I used to coach a lad who had it in his head he could never go hard from the off in XC races. We designed a few sessions that had him warm ups as normal, then stand around just chilling (litterally getting cold ish) as you do at the start of a race. He then had to go flat out from the start up a 10min climb, into a tech descent and then some fireroad -all about 20 mins.
After a few times doing these come race day he found it was easier than the training. Got a massive mental boost then started attacking from the off, no one knew what was going on as he was renouned for being a sitter. Resulted in some nice medals at the end of the season, so win!
Maybe just try to step outside what you do normally, change it, if it sucks, its probably what you need to be doing. We do like to stay at rest until an external body acts uppon us. Good old Newton.
