What's stopping you?

I have been training to participate in an adventure race and will also do a marathon this year.  I have talked with a few people about these events and just talked with a Soldier yesterday who is an ultra marathon runner.  He told me a story of how he got started and its amazing and inspiring.  He was in a fire fight in Iraq when his vehicle hit a large hole and bounced him up in the air causing a bunch of heavy ammo cans to fall on him and his foot.  One of his feet was moved 180 degrees in the wrong direction and subsequently broke his foot, leg and tore the tendons and ligament's in his foot.  Most of the bones in his foot was broken and spent 8 months in care to get rehabilitated for this injury.  Fearing he would be kicked out of the Army he did everything he could do to recover quickly and stay motivated.  He did this with his wife and family, also with the support of a running group he was in at his local YMCA.  The doctors told him they was thinking of amputating his leg and if they didn't he would never run again and would most likely walk with a cain or wheel chair the rest of his life!  Through his support of friends and family he is now an ultra marathon runner doing very well.  They did several surgeries on his leg/foot to get it to where he is today but he can't move his foot left or right at all.  They also took a portion of his calf muscle!  My question to you is what is stopping you from training to achieve your goals?