Exercise Induced Collapse (EIC)

Weakness starts in the rear limbs but then progresses rapidly to the forelimbs, resulting in a generally weak, wobbly gait. Dogs ultimately collapse and are unable to continue exercising. After 10 to 20 minutes of rest, however, they return to normal.

A few affected dogs have died during exercise or while resting after an episode of exercise-induced collapse. Affected dogs are less likely to collapse while swimming than when being exercised on land. Actual ambient temperature does not seem to be a critical factor contributing to collapse, but if the temperature is much warmer than what the dog is accustomed to, collapse may be more likely.

Symptomatic dogs are rarely able to continue training or competition. It seems that if affected dogs are removed from training and not exercised excessively the condition will not progress and they will be fine as pets. Littermates and other related dogs are often affected, but the genetics of the condition have not been well established. 

The first clinical symptom observed is usually a rocking or forced gait. The rear limbs then become weak and unable to support weight. Many affected dogs will continue to run while dragging their back legs. Some of the dogs appear to be incoordinate, especially in the rear limbs, with a wide-based, long, loose stride rather than the short, stiff strides typically associated with muscle weakness. In some dogs the rear limb collapse progresses to forelimb weakness and occasionally to a total inability to move. Some dogs appear to have a loss of balance and may fall over, particularly as they recover from complete collapse. Most collapsed dogs are totally conscious and alert, still trying to run and retrieve but as many as 25% of affected dogs will appear stunned or disoriented during the episode.