HONG KONG (AFP) - High up in one of Hong Kong's ubiquitous skyscrapers a group of women are being put through their paces, straining against the weight of a novel training accessory - their children.
Dubbed "Mumba", these exercise classes are a new twist on the baby-wearing trend gripping mothers in the city.
Once the preserve of traditional communities, the art of wrapping a baby across a caregiver's body so it can be carried during daily activities is being taken up by modern parents.
In Hong Kong, where narrow hilly streets and unforgiving urban landscape often render strollers and prams useless - many frustrated parents are now going back to basics out of necessity.
Proving the old adage, invention has followed. Mumba fitness, baby-wearing bellydance, ballet, yoga and pilates classes, and even suspension training (TRX) classes have sprung up in recent months - all allowing parents to exercise while their baby is strapped to them in a carrier.
"There is huge demand from mums who wanted to get back in shape and to get strong again after the challenges of labour, but who also didn't want to leave their young babies behind while they spent time exercising," explains Ms Ifat Hindes, co-founder of Mumba Fitness.
"We have combined different types of exercise including yoga, dance, TRX, and pilates, and the bonus is that you are using your baby for weight training," she says.
"There's no need for expensive gadgets - it's just you and your baby, with other parents, being guided by a professional. You know everyone is in the same boat. Hong Kong can be a difficult and unwelcoming city for new mothers."
While in many cities frazzled parents can soothe their baby - and stretch their legs - by strolling through the park with the pram, Hong Kong's high-rise living and unwieldy streets can leave many here feeling trapped and lonely in relatively small apartments.
New mother Angela Gou explains: "I was looking for a way to get out and meet other mums. I always want to exercise but it's hard to leave the baby at home. So these sessions solve the problem. Plus my baby likes it and thinks we're playing a game."
Most baby-wearing exercise programmes recommend infants are three months or older to take part to ensure adequate neck control, and check positioning to ensure babies hips are protected.
Chartered physiotherapist Helen Binge, who runs paediatric firm Physiobaby, told AFP: "The growing trend to exercise whilst baby-wearing is fine, as long as the baby sling is very supportive, and the activity level of the baby wearer is not too vigorous."
From structured types for sport to traditional woven cloth style, there is now a baby-wearing option for every occasion.
"Carriers have been used across cultures for thousands of years, but, like breastfeeding, went out of 'vogue' for a long period as people moved toward a more product-driven approach toward caring for small babies," says Ms Trish Kelly who co-founded Hong Kong's Babywearing group.
She adds that renewed interest in natural birth and breastfeeding has meant traditional approaches to child-rearing are back in fashion.
"But for Hong Kong I think it comes down to practicality. Moms like what works. Baby-wearing is a practical way of getting around. It is notoriously wheelchair and stroller unfriendly - I feel like every ramp has a set of stairs at the end."
Retailers and fitness services in the city have picked up on this desire for a practical solution.
Ms Mey Jen, director of Oasis Dance Centre, adapted her traditional belly-dancing class to incorporate baby-wearing after requests from mothers desperate to keep up with their hobby once their children were born.
She says: "The mothers want to belly-dance and they want to be with their babies at the same time. The little ones react very naturally to the beats and the movement. Often the babies become very calm and fall asleep."
Hong Kong retailer Bumps to Babes has seen carrier sales jump by 9 per cent in 2015. Director Katrin Walker comments: "Virtually every new parent who comes into the store has it on their list and we highly recommend them. Parents that think a pushchair is the only thing they need invariably come back within the first month to buy one anyway."
Ms Victoria Chuard who runs local boutique Petit Tippi adds demand for activewear wraps is rising.
"Since we began selling the Wrapsody Duo - which is perfect for exercise, swimming, even showering if you can't put your baby down and desperately need one, as well as normal use - we have seen a 200 per cent increase in sales," she explains.
Brands such as Ergo, which has a carrier that allows the baby to be carried on the hip, on the front or at the back, are now as well known to parents as big stroller names such as Bugaboo and Maclaren in the city.
Mother-of-two Kelly says: "I have three high-end strollers that have sat mostly unused since I began wearing. It's simplified things."