Vertical oscillation: What it is and why it matters for runners
From cadence to stride length and resting heart rate to average pace, runners – and, of course, most running apps and GPS running watches – now record and track and wealth of health and fitness-related metrics. However, one metric that may have passed you by is vertical oscillation, an important but often overlooked aspect of running form which can, in turn, affect your running efficiency.
Confused? Here’s what to know about vertical oscillation and how it can affect your overall performance on the run.
What is vertical oscillation?
Vertical oscillation, also known as vertical displacement, refers to the way that your entire body moves up and down when you run. It’s where the running ‘spring in your step’ comes into play, if you like.
While some degree of vertical movement when you run is obviously natural, too much or too little of it can lead to inefficiencies. If your vertical oscillation is too low, for example, it can cause you to shuffle your feet, while if it’s too high, you can over-expend energy.
In other words, you bounce when you run – and the amount that you bounce is important because it affects your running efficiency. Specifically, it impacts the mechanical work that your muscles do when you run and influences your metabolic efficiency (which is how much oxygen you need while running).
‘If you have a very low vertical oscillation, below 5cm, that can be very inefficient – and if you run with a lot of vertical oscillation, above 10-12cm, that can also be very inefficient,’ notes Bryan Heiderscheit, a professor in orthopaedics at the University of Wisconsin Madison.
What determines vertical oscillation?
Several factors can affect your level of vertical oscillation. These include aspects of your running form, such as your cadence, as well as muscle strength and flexibility.
‘Factors contributing to excessive vertical oscillation include decreased gastrocnemius and soleus flexibility (or tight calf muscles) and stiff ankle joints,’ adds Colleen Brough, an assistant professor of rehabilitation and regenerative medicine at Columbia University and director of Columbia RunLab. ‘Tight calves will cause more vertical oscillation [due to] early heel rise and prevent the leg from moving into full hip extension, [making you go up] instead of forward.’
Cadence, meanwhile, affects vertical oscillation because you’re making an effort to increase the speed of your turnover, which tends to draw the foot closer under your centre, adds Brough. This works to minimise that bouncy, up and down movement when you run.
What is the ideal vertical oscillation measurement?
An optimal vertical oscillation measurement, according to Brough and Heiderscheit, is anywhere between 5cm and 10cm. While it’s possible for runners to experience either too much or too little vertical oscillation while running, it’s more common for runners to experience the former and ‘over-bounce’. Thankfully, your vertical oscillation measurement – like other aspects of your running form – is not set in stone and can be changed with the guidance of a physiotherapist.
‘When you think about vertical oscillation, there are two elements to it,’ says Heiderscheit. ‘First, there’s the high point, called the flight phase, where both feet are off the ground and your whole body is up in the air at the highest point. Then, there’s the low point of vertical oscillation, which is the mid-stance phase, where one leg is on the ground and your knee is bent and you’re sinking low. Runners can either be too high or too low [at those points].’
According to Heiderscheit, runners should aim to minimise time on the ground by manipulating their step rate or foot ground contact time. This helps to increase their cadence, which, in turn, helps to avoid mechanical issues during the stance phase.
How can I track my vertical oscillation?
Many GPS watches now measure and track vertical oscillation (which is sometimes referred to as stride height) to a high level of accuracy, although this does vary from one watch to another.
You can also try to manually capture your vertical oscillation measurement by setting up your smartphone to film a 10-second video of you running on a treadmill or on flat terrain outside. Once you have your recording, watch it back in slow motion and measure the distance in up-and-down movement from a certain marker, such as your nose or shoulder.
Why does vertical oscillation matter?
Runners should be mindful of vertical oscillation because it can be linked to injuries.
According to a small study of 20 runners, published in the International Journal of Sports Physical Therapy, those who have a vertical oscillation that is too high experience greater impact force when their feet hit the ground. This, in turn, increases their risk of injuries – especially bone and joint stress injuries. The researchers found that reducing runners’ vertical oscillation, and increasing their cadence, resulted in less ground reaction forces, which is an important aspect of injury prevention.
‘Vertical oscillation is often a yellow flag that indicates a runner may have some path of mechanics going on with their form that is consistent with a lower extremity injury,’ says Brough. ‘Runners with tight hip flexors and tight calves have a limited ability for their foot to remain on the ground and move back behind them to get a healthy, strong push-off. So [when the leg doesn’t move back], you see increased vertical excursion, where instead of having that foot stay on the ground and the leg move back behind them, it comes off the ground.’
This results in overstriding, continues Brough, which is consistent with injuries of the lower limbs and soft tissue, as well as problems like plantar fasciitis, Achilles tendinitis and bone stress reactions or fractures.
Should you adjust your vertical oscillation?
Although we are yet to see conclusive research proving that suboptimal vertical oscillation can negatively affect running performance, it is still worth determining your vertical oscillation to see if any adjustments can be made – especially due to its association with stress injuries.
If you want to work toward an optimal vertical oscillation measurement that sits between 5cm and 10cm, first try to increase your cadence. While you can use your GPS running watch to record your cadence, you can also determine your cadence by counting the number of steps you’ve taken in 30 seconds.
Then, work to increase your step rate. You can do this by using either a metronome app or a music playlist that features songs with a tempo of 155 beats per minute, for example. This is a tangible place to start on your own if your current cadence is around 140 to 150 steps per minute, as this would increase it by 5-10%. If you’re working toward a faster cadence, like the often-targeted 180 steps per minute, find songs with a higher tempo that match your goal.
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