У вашего броузера проблема в совместимости с HTML5
http://www.bestfreeworkouts.com
FREE workout (no equipment required) at that url.
We've already talked about perfect pull up technique. But what if you can't YET do your first pull up? Here's a trick you can use to add an "assist" to your pull ups without a training partner or fancy equipment.
The secret is to use a stretch band to help overcome gravity and give yourself a little "cheat" to your pull ups. This allows you to practice perfect form without struggling against excessive resistance.
Our favourite tool for this is at http://www.mygyminabag.com, but you can use any high quality stretch bands designed for use in sports training.
Enjoy!