Chief among those skills is explosive strength. To gain speed and efficiency, building this type of strength is imperative. In the most basic sense, explosive strength, built through exercises such as jumping and squatting, will help improve your ground contact time—reducing the time your feet spend on the ground with each strike—thereby increasing your speed. Think of the runner who plods versus the one who appears to almost float. The latter has better ground contact time.
"Speed is dictated by one singular quality: The rate at which force can be developed," says Michael Stack, an exercise physiologist and CEO of Applied Fitness Solutions in Michigan. "Specific to running, that means the rate at which your foot and leg can produce force in the split second you make contact with the ground."
In order to develop explosive strength for running, you must train your muscles to repeat these powerful movements over and over again. This only happens through the coordination of body and brain. Explosive strength training works to sync your brain with your legs to be able to forcefully push off the ground and quickly turn your legs over repeatedly with each stride.
Of course, if your body isn't prepared for this type of training, you risk potential injury. To determine if you're ready to implement explosive moves into your training, Stack suggests testing yourself. He says that a man who is able to barbell back squat his body weight 10 times, or a woman who can back squat 75 percent of her body weight are adequately prepared. Another strength metric that suggests readiness for explosive exercises is the ability to do eight near-maximal height vertical jumps in a row, without your heels touching the ground upon landing.
Once you deem yourself ready for this type of work, Stack recommends high intensity, but a low number, of repetitions. "Typically, sets are less than eight repetitions, with two-minute rest intervals in between sets," he says. "We will maximally do 8 to 10 sets of explosive strength training with an endurance athlete in a training session."