Just Jump handheld computerCompanion Jump Mat

Explosive Leg power and reaction time

Introduction - Explosive Leg Power

Within the training and sports community there has been a gradual recognition of the critical importance of the rapid application of leg power. In the past the simple measures of speed for some sports and strength for others often left coaches and athletes scratching their heads at the outcomes of actual sporting events. Recruiting efforts that relied too heavily on these systems often did not yield the desired results.

More important is the combination of strength and speed that we refer to with the phrase "explosive leg power". Indeed there is also the mental state of an athlete to consider but that is outside the scope of this discussion.

Probotics, Inc. recognizes the importance of measuring this combination of strength and speed. The Just Jump or Just run handheld computer includes two measures to quantify and encourage the development of this combination.

Explosive Leg Power - measurement of

Measuring explosive leg power

To determine explosive leg power the Just Jump or Just Run computer includes a "Jump 4 Times" setting. This setting will measure the subject as he makes four successive jumps and will then display the following:

  • average ground time - measures the average time on the ground between jumps. This simply and accurately demonstrates an athlete's quickness.
  • average height - measures of the average height of the four jumps. This will simply and accurately show the subjects leg strength.
  • explosive leg power index ("Power Factor") - this is air time divided by ground time. It is a direct result of leg strength and quickness and will capture the combined strength and quickness measure we are after with an easy to use single number.

see figure below

Explosive Leg Power - fatigue factor

What about endurance

The "Jump 4 Times" will measure explosive leg power but will not necessarily tell you anything about explosive leg power over time. For this the Just Jump or Just run has a 60 jump setting. Here the computer will average heights, contact times and leg power for the first 15 jumps and the last 15 jumps, in addition to a fatigue factor rating.

In summary...

In summary coaches, trainers and athletes now have a tool for measuring not just speed and leg strength alone but the speed at which leg strength can be applied. It can also be a great tool for charting rehabilitation. Both trainer and athlete can get immediate feedback on progress and this has been shown to be a great motivator.

4 jump measurement