Having been introduced to CSS based swim training principles a few years back I was eager and ready to adopt as it resonated with most of what I already knew about training principles in running that have been the foundation of much of my coaching methods (Frank Horwill’s 5 tier pace system) and that I had already adopted into cycling – 5mTT. 10mTT, 25mTT, 70.3 & IM power/paces.
However for myself I soon found some major challenges with CSS based training and in particular the Red Mist Session which is traditionally 10×400 performed off a 1 length (50mtr pool) equivalent recovery time and at a progressively faster pace. Typically we cut this to 9 x 300’s to make the volume and time taken fit with our training needs – we call it pink mist. Quite simply I’d run out of gas by about rep 7 or 8 to go faster and would blow.
What had always bugged me was that the CSS Test Protocol as a predictor of threshold was that the short duration of the effort suggested a higher intensity to me, and this was reinforced by virtue of my failure to complete the session at the prescribed pace. So by working the numbers I felt comfortable that CSS +4 equated to something more like threshold / 1500m swim pace. So it was really interesting to have my experience validated to an extent in a recent Training Peaks article where Simon Ward reveals his methods to assess threshold pace and predict CSS pace, which also tally with my thoughts.
Simon Ward, in my opinion, correctly identifies that a 400mtr swim test which takes an athlete 6-8mins to complete is actually a predictor of VO2 Max. No coincidence then in running that a Vo2 Max running speed benchmarking test is based on the distance achieved in 6 minutes of running. (Verionque Billat vVo2 Max)
So is Red Mist / Pink Mist still a useful session ? Yes and I keep setting them especially in winter and spring preparation phases. Where an athlete has headroom for performance improvement the standard protocol still works as they have some performance space to improve into. For myself, I’ve plateaued in swim performance and until / unless I can breakthrough my current level then I simply adjust my CSS target times in line with what is achievable – so instead of starting at say CSS+6, I’ll start at CSS+8 and progress from there. It’s still a great session, and using CSS paces to set the targets for other sessions works well too.