The aim of this study was to provide a comprehensive description of barefoot running and to compare barefoot with shod running. The researchers found that wearing shoes changes the way you run, which running on soft surfaces or uneven surfaces does not. So running with shoes on is not the same, theoretically, as running on foam or grass. Wearing shoes makes people start heel striking, which is associated with amateur or beginner runners. The researchers took nine male long distance runners and tested them while running barefoot and shod at three different speeds.
The researchers used force plates and video cameras to take the various measurements. The researchers put markers on the skin at the hip, the knee joint and at the ankle joint at the outside of the ankle. In this study, the researchers also put a marker at the shoulder, at the height of the acromion, which is above the shoulder. In the barefoot condition, foot markers were placed at the tuber calcaneum and at the pinkie joint. In the shod condition, markers were placed on the shoe at the height of those landmarks.
After the experiment the researchers noted that the runners had many differences between running barefoot and shod. One of the key differences was shorter strides. For all the tested speeds, the runners took significantly smaller steps while running barefoot. This leads to a shorter contact time for all the runners that ran barefoot. Another difference was a higher cadence. When running barefoot, the runners ran with more strides per minute. All of the runners that ran barefoot were characterized by a significantly larger loading rate than in shod running, but not greater forces at the maximum point.
Which means that more than one impact peak was found for the barefoot condition. You can see this in figure 3 where the chart shows the difference between the forces experienced barefoot and experienced using a running shoe. You can see clearly how the barefoot runner gets a sharp shock immediately at the beginning and then a secondary shock that is larger. However, the shod runner gets his initial shock later and less sharply, followed by the same secondary shock. In this paper the researchers also ound that when the subjects were barefoot running, a significantly larger loading rate during impact was found. There were also many references to other studies from the 1980s which had many similarities but also many differences in the results. They noted that these previous studies had assumed that the initial sharp shock that runners felt when barefoot running was the driving force behind the change in gait. This simply meant that the runners experienced the jolt and therefore modified their running pattern. The running pattern caused a flatter foot placement, rather than a heel strike.
However, the researchers found out that the more horizontal foot placement of the runners was prepared well before touchdown. In the barefoot condition, the ankle was already significantly more flexed at 0. 03s before touchdown. This meant that the initial shock was not the driver of the changed kinematics. The researchers also found that, in the barefoot running condition, the maximal local pressure underneath the heel is negatively correlated with the foot angle at touchdown. In other words, the more horizontal the foot, the smaller the maximum pressure will act on the heel.
Having understood what was going with running barefoot, the researchers now knew that the shod runners kinematics were very different. When the shod runner’s front foot hits the ground, it does so with much less initial knee flexion but as the body catches up with the foot that is placed on the ground. Knee flexion in the shod condition becomes much greater than in the barefoot condition. As the body passes the foot, the knee flexion is still greater in the shod condition and it only coincides again with the barefoot condition once take-off is achieved.
So, when subjects run barefoot, runners do not maintain similar running mechanics. The researchers noted these contrasts to the findings of other studies for running on different resilient materials. The point is that running with shoes on is not the same as running on a forgiving surface. Your shoes are doing something that is changing the way you are running. The researchers concluded that the adaptations in stride kinematics to barefoot running are primarily due to changes in touchdown geometry and the following joint movements during initial ground contact.
There are changes in the running patterns between barefoot and shod running, mainly characterized by a larger external loading rate and a flatter foot placement at touchdown. The researchers also found that in barefoot running, the joint configuration of the leg is already prepared in free flight by a larger plantar flexion; by more knee flexion and a larger knee flexion velocity and that this must therefore be actively performed. Therefore, it is to say that it is the shoe that is causing an active adaptation and not the other way around.
Better to say that wearing running shoes greatly changes the way that people run, leading to more heel striking and greater knee flexion in the stance position. The researchers also found that in the barefoot condition there is a correlation between a flatter foot placement and lower peak heel pressures. Therefore, runners adopt a flatter foot placement in barefoot running in an attempt to limit the pressure on the heel. These runners alter their style from shod to barefoot running.
I believe that runners adapt by increasing motion during their stance phase. Initial contact positions demonstrate differences in strike pattern and higher sagittal plane values for barefoot trials may indicate more midfoot landing. From reading this paper I concluded that there are running pattern changes, adaption strategies, and greater heel pressure differences between barefoot and shod running. I consider this data can enhance the understanding of shoe-wear and help in learning how to run correctly.