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Fall forward

J. R. Soc. Interface 16, 20190292 (2019)

Consider for a moment how something as innate to us as running or jumping actually works. The complexity of such seemingly simple tasks still keeps those who engineer robots or wearable devices busy. Taylor Dick and co-workers have now investigated the mechanics of our capacity to stand upright when encountering changing terrain or — put more simply — when falling into a hole.

The team had people hop on a platform and used motion capture to record the coordinated kinetics and kinematics of their lower-limb joints when the platform was suddenly pulled from under their feet. Calculations of the mechanical work and power at each joint showed that we are able to recover from short falls — up to 10 cm — with minimal changes to our legs’ mechanics as the ankles absorb the shock. Fall higher, however, and the hopping mechanics change to redistribute the shock to the higher joints — knees and hips — possibly to prevent damage to our smaller distal muscles.

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Correspondence to Federico Levi.

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Levi, F. Fall forward. Nat. Phys. 15, 1105 (2019).

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