just hit as quickly as possible...........like do it in the gym or in your car if at all possible. I had one experience where I hit the muscle not more than 30 minutes after inject............the workout was mostly unaffected, but the muscle was toast for the whole week. There would have been no difference had I not worked that muscle that night...........but there was NPP in the mix so that might have had something to do with it. I'm a newb to spot injects, so I have to have some more experience with different compounds to really gauge time and effectiveness.