a) Increasing the force of the right leg after the fumikomi (like stepping on stairs, pulling the body up) in order to have a powerful entrance
or
b) Pulling up and forward your right knee and leg in order to reach a longer distance?
Thank you for your reply
Answer: a) is the answer for your question.
Once you launch your strike, how far you can jump in is up to how strong you kick the floor with the left foot. Pulling your body up and forwards with the right leg/knee helps to maintain and increase the power of your fomikomi.
In order to reach further, the left kick has to be strong and we have to take a big step forwards on fumikomi.