With the latest advance in technology we hear more and more about Velocity Based Training and how to pick loads and repetitions on the speed of movement. Actually, early in the 80’s Linear Position Transducers (LPT) were used by researchers in Europe and Russia to measure speed and power of the repetitions. The italian Carmelo Bosco (PhD) was among the first to elaborate and experiment on this topic and came out with tons of research and one product, the Ergopower, to daily tailor training programs. The Ergopower was showing speed and power of the exercises in real time allowing coaches to select loads and adjust repetitions on-the-go. This was also named the Bosco System or Method.
In the following years the speed measure took over power. Reason behind this is the simplicity of the measure: “Lift more powerful!” may result quite hard to understand compared to “Lift faster!”.
Infact Speed is only space and time dependent, where Power is omni-comprehensive being load, space and time dependent.
Speed = space / time
Power = Strength x Speed
Because Strength greatly depends on the Load, we can assume that the comparison of two reps based on velocity will show us the same differences as the comparison based on power, if the load is the same.
Once the load is out of the equation, targets can be established defining training zones for the different strength trait.
The last step remaining is to adjust training by live tracking speed: by staying in the correct Speed-Zone the workout goes on, once we’re out we’re done. Once lifting in the same Speed-zone with a higher load means improvements. We’re not only getting faster, we’re also becoming stronger, more explosive and more powerful. .
Among the negatives of Velocity Based Training:
Velocity depends on Space and Range of Motion
The longer the movement, the highest the peak, simply because an athlete has more room to accelerate. Try yourself with Beast, the longer your squat, the highest Peak Velocity you will reach, provided you’re pushing through all your range of motion.
Faster doesn’t necessarily means stronger
Even when the load is the same, mean Velocity can be calculated by
V = Space / time
where Space strongly depends on athlete’s biometrics. Provided that the range of motion between two athletes with different heights is the same, which means from parallel to complete standing for both, longer legs will lead to a longer trip for the barbell to travel. This means more Space and thus only a shortest concentric time will keep the speed even for both athletes. The difference in concentric time could influence the kind of Strength trained.
More research is needed to understand how to adapt and stretch target speed zones to athletes of different heights and biometrics.
Further, VBT respect the SAID principle and the Dynamic Correspondance Method but … it could be improved.
Infact, provided the range of motion is equal between the training movement and trained movement, the same average velocity could actually be obtained with very different acceleration profiles.
Therefore by using Velocity we’re not sure to fully respect the correct dynamics nor the accentuated region of force production. Another approach to training could be using acceleration as a target, in the same manner we’re using Speed.
Acceleration Based Training
Before we dive into this, I want to say this is totally experimental: we definitely need more research on this topic, especially on basic entities like speed of movement. Once we have the correct numbers, then we will be able to apply this method.
The process is similar to those that brought us to consider Velocity from Power.
From basic Physics, we know the relationship between Velocity and Acceleration :
A = V / time
Let’s focus on the Characteristic Time needed to complete the movement (about dynamics….)
We can obtain the Target Mean Acceleration by defining the Concentric Time of the Rep.
which can be established through the Principle of the Dynamic Correspondence by analysing the time needed for a determined effort.
Ground Contact Time could be an example Characteristic Time when we want to work lower body Strength to improve Sprint velocity, Acceleration, Deceleration, Change of Directions.
Application Example: Speed-Strength and Box Squats,
Following Bryan Mann’s research in “Developing Explosive Athletes: Use of Velocity Based Training in Training Athletes”, our target Mean Velocity is between 0.8 m/s and 1 m/s. The equivalent Acceleration for this can be easily calculated assuming ground contact times of 0.2″ which is a typical GCT for a field sport athlete :
A = V / time = 0.8 / 0.2 = 4 m/s^2 = 0.4 G
We should then look for a target acceleration between 0.4G and 0.5G.
Until recently Linear Position Transducers were the most used devices on the market to gather bar speed data. LPTs are reliable but for sure unadaptable and cumbersome compared to Inertial Measurement Units like Accelerometers and Gyroscopes. Hopefully the versatiliy of an accelerometer will help Strength Coaches experiment on this topic and establlsh more target data which could help improving the performances of any athlete out there. I would like to write more about this.