Not really from pain — perhaps just weakness but it's hard to think that. I'm 5'7" and weigh 158 pounds which isn't just obese —- I've been to therapy for elders and can push with legs 100 repetitions of 85 pounds in about 6 minutes. Why won't my legs bring me up? Could it be my back? I've been to many orthos and no one can figure it out. Has anyone experienced such a thing?