Advice on Arm Extension Machine Needed.

[RSutton84]

Well I was on the arm extension machine today and I noticed when I started getting to failure my left shoulder fealt like it was doing most of the work and then I started to feel pain in it, Shortly after I felt a sort of crack feeling ( no I did not sprain anything ) but it was just weird to me because during that exercise I was under the impression that the exercise it is supposed to be working on the Biceps. (That machine basically has you sit on it and you grab the two bars above the shoulders and it rotates down from the top of your side to the bottom in a half moon motion.

My question is, what am I doing wrong or is this normal to feel as though my shoulders are doing most of the work due to the soreness indifference between them and my biceps or other arm muscles. I am new to this so be nice in responses please. I am Looking for advice to make sure I am not doing anything wrong in my form for how I am approaching the machine, due to not wanting to injure myself due to lack of knowledge.

[abendm]

Well I was on the arm extension machine today and I noticed when I started getting to failure my left shoulder fealt like it was doing most of the work and then I started to feel pain in it, Shortly after I felt a sort of crack feeling ( no I did not sprain anything ) but it was just weird to me because during that exercise I was under the impression that the exercise it is supposed to be working on the Biceps. (That machine basically has you sit on it and you grab the two bars above the shoulders and it rotates down from the top of your side to the bottom in a half moon motion.

My question is, what am I doing wrong or is this normal to feel as though my shoulders are doing most of the work due to the soreness indifference between them and my biceps or other arm muscles. I am new to this so be nice in responses please. I am Looking for advice to make sure I am not doing anything wrong in my form for how I am approaching the machine, due to not wanting to injure myself due to lack of knowledge.

Solution... don't use machines... read stickies: specifically the SS faq sticky.

To address your actual question... no, that's not normal. An "arm extension" machine should be working tricepts, not bicepts. If you don't keep your elbow on the pad, I guess it's possible to be using shoulder (likely rotator cuff) muscles to do the work as those machines usually put your shoulder in internal rotation.

But back to my original point. At your height, weight, and post count: the best advice would be to start out on one of the beginners programs outlined in the stickies at the top of this forum, where the vast majority of your lifting comrpises squats, deadlifts, benching, rowing, and overhead pressing.