My problem with the Australian study was the failure to actually prove a link.
One of their findings was that increased funding of cycling infrastructure "accelerated the decline in head injuries", suggesting that helmet use alone is not responsible for any decrease in head injuries
There is also the claim that cyclist numbers are increasing - this may well be true especially if infrastructure (as suggested by the authors) is making cycling a safer activity. However the word
increasing is subtle, numbers have increased, but has the decline been reversed?
Noting the bias of the authors,
this work suggests that in at least some of the states that the number of cyclists has not risen at the same rate as th population. Simply there is still a lower uptake, and in many states this is significant.
As for arms.... the theory is that if the number of cyclist increased then so would the number of injuries. Hence by looking at arm injuries they reflected the number of accidents and that they would exactly mirror the head injury rate. As head injuries have decreased and arm injuries have not, helmets must work!
This totally ignores the difference in cycling behaviour. With increased segregation, it is entirely possible that the nature of cycling has changed. The authors note (and then refuse to consider) that cycling infrastructure had a greater effect on head injury reduction than compulsion.
Could it be simply because the cyclists are simply experiencing different accidents?
Falling on a cycle track - you put your arm out to break your fall and it becomes injured, at slower speeds and with no vehicular traffic involved it may be more simply that heads are not coming into contact that explains the difference?