Only across cosmological distances. This would be negligible for gamma rays emitted within, say, the local group, which is gravitationally bound against Hubble flow.

Radiation dissipates with distance squared :-) Throw in any medium (dust, gas) and it dissipates even more

I played competitively until college. I fucked up my back and right knee - I used to be a killer with a passing forehand ending with a slide on my right leg (on hard court). It just really messed up my knee and now I can't run like that more than once or twice in a match despite better overall fitness. I definitely can't do weekly matches either