Training for speed is not the same as training for endurance. The muscles of the human body exist as one of two fibers: fast twitch and slow twitch. The former excel at activating rapidly and the latter are best at resisting heavy loads over time. Both have their strengths, but one cannot replace the other. To get faster at any sport, use an resistance band to isometrically exercise the hip flexor; the primary muscle responsible for lifting the leg.
“Having fast muscles is not the same as having strong muscles and you can not get faster contracting muscles by training for strength using traditional weight training routines – in fact that could actually make you slower.”
Read more: https://athleticquickness.com/fast-muscles/