Nervous twitching - Kneeling

[Joshua]

I shot in a local match last saturday and durning the kneeling position I have some muscle movement in my left shoulder (the shoulder in which the rifle butt is placed). This does not happen in practice and it is not coming from my sling. Any suggestions?

[seemehaha]

did you stretch before the match? i find that when i get a twitch stretching usually helps.