When looking at the video clip for some seconds you will be hopefully able to follow the retraction of the muscle into the leg where it becomes thick and roundish. This is an interesting example for a miniature construction:
the claws measure some microns in thickness only, nevertheless they are working tools. Furthermore we should not forget that the dimensions of the muscles shown are many thousand times smaller than those of a comparable human muscle.
By means of this miniature tool-box the water bears have conquered the world as Ian M. Kinchin puts it: "Also the fact that tardigrades exhibit a range of extant species means that the tardigrade "Bauplan" is a success in that the animals have been able to colonize geographically diverse habitats (terrestrial and marine) with little anatomic modification".

© Video clip by   Martin Mach