Tag: sprinting

Improving Sprint Technique Part 2

I’m trying to improve my sprinting by videoing myself and then comparing it to the theoretical model of the best sprinters in the world. It’s not rocket science but I’d like to feel like I’m running rocket powered. While there are distinct differences between sprinting and distance running, even distance runners need to be able to sprint for the finish line and there should be some common mechanics which will carry over to make me efficient over any distance.

For example, as detailed in part 1, I noticed my foot was landing too far out in front of me causing me to vault over it. When I brought the foot closer, my runs began to feel like I’d taken the brakes off and my glutes were doing the work.

The best sprinters have cadences well over 250 steps per minute, often approaching 300 yet I struggle to even reach the 220s. Watching the video of my sprinting it all seems lumbering and cumbersome. While a still image can look fairly decent, watching actual footage tells a better story. When my foot lands it seems like I’m stuck to the ground for an age as my body passes over it.

Watching and rewatching footage I began to see my head and shoulders were rising and falling against the background. The next questions was “Why is that happening?”.  And from that I began to see both my knee and ankle were collapsing and I was flat footed with each step which produced the illusion of being stuck to the floor for so long.

Knee bend just after landing (thigh yet to reach vertical)
Ankle bend

Good sprinters try to maintain leg stiffness (of their support leg) with the knee hardly bending. Their ankles don’t flex much either and they stay up on their toes – the heel never touches the ground. Inevitably there is some flexion in the knee and ankle due to the forces being generated as the weight of the runner lands but the more it can be minimised, the better. Likewise the heel will move towards the floor slightly but never makes contact. This flexing allows the Achilles tendon to load up with elastic energy and then release to help propel them forwards.

Usain Bolt – knee and ankle flexion

If you compare the pictures you’ll see both myself and Bolt are at the same stage of the stride; the arms match, the knee coming forward matches and the thigh of the support leg is vertical. But the foot is completely different. My ankle has collapsed and flexed and the heel is barely off the the ground; Bolt’s heel is notably raised and the foot is at right angles to the lower leg.

Initially I thought there was too much knee flexion but I’m no longer so sure. But there’s a definite lack of ankle stiffness which is causing an energy leak and it’s that which I’ve been looking at over the past month or so.

How to improve is of course always the harder question to answer when you locate an issue. Trying to resolve this became a matter of trial and error. I tried to focus on keeping the joints stiffer. I felt I had the requisite strength to keep my legs and ankles stiffer – after all when I skip / jump rope they don’t collapse, it was just the sprint technique wasn’t allowing me to get it right.

When I ran my sprints and strides I made an effort to maintain stiffness in the joints. I think it was a little beneficial but it put new stresses through my joints and for a time the tendons in the rear of my left knee were feeling swollen. It didn’t stop me running, it didn’t hurt training; but the knees were certainly unhappy if I was squatting down to say get something out of a cupboard. I made sure to keep the volume of these sprints lower though as I knew there was a danger of trying to do too much and injuring myself.

Note – while leg stiffness is important you don’t want your leg to be locked out at the knee because that has a high chance of leading to an injury. Failure to flex under high forces can lead to bone jarring into bone.

Similarly trying to stay up on the toes can lead to issues with calf muscles and tendons and there’s a good reason for allowing some ankle flexion. When the ankle flexes (i.e. the toes lift up and move closer to the knee) the Achilles tendon stretches and just like an elastic band it stores energy. When this elastic energy releases it provides some of the propulsion for moving forwards. While sprinters’ ankles flex the heel stays off the ground but a distance runner’s heel will come into contact with the ground momentarily and this needs to be allowed to happen for the storage of elastic energy.

One of the mental models I’ve been using is to think of how skateboarders paw the ground to keep their deck rolling. They time the kickback to add speed as the board begins to slow. It seems to me sprinters are doing the same thing; but where the skateboarders are able to take a foot off the board, paw the ground and then rest the foot back on the deck; sprinters are trying to stay airborne with just their legs extending down to make a short but powerful contact. You could think of the Roadrunner’s legs whirring along at speed..

The other adjustment I made was to try and get my foot down to the ground quicker – what coaches refer to as a hammer action. If I could move the leg down quicker then it would apply force quicker and the foot would go through quicker leaving less time for the joints to flex but still allowing some ankle flex to load the Achilles.

In trying for this quick contact and to stay more airborne, I’ve found my sprinting begin to morph and on occasions I have felt myself springing along as the Achilles does more of the work. There’s still more to do but I think it’s heading in the right direction.

Improving Sprint Technique Part 1

This me in full flow sprinting. Other than the pained expression, to the untrained eye I’d say it looks pretty good but I’m not fast and never have been. Improving my sprinting has been a large part of my summer training while doing 3-5miles each day along with an interval session and weekly 5K parkrun.

I’m very aware elite distance runners have good speed over short distances – a 400m lap in under one minute is normal to them. Yet despite my physical attributes, it something I’m not achieving and I don’t understand why. For sure I’m ageing but even when I was young I was never able to do it and yet my physical attributes suggest it, or something close, should be within my ability. There are men ten years old than me who can so I’m discounting the age problem.

Maybe it’s been down to the wrong training but I had a strong suspicion my form was poor so I bought a tripod off eBay to be able to film my sprints and analyse the technique. Last year I received a copy of Ralph Mann’s The Mechanics of Sprinting and Hurdling for my birthday which explains in great detail every important position the most efficient sprinters achieve. While I don’t expect to be able to replicate or measure them in the detail provided in the book, I hoped to be able to make some comparisons between what I’m doing, what the book states and then to rectify any anomalies.

Unfortunately my phone didn’t have a very good camera on it, or more specifically it could only capture 30 frames per second. At high speed that just doesn’t give enough detail, for example I couldn’t tell whether I was landing on my heel or toes. So I got a new-to-me phone from my nephew which has 4K and 120fps and enabled me to see what was happening.

Landing foot in relation to Centre of Mass

I took some footage and then stepped through frame by frame. I didn’t have any preconceived notions about what I was looking for but the nuances of how I was running began to emerge. Eventually I settled on this frame.

On the surface not that much seems wrong with it because it’s not heel striking – the toes are just touching first and from the knee down to the foot, the lower leg is almost vertical below the knee. Those are the sorts of pearls of modern wisdom that get preached as good technique.

But I could see the foot just seemed too far ahead of the body and when I checked Mann’s book, he states that while world class sprinters are unable to get their feet to land directly below their centre of mass, they can get it to land only 20cm ahead of them.  For an average sprinter, it’s 28cm and a poor one it’s 35cm. Think about those numbers for a moment – they’re not particularly big distances so it’s easy to be unaware if they’re wrong.

I’ve drawn some lines on the picture below to explain how it’s calculated. The yellow circle is approximately where my centre of mass is, and the yellow line up from the foot shows where it is landing. The pink line indicates how far ahead it is and I’ve created an orange line of the same length and then measured it from my elbow. Getting out a tape measure it’s a distance of 35cm – poor sprint technique as predicted!

When I ran recovery the next day I worked on getting my foot to land closer to underneath me. The difference was immediate. Every step began to feel like I was being pushed along by my glutes and it became apparent my previous form was creating a braking force out in front – every step needed me to pull my body over the foot. I’ve heard this phenomenon likened to driving a car with square wheels rather than just rolling along. While the new form bedded in quickly, it took a while for the body to adjust to using a different set of muscles, I had a few aches and pains. I backed off training while this was the case.

Five weeks later in early September this is how it looks. I’ve picked like-for-like frames based on the the foot placement with toes touching and heel about to touch. It’s clear the foot is now landing closer to my centre line and while there are some slight changes to my upper body posture, the non-landing leg is coiling up in the same position.

I’d say that’s an improvement and I certainly feel it’s easier when I run at any speed, not just sprint. I’m beginning to flow over the ground and I can hear it in a less noisy foot contact. And when I did the measurements again the foot is now landing 25cm out in front of me. Better than average, not quite elite!

Next time I’ll look at a couple of other changes I’ve spotted that might help!