This is one of my favourite narrative expert reviews that discusses the benefits of human biologic springs like the Achilles tendon. These benefits can be summarised as follows: 

Metabolic energy conservation Amplification of muscle power output Attenuation of muscle power input

Some really interesting mechanisms and insights for rehabilitation . I hope you enjoy!

Here is the link to the study:

Roberts, T.J. and Azizi, E., 2011. Flexible mechanisms: the diverse roles of biological springs in vertebrate movement. Journal of experimental biology, 214(3), pp.353-361.

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