Complex sentence: Although every parachutist practiced the process over and over while being dragged at 15 miles an hour, the dirt and small rocks while pounding the ground frequently fouled the quick-release, making it ineffective.
Split into simpler sentences: Although every parachutist practiced the process over and over. Being dragged at 15 miles an hour while pounding the ground frequently, the dirt and small rocks fouled the quick-release making it ineffective.