Q: I have been doing leg curls at 50 pounds, 3 sets,8 reps. I cant seem to get beyond 50 pounds even though I've been doing this for 6 weeks.

A: Well if the next weight you can select on the machine is 60 pounds or even 55 pounds, then it's certainly understandable why you're having trouble. It would be a 10-20% increase from the current weight you're lifting, which is actually a huge jump.

Assuming that the next weight you can select is 60, I would try to scale this hurdle in smaller steps, as approximately following:

Week 1: 60 x 4, 60 x 3, 50 x 8

Week 2: 60 x 5, 60 x 4, 50 x 8

Week 3: 60 x 6, 60 x 5, 60 x 3

Week 4: 60 x 7, 60 x 6, 60 x 4

Week 5: 60 x 8, 60 x 7, 60 x 5

Week 6: 60 x 8, 60 x 8, 60 x 6

Week 7: 60 x 8, 60 x 8, 60 x 8

So it'll take you a few weeks, but in small increments you'll get to doing 3 sets of 8 reps with 60 pounds! Don't worry about following this sequence exactly or about it taking you longer than 7 weeks -- just take away the lesson about making small increments which over time will add up to big progress!