Ed Yong summarizes a new study:
The simple act of comparing yourself against someone else can stoke the fires of competition. When there are just a few competitors around, making such comparisons is easy but they become more difficult when challengers are plentiful. As a result, the presence of extra contenders, far from spurring us on by adding extra challenge, can actually have the opposite effect.
This appears to hold true even when the chances of success remain the same. Join a smaller gym.
(Hat tip: Vaughan)