Thanks for writing your query.
Strenous exercise can result in rhabdomyolysis
. This result in breaking of muscle myoglobin which when excreted in urine can result in dark coloured urine.
can also result in dark colored urine due to concenteration of urine.
Pain killer can also cause concenteraed urine and should be avoided for mild pains.
Hot fomentation and application locally of pain relieving gel will be helpful in relief from pain.
You should drink lots of pure water.
Also get following investigations done :-
1. Serum myoglobin.
2. Urine examination ( Routine/Microscopic and for myoglobinuria
I hope this is helpful to you.