Critical Swim Speed (CSS) and Total Immersion Swimming

CoachSuzanneOlympicSwimClubI was always a math geek. Way back in 2007 or 2008 I took a clinic from Dr. Phil Skiba on periodization…but it was much more than that. Phil is an experienced coach who also has a lot of expertise in physiology and testing.   Phil’s clinic was one of the first times I can recall that the formal idea of a “time-distance” relationship in endurance sports was brought up in the context of how to coach athletes and interpret their abilities.

I started experimenting with using this assessment in my own swimming & my athletes.  Several years later I began combining this idea with what I had been practicing as a Total Immersion coach.  I tried combining ideas that were well studied in traditional sports science literature with what I’d been doing in developing better swimming agility on my onw.

Shortly after experimenting with these ideas…in fact the very first day I used it in a  group of triathlete swimmers, many of my swimmers set PRs for 50 & 100m swims just by refining and defining their control over their stroke.

in 2012 I shared some of my thoughts on the total immersion website. I have often gone back to that thread to review what I wrote at the time as well as revisit the thoughts of another coach, Charles Couturier of Montreal, Canada. Charles is an outstanding coach at the University of Montreal and runs a large tri training program for people of all abilities.

Here is the largely unedited text of what I shared that day in response to using CSS to train speed and pace. CSS is concept that dates back to at least 1965 when a distance-time model was prposed by Monod and Scherrer as they evaluated world records in swimming, running, speed skating and cycling.

Since that time many sports scientists have examined and used the model to try and define specific stroke rates and stroke lengths in swimming, resulting paces, power targets for cycling and running paces. Swim coaches began using “Critical Swim Speed” as measured by using either a 400m & 50m swim test or a 400m & 200m swim test. The choice of distances affects the resulting slope & intercept (speed and anaerobic work capacity) as calculated by the model.

In theory the shorter test, which taps into anaerobic energy stores, helps to “strip out” the anaerobic contribution from the longer test. The resulting pace represents an aerobic swimming speed that can be sustained for long durations by trained swimmers.

I use the CSS concept to establish initial goals along with tempo & SPL targets for my masters swimmers who are new to pacing, or have not trained with me long enough to have a feel of their targets or points of improvement.

About once a quarter I’ll have my swimmers do the following:

Assessment Set

10 minute warmup
300-500yd/m time trial (this should be at  least at least 5 minutes)
8 minutes of active recovery in the pool
50m-100 yd/m all out sprint (this should be 90 seconds or less)

The critical swim speed plots the time vs. the distance of each of the two swims. A line drawn between the two is described by the basic algebraic equation:
y = mx + b

m is equal to the theoretical critical speed (or power in the case of cyclists)
b is the intercept and represents the anaerobic work capacity

by plotting a “long” and a “short” time trial test, the anaerobic and aerobic capacities for each effort are normalized. The above equation to determine the slope, removes the anaerobic component from the longer time trial (whether it is 300, 400 or 500yd or longer TT).

Here is the easy way to calculate it Critical speed = [long distance – short distance] / [long time – short time]

400yd TT: 8 minutes
50yd TT: 35 seconds

critical speed = 400 – 50 / 8 * 60sec – 35sec
critical speed = .78 yds/second

Even in a yard pool, I like to normalize in meters per second as a lot of the literature is written that way. Just 1.1 yards = 1 meter so .78 yd/sec = .78/1.1 m/s = .71 m/s

.71 meters/second (or .78 yards/second) is the critical swim speed for that swimmer, or 2:08/100 yards

Why is the critical speed slower than the 400 yard time trial speed?

In an activity lasting 8 minutes, even 20-30 minutes or more, a component of the speed comes from anaerobic muscle activity…brute force.

The comparison between the long time trial where the aerobic system makes a significant contribution and the SHORT time trial which is primarily anaerobic, allows you to subtract the brute force component out of the longer time trial speed.

This leaves us with what should in theory be completely aerobic training.

In the Total Immersion approach to swimming, this is vital because the intensity level is low enough to allow us to focus on technique improvements while swimming at a pace that isn’t “too slow” by anyone’s standards as long as the CSS was calculated from two recent time trials.

We are left with what in theory, represents the highest aerobic speed a swimmer can swim, meaning that at this pace and anything slower we should be able to more easily implement technique changes and adjustments.

Just as you would practice a new or challenging passage of a piano piece or any other musical instrument slowly enough to allow you to learn proper timing & finger placement, an aerobic pace in swimming allows you to learn and imprint new and better neuromuscular pathways to make your swimming faster and more streamlined.

Here is where the Total Immersion twist comes in….

With Total Immersion we focus on the neuro-muscular connections and movement pathways from brain to muscle. We can swim at the critical speed in many different “gears”, but we want to find the optimal gear, or stroke length and rate, that will allow the swimmer to work in a comfortable capacity while leaving ample room to grow in speed and get faster.

Once I’ve calculated the speed with a spreadsheet I’ve set up to do that, I”ll give my swimmers a test set of 10×50 at critical speed + 5 seconds rest. Again I have this already set up in a spreadsheet so the set is ready to hand to them when they finish the test and I put the numbers into a calculator on my ipad.

While they are swimming their 10×50 they count their average SPL. For some this the first time they have every done that, but it’s in the context of a familiar type of training…a time trial followed by sets at a prescribed pace. This helps people understand that counting strokes is not the same thing as aiming for lowest stroke count…we are just collecting information at this point.

With this 2nd data points, average stroke count per 50 at their CSS pace, they are now honing in on a really valuable set of training parameters…not JUST critical speed, which can be swum at many tempos and stroke lengths (ie many different stroke techniques or GEARS) , but they are establishing an average SPL, which turns into as well as a target for improvement.

After the 10×50 counting strokes, their next set (on a subsequent day perhaps), will be to use that SPL and the critical swim speed, and swim the long set again, but with focus on holding SPL at that average number and not exceeding it.

What we’ve done is used the swimmers current fitness & ability to give them a starting point, without placing any specific focus on the swimmer adhering to SPL or tempo constraints while swimming the initial time trial. This allows anyone to do the set, not just people who are math inclined.

I can take any of my swimmers with any level of experience, have them do the assessment set, plug their times in and my spreadsheet does the calculations, recommends the 10×50 pacing and the swimmer then begins their journey!

Periodization – How to Reach Your Peak Performance

What is periodization?

“It pays to plan ahead. It wasn’t raining when Noah built his ark”. -original author unknown

Periodization is a way to divide your training into phases with each phase having it’s own purpose in developing your skills & fitness according to your primarily sport or goal. Training progresses logically throughout the season by changing the total volume, intensity and specific skills that the athlete focuses upon. Rugby coach Fredick Claro stated it nicely:

Each of these phases is interacting with the other ones like the links of a chain, making the final result an optimally prepared athlete or group of athletes, physically, technically, tactically and psychologically ready for the toughness of competition.

Most endurance athletes who do their own reading and research will be familiar with the periodization method adapted by Joe Friel in his popular “Training Bible” series of books. While Joe’s model will bring success to many who plan their season according to it, many athletes would be even more prepared for their competitive race season by following other methods of periodization. If you want to reach your maximum potential as an amateur or recreational endurance athlete, keep reading for some new ideas that could give you even better results this race season.

The History of Periodization

In the 1950s, a Russian social scientist named Matveyev surveyed Soviet track & field athletes in their preparation for the Helsinki Olympics. He recorded and published this information as the basis of his training theory. He summarized that there must be extensive preparation, including a fundamental period which “focuses on the necessary pre-requisites for top performance.” He also noted that there was a reciprocal relationship between intensity and volume and that when one goes up, the other must come down.

The current implementation of this traditional view of periodization is that a long period of “base” training consists of solely low intensity, long “steady” or long “slow” endurance training. While this information was published and reached western (english speaking) audiences, German and Soviet sports scientists were pursing an entirely different pathway. Sadly, their ideas were not communicated to the Western audiences as thoroughly as Matveyev’s theories were.

Scientists such as Peter Tschiene (German), Mellenberg and Verkhoshansky focused on the fundamental biological changes that take place while training, rather than relying on an empirical model of periodization. They observed that most high level athletes continued to train year round, and that they not only trained frequently, but trained hard as well. They encouraged training blocks that focused on improving oxidative (ie fat burning) capacity of the muscles, improving contractile properties (increasing power), improving pumping output of the heart (increases in stroke volume) as some of the fundamental building blocks of early training.

A focus overall velocity (ie. race intensity) as being the primary target outcome of training allowed for the acceptance of the ideas of athletes training both hard and long, often at the same time period, without requiring extensive periods of general (non-sport specific) training as encouraged by Matveyev & Bompa.

The New Realities of Periodization

The single biggest predictor of performance for triathletes, runners & cyclists is their velocity or power output at their “threshold” capacity. Despite the many different definitions of threshold you may have heard of, the underlying physiology is the same. Whoever has the highest velocity for their body’s limits of oxidative (aerobic) capacity is going to have the best performance in the race.

Studies that show varies modes high intensity interval training improve endurance performance are not new. If you’ve heard of “HIIT” or “Tabata’s” then you’re hearing about methods that trade intensity for duration in the development of endurance abilities. Since an athletes overall ability to go fast at their threshold is fundamental for performance and success, it stands to reason that much of the athletes time should be devoted to either maintaining or improving this aspect of fitness – in other words, raising their threshold.

This then becomes the “general preparation” phase of a periodized training plan. I refer to it as the “global power” phase after Dr. Skiba’s peridization method. Along with workouts that improve or maintain threshold performance, there will also be abilities that support and improve athletic performance such as core strength, flexibility, technique, skill etc. that can fit nicely into this period.

Race Specific Periodization Phase

In the traditional peridization scheme as popularized by the “Training Bible” series, Specific preparation phases are referred to as a “Build” phase. Typically, not until the “Build” does the athlete do any significant training above the endurance pace. As you can imagine, the overall peridization scheme of an ironman athlete and a criterium racer will look very, very different. However in both cases, having a high functional threshold is key to performance. Developing threshold therefore becomes a “general preparation” activity, rather than something done in the weeks leading up to your race (the Build)

As the athlete gets closer to their competitive season, more training time needs to be devoted to race specific intensity, duration and skills. If you are a long course athlete (half ironman, ironman, marathon mountain bike races, 12 hour/24 hour mountain bike racer) your race specific intensity will be much lower than a short course athlete such as a 5k or 10k runner, a 20k or 40k time trialist, or a sprint/olympic distance triathlete. Furthermore, your race specific duration will be much longer.

For an Ironman athlete, the general period of preparation will be made up of shorter workouts (1-3 hours) focused on raising threshold as high as possible during that phase (12 weeks for example). The specific period of preparation would then consist of extending the efforts to race specific distances while lowering the intensity. The result is that the athlete will begin their endurance training with a higher threshold, and higher average velocity than they would have if doing only “LSD” training in the base period.

Similarly, various bicycle racing disciplines require racing specific abilities such as sprint, lead out, breakaway, bridging, hill climbing, etc. As you approach your peak races, your peridization plan will focus more on these anaerobic abilities specific to your style of racing and your strengths amongst your teammates.

For example, a road racer’s “base” or general preparation period would consist of rides and workouts that raise threshold, while the race specific preparation would consist of preparing the rider for specific terrain, distances and short harder efforts pertinent to their racing strategy. The role for long aerobic rides serves as a way to build fatigue resistance, but hardly constitutes the foundation of training during the general preparation phase.

Putting it all Together – Planning a Season

The overall picture of your periodized training plan requires a long term view…at least a year/competitive season. I like to start training with athletes at least six months prior to their race season so that we can fit in several months focused on threshold building efforts while allowing ample time for recovery and rest. The first few weeks of traiing generally include effort based sessions with short excursions into hard efforts, such as 4 x 5 minute “hard” intervals with a few minutes of recovery in between. With each week, the interval length can go up and the rest intervals can go down.

At the same time, I’ll have athletes do building efforts of both “tempo” and “vo2 max” work, starting with 10 minutes of tempo work at a time and as little as thirty seconds of VO2 work at a time.

Each of these three types of workouts are blended in a gradual fashion so that by the end of a 12 week block, there will be about 40-60 minutes per week of threshold work, 2-4 hours of tempo work and a max of 30-40 minutes of Vo2 work. If we are still far from the competitive season, the VO2 work immediately comes down to a maintenance level of about 12 minutes per week until it is time to peak for a race. The threshold & tempo work can stay and even increase gradually as overall training stress may continue to climb.

Rest Days & Rest Weeks – Are they still needed?

One saying about training is that whoever recovers the fastest will reap the most benefit from training. “fast” recovery is dependant on a number of things, some in the athletes control and others out of the athlete’s control. Everyone’s needs are different, but typically most will benefit from 1-3 rest days per week depending on their level of fitness & performance. Some high level athletes can go for 10-14 days without a day off, but they are few and far between.

Rest weeks on the other hand are a little more controversial. The “traditional” model of 3 weeks on, 1 week off is reported to stem from children living at training camps for 3 weeks at a time, then going home to their parents for a week. Coaches worked them hard for the 3 weeks they were there because the week off was going to have a big impact in their fitness.

Some newer ideas, discussed extensively among the Wattage folks, are to simply observe a gradual “ramp rate” in your overall training stress. Rather than train hard, get tired, sometimes really tired, then try to recover…the thought is to find a gradually increasing rate of training stress that you can continuously recovery from on a daily & weekly basis.

Every athletes needs are different, so you’ll have to experiment and find out what planning methods work best for you.

References (actual sources to be included soon)

Phil Skiba, MD

Frederick Claro

Peter Tschiene

Where Does Lactate Come From?

Lactate is a byproduct of carbohydrate metabolism. As you increase the intensity of your exercise, more carbs are used for fuel thus producing more lactate. Lactate can be measured in the blood using a handheld meter and a pinprick to get a drop of blood.  As your intensity increases, your lactate level also increases.

Physiologists have come up with 20 (or more) different ways to analyze this data that plots lactate level against some measure of intensity like heart rate, power or Vo2 max as measured by a specialized piece of very expensive equipment.

“Lactate Threshold” is therefore defined many different ways…one set of data can give you a handful of numbers. However, all of those will be functionallly close to what people have alluded to above…the maximum level of intenisty at which you can sustain a given activity for a “prolonged” period of time, typically an hour or more.

You don’t need to have it measured to be able to train with the same principals. Field tests like these (20 minute lactate threshold field test protocol, 30 minute lactate field test protocol) will give you the information you need to determine exercise intensity zones.

However having an actual lacate threshold test performed at a variety of times thoughout your trianing cycles can give you valuable  information to confirm that your trianing is working and confirm that your field testing is accurate.   If you are interested in having a lactate test performed either at my home studio or in your own home, feel free to contact me.

Oxygen Fuels the Work your Muscles Perform

The topic of VO2 Max intimidates may cyclists & triathletes, but understanding it’s importance can be pretty straightforward.  Here’s a simplified explanation that should give you an idea of why the topic should be of interest for you.

Short version: Oxygen Fuels the Work your Muscles Perform – VO2 Max is the maximum oxygen your body can currently  utilize


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