After several serious injuries and surgeries, I wanted to regain overall strength and fitness. I have used other Concept2 ergs in the past but felt that the new design would be more fluid and balanced. I was not disappointed. The Dynamic really forces you to focus on form. This, in turn, prevents "cheating" as you become fatigued. From the vantage point of someone trying to come back from injury (and prevent future injury) the focus on balance and fluidity allows the weakened areas to catch up rather than be compensated for. I also notice that the Dynamic seems to work the core muscles better than the earlier models. However this may again be the result of the need to focus on correct form. I had earlier written you regarding the wonderful help I received from your customer service rep. As a result of her knowledge and assistance, I felt comfortable on the new design almost immediately.