Drop (box or depth) jumps are used by many of us to increase power and strength and speed. But are we maximising their potential to enhance performance and are we using them in an ineffective way?
Yuri Verkhoshansky is the key man when it comes to the development of, and then subsequent mainstream adoption in training across virtually all sports, of the drop jump.
The former Soviet sports scientist studied the effects of different drop heights and jump types on speed and strength development, for example. He discovered that if maximum strength was the desired outcome then the optimum height from which to jump down from should be 1.50m using a double-foot off; land; double-foot jump for height method). In the same vein the optimum hight for developing speed and reactivity was 75cm.
So by varying the height from which you drop from (given Verkhoshansky’s parametres) you can manipulate the training outcome. This allows for drop jump training to be periodised, in much the same way as barbell loadings in the weights room can be to achieve different training results.
More on really knowing what drop jump height does and speed of landing vs jump height
Australian researchers looked at drop jump training on vertical jumping and quadriceps’ strength. Thirty-five males participated in the study and two training groups were established, together with a control group (1).
Both groups performed 72-90 drop jumps a week for 6 weeks. One group emphasised maximum rebound height and the other height and speed of reaction. Various tests were used pre-and post-testing to measure performance – these included, vertical jumps from standing and running and leg strength as measured under concentric and stretch/reflex (plyometric) conditions.
The ‘reactive’ group improved their reactivity by 20% - but not vertical jump performance. Surprisingly the ‘height’ group did not improve on any measure significantly. This led the researchers to conclude that, training for height through slower reaction drop jumps was, “not specific enough to stimulate gains in strength qualities of the leg extensor or jumping muscles.”
So it's a pretty confusing situation albeit from this short post and the Australian study (and there's a lot more research out there). However I will say that having looked at a lot of it and written articles on the subject and through my own personal experiences with those I coach, that speed of reaction is key, as this fires the nervous system as well as fast twitch muscle fibre, and has a greater influence on rate of force expression, reactivity , neural recruitment and speed. I believe that this has enhanced performance.
Reference: Int J Sports Med. 1999 Jul;20(5):295-303.