Welcome to our first instalment of Metric Monday!
In this series, we take an in-depth look at a range of metrics which impact your running and one by one, detail their importance, what they mean, and how understanding and working to improve on each metric can help you in your running performance.
Metrics are a vital part of understanding the make-up of how you run. Coming to terms with important running metrics can and will tell you a lot about your running — from the effectiveness of your movement, how economical your running is, to how you can help prevent the risk of injury.
By understanding and working on these metrics for those crucial, performance-boosting marginal gains, you can improve on the key aspects of your form and technique and become a consistently better runner.
First up – we’re taking a deep dive on your bounce.
Most runners will find that their bounce will have an effect on their running performance, even if it’s very minimal. This varies from runner-to-runner, with some having a small height on their bounce, while others are prone to over-bouncing, which can prove an inefficient trait.
Every runner should be aware of what their bounce means to their running performance. Thankfully, with a bit of attention to detail and careful tracking, you can improve on your bounce to take your performance to the next level.
What is bounce in running?
First things first, your bounce — or sometimes referred to as the vertical oscillation of your pelvis — is the vertical movement during a run.
Put simply, this is the amount that your body ‘bounces’ up and down while you run.
This is typically measured in centimetres, taking consideration of the height you reach in your bounce, with a larger height having more of an effect on your performance across various aspects.
Why does it matter?
The bounce metric mainly influences your running efficiency and aims to improve various other metrics, like time and energy. The majority of runners who have a high bounce are actually wasting a lot of energy in their vertical motion, which could be better used elsewhere.
Ideally, that wasted energy should be used to propel yourself forwards rather than upwards.
The higher that your bounce is moving you upwards, then the more energy used for vertical movements and not forward propelling movements – meaning that your spending more time moving in the wrong direction as your run becomes less economical and adds seconds to your overall time.
Your bounce also heavily influences your ground contact time (another vitally important running metric) by either increasing or lowering the amount of time spent with your feet touching the ground.
It’s also worth noting that a lower bounce will help to reduce the impact of force on your joints which, in turn, contributes towards injury prevention.
In short, higher bounces mean less effective runs, use up energy better spent elsewhere, and place more strain on your body.
What does the science say?
According to recent research, a study published by Stephen J. Preece in the European Journal of Sport Science on the biomechanical characteristics of high-performance endurance running details that the bounce of a runner is what causes some individuals to move faster than others.
The study found that runners with more of a spring in their step had a faster movement rate compared to flatfooted runners, who averaged an overall slower pace:
‘The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group.’ (Stephen J. Preece, 2018)
The study also found that runners with a springy bounce also ‘adopt[ed] a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment’, while also ‘maintain[ing] stride length with a prolonged aerial phase, rather than by landing with a more extended knee’.
So what does this mean? Well, the study suggests that runners can improve their overall performance and effectively cut down their overall time by tracking, analysing and adapting their bounce.
Spend time working on your bounce, and you’ll improve your overall performance no end.
How can I improve?
Ideally, for a faster and more efficient run, your bounce should be zero, however, it’s practically impossible to run without any vertical movement.
Instead, it’s suggested that the most optimal bounce score runners should aim for is 5% of your body height or lower. To find this out, you’ll need to measure your height and calculate what 5% of that figure would be.
That number will be your optimal bounce target score for you to aim for while running – and by achieving that, you can achieve a more economical and quicker running performance, shaving seconds off of your overall time and conserving energy while you do it.