Fred Duncan on Instagram: "Speed comes down to physics. How much force you can apply into the ground, how fast you can apply it and how well that force is oriented. That’s it. Sprint speed isn’t magic and it isn’t about fancy drills. It’s governed by force–velocity relationships, impulse, and mechanics. Impulse is force applied over time. Higher impulse during ground contact means a greater change in momentum. Greater change in momentum means higher speed. Elite sprinters don’t just produce more