Much to my dismay I find that uphill sprints are a detriment in regards to having good cardio for judo.
A quick note you can do all this interval training by sprinting as well. Please be aware that running uphill (although gets your HR through the roof) should not be used when tapering for competition. This is due to the fact that running uphill is a concentric movement (muscle building) and is slow a sluggish and trains your muscles to be slow, something we don't want leading up to a competition.
If you are going to sprint as part of tapering you must either perform your sprits on a flat surface or even better, by running downhill. I'm not talking about running down a steep cliff but at a decline that lets you safely run faster than you usually do without the risk of falling over. Downhill sprints are an eccentric movement and the theory is that if you are running faster than you normally are you are training your muscles to be explosive and fast. Leading up to the 2000 Olympics Gold medallist Judo player David Douillett only ran downhill as part of his cardio regime. This, along with other studies proves that down hill running increase speed, power and explosiveness above all other forms of running. The only problem with it is because it is eccentric the body takes a while to recover.