The head of American anti-doping agency USADA says the rules have failed to keep pace with science and that not every athlete who tests positive as the result of a contaminated supplement deserves to spend four years out of their sport.

Travis Tygart, who was a key figure in the investigations into BALCO and cyclist Lance Armstrong, believes blanket bans for otherwise clean athletes who find themselves returning inadvertent low-level positives should be dealt with on a case-by-case basis, not a “gotcha” style of policing that hands out hardline sanctions more suitable for systematic doping.

Many of the recent inadvertent positives in the US have involved the class of substance known as SARMs (selective androgen receptor modulators), which are increasingly finding their way into even reputable dietary and vitamin supplements. One of those is the anti-steroidal anabolic agent LGD-4033, which is what was found in the samples returned by Australian swimmer Shayna Jack.

The 20-year-old faces a four-year ban should ASADA impose the maximum penalty. International anti-doping bodies have shown little mercy in many cases, but an influx of positives has prompted USADA to lead the discussion about sanctions that closer fit the crime.

Read The Sydney Morning Herald