Impulse - change in momentum resulting from force (force x time)
Power - rate of doing work (force x velocity)
Most athletic tasks require fast rates of force development (RFD). Force development for someone who is running, for example, is the ground contact time or push-off phase. Whether someone is sprinting or distance running, the RFD should be as quick and as forceful as possible to make the most out of every stride. The rate, amplitude and direction of force is important in any movement but improving an athlete's RFD can have tremendous benefits.
The ability to achieve high movement velocities requires skillful force application across a spectrum of power outputs and muscle actions. To achieve desired power levels, an individual's resistance training program should involve a wide variety of concentric and eccentric muscle actions while using a wide range of loads and velocities.
The fact of the matter is that the forces that can be created by our limbs may change depending on the angle of the limb as its velocity and force is altered.
Training activities aimed at improving the stretch-shortening cycle performance should not only involve skillful multi-joint movements, but to also exploit the elastic-reflexive components of the muscles and tendons. In order to facilitate progress, work bouts should be short with longer periods of rest to allow ample time to recover.
Another aspect that I have discussed in my blogs before, but find that it is also applicable here, is power training for aerobic events such as distance running. Marathon runners are definitely not thought of as "power athletes", but using power training in their regimen could help reduce the amount of time that their feet are in contact with the ground, not to mention improving horizontal speed and velocity which can therefore improve running economy.