Dear Yosef,
If we are talking about sport players, their speed running training should include two main elements: specific running exercises with lateral displacements and classical forward running accelerations.
I think that uphill running and also downhill running should be used mainly as second type of exercise. The uphill speed running assures the development of the starting acceleration, the downhill running exercise assures the development of distance running speed.
The forward running accelerations in sport games are very similar to the T&F sprints, but are shorter: in soccer – 30 m, in basket – 20 m, in tennis – only 10m.
Longer is the start accelerations of the sport game, more useful could be, for this game players, the downhill running exercises.
Usually, for T&F sprinters, the uphill slope of speed runs should be not more than 4% (to not provoke the strides length decreasing). The sport games players that usually run on shorter distances could use some volume of uphill exercises on the steeper slope track.
Yet, regarding the downhill running, this exercise should be carried out only on the 2- 4% incline.
What is the exact grade of incline to be used? It’s difficult to say exactly, it should be find by the athlete: the grade of inclination should assure the facilitation of running without the change of execution technique.
Regards the article of Nurmekivi, it is an extract of his lectures in the Tartu University. This lecture, is mainly referred to my works, for example, my article “Speed Training for High level Athletes”.
Yuri Verkhoshansky