We have previously stated here that we think Usain Bolt can lower the 100 meter world record.
We have suggested that he can start faster, train harder on his fitness and of course refrain from celebrating before crossing the line. All of which suggests that his 9.58 second 100 m and 19.19 second 200 m world records will be broken.
On Saturday the BBC aired a documentary on Usain Bolt "Usain Bolt: The Fastest Man Who Has Ever Lived". In this documentary Michael Johnson, the 400m world record holder and second fastest man over 200m (after Bolt) talks about the biomechanics of Bolts sprinting.
Johnson says of Bolt: "He has ... an incredibly long stride combined with the ability to execute a race like a shorter sprinter - generating the same explosive power. That combination makes him so much faster than the rest of the field."
But he suggests that slow motion video shows that bolt has lateral movement in his sprinting mechanics. In other words he moves his body side to side as he runs. This sideways movement reduces his forward power by wasting energy in keeping his balance. If Bolt were to remain still with his upper body as all good sprinter should, he may be able to propel himself even faster.
Of course the lateral body movement may be a result of other inefficiencies with Bolts mechanics. It is possible that he turns his knees or feet out a little. As Michael Johnson is an excellent proponent of running mechanics and a highly qualified coach, we are sure that he and his team setup their cameras in the best way to measure these inefficiencies correctly.
One of the most important aspects of video analysis for sports is to ensure that we get video images that will allow us to do the analysis we want. If we are interested in Bolts side to side sway we need to have a camera directly in front and or behind him as he sprints down the track. We want to be able to measure how much his body moves laterally and see if his knees and feet are out of alignment. With this information we can help our athletes improve their mechanics and speed.
A recent thread discussing barefoot running impact forces on a biomechanics user group, reminded me of another important aspect of barefoot running and the main reason many researchers, runners and scientist are suggesting that it may be better to run barefoot than in shoes.
The impact forces are the forces that the muscles, ligaments, tendons and bones experience when the foot first hits the ground. Impact forces are absorbed by the foot and transferred and shared among all the muscles in the leg and up to the hips. Research has shown that this impact force has a higher impulse (change in force over a time period) when landing on the heel than when the runner lands on his mid-foot or forefoot.
Running in shoes has allowed runners to feel comfortable landing on the soft cushioned heel of the shoe and therefore the impact forces and impulses are increased sending larger shock waves through the body and possibly causing injuries. Barefoot running, forces the runner to land on the mid-foot or forefoot, reducing the impact forces and impulses.
The video below from the Nature channel on YouTube about the barefoot professor, Harvard professor Daniel Lieberman, gives a good explanation of the theory. Professor Lieberman also published an article in Nature magazine on barefoot running. Notice how they use video analysis to analyze the running mechanics. They also use force platforms in the treadmill that measure the forces. Force platforms are like large accurate bathroom scales that can determine the position of the foot.
There seem to be advantages to barefoot running, but there are many unknowns too. Even if there are advantages to barefoot running in lowering impact forces and the foot control that may reduce pronation, we may not be aware of the disadvantages that exist.
Barefoot running definitely seems to increase blisters, bruises and pain under the foot. The calf muscles are often more sore and stiff after running barefoot and other muscles may also be strained in ways that cause different injuries.
So if you plan to try running barefoot, start slowly and build up your tolerance and strength. Also record some video footage of your running and try to identify how you run differently in shoes and barefoot.
We are ready to help you with this analysis. Please contact us to see what we can do.
A large following and interest in barefoot running has been developed lately, encouraged by Christopher McDougall's book "Born to Run" which describes the Tarahumara or Rarámuri, an indigenous peoples from Northern Mexico, who have been known to run long distances in thin soled sandals. We recently assisted a runner with some video analysis as he trains to run a marathon wearing the Vibram FiveFingers minimal shoe.
Last year we discussed using video analysis to analyze rear foot pronation and attempted to see whether there was a difference in rear foot pronation between running in shoes and running barefoot. We described how a camera should be setup and the measurements that could be done. However, as we studied a runner who does not suffer from pronation we were only able to see a normal amount of pronation in the foot stance phase of his running.
Our runnerwanted to determine how much he was pronating when running in his FiveFingers minimal shoes. He also reported getting blisters under the pads of his feet and on his right big toe.
He used all the techniques for filming his motion that we have discussed on this website in the past and sent the videos on to us. He set up to run on a treadmill at a constant speed of 8.3 miles per hour and ran 12 miles in total capturing video at intervals along the way. Set his camera on a tripod at the level of the treadmill to capture the video and his foot placement. He captured video both from the side view and the rear view so that we could assist him in analyzing his foot strike. Take a look at the video below.
From the video we have taken a few snapshots to help us analyze his foot strike characteristics.
In the images above we can see a side view of the left and right foot strike. We can see that:
Both the left and right foot is inverted at foot strike. This means the feet are turned in and the athlete lands on the outside of his foot.
The main muscle used to invert the foot is the Tibialis Anterior (the muscle on the outside of the shin bone). These muscles are also used to dorsi-flex the foot (lift the foot up). This can be seen in the video as the foot and toes are flexed back just before foot strike.
Striking with an inverted foot can create a slapping of the foot onto the ground rather than a controlled foot placement.
Striking with an inverted foot can also exaggerate any rear foot pronation.
The foot strike is occurring toward the midfoot and not the heel. This is to be expected when running in minimal shoes. The runner in minimal shoes is trying to avoid heel impact and is taking greater care to control his foot strike.
Now we can look at his rear foot pronation. In this instance an estimate was made for rear foot pronation using a 4 point angle. Rearfoot pronation is measured as the amount of eversion (rotation inward) of the foot from heel strike through mid stance. The angle is measured by drawing a line along the center of the Tibia bone in the lower leg and another line describing the center line of the Calcaneus (heel bone).
As our runner was concerned that he was pronating more in his right foot, we have looked only at his right foot here:
The pronation angles displayed in the images above are estimates. As there are no markers identifying the necessary landmarks of the midline of the Tibia and the midline of the Calcaneus.
The athlete lands with an inverted foot position. The rear foot pronation angle of 171 degrees shows this. An angle of 180 degrees would be neutral while anything over 180 degrees is everted (pronated).
At mid stance the athlete has 13 degrees of pronation (193-180). The foot is expected to evert (pronate) by approximately 10 degrees through mid stance for normal pronation. Therefore this would be considered excessive pronation.
The eversion of the foot from foot strike to midstance is also rapid and large, pronating 22 degrees.
As can be seen from the video and the images our runner pronates while running at 8.3 miles per hour.
Our runner has been training in his Vibram FiveFingers shoes for less than 2 months. Prior to running in these minimal shoes he ran in a shoe offering maximum pronation support. It may therefore be too early to tell whether the minimal shoes are improving his pronation by encouraging him to control his foot placement.
Our runner has also been suffering from blisters, since wearing these shoes. Unfortunately a minimal shoe such as this will likely cause the foot to blister more readily. The shoes are worn without socks (as each toe is separated in the shoe)causing more friction between the shoe and the foot. Being that there is not much cushioning between the shoe and the road surface, any scraping on the hard road or treadmill surface will also cause friction and possible blisters.
It is possible that our runner is in fact suffering from the effects of his blisters and is running as seen in the video because of the blisters on his foot. The exaggerated inverted foot at foot strike may be a way of attempting to protect his foot from injury and further blisters.
We still believe that barefoot running or running in minimal shoes will help to improve a runners mechanics. Barefoot Ken Bob Saxton says, “Don’t strike the ground. If you do it’ll strike back!” The idea of running barefoot or running in a minimal shoe is to feel your feet and understand how much they can take and to learn how to control your running so that you can continue running faster and with less injury.
If you want to try running in minimal shoes, allow yourself sufficient time to get accustomed to running in them before trying to do to long a distance at too high a speed.
Also pull out your video camera and film yourself. This will help you to visualize what you are doing and possibly help you to achieve success in a minimal shoe. We are always ready to offer our services to help you analyze your motion.
In the 100m and 200m track sprinting events, the start can win or lose a race. In the 100m the winning difference is often measured in 100ths of a second, therefore any advantage that can be gained at the start could be crucial.
At the IAAF World Championships next week, Tyson Gay will take on Usain Bolt for the title of worlds fastest man. So far in 2009 both athletes have put up some impressive times and the first meeting between them this year should be fast, close and exciting. Usain Bolt is the Olympic champion and world record holder. We have previously discussed how fast he could possibly run. Tyson Gay is the reigning World Champion and recently ran the 100m in 9.75 seconds at the US Championships.
With both athletes being at the top of their game, victory may be decided by their start. Neither of them is known for their explosive or fast starts. Bolt has an incredibly long stride length and eats up ground with each step while Gay has unmatched leg speed. The start though is crucial and we have therefore decided to look at some video and examine the start.
Below is some front on video of Tyson Gay at the US Championships. We want to focus on his start.
A good start requires that the athlete sets up correctly. Here are some key factors for the set position before the start gun sounds.
The hands are set up on the line and the shoulders and upper body should lean forward over the hands. Track coaches suggest an angle of about 15 degrees (The angle between the shoulders and hands and the vertical). Although we cannot see the angle at which Gay is leaning (this would need a side on view of his start), we can see that he is leaning forward and ready to explode from the blocks.
The angle of the knees in the start position must allow the athlete to push away from the blocks with as much power as possible while at the same time being able to get their feet through to begin running. The optimal bend of the front knee should be around 90 degrees to provide the biggest lever to produce push off. The back leg needs to be bent less than this at about 60 degree so that it is able to still push off hard but will straighten before the front leg and have time to come through for the first step.
Both legs need to push off almost simultaneously at the start of the race. The athlete cannot be sitting back on either his front or back leg at the start.
Tyson Gay sets up well and in this video he explodes from the blocks, pushing off with both legs quickly. Both legs straighten completely, with the rear leg leaving the blocks and starting to drive through before his front leg (left leg) is completely straight.
Gay also uses his arms to explode out of the blocks, as well as maintain good balance. Watch as his right arm drives backward and his left forward. This motion provides extra forward momentum, but it also ensures that as he starts he does not fall over to one side. The arms act as a counter balance to the motion of the legs. In this start his right leg will take the first step on the track and therefore his left arm needs to be forward to balance this motion.
Moving forward to that first right foot step on the track, we can see that Gay's head and chest are still down low. His arms are driving hard and fast. If you pause the video you will see them as a blur. We can also see that his first step is not too long. In fact his head, chest and hips all remain in front of his foot for this first step. This allows him to continue to stay low with his body. If he took a longer first step, it would force his chest up, which would in turn slow down his speed. His chest and head stay down for as many as 16 steps allowing him to lean forward during this start and continue to accelerate.
His start technique looks great here and although we do not know what his reaction time to the gun was, we can see that he was able to accelerate well from the start and this is why he put up such a fast time.
As I looked through more videos on Tyson Gay's start, I came across one from tttjump that suggested that Gay's knee rolls forward at the start. If you study the slow motion of the start in the video above you will see what this means. Gay's front leg (his left) moves forward and down, in fact bends a little more, just after the start and as his hands leave the ground.
The suggestion is that this extra bend of the front knee at the gun, causes a delay in his ability to get off the blocks. On closer examination we can see that his back foot is driving already (straightening) as his front knee "rolls" forward. This may be causing him to push off with less power from his back leg as he may need to slow it down, to give the right leg time to get into a position to start its push off.
From a biomechanical standpoint, this would suggest that Gay's front leg is not bent to the most optimal position to explode out of the blocks. He may be bending it a little more after the start to get more push off power. The split second it takes to bend the knee that little bit more and the small amount of back foot push off power that he may lose, could determine the outcome of the race against a phenom like Usain Bolt.
Once again from the standpoint of biomechanics, this problem could possibly be solved by simply adjusting Tyson Gays starting blocks or position slightly, allowing his front knee to set up in a more optimal position for his starting style.
Of course for this World Championships, it is too late to make any changes and Tyson Gay should provide Usain Bolt some really stiff competition when they hopefully meet in the final in Berlin.
If you will be watching or filming some video of any of the action at the IAAF world championships and would like to share some video for analysis, please let us know.
Running is a great for fitness and weight loss, but as many runners know, it can often result in chronic injuries. Running shoe companies continually market their latest breakthroughs in lightweight footwear comfort, anti-pronation, impact reduction, and energy conservation. Grid systems, air pockets, smart chips, and step monitors all make their way into our running shoes. We all seem happy to shell out large sums of money for these shoes and to trust that the shoe company has done a proper analysis and is offering us a product that will improve our performance, reduce our chances of running injuries, or even solve our running injury problem.
We decided to use video analysis to examine how running shoes affect pronation. We are going to show you how to measure rearfoot pronation using your video camera. This measure is often used in speciality running shoe stores to help customers choose the correct anti-pronation running shoes. We will show you how its done and measure the pronation of an athlete running barefoot and with trail shoes.
Pronation of the foot occurs when the arch of the foot collapses and the foot turns outward. The higher forces incurred with running can force the foot into over-pronation, which is often associated with running injuries. Supination is the opposite of pronation and occurs when the foot turns inward.
Below is some video of both the barefoot and running shoe trials. To film this properly we needed to use a treadmill. It would be very difficult to get a consistent view of the foot and leg if the athlete had been running away from us and getting further away with each step. With the subject on a treadmill we can position our camera correctly on a tripod and know that we will have a consistently good view of the foot that we need for our analysis.
You will note that the camera is set up directly behind the subject and in line with the right foot. For this analysis we will concentrate only on the right foot; we therefore made sure that we had as straight a view as possible of the right foot when it was on the treadmill (it is not important when it is in the swing through as we are measuring pronation during the foot stance). Another important factor is running speed. we can only properly compare the pronation angle between the two videos if we ensure that the subject runs at the same speed in both videos. With a treadmill this is easy, as we can set running speed. In this case the subject is running at 6 miles per hour in each trial.
Let's look into the detail of these videos by taking some snapshots and comparing the pronation angle at each of three events. We could do a better job of examing pronation by comparing the changing angle vs time throughout the stance (foot on the ground) phase, but we want to do a simple analysis for now and the best way to do this is to pick 2 common time points. Therefore we will compare the pronation angle at first foot strike and mid stance (midway through the foot on the ground stage).
In order to do a proper comparison over various time points or events, it is always better to digitize points. Digitizing is done by identifying anatomical landmarks on the subject such as the bottom of the heel or the top of the Achilles tendon. Many expensive systems exist that use reflective markers to automatically identify points. For our comparison, we used a relatively inexpensive software called MaxTRAQ 2D, developed by our friends at Innovision Systems Inc., and manually digitized the necessary points to calculate rear foot pronation angles.
The runner running barefoot shows little difference in pronation angle between foot strike and mid stance. The measured angles are 178.6 and 178.7 degrees. A measure of 180 degrees would suggest that the foot has no pronation or supination, so 178.6 is showing 1.4 degrees supination (the opposite direction from pronation) which can be ignored. A angle higher than 180 degrees would show pronation.
We then asked our runner to put his shoes on and once again measured the pronation angle at the two stance events.
We can immediately see that our runner shows a little more supination throughout his running stance when he is wearing shoes than when he is barefoot. At foot strike his pronantion angle is 166.1 degrees or 13.9 degrees of supination. At mid stance his foot has come back into an almost neutral position showing only 4.1 degrees supination. Our runner would be considered neutral both in shoes and barefoot.
Our runner is wearing neutral shoes, meaning they do not offer support for pronation or supination. The supination of about 14 degrees seen at heel strike is also relatively small and as we cannot actually see the bottom of the runner's heel through the shoe, we may have estimated this position incorrectly and the foot could be in a different position inside the shoe (most likely closer to neutral).
If we have estimated the heel position correctly and there is slightly more supination when running in shoes, the subject's shoes appear to provide him a level of cushioning which allows him to land comfortably in a slightly unnatural position. Running barefoot can be painful and the runner therefore controls his foot using the muscles and ligaments surrounding the foot. In this way he can avoid pain and injury while running. There is no large difference in our trials though, and our runner does not pronate or supinate too much during his stance phase of running.
We are not all Abebe Bikele (the 1960 Olympic Marathon winner ran barefoot) and we believe the running shoe has more than likely prevented many more injuries than it has caused. Now that you know how to analyze rearfoot pronation, you can buy your next pair of running shoes with confidence and understanding.
If you would like more information on the software we used to digitize these running trials please email us. Also please comment on our post; we love to hear your opinions.
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