You absolutely can.
Train hard, climb hard, run hard, eat lard (optional), max it out, take it to the limit.
Then a bit further…
HIIT, three rounds of the following six exercises (10 seconds rest, 50 seconds work)
- High knees skipping
- Medicine ball knee tuck, then leg back and up, then press up (feet on the medicine ball) alternate legs
- Jumping jacks skipping
- Medicine ball jump lunge, extend arms with ball and twist over front leg
- Scissors skipping
- 90 degree medicine ball touch
Then cool down with 12 minutes skipping, free style (10 seconds rest, 50 seconds work)