What are they?
Very short intense bouts of running, typically <20 seconds in length.
How and why do they work?
Running fast is one of the best ways to improve your running form and economy. A strong neuromuscular stimulus to your prime movers results in an adaptation to recruitment threshold, organization and patterning. Hill Sprints add especially high central demands resulting in changes to oxygen exchange kinetics.
For the small investment, these can pack great value to your overall fitness!