Last month we have filmed 29 members of Glasgow Triathlon Club and are currently working through the footage. The common flaws in no particular order 1. Breathing issues 2. Low hips and or legs, dragging an anchor 3. No catch 4. Dropped elbow 5. Sloppy propulsion 6. Tension and stiffness 7. Ineffective or detrimental kick These are just the common ones. As an example if you swim better with a pull buoy than without..you most certainly have 2 and or 7.