overtaxing

The effort to carry food, water and cartridges to the firing lines is already overtaxing the Corps.

Dont you suppose I can see how you are overtaxing your strength?

Not a countenance but wore that immobile look, the fixed, unseeing eye of the spent runner, who is overtaxing heart and lungs.

The apparent delight with which he entered on the work removed from my mind all thought of overtaxing a friendship.

Moreover, carrying full loads does not constitute such an overtaxing as calls for the higher rates.