The Lifestride model 9100 treadmill has a traditional top-mounted motor with housing, but that's where the similarity to traditional treadmill designs ends. The Lifestride 9100 trainer has most of the exciting reliability features that have made the model 9500 the most durable running machine ever. The Flexdeck minimizes impact. Bones, joints and muscles are protected from unnecessary impact by patented elastomeric shock absorbers mounted beneath the deck.