Gastoric Ham Raises. I'm sure your gym doesn't have the machine but you can get creative. If i'm at a gym that doesn't have them i use the incline ab board. I lay it flat on the floor. You kneel on the board with your legs under the pads and just lower yourself to the ground and raise yourself back up. for the first 2 or 3 weeks you'll basically be doing negatives because it's one of the hardest exercises to do but it definitly reaks major benefits. one of the number one exercises for incresing running speed and hamstring power. the majority of pro track athletes, or any pro athlete for that matter, incorprates this into their routine. try it out, you're hammys and ass will love you for it.