Increasing speed endurance allows you to work at a higher rate for longer periods of time. According to sportsfitnessadvisor.com, any athlete who is required to repeat high intensity sprints in quick succession can benefit from this type of training. Repetitions and rest intervals are kept short to develop the ability to tolerate high levels of lactic acid in the muscles. Experts at speedendurance.com say that keeping tall and relaxed is the key to success.
Fartlek means "speed play" in Swedish and was developed in 1937 by a Swedish running coach. This workout involves short bursts of running efforts followed by short periods of easy recovery effort. For instance, you can run fast for one minute and then recover with a slow jog for one minute. Repeat this interval multiple times. A proper warmup and cool down are recommended.
Short Sprint Intervals
Measure 30 to 50 meters on grass, basketball court, or running track. Place a cone at the start and at five meter intervals. Sprint to the first cone and back. Then, turn and sprint to each cone until you've completed the entire distance. Rest for approximately 90 seconds and then repeat several times.
According to the triathlon website, trifuel.com, track intervals are not all-out runs. They are quick, controlled runs with adequate rest between each repeat. The training benefit occurs during the rest interval as the body is given time to adapt. The length of the speed intervals vary depending on the sport and fitness level of the athlete. Athletes training for a shorter race may do 400 meter repeats with 90 seconds rest in between each interval. Those training for a longer race may do 1,200 meter repeats with adequate rest between each interval.
Similar to short intervals, measure out a short distance between 75 meters to 100 meters. Sprint a short distance and "cruise" to end of the measured distance. For each repetition, the sprint portion grows longer as the cruise distance decreases. By the final repeat, you will sprint the entire distance.