maximum power by using the stretch reflex. After 2 seconds the benefits of the stretch reflex and accumulated energy is lost and the exercises loses a lot of its efficacy. On the other hand I'm not a fan (anymore) of rebounding up super fast either (imagining that the floor is hot)... the only thing that matter is the power produced and for most people trying to rebound as fast as possible will lead to less power production... the only coaching cue should be "jump as high as possible". Let your CNS pick the best strategy.
That makes sense. About it being to intense on the CNS for preactivation...kind of what figured.
And no, for the "longer eccentric" phase I was referring more to jumping off a high box which would obviously increase the time it takes you to hit the floor (aka the eccentric?).
Also, as far as power goes, what you said about not taking to long or going to fast makes sense. If you want to develop power, you need to optimize the the two...BUT what if you were using the depth jump for a completely different purpose; say to increase your squat--if that's even a legit method for doing so. I read somewhere that Loui Simons recommended using a high box for developing strength and a lower box for power.
No you are referring to the suspension/or kinetic energy accumulation phase. The eccentric phase in a jump is from the moment you land up to when you initiate the jump.
But as I mention in my post going too high is the NUMBER 1 AND MOST STUPID MISTAKE people make with plyometrics. The goal is not to see how high you can still rapidly jump up from but rather pick a height that allows you to jump higher than normal.
If the box height is excessive and your jumping height is lowered you are training the wrong thing.
That makes sense. With all that being said, is there ANY possible application for jumping off a high box? Maybe jumping off a high box (NOT following it with a jump) simply to help condition the joints/ligaments and learn how to decelerate maybe? sorry for all the questions, just really trying to learn all the proper applications of this stuff as best and fully as I can.
Not Christian, but best trained on lower boxes or from the floor if deceleration is a skill that is lacking IMHO. As CT mentioned jumping off a box of ANY height and pausing before jumping is to teach deceleration and help the tendons learn how to absorb force. You should always start lower than higher. Advanced athletes may effectively use a higher box, but that is kind of the plyometric equivalent to doing a Westside style "circa max" phase or adding tons of band and chain tension to your dynamic squat day--you need to be advanced before it even makes sense to train that way.
Exactly correct. If you can't land by activating the proper muscles (glutes and hams, not only quads) then you are doing more harm than good by doing depth landings
You can get more out of regular box jumps (up) by adding ankle weights or holding a medicine ball or something.
You can also do multiple "hops" or 1 legged jumps, before you land on 2 feet then broad jump.
You can sit on a box, then jump up to another box.
This guy is a Super Freak, at the end of a long training cycle, and you can see, they don't even let him depth jump much.
That dorsiflexion isn't normal. Amazing calf and ankle power.