It's probably okay. Do a warm up for 3-5 minutes, then stretch them before doing your regular cardio, it will help. They might feel sore initially, but after the muscles warm up, they should feel better. If they don't feel better, and start hurting or cramping more, stop and rest for the day.
1/1/2013- 95 pounds to lose... wow
12/18/13- Halfway there!
| Pounds lost: 46.0