In what way did trench warfare turn out to be a disadvantage to both germany and the allies in the war? trenches were too deep to allow troops to fire their weapons, so the troops were weak and vulnerable. trenches were poorly dug and collapsed often, greatly slowing the troops’ movement. troops from both sides often overran the same trench, leading to many deaths and injuries. troops were basically trapped in their trenches, preventing progress toward seizing enemy territory.