Every time I open my Twitter account, there seems to be more research and information released specific to Force-Velocity Profiles (FVP). It is becoming of greater interest to understand that although homogenous training is necessary at specific times during the training plan, it is also necessary to understand if any physiological and neuromuscular imbalances exist. This is where profiling your athletes can become advantageous.
At one end of the Force-Velocity Curve, see below, we have High Force-Low Velocity (heavy back squat) and at the opposite end, Low Force-High Velocity (assisted jumping). Using sprinting as an example, overcoming inertia and accelerating from the blocks (0-40m) would be HF-LV, whereas maximal velocity sprinting (40-100m including some decel time) would be LF-HV.
Power is one of the key elements to sporting success. How much force can you apply at the highest possible velocity? How much work can you do in the shortest period of time? Whether it be in a horizontal (acceleration>sprinting) or vertical (jumping) vector, the rate at which (plus magnitude & direction) force is applied is largely a limiting factor to overall performance.
Leading the way in this field are the following researchers/practitioners: JB Morin, Pierre Samozino, Pedro Jimenez-Reyes, Matt Brughelli, Jake Schuster and Matt Cross. These guys are doing fantastic work, continually challenging the thought process of how to improve our athletes.
Instantaneous Power output is the product of the external force developed by velocity. How quickly can you apply the force to throw an external mass (Discus), perform a CMJ, change direction or accelerate from a stationary position away from your opponent?
Using a common ballistic movement such as jumping (vertical profiling), an athlete’s maximum power, Pmax, can be calculated by performing a series of loaded jump squats (from above paper). For example using a Smith Machine at, 0% BW (CMJ), 25% BW, 50% BW, 75%, 100% BW, you can start to see how the athlete can demonstrate velocity at increasing loads. This protocol, or a variation of this, is shown in various papers by the above researchers. There are some papers which only use one to three external loads to develop the profile however most of the recent research endorse the use of five randomized external loads. With the use of various pieces of technology, GymAware, Optojump, Push, Force Plates, MyJumpApp, depending on the level of values desired, the actual FVP can be generated, then the optimal FVP developed (see below).
Without rehashing all of the literature, the Optimal FVP for the athlete is calculated by extrapolating the intercepts for both components, providing F0, the theoretical maximal force the lower limbs can produce at null velocity (N/kg), and V0, the theoretical maximal velocity which the lower limbs can extend under zero load (m/s). The graph above identifies a significant Velocity imbalance (check papers for calculations) for Player A and a Force imbalance for Player B. The graph also identifies the issue of two athletes displaying similar maximal power W/Kg, yet vastly different FVP; as they have achieved the result through different mechanical qualities; which raises questions regarding impulse (another blog).
So once we know there is a deficit or an imbalance, what next? Well, the practitioner needs to understand how to address the imbalance through overloading aspects of the curve. Addressing a force deficit should essentially be quite easy; develop a program with bilateral compound movements aimed at increasing the athlete’s 1RM. However, addressing a velocity deficit can require greater thought. Just this morning, JB Morin via Twitter, suggested that performing squat jumps at bodyweight may even be too heavy to address a velocity imbalance; you must get creative with assisted means.
Like any intervention, how do you measure the transfer to the actual task? E.g. Will it improve them as a basketball or soccer player? That is the million dollar question and highly contextual. However, if you asked each player would they like to become more ‘powerful’? The resounding answer would be YES! Even with a limited understanding, athletes are highly aware that speed and power are what separates the elite from sub-elite.
So… Profile your athletes… Understand the imbalances… Develop your intervention… Re-Test.
Give the athlete what THEY need. Not what everyone needs!
Hopefully you can see a level of improvement towards the optimal profile?
(As a side note – in my opinion, some from testing athletes and the rest from anecdotal observations, most sub-elite sprinters have a significant velocity imbalance, and an over developed force profile).