also, though it's a little after the fact, i just want to add that bicep curls are not entirely useless. For a beginner looking to improve his/her strength for parkour, they aren't very worthwhile, but they can have a roundabout benefit for someone involved in parkour. For example, let's say you've gone through starting strength as recommended by several folks here, and have progressed to the point where you are benching/military pressing/dipping frequently and with lots of weight. To continue progress, or just maintain joint health, it can be beneficial to add in curls to provide muscular balance around the elbow.
in my personal experience, i've had full blown elbow tendinitis as well as little aches now and again due to elbow extension work, and i've always been able to alleviate/improve things but dropping in a set of curls to get some blood flowing into the joint.