I hadn’t had much to do with this type of training until one of my athletes was tested at a lab. Part of the testing included some overspeed work – running quickly down a slight decline – and… the results were good! Of course, sprinters have known this for decades, using a variety of bungee ropes and even mopeds to propel them down the track at pace. But as a triathlete, it’s probably best to use a slope to get those legs turning over at speed.
Use a slope so flat that on the bike it’s one of those you don’t really know you’re going down, but you sure notice it going up! Too steep and you’ll find yourself braking rather than letting your legs turn over naturally at a high speed. When we did this kind of training, it was a once-a-month type workout, which is probably going to work best for most endurance athletes. Run to the slope, do 12 x downhill sprints over 100-150m, a light jog cool-down and that should do it!