14 year-old female's legs always feel weak?

14 year-old female's legs always feel weak?

We have no idea why either. They always feel tired and weak, even when she has done nothing to strain them. The fatigue feeling gets worse in cold weather. Her father has artritis, but isn't she too young for that? Anyone have any idea what might be going on?

---

Could be a muscle strain.

---

if you hurt your low back your legs can feel weak from an injury to a low back