This exercise involves the athlete dropping (not jumping) to the ground from a raised platform or box,
and then immediately jumping up. The drop down gives the pre-stretch to the leg muscles and the vigorous drive upwards
the secondary concentric contraction The exercise will be more effective the shorter the time the feet are in contact
with the ground. The loading in this exercise is governed by the height of the drop which should be in the region of 30
to 80 cm. Drop jumping is a relatively high impact form of plyometric training and would normally be introduced after
the athlete had become accustomed to lower impact alternatives, such as two-footed jumping on the spot.
Drop jumping activities must be optimized to ensure their effectiveness.
This is done primarily by optimizing the drop height. Too great a dropping
height can increase the eccentric loading beyond the reactive strength
capabilities of the athlete, while too small a drop height may not encourage
a prestretch sufficient enough to maximally augment the concentric portion
of the jumping action. The appropriate drop height to perform drop jumps
from can be optimized through analyzing the height to which athletes jump
to and their ground contact times during drop jumps from varying heights.
All sorts of box height recommendations are thrown out for depth jumps and
the original recommendations called for box heights of .75-1.15 meters.
A very simple and effective box height recommendation is to perform your
depth jumps from the height of a box that allows you to jump the highest
immediately after ground contact. As stated earlier, if you can't perform
a depth jump from a box of any height and get up higher then you can in a
regular standing jump then you shouldn't be using depth jumps to begin with.
One should aim to increase the speed, acceleration, and height of the jump
before increasing the drop height. According to the founder of shock method
training,Verkhoshansky, you should not spend in excess of 0.2 of a second on
the ground after landing.
Drop jumps should be done from a box height that enables you to absorb the
most energy without faltering. Aim to "stick" the landing soft and silent on
the balls of your feet just like a gymnast doing a dismount. If the heels
hit the ground the box is too high and if there is a thud at impact the box
is too high. When the box is the correct height the jump should be silent
and soft with a reflexive gathering of energy and often a reflexive bounce
at impact. When your body is gathering energy efficiently you will feel your
system want to reflexively use that energy to advance out of the landing.
Generally a good starting point for drop jumps is from a box 20% higher then
the best vertical jump and eventually on up to 1.15-1.25 meters.