I get it, not everyone can afford a personal trainer but we do all have access to the internet and believe it or not knowing what you are doing (or going to do) in the gym is far more important that just going there and putting time in on "whatever." This is especially true if you just grab some weights or get on a machine with no really idea about what you are doing. These two exercises are something that I see people do wrong at the gym constantly.
In a perfect world I would approach these people and tell them they are doing it wrong but I am not that kind of person and I really don't want to embarrass people at the gym. These two things are dead giveaways that you (if you are doing them this way) don't really understand the intent of the exercise and are not really benefiting the muscle groups that the exercise was intended for in the first place. In these instances, the person in question - and it might be you - could benefit by having proper form instead of lifting so much weight.
Form is ALWAYS more important that how much weight you are lifting, remember that.
Moving your arms too much on curls
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First off, abandon all hope of looking like Arnold. That is unless you are currently 16 years old and plan on devoting 4 hours a day to exercise, have a very strict diet, and are not opposed to steroids.
For the rest of us, we probably just want a bit of tone in our arms and I think this is why so many people go for high weights that they aren't really capable of lifting. For any sort of standing curl, keeping all but your forarms isolated and in the same position is absolutely paramound.
If you ever find yourself in a position where the weight you have chosen is too heavy for you to get to the upper position without swinging your arms then the answer is simple: Step back on the weight a bit because when you do this sort of cheat movement you are transferring the muscle use to your shoulders and back (which are considerably stronger than your biceps) and not only that, it is in an odd angle so you could hurt yourself. Basically, just stop trying to be a hero and lift what you are capable of for slow, controller reps. You'll look like less of an idiot and will see better results.
Leg raises that turn into "leg kicks"
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When I'm in my gym, it's not like I am trying seek people out that are doing exercises wrong but in my particular gym I think more often than not people are using this machine incorrectly. It is understandable why it is popular because situps suck and this kind of mixes things up a bit. I also find that I feel a burn using this method a lot faster. I think most people agree with this notion. Howver, this doesn't mean that everyone has any idea how to do it properly.
See the guy in the picture up there, he can probably hold his legs in that position for a half a second, or probably even longer... This is the entire idea behind this exercise and at all times your back should remain on the backrest. You should be lifting your legs in a slow, and controlled motion. If you can't pull this off the immediate reaction of most people is to "kick" their legs up in order to get through a rep. Once again, people need to focus on reps less, and focus more on form. If you can't control the motion all the way through then it is better to do fewer reps and control them.
If you are experiencing difficulty with your legs straight it is amazing how much easier it is to do it with your knees bent. Some guys at the gym consider this "girly style" and that is just stupid. Much like people that do pushups incorrectly in the chase of being more manly, you are doing them wrong and potentially hurting other parts of your body by doing the "kick up" method. In this particular instance you are potentially damaging your lower back, which is one of the worst things you can wear out if you plan on ever getting older. Trust me, I'm getting up there in years and I still have a recurring injury from doing shrugs incorrectly and I will likely be suffering from that for the rest of my life because I was a numb nuts 15 years ago.
A good rule of thumb at the gym is to go there with a plan. There are tons of resources available for free on the internet so rather than go there knowing nothing and swinging your arms and legs around like a madman, you could actually be hurting yourself less and getting much better results.
Take a little time to know what you are doing and if you are doing it wrong, admit that it is time to step the weight back. It might be a little humbling, but if you ask any professional in this field they all say the same thing: Form is the most important part of weight training.
you mean to tell me that I can't look like Arnie by going to the gym a few times a week and eating whatever i want? well that just ruins my whole world buddy! In all seriousness these are good tips and yes, i see people doing the wrong stuff you describe on a regular basis.
I know you speak in jest but even most gym junkies can never look like Arnie with years of dedication. Some people are just wired different. I think if Arnold were being honest he would tell us that he did a lot of things that he probably advocates against these days... which is odd because if he hadn't done those things we wouldn't know who the hell he is today!
Probably not the best message to be sending to people though.
I went to a gym once that had an arm-blaster and what an amazing piece of equipment that was. It was also very popular and constantly covered with elbow sweat. I don't know why people can't clean those things off after using them. So gross.
this is news to me. I always thought that cheating on the "up" with a heavy bicep curl and then slowly doing the "down" with proper form was a good way to really use the hell out of the muscle? Is this not so?