Four more implicated in T-Mobile ring

Blood doping boosts available oxygen allowing athletes to do more work. While EPO use can be detected, adding back one's own blood is still difficult to catch.

Blood doping boosts available oxygen allowing athletes to do more work. While EPO use can be detected, adding back one's own blood is still difficult to catch. (Image credit: AFP)

The investigation into two former Freiburg University Clinic doctors at the centre of controversy surrounding alleged doping of T-Mobile riders has been extended to include four more practitioners, according to sports agency SID.