go to a local football ovel and do some shuttle runs
back in the old days my footy coach made me do lots of shuttle runs it made me fit as a fiddle
a shuttle run is when u start on the base line and run up to the next line then run back
then run to the line beyond the one you just touched
do 3 sets of 10shuttle runs every 3days
in 2weeks ull see some massive improvements
peace