1.   But Radcliffe feels no burden about having used an altitude tent on occasion, most recently for several days before she won the world cross-country title in March.

2.   If you say an altitude tent is unfair, you have to ban people living at altitude.

3.   Moses uses an altitude tent for sleep only.

4.   These include hyperbaric chambers and altitude tents, which athletes sleep in to boost their oxygen-carrying red blood cells.

5.   These include the use of the hormone EPO and EPO gene therapy, as well as technology such as altitude tents.