Flight Ratio: A Key Metric for Analyzing Running Technique

Running technique is a fundamental aspect of the sport, and each runner exhibits a unique style when they hit the track or road. One crucial biomechanical parameter that can help differentiate various running techniques is the Flight Ratio. In this blog post, we’ll explore what Flight Ratio is, its significance in understanding running technique, and how it is employed in the Runeasi running gait analysis app to provide valuable insights into a runner’s performance.

What is flight ratio?

The flight ratio is a metric that quantifies the proportion of time you spend in the air (with no ground contact) compared to your overall step time, which encompasses the time from landing on one leg to the other. By delving into the spatiotemporal aspects of running, the Flight Ratio adds a crucial dimension to understanding a runner’s gait, making it an essential piece of the puzzle.

Flight ratio (%) is the amount time spend in air compared to total step time

Linking Flight Ratio with Running Technique

In recent years, researchers have extensively studied duty factor, a similar metric focusing on the ground contact part of running as it significantly influences the movements (or kinematics) of a runner’s gait (Patoz et al. 2020; Lussiana et al. 2017; Grosprëtre et al. 2021; Lussiana et al. 2019). By analyzing the differences between aerial running styles and terrestrial running styles, experts have gained valuable insights into linking kinematic information and impact-related measurements.

Flight ratio & kinematics
Kinematic differences between high & low flight ratio runners (Patoz et al. 2020)

Flight ratio is not the sole factor influencing running kinematics; rather, it bears an indirect yet significant relation to running kinetics and its impact on our bodies. This connection is rooted in the way we propel our center of mass (COM) forward, which directly influences the loading experienced during each stride (Bonnaerens et al. 2020; Hanley et al. 2022)

Role of Flight ratio within runeasi - Running Gait Analysis App

Runeasi, a scientifically validated running gait analysis app, has incorporated Flight Ratio as a key component in assessing a runner’s technique. By using Flight Ratio alongside other spatiotemporal parameters such as running cadence and ground contact time, Runeasi provides objective and valuable information on what strategy a runner is using.

By analyzing Flight Ratio and other metrics, Runeasi aids in building a comprehensive runner running quality profile. This profile provides detailed insights into a runner’s performance and sheds light on how well they are executing their running technique. Understanding this profile can help runners identify areas for improvement and optimize their performance.

Example of a session report including running quality and flight ratio information


Flight Ratio is a critical biomechanical parameter that plays a significant role in evaluating running technique. By accounting for the time spent in the air and on the ground during running, it offers valuable insights into a runner’s gait and kinematics. With the integration of Flight Ratio into the Runeasi running gait analysis app, runners can now access objective and scientific information about their performance, enabling them to refine their technique and achieve their running goals more effectively.

Picture of Written by Philip Cortvriendt

Written by Philip Cortvriendt

Philip achieved a master’s degree in physiotherapy & rehabilitation sciences and has core expertise in the field of running, working with both recreational and elite runners. Philip has the unique role of educating Runeasi physiotherapists and helping them translate biomechanical insights into targeted strength and conditioning exercises- specifically on how they can improve their client care using scientifically validated biomechanical insights from our Runeasi analytics.


1. Global movement quality

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2. individual recommendations

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3. Real-time feedback


4. Session trends

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5. Quick comparisons

Compare pre-post data to show intervention effects on the movement quality. 


1. No motion artifacts. The Runeasi belt is secured tightly against the body and the skin to capture the actual movements of the body’s center of mass. Attaching or clipping the sensor directly to the pants would allow the sensor to wobble from side to side (i.e., measuring the wobbling of the pants, and not the human body.

2.  Easy to standardize the sensor’s positioning. The Runeasi belt makes it easy to consistently position the sensor close to the center of mass. Attaching the sensor directly to the pants would dramatically affect the reliability of the outputs as the height and tightness of the pants will affect the results. Moreover, these pants attachments often shift sideways while running which further decreases the data quality. 

 3. Comfortable to wear.  Hundreds of runners confirmed that they immediately forget about our belt while running. This allows them to move without any restrictions and allows us to capture movements that are representative of a client’s true biomechanics.



Accurately captures full range of motion and kinetic parameters by leveraging wide sensing range (16 Gs) & high sampling frequency (1000 Hz)


Built to withstand high intensity training and sweating. Suitable for the outdoor elements, come rain or shine. Robust to handle the repetitive and ruthless impact shocks of running.

Lightweight & SLIM

Seamlessly integrates onto the body to support movement without restrictions. Weight: 9.4g/0.33oz with battery. Dimensions (36.6mm/1.44” dia. X 10.6mm/ 0.42” thick)

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