Vertical oscillation in running: what it means and what it indicates

As advanced runners we are now used to observing the data from our watches: speed, heart rate, cadence, stride… However, some numbers take a back seat, probably because they are less comparable and “absolute” or simply because they are more complicated to interpret.

What does vertical oscillation indicate?

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Among the most important and underestimated data in running there is thevertical oscillationreported by some more sophisticated instruments, but increasingly present in GPS files. Vertical swing indicates in centimeters how much we move upwards when we take a stridethat is, how much our center of gravity (not our feet) rises from the ground. If we observe a speed race on the track and focus on the frontal shots, we will notice that the athletes’ upper body remains essentially at the same heightthe head remains almost still. In a very similar way if we look at the race lead of a marathon, marathon runners complete a circular movement of the legs, even raising your feet a lot off the groundbut from the hips up they are almost stationary. Now, however, we look at those who run in the park, ordinary people, and understand what happens. More or less, it makes small leaps upwards and sometimes swings sideways. What happens?

the race, a parabolic motion

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When you run, your legs do a push job that allows you to move forward, on the sagittal plane. The motion is similar to that of a small ball and that is a parable takes place, which can have different forms depending on how we orient the push we give on the legs and feet. The more we direct the thrust upwards, the taller and shorter the parabola will be. If instead with the same force exerted we will orient the thrust forward we will have a lower, but wider parabola. Obviously these movements occur on the center of gravity, not on the legs. The “perfect” run will therefore have an ideal parabolic motion, with a relationship between jump height and length that optimizes the mechanics of the gesture. Therefore, if we apply a great force, but direct this force towards the other, we will have an exaggerated relationship between vertical oscillation and stride, vice versa if the jump is too far forward and not high enough, the stride will remain reduced.

the correct measurements

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The ideal relationship between vertical oscillation and stride length varies between 6 and 8%this means that if our run has a one meter stride, the correct vertical oscillation will be close to 6 centimetres. Lengthening the stride usually also increases vertical oscillation. When the ratio between these two measurements is too large, there is a “skipped” run, with a large, useless expenditure of energy. When the thrust is oriented upwards, part of the force is used to move the body against the force of gravity, without however making any changes to the speed. This results in an inefficient stroke. Likewise, a “sliding” run forces the hips to rotate excessively in order to open the stride, an ineffective dynamic and risky for injuries related to the pelvis area.