Let me start off by making a crucial point. Unless you are a powerlifter (someone who trains purely to get stronger, as opposed to bodybuilders who train to actually get more muscular), you should not give a damn about how much weight you can bench. The question, "how much do you bench?", is one that is often asked. Forget about your ego, and understand that you can bench much less than your friend, yet have a much better developed chest than them. The difference between maximising your chest growth potential, and failing to do so, lies in HOW you perform the flat bench press.
The Barbell Bench Press
- Lay down on the bench, with your feet firmly on the floor
- Squeeze your shoulder blades together (imagine there is a pencil between them, and you are trying to "pinch" it), and keep them tight like this for the entire lift
- Push your chest upwards, imagining you want to touch the ceiling with it (even though this is impossible) and maintain a very slight arch in your lower back
- Grab the bar with a grip that is shoulder-width apart (no wider, because you put unnecessary strain on your shoulders). Your elbows should not flare out perpendicularly. They should be at a 45 degree angle from your torso if you were to view yourself from a birds eye view.
- Inhale while slowly lowering the bar till it touches the lower part of your chest (this should take at least 3 seconds)
- Pause at the bottom for a second, then exhale and push the bar upwards explosively almost all the way to the top, but not quite (never lock out your elbow joints). Imagine in your head, that you are pushing yourself "down through the bench" instead of pushing the bar upwards. This tip helps some people activate their chest muscles better.
- You can lift more weight, which can cause more muscle breakdown and subsequent growth (only if your technique is perfect)
- You are more likely to get an injury such as torn pec or rotator cuff
- You may develop an asymmetrical chest without realising it, if one of your pecs is stronger
- You will probably not achieve optimal chest growth, as your shoulders will also be reasonably involved in the lift, regardless of how perfect your technique is
- Need a spotter if going to failure
The Dumbbell Bench Press
- Exactly the same as the barbell bench press in terms of technique, except:
- To get in position, start with the dumbbells rested on your knees, and as you lean back onto the bench "kick up" the dumbbells with your knees to help get them up to that starting position
- Don't lower the dumbbells below the plane of your body, as you will put unnecessary strain on your shoulders
- Feel free to bring your hands closer together at the top for a better contraction
- Symmetrical chest development since each pec is working separately
- Less chance of injury since your arms are not "fixed" to the bar, and can move in a more natural motion (also, your stabilizer muscles will be worked more effectively from having to balance the weights, which will contribute to injury prevention in the future)
- Maximal chest involvement due to a greater range of motion (better stretch and contraction)
- Don't need a spotter (just put the dumbbells on the floor to your sides when you fail)
- You can't use as much weight as with a barbell. The exercise is simply more difficult.
As you can see from the advantages and disadvantages outlined above, the dumbbell bench press is a better choice for those who care about the appearance of their chest. This doesn't mean that the barbell bench press is useless for bodybuilding, but in my personal opinion the risks are not worth the reward, and the same (if not better) results can be achieved using dumbbells.