THE FORCE-VELOCITY CURVE
The force-velocity curve (FVC) is important for both coaches and athletes to understand for correct exercise prescription in terms of exercise selection & loading parameters. Having an understanding of the FVC and how to use it to program & train effectively will also ensure that training is maximising performance improvements.
Force can be thought of as muscle contractile force, or the amount of ground reaction force (GRF) produced. Ground reaction force is the force exerted by the ground on the body. Force is usually expressed in the unit Newtons (N).
Velocity can be thought of as muscle contraction velocity (speed) or velocity (speed) of movement (meters per second).
Power = Force x Velocity
You could be the strongest person in the world, but if you don’t bring velocity you’ll be as powerful as a wet paper towel.
WHAT DOES THE FVC SHOW?
The FVC shows the relationship between force (F) and velocity (V). The relationship between force and velocity is inverse. What this means is that if force increases, the velocity of movement will decrease and if velocity increases the amount of force produced will decrease.
There is a trade-off between force and velocity. When an exercise produces a high level of force it will also produce a slow movement velocity.
An example would be a 1RM deadlift vs a box jump. The 1RM deadlift would produce a large amount of force but the weight would be lifted at a slow velocity. Whereas, a box jump would produce a high movement velocity (moving fast) but a low amount of force.
This means that different exercises and intensities can be categorised into various parts on the force-velocity curve. These parts and example exercises can be seen below.
WHY IS IT IMPORTANT TO UNDERSTAND THE FVC AND HOW WILL IT AFFECT TRAINING/PERFORMANCE?
For athletes, the goal of resistance training is to become stronger, faster and more powerful. Through correct training, the FVC will shift to the right indicating that the person can apply a larger force at a faster velocity or move at a faster velocity while producing larger levels of force.
By shifting the force-velocity curve/profile to the right there will be an increase in power and rate of force development (RFD) which is critical for athletic success in many sports.
RFD can be thought of simply as how fast an athlete can develop/produce force.
An athlete with a larger RFD will be more explosive as they will be able to develop larger forces in a shorter amount of time.
If you want to run faster, change direction quicker, jump higher and throw further you need to be training to increase RFD and power/explosiveness.
The most effective way to improve RFD is through training methods that will develop both the force and velocity ends of the spectrum. So it is vital to train all parts of the force-velocity curve.
By training only one part of the FVC an athlete will only improve their performance at that section of the curve. For example, if an athlete only trains maximum strength, that athlete will only improve their performance at the maximum strength section of the curve. So, while they may improve maximum force production, it may also cause a decrease in muscle contraction velocity…not great if your goal is to become fast, powerful and explosive.
Therefore, it is important that strength training is combined with training to improve power i.e. train all parts of the Force-Velocity Curve for best results.
The time dedicated to training each part of the FVC will depend on a number of factors such as the individual’s strengths and weaknesses (their own unique force-velocity profile), sport, position, training age and time of the year e.g. pre-season, competition or off-season.
- The FVC shows an inverse relationship. When an exercise produces a high level of force it will also produce a slow movement velocity.When an exercise produces a high velocity it will also produce a low amount of force.
- For athletes wanting to maximise their performance it is vital to train all parts of the force-velocity curve
Credit to the guys at Science For Sport for some of this blog content and graphs