Here's an article from IM that has helped both me and my freinds a great deal.
http://ironmagazine.com/go/benchpressArchive: How To Do The Perfect Bench Press Rep
Posted on Saturday, November 01 @ 12:00:00 MST
Written by:
Nick_Nilsson
Learn the secrets to bench press form that will send your strength and muscle development through the roof! The Flat Barbell Bench Press is one of the most popular exercises in the gym, yet how many people know the most important techniques for maximizing strength and power during each rep?
In this article, you will find solid tips without the fluff. These tips will instantly help you to improve your bench press RIGHT NOW! You don't need any special equipment to use these techniques, just a willingness to learn.
Several of these tips will be further demonstrated with pictures (there will be a link to this picture page at the end of the article).
1. The perfect bench press rep starts without any weight on the bar. Why no weight? The first thing you need to do is determine your proper hand spacing on the bar.
Lie down on the bench and unrack the bar as you normally would. Lower the bar to your chest and have a partner take note of the orientation of your forearms. For optimal power, your forearms should be as close to vertical at the bottom of the rep as possible. Adjust your grip accordingly and take note of where your hands are in relation to the smooth rings on the Olympic bar.
The reason for this is simple: if your hands are placed wider, some of your pushing power will be expended pushing outwards rather than upwards. If your hands are placed closer, power is expended pushing inwards. When your forearms are vertical, the vast majority of your power goes to pushing the bar directly up.
2. Now that you have your grip properly positioned, put some weight on the bar. Lay back on the bench and plant your feet firmly on the floor. Your knees should bent at about an 80 degree angle (I will explain the reason for this later - this tip has an accompanying picture). DO NOT place your feet up on the bench. You will lose stability and potential power by doing this.
Place your hands on the bar in the grip width that you determined previously.
A technique that I like to use to lock my shoulders into the position for maximum strength and stability is as follows:
Instead of placing your palms on the bottom of the bar, place them on the back of the bar (this tip also has an accompanying picture).
Now, without removing your grip, rotate the bar down so that your palms are now directly under the bar. This has the effect of placing your shoulders into their most stable and strong position. It will almost feel as though you are "locking down" your shoulders.
As you are rotating the bar and locking down your shoulders, lift your torso slightly off the bench and force your shoulder blades together tightly underneath your torso.
This will force your shoulders back and puff your chest out, placing the pectorals in a position where they have a more effective line of pull. It also has the added bonus of making your torso thicker, reducing the distance you need to press the weight.
Keep your shoulder blades squeezed tightly behind you for the duration of the set.
3. Remove the bar from the racks and tighten up the muscles of your torso. Begin lowering the bar under complete control to a point at the bottom of your sternum (about even with the bottom of your sternum, a.k.a. the breastbone). Imagine as though your muscles are springs storing up all the energy of the weight lowering and getting ready to explode it all back out. Inhale as you lower the bar and feel it tightening up your chest.
Lightly touch the weight to your chest. DO NOT bounce the weight off your chest! This can cause injury in the form of cracked ribs or even snapping the tip of the sternum (a little bony protrusion known as the Xiphoid Process). It also diffuses the tension you've built up in the pectorals, reducing the effectiveness of the exercise for building strength and muscle mass.
4. As you start to change the direction of the bar and begin the press up, drive with the legs. This is a technique that most trainers do not know about. It's strange to think about it but your leg power can actually help you bench press more weight!
This technique should be practiced with an empty bar before attempting it during a regular set. Start by planting your feet flat on the floor with your knees bent about 80 degrees. This angle is very important as it is what allows you to push with your legs.
Lower the empty bar to your chest. The moment you start to push the bar back up, push hard with your legs as though you are trying to slide your body up the bench.
With an empty bar you probably will be able to slide yourself up the bench. When you have a loaded bar, however, the weight will keep you from sliding and the pushing power from your legs will get transferred through your body and into pushing the bar up.
This is what's known as driving with your legs. It can really beef up your power out of the bottom of the rep.
5. Exhale forcefully through pursed lips as you continue to push the weight up. This will help maintain your torso stability better than simply exhaling all at once.
Keep your feet firmly planted on the floor even if you start to struggle with the weight. The moment you lift your feet off the floor, you break your base of power and the odds of you completing the lift diminish greatly.
If you have a tendency to shift your feet around, try placing 2.5 pound plates on your feet. This is not to weigh your feet down but to help you be more aware of what is happening with your feet. If a plate falls, your foot has moved. Strive to keep those plates in place.
The bar should follow a slight backwards arc as you press it up, moving from your lower rib cage to over your face at the end of the rep.
Be aware of your sticking point and try to drive the bar through it rather than letting the bar slow down as you come up to it. There are many training methods for working on sticking points but those are beyond the scope of this article.
6. Power the weight up to lockout. You have just completed the perfect rep! Now do it again!!
Using these techniques can add immediate poundage to your bench press. Your chest will thank you for it!
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I think you've already determined what's wrong 
