There are a few different ways to stretch out your triceps, and I'd like to explain one of them to you today (my preferred one), and how to do them the RIGHT way.
Time and time again, you see people walk into the gym and start lifting weights right away.
Horrible! Sure, maybe there are people who enjoy pulling hammies and calf muscles, but my guess is that most people who don't stretch simply don't understand the importance of it - and it's something that I've stressed countless times over the years.
Let's get to it.
Before beginning your workout, stand flat against a vertical bar or something that won't move (not a wall, as you need to be able to extend your arm back).
Hold onto the bar and push your shoulder up against it.
If done correctly, this should push your triceps muscle up.
Bend your arms behind your head, pointing your elbows up toward the sky (ceiling!).
While doing this, grab your triceps with your free hand and slowly pull it back (remember to bend your knees).
Then simply straighten your knees.
Try and hold the stretched position for at least ten seconds (actually, I always like to tell people fifteen seconds: the reason I do this is because there is a tendency to let go as you near the tenth second.
If we say fifteen, then we're more assured that the stretch will last, and will be effective).
This should help you have a much better workout, with less chance of injury!