Slow start during meet up race

So I am racing a meet up ride, at the start people are getting a head start by about 5 seconds, by the time I am catching half the group I am toast. How do I avoid taking off last? I am standing and sprinting at 10 seconds to go and yet and not taking off very fast. What are these other guys doing to take off so fast?

Meet ups aren’t designed for races. People shouldn’t use them for races, if they do they should wait for a group to form and then start the race.

10 seconds is too long. 3 seconds max before set off is when you put the power in for a race. In a meet up sometimes people get let off at different times. And let’s not forget everyone is lined up along the road (giving people at the front less distance to ride). I’m not sure if the starting position is based on when you go to the meet up or is the order In Which people accepted the meet up, or alphabetical order etc.

Are the other people lighter than you? Or stronger?