"Most of the people who join us suffer from chronic diseases and need a certain amount of exercise," says one 65-year-old man, who suffers from arthritis in his shoulders. "It isn't just for my shoulders - it also helps me recover from pain in my lower back and legs."

Taichi Tennis                                           Swordplay

The elderly often prefer exercising in a public park to using treadmills in a gym because fitness centers are usually too expensive for them.

Nordic walking was such a hit at Ditan Park that the State General Administration of Sport helped expand it and groups can now also be found at Yuandadu Relics Park on Fridays and Beihai Park on Sundays.

Soft-strength ball, or taichi tennis, originated in Beijing and is popular among the elderly for developing their flexibility. It is played using soft, yet powerful, flowing movements generated from the waist and legs to control the ball with skill and subtlety. The smooth flowing action offers a safe workout.

Over in the northwestern corner of the park is an altogether more sedate atmosphere, a spot to enjoy the scenery and admire the work of numerous ground calligraphers. Some happily paint in solitude while others command an audience of passer-bys.

Ground Calligraphy                                Mulan Quan

Liu Yuxi, 77, has been doing ground calligraphy for 11 years and, unless it's raining, can be seen practicing his skills every day.

His slow, peaceful moves seem to demand little of his body but he insists that is not the case, saying it offers a physical as well as spiritual workout. "It strengthens your wrist, upper legs and knees," he insists. Liu carefully draws a separate character in each square, using a large brush dipped in a bucket of water. He moves up and down each row and starts over when his strokes evaporate.

"In the past, we only had a mop to write characters," he says. "People found it difficult to write with such a heavily soaked mop so the long sponge brush was invented and is now widespread in Beijing parks."