Found a really useful website Pubget Medical Subject headings (MESH) that summarises and provides pdf downloads of sports science articles researching rowing and indoor rowing machines including Concept2 and Rowperfect. Pubget Ergometry Articles.

A list of some of the articles includes

•  Rowing performance and selected descriptive, field, and laboratory variables.
• Strapping rowers to their sliding seat improves performance during the start of ergometer rowing.
• Stroke power consistency and 2000 m rowing performance in varsity rowers.
• Prediction of 2000 m indoor rowing performance using a 30 s sprint and maximal oxygen uptake.
• Does 2000-m rowing ergometer performance time correlate with final rankings at the World Junior Rowing Championship? A case study of 398 elite junior rowers.
• Physiological responses to exercise on different models of the concept II rowing ergometer.
• Muscular coordination of the lower extremities of oarsmen during ergometer rowing.
• Relationships between rigging set-up, anthropometry, physical capacity, rowing kinematics and rowing performance.
• Responses of blood hormones to the maximal rowing ergometer test in college rowers.
• Reliability of power output during rowing changes with ergometer type and race distance.
• Towards an ideal rowing technique for performance : the contributions from biomechanics.
• The RowPerfect ergometer: a training aid for on-water single scull rowing.