Assessing the equipment involved in aquatic exercises I found there was a limited ability to adjust the level of difficulty, compared to working out at the gym where you can adjust the weight applied.
Through researching different equipment and concepts I came to incorporate the iris diaphragm mechanism into a set of hand paddles, flippers and kick boards. Creating and testing out these prototypes I found that the hand paddles had the most noticeable quantifiable difference with the iris being open and closed.
Counting my strokes per length (25m) I found that when I didn’t have paddles on my average stroke rate was 21 per length. When I had my iris paddles on with the iris opened the average number of strokes, I took was 19 per length. Finally, with the iris closed to block as much water as possible my average stroke rate was 17 strokes per length.