Sydney  - With Australians now buying more bicycles than cars, you would think that cycling to work would be accelerating at a similar rate.

It's not.

Of the commuting done in Sydney, only around 1 per cent is by bike. In comparison, in some Scandinavian cities the proportion of those cycling to work is around one-third.

Statistician and avid cyclist Dorothy Robinson has pondered this conundrum. She reckons that repealing laws passed in the 1990s requiring cyclists to wear helmets would get bikes out of garages and onto the roads.

Writing in the British medical journal BMJ, Robinson noted that in the two years after the law was passed, bicycle use was halved.

"The overall effect is bad, with fewer people getting fit by bicycling since the laws came in, and more driving," she said.

Cyclists find the laws a bother because helmets are expensive, easily stolen, mess up your hair and are of marginal help in reducing injuries in traffic accidents. No one looks better in a helmet.

Robinson is in good company: Bill Curnow, head of a cyclists lobby group in Canberra, argues that helmets can actually increase injuries because they increase the rotation of the head in accidents.

Curnow notes that whenever laws are brought in requiring helmets, the incidence of cycling declines - and when that happens, health suffers. (dpa)