Simply Rate of Force Development (RFD) is a measurement of how long it takes to get to peak force in a movement. The faster you can do this the greater speed of the movement. The term beating someone to the punch kind of exemplifies what we are talking about. Much of this is based on RFD. Different movements have different speeds to get to peak force. Some RFDs are heavily influenced by the biomechanics of the movement. Shorter movements have higher RFDs. Sprinting would be a shorter biomechanical movement when compared to a counter movement jump. The jump has a longer range of movement and will be considered a slower RFD. A sprinter is trying to optimize ground contact for faster velocity of movement. The RFD for sprinting is much faster than a countermovement jump. RFD also influences dead stop movements. The faster the muscle contracts (RFD) the quicker the sprinter is out of the blocks.
When I evaluate my athletes training needs I first identify the RFD needs of their particular sport. A weightlifter would have a slower RFD than a sprinter. However, this slower RFD can be improved by working on the faster end of the velocity curve to improve their ability to produce faster RFD. Overall force production as well as velocity influence RFD. I try to find the tipping points where time spent can improve the RFD needed for the sport. This is not random or a system. It is based on a number of athlete factors. Maturity of the athlete, genetics, biomechanical advantages or disadvantages etc.
So to keep it simple, I look at where the athlete is lacking and try to weight the type of training to most quickly improve the RFD for their sport.
I look at three areas of training. Very high speed velocity with little force. Some velocity with moderate force. Maximum power output with lower velocity. And much slower velocities with maximum force. Each of these areas need to be looked at and once you establish your weakest links and you can adjust your training to reflect the need. You must also look at the entire kinetic chain to see if RFD is being scrubbed off because of an ancillary weakness.
I train a lot of cyclists. Most cyclists are slower twitch athletes. I will look at where on the force velocity curve I need to spend the most time to improve their absolute power as well as power efficiency.
You need to have some way of measuring the output to measure. I believe a good coach can eyeball velocity and tell what RFD zone an athlete is training in. However, it is not hard to tell really fast movements with little force, moderately fast movements with some force, and slower movements with higher force outputs. You can create your own poor coach power meter with time and distance as the measuring tool.
Train in all three areas and then mix and match until you see a direct improvement in the movement speeds of the sport. It will not take that much time to figure out what is working and what is not. The athlete typically sees the improvement in a short amount of time.
Truth in Fitness,
Jacques DeVore, CSCS