He used to enjoy doing push-ups in his 20s but did not continue as he grew older.
The fish vendor from a local market said he achieved his “incredible” body by going to a public park.
Exercise equipment is installed widely in China’s public parks and residential compounds for people to use for free.
Zhou said he exercises at the park at lunch time every weekday, except when it is raining.
He was surprised when he discovered his “talent” for fitness training and found it relatively easy.
Zhou said he does not need to try hard to accomplish difficult moves such as so-called planche push-ups. He also finds it easy to do the type of pull-ups, which were invented by the US street workout master Hannibal For King.
Some young people have tried to copy his success, but failed.
Zhou said he seems to have naturally powerful arms and fingers.
“It is incredible that I can achieve such a level at my age,” Zhou said.
He did not specify his diet plan, but an online observer said he “must have eaten a lot of protein”, which is known as the building block for muscle growth and strength.
“He is 50 but has got a body like a 20-year-old young man,” one person said on Weibo.
“He proves that we do not need to go to a gym to be fit. Even a park works as long as you have the will,” another said.
“Middle-aged people are youthful and vibrant. Young people are weak and useless,” said a third.
Social media is constantly amazed by middle-aged and elderly people with good fitness levels.
Last year, a 78-year-old grandmother from northern China’s Tianjin municipality went viral. The woman, surnamed Bai, started working out at the age of 60.
Before that she had three operations for cancer, which made her realise the importance of health and fitness.
In 2018, a 53-year-old man took only six months to change his beer belly into six-pack abs. He used to lead an unhealthy life and once fell over in the middle of the road. He started jogging shortly after that, followed by training in the gym.
In 2016, a 94-year-old grandfather from southern China’s Guangdong province was still going to the gym for one hour every day.
The man, surnamed Shen, could do 10 pull-ups at a time.
He said he worked out to extend his life, and preferred the gym over square dancing or tai chi that are popular among elderly people because “they are too mild”.