The anatomy of speed. Researchers used MRI to look deeper at Asafa...
Fred Duncan@Fred__Duncan
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Nov 26, 2025
~1 min read
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The anatomy of speed.
Researchers used MRI to look deeper at Asafa Powell, one of the fastest men in history. They found His psoas major was nearly twice the size of another elite sprinter’s. That muscle drives hip flexion and leg recovery, helping reposition the thigh quickly
Researchers used MRI to look deeper at Asafa Powell, one of the fastest men in history. They found His psoas major was nearly twice the size of another elite sprinter’s. That muscle drives hip flexion and leg recovery, helping reposition the thigh quickly
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at top speed.
Next, they analyzed his tendons. It took 114 kg of force just to stretch Powell’s tendon by 1 cm, more than double another elite sprinter. That kind of stiffness lets him generate huge rebound forces in minimal ground contact time.
But this video isn’t just
Next, they analyzed his tendons. It took 114 kg of force just to stretch Powell’s tendon by 1 cm, more than double another elite sprinter. That kind of stiffness lets him generate huge rebound forces in minimal ground contact time.
But this video isn’t just
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about one muscle, it’s a look inside the entire morphological profile of an elite sprinter.
Powell’s structure, from tendon stiffness to muscle size and coordination, lets him apply and redirect massive forces efficiently.
His tendons act like springs, storing and reusing
Powell’s structure, from tendon stiffness to muscle size and coordination, lets him apply and redirect massive forces efficiently.
His tendons act like springs, storing and reusing
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energy between strides. His strength allows him to manage collisions with the ground. His coordination and nervous system timing determine how effectively that stored energy turns into propulsion.
These qualities don’t exist in isolation. They’re intertwined…muscle
These qualities don’t exist in isolation. They’re intertwined…muscle
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architecture, tendon stiffness, neural control, and skill all work together to produce what we see here.
When we understand how these systems interact, we can begin to reverse engineer training to develop them…strength that enhances stiffness, plyometrics that refine timing,
When we understand how these systems interact, we can begin to reverse engineer training to develop them…strength that enhances stiffness, plyometrics that refine timing,
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sprint work that integrates it all at maximal speed.
If you want to go deep into how speed is built, start with Speed Kills, my best-selling resource on the science and application of sprint performance. It covers everything that drives speed: what muscles matter,
If you want to go deep into how speed is built, start with Speed Kills, my best-selling resource on the science and application of sprint performance. It covers everything that drives speed: what muscles matter,
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how acceleration differs from max velocity, how to program sprint work, strength training, plyometrics, tempo runs, warm-ups, and more, plus a complete multi-week program.
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