This is the 6770th most frequent Chinese word.
气力
Physical strength or energy.
In this sentence, '气力' refers to physical strength as exerted during an effortful activity.
他用尽了所有的气力爬上了山顶。
He exhausted all his physical strength to climb to the mountaintop.
Here, '气力' denotes effort and energy necessary to accomplish a demanding task.
这个任务比较费气力，需要大家共同努力完成。
This task requires considerable energy and effort, and it needs everyone's collaboration to complete.
In this example, '气力' is used to describe the general physical strength characteristic of an individual.