Final answer:
Mechanical resistance devices are tools that can be used to apply or resist forces, and include simple machines like levers and pulleys, which have mechanical advantages.
Step-by-step explanation:
Mechanical resistance devices include various tools and equipment designed to augment or multiply force. One category of these devices is simple machines, such as levers, pulleys, and wedges. These devices operate on the principle of mechanical advantage, which is the ratio of output to input force magnitudes. Mechanical resistance in the context of exercise might include devices like weights, which rely on gravity to provide resistance, and spring tension systems that resist through elastic force. Treadmill and StairMaster are cardio equipment and do not fall under simple machines. On the other hand, a TENS unit, used for pain relief through electrical stimulation, or cervical traction, which applies force to relieve neck pain, are not generally considered simple machines or mechanical resistance devices in the traditional sense.