Some Working Rhythms

Repetitive stress does not necessarily imply injury.  It can be musically useful. 

From a Ghanaian post office, a worker cancels stamps, spontaneously changing the pattern to fit each envelope:

Another example from a Ghanaian post office, an ensemble:



Various styles of counting cash, far less interesting than the basic pulse of each sequence are the rhythms internal to each pulse:



(See also this: Villagers in Iseh, Karangasem, Bali, stomping rice, in interlocking patterns.) 

And this: from Robert Bresson's film Le Diable Probablement. Bresson, preferred not to use non-diegetic music in his films, but his use of sound was nevertheless extremely musical.  This example uses diegetic noises to propel, through their increasingly rhythmic character, a didactic sequence (Bresson wrote: "Image and sound must not support each other, but must work each in turn through a sort of relay.")