Why You Should Prioritize Unilateral Training in Earlier Phases of Speed Development
Movement Physics Tell the Story, Not Movement Appearance
Triphasic Training by Cal Dietz and Ben Peterson, where they wrote the following:
“A single leg plyometric, as shown by [a] motion analysis machine, is so much slower in producing forces…With double leg plyometrics…there is higher potential for developing speed because of the shorter amortization phase, and thus, a more explosive rebound…Single leg plyometrics should be viewed more as a strength plyometric whereas double leg plyometrics develop speed.” 4
We often assume that single leg training is more “sports-specific,” since most athletic actions occur on a single limb. When speaking strictly kinematically—that is, based on how a movement appears—then yes, that’s true. But when we consider the kinetics of the motions—that is, how the movement was caused in terms of the forces and time frames involved—we start to see that we can’t just look at the appearance of a movement. In order to better determine the desired training effect, we must also consider the physics involved.
Here are 3 Reasons You Should Prioritize Unilateral Training in Earlier Phases of Acceleration:
#1 Unilateral Training matched the ground contact times experienced in earlier phases of acceleration.
Each step in acceleration you’re experiencing greater time on the ground (.16-.20) of a second. This is to allow stored energy within one’s structure to coil and fire. Consequently, greater ranges of motion are presented. In the weight room, unilateral training allows you to get similar ranges of motions and musculature used based on the joint position.
#2 SAID Principle
Where specific adaptations occur based on imposed demands. So, it’s typically reported that training with unilateral activities will have the greatest impact on unilateral actions, though some research has suggested that bilateral countermovement jump performance may also improve following a period of unilateral jump training.
#3 Contractile Speed in Unilateral Activities vs, Bilateral
Inherently, training unilaterally, restricts how fast motor unit firing can take place. Bilateral movements are performed faster than unilateral movements. Therefore, when ground contact times and forces are slower, the weight room should help contribute to the task at hand.