Triple extension is your hip, knee and ankle straightening together as your foot pushes off the ground. It matters most in the first steps of acceleration, where long pushes should finish with ankle, knee and hip on one straight line with your body. At top speed the job changes: the hip does its main work early in ground contact, the knee adds little, and faster sprinters spend less time on the ground, so you leave the ground quickly instead of pushing longer. From the side, a camera can see how far your leg extends at push-off.
Acceleration: finish the push in a line
In the first steps out of a crouched or block start, use long, deep pushes. Longer ground contacts are normal and wanted here.
pushing the ground back and away behind you.
Finish each push with your ankle, knee and hip on one straight line that runs up through your shoulders. Push along that line, not up and not just down.
one long, straight lever from your foot to your head.
Raise your hips and shoulders a little with every step. As you speed up, contacts get shorter and the push shortens with them. Pushing back for too long makes the lower leg swing too far behind you.
Top speed: get off the ground
At top speed, don't try to push longer or chase a locked-straight knee at toe-off. Faster top speeds go with shorter ground contact, and in one study of 24 sprinters, leg extension at lift-off was not linked to top speed.
quick, springy contacts that are over before you think about pushing.
Keep the stance leg firm and let your thigh sweep back fast through contact. Your leg ends up behind you because your body moved past the foot, not because you held the push.
landing on a stiff spring, not sinking into the ground.
Drive from the hip
Start the push from your hip: drive the thigh down and back into the ground. At top speed the hip extensors produce most of their power early in contact, and the knee acts mainly to pass that power down to the foot.
"whip from the hip": the thigh doing the work, not the knee.
Keep your ankle firm so it can finish the push late in contact. Don't let the heel sink far or flick the foot from the calf alone; hip, knee and ankle work as one chain.
After toe-off, fold the heel up toward your buttock and bring the leg through close to your body. A short, folded leg swings forward faster than a long, trailing one.
Feel it
Early in the sprint: long, powerful pushes that leave you in a straight line from foot to head, rising a little each step. At top speed: quick, firm contacts that start at the hip, with the leg folding and coming back through as soon as it leaves the ground. If your leg hangs out behind you or contacts feel long and heavy at speed, you are pushing for too long.
Fix-its
- Bent at the waist at the end of the push in acceleration (hips left behind) Push along the line from ankle through hip to shoulder so all three finish in line; film from the side and check the toe-off frame of your first steps.
- Pushing too long at top speed, leg trailing far behind you Think short contacts and a fast thigh return: fold the heel up after toe-off and bring the knee through, instead of holding the push.
- Soft, collapsing stance leg Land on a firm leg under your hips and keep the ankle firm, so the thigh can sweep back quickly through contact.
- Reaching ahead to land so there is more leg to push with Land at or slightly behind the hip in the first steps and only slightly ahead of it at top speed; reaching forward adds braking.
- Pushing up instead of back in the first steps (popping up) Keep the push aimed back along your body line and rise gradually, a little more each step.
Drill
- Acceleration runs from a crouched or block start: 10–50 m at full effort, 2–7 min rest, 100–300 m total per session, cueing a straight line at the end of each push.
- Flying sprints for top speed: 20–40 m build-in, then 10–30 m fast, 4–15 min rest, 50–150 m total, cueing quick contacts rather than a long push.
- Bounding, jumping and skipping for horizontal power, using traditional plyometric drills; very demanding stiffness work (such as weighted jumps) likely raises Achilles injury risk, so build up gradually.
- Combine strength work with your sprinting; heavy, vertical leg strength doesn't automatically turn into a better horizontal push.
- Film from the side with slow motion (120–240 fps) and compare the toe-off frame in your first steps with one at top speed. Warm up first, leave 48 hours between hard sprint sessions, and end the session when your times drop or your form breaks down.
Sources
- ALTIS (Kormis / Enyia) — Acceleration Development (2015)
- ALTIS (Kormis / Imdieke) — Upright Sprinting (2015)
- Bezodis, Kerwin & Salo — Lower-limb mechanics during the support phase of maximum-velocity sprint running, Med Sci Sports Exerc (2008)
- Bezodis, Salo & Trewartha — Lower limb joint kinetics during the first stance phase in athletics sprinting: three elite athlete case studies, J Sports Sci (2014)
- Haugen et al. — On the importance of "front-side mechanics" in athletics sprinting, IJSPP (2018)
- Clark, Meng & Stearne — "Whip from the hip": thigh angular motion, ground contact mechanics, and running speed, Biology Open (2020)
- Haugen et al. — The Training and Development of Elite Sprint Performance, Sports Med Open (2019)
- Surf Life Saving SA — Beach Sprinting Coaching Manual, 5th Edition
Last checked 2026-10-26.