Wrapped up from head to toe in a white bag and gently rocking from side to side, five Japanese mothers are hopeful Tokyo's latest health trend can cure their post-pregnancy aches and pains.

According to its exponents, otonamaki, which translates as "adult wrapping," was devised by a Kyoto midwife who thought replicating how children are swaddled at birth could help mothers overcome post-labor shoulder and hip pain.

The five mothers at a recent session in Tokyo lay on their backs with their knees on their chests bundled up in white cloths. Staff then helped them rock over cushions.

"It felt warm and there was this feeling with my body," said one mother who tried the 20-minute session. "I have never experienced this before so its quite hard to describe properly."

Not everyone is a fan. Chiropractor Shiro Oba was sceptical about its powers of healing and encouraged mothers with back pain to visit a physician.

"There may be cases where people with asthma may find it easier to breath (in that position), but once the cloth is off it's the same thing," Oba said. "But apart from that, I just can't think of how people can benefit from this even as a form of reflexology or exercise."