There are two different events in the weightlifting portion of the Olympics, the snatch and clean-and-jerk.
In the video you see the snatch lift, which is done in one entire motion. The more kinetic energy obtained at the beginning allows for an easier lift, but having proper technique is arguably more important.
Considering how much weight the Olympians will attempt, anyone who has ever weight lifted knows the potential dangers if the proper technique is not executed. Along with quick inertia to make the lift, strong wrist and fingers are needed to maintain a strong grip of the bar throughout.
After all, no lift can happen if the bar isn't controlled.
Clean and Jerk
The other lift in the Olympics is the clean-and-jerk. Similar to the snatch, the clean-and-jerk is just broken down into two movements.
The clean part is snatched up to the lifters shoulders, and then the jerk part comes from squatting down to use the feet, back, and hips in helping propel the weight over the head.
Each require an athlete to use every bit of strength, power, and explosiveness to successfully complete the lift. The more impressive aspect is how much an Olympian will attempt/lift more than their body weight.