Your position on your bike is a crucial element of having a successful triathlon. Because triathletes need to hop off their bikes and start running, it's more important for us to make sure we are exhausting some muscles more than others, and saving as much of our running muscles for the run as possible.
Additionally, we can put damaging stress on our backs and cause strains and injuries that carry over to the other sports, just from sitting in the saddle wrong.
If you are on a bike that is the wrong size, or not adjusted to your properly, nothing you do with your posture will prevent these problems. However, even if your bike fit is perfect, you may have habits regarding pelvis position or how you put weight on your seat, arms and pedals that will make you less successful as a triathlete.
The following video will help you make adjustments to correct or prevent these problems.