Front-side mechanics is a coaching model for upright, top-speed sprinting: more of each leg's swing happens in front of your body and less trails out behind it. In the model, seen from the side, your thigh shouldn't swing back past a line running along your trunk; when it does, coaches call it back-side mechanics. The research is mixed: faster runners in mixed groups show a more front-side pattern and a faster thigh swing, but among trained sprinters body positions alone didn't predict top speed, so treat this as a way to avoid a trailing, late leg, not a pose to copy.
Finish the push on time
Run tall with your hips high and your pelvis level. A pelvis tipped forward is one of the listed causes of back-side running, because it stops the thigh springing back to the front.
tall through the hips, not sitting or arching.
At top speed, leave the ground as soon as the push is done. Holding the ground too long lets the leg drift far behind you; in the model the thigh shouldn't swing back past the line of your trunk.
quick off the ground, the leg not hanging back.
Recover the heel
As the foot leaves the ground, fold the heel up toward your buttock and keep the leg close to your body. A short, folded leg is quicker to bring forward.
a tight fold of the lower leg under your hip.
Swing the thigh forward fast from the hip. In research, how fast the thigh swings tracks running speed much more closely than how high the knee ends up.
whip from the hip.
Keep the action in front
Have the swing knee in front of your hips when your other foot lands. In one study the swing thigh was on average about 11 to 15° ahead of vertical at that moment in college track athletes, while team-sport athletes had it slightly behind vertical.
your knees passing each other early, out in front.
As the knee nears the top, let the lower leg open and drive the foot down to land just ahead of your body. Coaches cue "step over the knee and straight down into the track". Reaching the foot far out in front is another cause of back-side running.
stepping down under you, not reaching out.
When it applies
Use this at top speed, not in the first steps. In 24 sprinters, the better accelerators actually had more thigh and knee extension behind them as the foot left the ground in block starts. Early on, long pushes that finish behind you are normal.
push long out of the start, cycle in front once you're upright.
If you play a team sport, don't force a track sprinter's shape. Researchers suggest the front-side model may need adjusting for athletes who change direction or carry a ball.
fast and in front, but still ready to cut.
Feel it
The legs cycle quickly under and in front of you, with the heel folding up after each push and the knee arriving early. If your legs feel like they're trailing out behind you and the next knee comes late, check two things first: are you staying on the ground too long, and are you reaching the foot out in front? Both are named causes of back-side running.
Fix-its
- Your leg trails far out behind you at top speed You're probably pushing too long. Get off the ground sooner and fold the heel up toward your buttock right after the foot leaves the track.
- You reach the foot out in front of you to land Think "step over the knee and straight down" so the foot lands just ahead of your body. Wicket runs help you feel the vertical step-down.
- Your hips sit low or tip forward Run tall with your hips high and your pelvis level, so the thigh can spring back to the front.
- You lean back to lift the knee higher Stay tall and chase a faster thigh swing, not a higher knee. Peak knee height is only weakly linked to speed.
- You cut your pushes short out of the start to stay "front-side" In the first steps let each push finish behind you. Save the front-side focus for when you're upright.
Drill
- Warm up fully first. Stop the session if you feel a sharp pull or pain in the back of the thigh.
- Butt kicks and high knees at a slow run: heel up toward the buttock, then a high hip and knee. Use them in the warm-up; drills are slower than real sprinting and work best as preparation.
- A-skips: knee up, toes up, punch down. The thigh swings much slower than in a sprint, so treat them as warm-up and rhythm, not a copy of top speed.
- Wicket runs (low mini-hurdles in a line) to practise stepping down vertically under you instead of reaching.
- Flying sprints: build up over 20 to 40 m, then hold top speed for 10 to 30 m, with 4 to 15 minutes' rest and 50 to 150 m of fast running per session. Film from the side in slow motion (120 to 240 fps) to see where the swing knee is when the other foot lands.
Sources
- Haugen et al. — On the importance of "front-side mechanics" in athletics sprinting, IJSPP (2018)
- Clark, Meng, Walts, Ryan & Stearne — Angular kinematics during top speed sprinting in male intercollegiate track and field and team sport athletes, Front Sports Act Living (2025)
- Clark, Meng & Stearne — 'Whip from the hip': thigh angular motion, ground contact mechanics, and running speed, Biology Open (2020)
- Miyashiro et al. — Kinematics of maximal speed sprinting with different running speed, leg length, and step characteristics, Front Sports Act Living (2019)
- Haralabidis et al. — Modifications to the net knee moments lead to the greatest improvements in accelerative sprinting performance, Sci Rep (2022)
- ALTIS (Kormis / Imdieke) — Upright Sprinting (2015)
- Surf Life Saving SA — Beach Sprinting Coaching Manual, 5th Edition
- Australian Athletics — Rethinking the role of A and B skips in improving sprinting performance
- Haugen, Seiler, Sandbakk & Tønnessen — The Training and Development of Elite Sprint Performance, Sports Med Open (2019)
Last checked 2026-10-26.