Strenuous exercise can destroy girls' bones

Girls who do too much exercise may be putting themselves at the same risk of crumbling bones and a weak skeleton in later life as those who slouch in front of the television and travel everywhere by car, according to research.

A study that compared teenage ballet dancers who exercised for several hours a day with musicians from a performing arts school and girls from an ordinary academic school found the ballet dancers had the lowest bone density.

Bone density is the key factor in the bone thinning disease osteoporosis. One in three women and one in 12 men suffer from the disease during their lifetime but evidence is mounting that the years between the age of 10 and 20, when the skeleton is growing, are crucial to its prevention.

Dr Nicola Keay, a research fellow at Guy's and St Thomas' Hospital, who led the research presented to a conference of the National Osteoporosis Society this month, said: "There is definite evidence that if a girl gets it right when she is young she has a better chance later on. The teenage years are crucial - after the age of 20 the bones don't do much."

Adolescence is marked by growth spurts followed by periods of consolidation when the bones fill out. Between 50 and 70 per cent of bone density is determined by genetic factors but the remainder is influenced by diet, including the level of calcium, and exercise.

Conventional advice is that weight-bearing exercise - including running and walking but not swimming - is necessary to build up the bones. Dr Keay said: "Jumping up and down is good for you. But it seemed to me worth asking how much was good for you. If you carry on doing more and more, is it bad?"

She studied the diet, level of exercise, menstruation and bone density of 87 girls aged between 11 and 16 years. One group - "self-confessed slobs" according to Dr Keay - played an occasional game of netball but otherwise spent their free time hanging around with friends or watching television.

A second group of performers, training for West End musicals in London, did daily dance classes and a third group from a ballet school spent half of each day in dance classes.

The results showed the musicians who did regular but not excessive exercise had the highest bone density - higher than either the ballet dancers or the couch potatoes.

Dr Keay said: "The ballet dancers were eating regular amounts - they were not starving - but they were expending so much energy they were not in the right balance. Their periods started late, at age 14 rather than 12 or 13 in the other girls, and were erratic. There is a big surge in bone density when the periods start and bone is still accumulating two years later, which is why it is such a crucial time." Marathon runners who have failed to maintain an adequate diet have developed the bones of 80-year-olds and sustained fractures in minor falls, Dr Keay said. Ballet dancers would benefit from extra carbohydrate in their diet and variation in their exercise regime.

"Instead of doing slow graceful movements which are good for muscle control but not for the skeleton they need to do more high-impact stuff such as aerobics. The ballet schools are taking this on board and starting aerobics classes."

She added: "There is an onus on young girls' parents and coaches to get it right. My argument is that this is what they should be focusing on."

Life and Style
ebooksA superb mix of recipes serving up the freshest of local produce in a delicious range of styles
Life and Style
ebooksFrom the lifespan of a slug to the distance to the Sun: answers to 500 questions from readers
Arts and Entertainment
Judi Dench appeared at the Hay Festival to perform excerpts from Shakespearean plays
tvJudi Dench and Hugh Bonneville join Benedict Cumberbatch in BBC Shakespeare adaptations
Arts and Entertainment
Exhibition at the Centre Pompidou in Metz - 23 May 2012
Is this how Mario Balotelli will cruise into Liverpool?
Ronahi Serhat, a PKK fighter, in the Qandil Mountains in Iraqi Kurdistan
Arts and Entertainment
Alfred Molina, left, and John Lithgow in a scene from 'Love Is Strange'
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Junior Quant Analyst - C++, Boost, Data Mining

    £25000 - £35000 per annum: Harrington Starr: Junior Quant Analyst - C++, Boost...

    Service Desk Analyst- (Desktop Support, Help desk)

    £25000 - £35000 per annum: Harrington Starr: Service Desk Analyst- (Desktop Su...

    Junior Quant Analyst (Machine Learning, SQL, Brokerage)

    £30000 - £50000 per annum: Harrington Starr: Junior Quant Analyst (Machine Lea...

    UNIX Application Support Analyst- Support, UNIX, London

    £45000 - £55000 per annum: Harrington Starr: UNIX Application Support Analyst-...

    Day In a Page

    10 best men's skincare products

    Face it: 10 best men's skincare products

    Oscar Quine cleanses, tones and moisturises to find skin-savers blokes will be proud to display on the bathroom shelf
    Middle East crisis: We know all too much about the cruelty of Isis – but all too little about who they are

    We know all too much about the cruelty of Isis – but all too little about who they are

    Now Obama has seen the next US reporter to be threatened with beheading, will he blink, asks Robert Fisk
    Neanderthals lived alongside humans for centuries, latest study shows

    Final resting place of our Neanderthal neighbours revealed

    Bones dated to 40,000 years ago show species may have died out in Belgium species co-existed
    Scottish independence: The new Scots who hold fate of the UK in their hands

    The new Scots who hold fate of the UK in their hands

    Scotland’s immigrants are as passionate about the future of their adopted nation as anyone else
    Britain's ugliest buildings: Which monstrosities should be nominated for the Dead Prize?

    Blight club: Britain's ugliest buildings

    Following the architect Cameron Sinclair's introduction of the Dead Prize, an award for ugly buildings, John Rentoul reflects on some of the biggest blots on the UK landscape
    eBay's enduring appeal: Online auction site is still the UK's most popular e-commerce retailer

    eBay's enduring appeal

    The online auction site is still the UK's most popular e-commerce site
    Culture Minister Ed Vaizey: ‘lack of ethnic minority and black faces on TV is weird’

    'Lack of ethnic minority and black faces on TV is weird'

    Culture Minister Ed Vaizey calls for immediate action to address the problem
    Artist Olafur Eliasson's latest large-scale works are inspired by the paintings of JMW Turner

    Magic circles: Artist Olafur Eliasson

    Eliasson's works will go alongside a new exhibition of JMW Turner at Tate Britain. He tells Jay Merrick why the paintings of his hero are ripe for reinvention
    Josephine Dickinson: 'A cochlear implant helped me to discover a new world of sound'

    Josephine Dickinson: 'How I discovered a new world of sound'

    After going deaf as a child, musician and poet Josephine Dickinson made do with a hearing aid for five decades. Then she had a cochlear implant - and everything changed
    Greggs Google fail: Was the bakery's response to its logo mishap a stroke of marketing genius?

    Greggs gives lesson in crisis management

    After a mishap with their logo, high street staple Greggs went viral this week. But, as Simon Usborne discovers, their social media response was anything but half baked
    Matthew McConaughey has been singing the praises of bumbags (shame he doesn't know how to wear one)

    Matthew McConaughey sings the praises of bumbags

    Shame he doesn't know how to wear one. Harriet Walker explains the dos and don'ts of fanny packs
    7 best quadcopters and drones

    Flying fun: 7 best quadcopters and drones

    From state of the art devices with stabilised cameras to mini gadgets that can soar around the home, we take some flying objects for a spin
    Joey Barton: ‘I’ve been guilty of getting a bit irate’

    Joey Barton: ‘I’ve been guilty of getting a bit irate’

    The midfielder returned to the Premier League after two years last weekend. The controversial character had much to discuss after his first game back
    Andy Murray: I quit while I’m ahead too often

    Andy Murray: I quit while I’m ahead too often

    British No 1 knows his consistency as well as his fitness needs working on as he prepares for the US Open after a ‘very, very up and down’ year
    Ferguson: In the heartlands of America, a descent into madness

    A descent into madness in America's heartlands

    David Usborne arrived in Ferguson, Missouri to be greeted by a scene more redolent of Gaza and Afghanistan