Hi gally never said that, big beleiver in running but in context with what you want to achieve. Theres so many things you can do for Speed Endurance, the permatations are endless, using elastics 25 metre lengths and Parachutes for resistance and speed. Using your imaganation you can achieve a lot of wonderfull stuff as Ive mentioned before elastic has wonderfull propertys. The more it is stretched the faster it becomes, and the resistance is less its not constant a very good point for your Biomechanics