Based on the context and the answer, generate a question. 

Context: I know with my full ability I will not be able to complete the full marathon without injure myself . Mentally I am ready but physically not ! It is a bad time to be out of training particularly triathlon season is beginning in next few months . So , I ' m thinking of doing a half this year ... .

Answer:

I suffered an injury last year and have n't been able to practice as much since then .



Why do n't I have my full ability to complete a full marathon this year ?