LYNX offers “CSS development” swims in our weekly sessions.

I want to take the time to define CSS and explain why it might be relevant to you.

CSS stands for Critical Swim Speed. It is the 100 meter (or yard) pace you can sustain for a 1500m time trial. It is also an approximation of your lactate threshold speed or “threshold pace” for short.  Think about threshold effort as the transition from swimming comfortably hard to uncomfortably hard.  For open water swimmers and triathletes competing in distance events (750m or longer) the goal is to improve threshold pace to maximize race day speed. Outside of sprint triathlons, your ability to swim anaerobically is largely irrelevant unless you are a Master’s swimmer targeting 50-100-200-400m events.

What does this mean to you?

If you are an Olympic distance (or greater) triathlete or an endurance open water swimmer, to improve your threshold pace you will want to do your quality swim sets at your current threshold pace or just below it. For most swimmers, the shift to CSS sets will mean more swimming with less recovery.  This can be a tricky change in mentality for athletes. Early in a session swimmers new to CSS sets make comments like “I don’t feel like I’m working hard enough” but midway through the set they are winded and wanting more rest…and that’s when the real work begins.

How do you determine your CSS pace?

There are 2 fitness tests utilized to determine CSS pace. One method is having the swimmer complete a 400m and 200m time trial where total times are recorded as well the first 100m split of the 400. From this information, I can calculate a CSS pace and provide feedback to the swimmer about how well they are currently trained for distance swimming. If a swimmer’s data shows that they are more of a sprint machine versus a diesel engine, and their target races involve swims >750m, I will recommend more CSS / Endurance training to get better over longer distances. A second method to determine a person’s CSS pace is to do a 1500 time trial. The average 100m pace held during the test is the swimmer’s CSS pace.  Regular CSS tests are run during the Fall CSS development sessions  to help swimmers’ monitor their progress.

As a Swim Smooth certified coach, every group swim I run through LYNX Triathlon includes technique and fitness work. The balance of each swim depends on the specific session. For example, the Pure Technique sessions will be primarily technique work while the CSS Development sessions are primarily fitness training. Technique work is always included during warm-up drills.

To maximizing improvements in your swimming ideally you want to get in a variety of swim sessions each week.  If you are swimming 2x per week pick 1 technique oriented session and 1 CSS session to improve your threshold speed. If you swim 3x per week, you will want to add in an endurance session with longer steady paced swims.

CSS development work is beneficial because it’s race pace specific training that doesn’t take you days to recover from. Win – Win!

If you are serious about turning yourself into a diesel engine, contact us.

See our classes page for full details

Coach Mary