Leg muscle pain when running at altitude

Question
My son has been running daily for 2 years in Colorado Springs.    He also runs daily when he comes home (for two to three weeks) to sea level  (1.5 to 5 miles both places).  He says he can run forever without his leg muscles (ankle to thigh) hurting when he's at sea level.  However, when he's at 6000 ft. his legs really start to hurt even after 3 months at altitude.   He is also having a hard time decreasing his 1.5 mile time.  He needs to be at about 10:30 but sticks at 11:45. His time is the worst when he runs on the indoor track. He's 6'3 and about 180.  Any suggestions?  Thanks!

Answer
Hi Christy
The altitude should not make any difference.He is probably pushing to hard and not including some easy days.Also the terrain maybe might be adding the stress.I don't know his schedule etc.so it is hard to pin point.The altitude does not have anything to do with it.It is all in his training and diet.If you come down from altitude it will be a much more relaxed run,but if you hammer it you will feel it at sea level also,that is for sure.As far as reducing his time, it requires a program that incorporates a lot of different workloads.Just going out and running is not going to produce the kind of results he is looking for.If you have other questions just get in touch christy.

All the best
John