When it comes to elite artistic gymnastics, most female competitors begin the sport at before the age of five and train around 40 hours a week, pushing their strength and flexibility to the limits, at times defying anatomy and biology to stick their routines.
Naturally, that level of physical and psychological stress can have an effect on a growing body, with most elite female competitors retiring from the sport in their early twenties.
Of course, there are exceptions like Oksana Chusovitina.
But what happens once a female gymnast hangs her leotard for good? What happens to the body as the years go by, as they complete puberty, maybe bear children, and go through menopause?
Injuries can emerge decades later
"Stress fractures are common amongst former gymnastics," says Natasha Melacrinis, a physiotherapist from the Sydney Sports Medicine Centre and former elite sports aerobics competitor.
Many female gymnasts have low bone density issues. Decades of extreme physical exercises can lead to a later onset of puberty and therefore a lower level of oestrogen being released in the body. As a result, "bones play catch up" to fast-growing muscles.
"Oestrogen in essential to bone development," says endocrinologist Dr Monique Costin from Northern Sydney Endocrine Centre.
These low bone density issues come to the fore later in life as muscles weaken, or lose their "competition-ready" form, and can no longer compensate for weaker bones.
Also as the body adjusts from a high-intensity training to a more relaxed exercise routine, stress fractures can come about. The adjustment process can take a lifetime for some gymnasts.
"Each person is different," says Ms Melacrinis, "but for some gymnasts, the body gets used to the high stress of training and needs it to remain stable."
A greater risk of osteoarthritis and chronic pain
Gymnasts are also at a higher risk of osteoporosis and osteoarthritis, says Ms Melacrinis.
"Mostly in their wrists, knees, back, and ankles, where the impact of hitting a mat is felt most," she says.
And as the body ages, or undergoes further stresses - like pregnancy, for example - some can face even more stress fractures or more severe chronic pain.
Chronic pain, particularly back pain, is something gymnasts experience, though it can usually be managed through ongoing rehabilitation and physiotherapy.
"But most former gymnasts keep up some kind of training routine for the rest of their lives. Their bodies tend to stay fitter and stronger than most people their age, joint and bone issues aside," says Melacrinis.
Hormonal side effects
High-intensity exercise can throw your hormones out of whack, especially if you are training during or just before the onset of puberty.
"Training that hard, nearly 40 hours a week, can result in delayed pubertal onset, particularly in young women," says Dr Costin.
Though female puberty is a multi-staged process, delayed ovulation and amenorrhea (when you don't have a period at all) are the most common effects of elite athletic training.
"The typical female body has 20 to 30 per cent of fat, and when that level of fat falls, as can be the case in elite athletes, the levels of the hormone leptin can be reduced," says Dr Costin.
Leptin signals play an important role in the start of ovulation, which in turn encourages the production and release of oestrogen, necessary for several body growth functions in young girls.
"The hypothalamus speaks to the pituitary gland which talks to the ovaries. Leptin is essential for this process."
Once a gymnast stops intense training, ovulation should resume as per normal, but if not gymnasts can look into induced puberty options, she says.
So how is it Oksana Chusovitina still competing at 41-years-old?
"I'd say it all comes down to genes, which can make a big difference on how some athletes cope with body stress and how well they recover," say Ms Melacrinis.
"She probably has had to adjust her load - or the intensity of her training - over the years. And probably has a great rehab and physio routine."