How do humans measure swimming efficiency?

https://www.swimwell.com.au/single-post/how-do-humans-measure-swimming-efficiency

By Peter Hendriks This is a hot topic all over the world and draws a lot of different opinions. I personally am fascinated by the subject and apply it to my own swimming at all times. As a specialist technique coach who spends his week either videoing, analysing or correcting swimmers, of all levels and technique, it is important to understand the subject.In order to understand swimming efficiency we first need to understand the KPI’s. Measurable KPI’s 1. Stroke Length (SL)