Treadmill vs Overground Running: Do Biomechanics Change?

Many runners ask if treadmill and overground running biomechanics differ. As one of the top FAQs among patients considering a running gait analysis, running experts should be ready with an evidence based answer. The reason for this question is athletes are often concerned that their lack of treadmill experience will translate to an inaccurate representation of their running gait. Emerging research suggests that treadmill and overground running are largely comparable. However, there are some key differences in treadmill biomechanics. Here are the differences of treadmill vs overground running and how to minimize their effects on runners. 

The Differences Between Treadmill and Overground Running

Treadmill and overground running have similar biomechanics. However, several key differences in the sagittal plane should be noted. This includes decreased peak propulsive forces, increased sagittal plane joint moment, decreased knee flexion range of motion during stance and decreased vertical displacement. While some of the reasons behind these biomechanical differences are not fully understood, several emerging correlations are being made. One explanation for smaller vertical displacement may be a consequence of a higher stride frequency in treadmill runners. Another correlation researchers found suggested the reduced peak propulsive force was due to insufficient familiarization/comfort with treadmill running. Both insufficient familiarization/comfort with treadmill running and the known perception of running faster on a treadmill cause runners to increase their cadence and reduce their stride length. Here’s an image to illustrate these points. 

How To Minimize The Biomechanical Differences of Treadmill vs Overground Running.

Many running experts use treadmills to simulate overground running for a gait analysis. Therefore, it is important to minimize the biomechanical differences between treadmill and overground running. Here are several suggestions. 

• Match the runner’s outdoor surface stiffness to closely match the treadmill surface stiffness. With most runners utilizing concrete/asphalt running surfaces it is suggested for clinicians to choose a treadmill with a similar stiffness surface. While many treadmills do not provide values of the stiffness of their running surfaces clinicians should make sure to avoid using treadmills with excessively “soft” surfaces. 
• Treadmill belt speed fluctuations have been shown to change running biomechanics. This can be a result of underpowered treadmills not being able to handle excessive braking and propulsive forces from runners. This is most commonly seen in heavier runners using a high rate of speed. Running experts can often avoid belt speed fluctuations by purchasing high quality treadmills with adequate motorized power to the belt system. 
• Familiarization and comfort with treadmill running can affect running biomechanics. While more research is needed on this topic, recent evidence suggests runners unfamiliar with using a treadmill should take 8 minutes to improve their comfort with treadmill running. 

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Treadmill Brands

Not all treadmills are created equal. The quality of many treadmills are reflected in their cost. Several attributes to consider when selecting a treadmill to use for running gait analysis include side arms that are removable or absent, a flat running surface, variable running speeds to accommodate both fast and slow runners, and stable sturdy running surfaces. The best brands for running gait analysis include

• NordicTrack
• Sole
• Landice
  

While it’s tempting to buy the lowest cost treadmill when starting to analyze running gait, high quality treadmills specific to your clinic needs will improve the data you collect from the runner and improve their outcomes. To learn exactly which treadmill to purchase check out The Essentials of Running Gait Analysis (6.5 CEUs). Inside you’ll learn a step by step guide to purchasing your treadmill and making a thriving running practice. 

Reference:

Van Hooren, B., Fuller, J.T., Buckley, J.D. et al. Is Motorized Treadmill Running Biomechanically Comparable to Overground Running? A Systematic Review and Meta-Analysis of Cross-Over Studies. Sports Med 50, 785–813 (2020).

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