Final answer:
The leg straps on a class III parachute torso harness provide additional support and stability during jumps and help to adjust the fit of the harness for the jumper's safety and comfort.
Step-by-step explanation:
The leg straps on a class III parachute torso harness are used for providing additional support and stability during parachute jumps.
These straps are crucial as they help in distributing the forces experienced during deployment and landing, and they play a significant role in keeping the harness secured to the jumper's body to prevent slippage, which could lead to serious injury or an unsuccessful jump. The leg straps are also sometimes used to help adjust the fit of the harness so the jumper can achieve a snug and secure fit, enhancing both comfort and safety.