Should your arms be moving in a 100% arc motion while doing tricep exercises?

[Rock Lee]

I'm worried I might be using bad form and too much weight. When I do things like skulls and pressdowns towards the end of my set my motion seems to turn into more of a pressing movement then an arching one; is this normal or am I using too much weight.

 

[jetset]

Too much weight. Another way to tell is if you are feeling the movement in your chest or shoulders. lighten it up alittle and focus on your form.

 

[azgymrat]

Pushing the limit on weight isn't bad but on skulls and pressdowns it can be hard on the elbows. Maybe try close grip bench and reverse grip bench and only one isolation movement. Done with chest you may be able to get away with counting them as a chest movement too and kill 2 birds with one stone.