Here is a cardio circuit that will kill you and is also relevent to boxing. This one made me sweat buckets and if you have fat to burn or making weight in a short space of time, then this will definitely work. All you need is a hill, two 2.5kg dumbbells (or anything else you can hold) and commitment! Each exercise is for one minute. Do two circuits and gradually increase. Rest two minutes between sets.
Dumbbell Punchouts (go for it, for speed and power, don't stop!)
Sprint (flat out for 60 secs, finish next to the hill!)
Hill Sprints (once you've done 60 secs, run straight back down)
Press-up Burpees (like a normal Burpees, but press-ups on the down part)
Dumbbell Punchouts (this is a killer!)
Keep going for the entire minute. Heart, soul and commitment. Good luck!
Dumbbell Punchouts (go for it, for speed and power, don't stop!)
Sprint (flat out for 60 secs, finish next to the hill!)
Hill Sprints (once you've done 60 secs, run straight back down)
Press-up Burpees (like a normal Burpees, but press-ups on the down part)
Dumbbell Punchouts (this is a killer!)
Keep going for the entire minute. Heart, soul and commitment. Good luck!