Sport is big business. And there is a danger that commercial pressures might drive competitors to a "win at all costs" mentality.

So it is reassuring to see a sporting giant exercise its influence against doping.  It emerged this weekend that Adidas is thinking of cutting ties with the IAAF over the current doping scandal.  

Adidas says that it has a clear-anti doping policy in place - it will immediately terminate the contract with athletes who are found guilty of doping.   

The aim is commendable, but being found guilty of doping is a high bar.  Athlete endorsement contracts and governing body rules often include sanctions for the lesser sin of bringing the sport into disrepute. 

And Adidas is still on the partner list for Russia 2018 - despite around 30 current and former FIFA officials and associates facing corruption charges in the USA last year.

At least, Adidas' position on the IAAF tie-up highlights the need for commercial partners to consider carefully whether needs are best served by staying in to help clean up, or getting out to make the point.