In the countryside, a normal man like my dad can carry about 40-50 kilograms and walk about 1 mile.
I was able to carry about 30 kilograms when I was about 16 years old. After spending a few years in schools, I never can do better. My dad was very kind to me and he always asked me not to carry heavy dan zi (burden). My shoulder can not bear heavy load as before since I don't much labor work.