You may have the strength for a task, the ability to perform it. However, you can be out of energy for the task.
An interesting thought is that the world may continue to build our stamina naturally in the areas we already bring energy. If you bring a load of physical energy, it’s likely you’ll find more tasks and activities that require physical energy. The more those physical exertions are put on you, the more stamina you build and in a cycle you find even more stamina as the activities become the norm for you.
Alternatively, if you bring an abundance of empathetic energy, you may find yourself playing counselor often. The more your do that, the stronger your empathy and energy to handle situations requiring empathy becomes.
This can be true for energy for all sorts of tasks:
If you bring energy for something, the world will often find a way to allow you to do more of it. Doing more of it, will grow your energy for it.