Olympic athletes are some of the most determined people you're going to meet. At that level, they've got to be driven to succeed. Otherwise, their opponents will surely beat them.
If you want to reach your goal, you must be determined to do so. To be determined is to be motivated, driven, or really focused on the task at hand — and that can be something as big as winning a prize or as small as fixing a squeaky door. No matter the task, the folks who get the job done are almost always the most determined. Determined can also mean "decided." For instance, a judge can determine what the sentence will be. If that sentence is "pre-determined," then it's already been decided.