Training Specificity Part 1: crits and sprint metabolism

The capacity of sprinters?  It takes more than just a killer sprint to win a race (like positioning, but my power meter doesn't record that), we need to consider other factors.  I will do so by considering some interesting power metrics, but they'll tie back into well known exercise physiology, if not by the end of this post then in the next one.  Today we look at neuromuscular power.

As always, charts are from WKO4, build 260.  Unlike usual, I will mostly focus on my own data.  Not for ego, but because I coach no track racers with power data, I end up as the purest sprinter for whom I have data.  That is to say, I'm the only athlete whose WKO4 phenotype didn't change from "sprinter" to "all-rounder" during base training.  To be fair, I'm not even a great sprinter.  This is my power curve from 2015, a year in which I sucked at criteriums.

In crits, repeated accelerations are arguably the most important factor.  This year I started training that ability and it's paying off.  The following is the power readout from two criteriums last sunday (I doubled up).

The course was 0.6 miles with two gentle corners and two right angles.  In each race there was no more than 6 minutes of coasting.  I did over 90 laps of the course this day, and the routine went: turn, accelerate, gain position, repeat.  You can tell that to haul my 163lb bulk back up to speed I had to hit about 600-1000w repeatedly.  The 1200w peak in the first race was an attempt to establish a break, and in the second race it was snagging a prime.

The highest average power for 5 minutes was less than my FTP.  Since FTP can be held for an hour, 5 minutes isn't really a big deal.  I selected a random 20 minutes from the first race and looked at the normalized power: 285w, right near FTP.  Random 20 minute chunk from the second race: 275w NP.  This is where the training specificity principle comes into play.  In order to meet the demands of an event, you have to prepare for them in ways that replicate those demands.  Hence this workout:

Since races are about 45 minutes long at the non-elite level, that workout is 40 minutes of 10 second sprints, one every minute.  Besides matching the neuromuscular demands of a criterium, the normalized power of this workout was 297w, over FTP by a few watts.  Excellent criterium specificity.

I've been learning that one mark of a sprinter or pursuiter (besides the obvious) is the ability to create normalized powers well over their FTP.  If you're well steeped in traditional power analysis, you may be thinking that NP represents the physiological demand if you had been working at a steady state, and you're right.  This doesn't mean that if you can normalize a power that you can recreate it steady state.  Believe me, I've tried.  So let's get into why.

The metric I've been working with is 1 hour NP way over FTP, which really only applies to sprinters and pursuiters, and modestly to all-rounders.  How does this happen?  It comes down to stored energy.  As you can see from the sprints above, I'm pretty good (but not amazing) at recharging PCr stores in my muscles, hitting between 950-1050w consistently.  Were I any better at this I would have normalized a higher power, or perhaps there's an optimal rest-sprint ratio to maximize NP for the workout.  Doing 12 sprints in an hour also normalizes 300w for me while hitting about 1250w each time.

What's this have to do with stored energy?  Phosphocreatine is recharged from two molecules that have higher stored energy, phosphoenolpyruvate and 1,3-bisphosphoglycerate (PEP and 1,3BPG).  PEP is shunted off from the TCA cycle and 1,3BPG is a glycolysis intermediate.  As the reaction ADP+PCr->Cr+ATP proceeds for each sprint, we can safely assume that the PCr levels in a muscle cell are well below normal levels.  This increases the demand for PEP and 1,3BPG and thus the glycolytic and aerobic systems.  See here (page 5) if you're rusty on your standard free energies and why this works.

Glycolysis is probably more taxed in sprinters with good anaerobic power since glycolysis can create energy more rapidly than aerobic metabolism.  Looking at it another way, because the normalized power a sprinter can create is much higher than FTP (here representing the aerobic ability of the athlete), the difference must be made up by stored energy in the form of PCr and glycogen.  This ability to rapidly mobilize non-aerobic energy (during and while recovering from high intensity efforts) is why sprinters and pursuiters can't simply put out their normalized powers at a steady state.  It should be obvious that FTP is also important for criterium racing.  Greater demands on stored energy during the race means there will be nothing left for the final sprint.

Next post will look more closely at the ability of some sprinters and all pursuiters to chew through glycogen at rapid rates.  I'll also look more closely at a couple cases of 1 hour NP > FTP.

Race prep: off season training targets

There are a few different sides of a coin when it comes to early season training, which maybe makes it more like a die.  I like to pick two things for an athlete to work on at the same time, and not just to shore up the coin analogy.  Over the winter with lots of trainer time, the obvious priority is FTP (because I don't like to assign 4 hour trainer rides).  The other thing is dependent on the athlete and their goals.  This will go through the process for a few athletes as well as the results.  Any charts are from WKO4, build 255.

Athlete 1, CX focus.  Goals: FTP and force production

The first person we'll look at has been doing road training for about two months now, and after finally having gotten a power meter in late December, his needs are exactly what I expected they would be but there's not deep historical data to compare with so I can't show you any pretty graphs illustrating progression, but here's the graph of his weekly peak values.  The first set of points in the 12/28 week is the testing protocol to establish baseline maximal values.  He has not done a maximal 1 minute effort since, but I doubt the anaerobic power has much increased.

This athlete's main focus is cyclocross, so with half a year before that racing starts, there's a lot of time to work on many things.  His slim 70kg build and tendency to ride at high rpm indicate a lot of slow twitch fibers, so the goal is to increase his threshold and muscular power, even if it means putting on weight.  These improvements will be the foundations on which we'll build his high end power for CX, but right now he needs to improve his musculature and maximal force production.  For the last two months he's been doing almost entirely endurance and tempo riding with strength training on and off the bike.  His training weeks are about 13 hours, plus one 20 hour week.

This training alone has been enough to bring up his FTP from 240w to 270w and raise his Pmax by 150w.  In just two months the two training targets are improving dramatically, and he's on track for a great season.

Athlete 2, road/stage race focus.  Goals: FTP and muscular endurance

The next athlete is a 61kg road racer who excels at climbing.  She's been training since October and, like the previous athlete, has a naturally high cadence but felt a lot of muscular strain and fatigue while climbing steep grades.

The last couple months have seen her intervals build from 3x10' to 3x20' at threshold.  In addition there was a lot of strength work in the gym and low cadence climbing on the bike, but it was different from Athlete 1's program.  We focused on muscular endurance for climbing, but it had the benefit of increasing her anaerobic power as well since the lifting was similar in demands to a short anaerobic effort.  Here's the graph of her build since October.

We can easily see that she's natural athlete, able to maintain high workloads and recover well.  Whether doing endurance, sub-threshold, or threshold efforts, her FTP has built from 210w to 250w.  The purple dots are 20' maximal power values, and they show steady progression upwards.  Also worthy of remark is that she did no anaerobic work until December with her first 1' power test (450w) around 20 December, which was already a full 100w better than her 2015 best.  After some time off in January for exams, she spent most of February maintaining the weight lifting and reestablishing her endurance, and her 1' power is still the same.  In terms of meeting the goal of increased muscular endurance and power, she is able to handle VO2max hill repeats at low cadence (up to 40 minutes of climbing) and her Pmax increased from 680w to a high of 820w in December.

Athlete 3, road race focus.  Goals: w/kg and endurance

This last athlete went through a real transformation in the last couple months.  His goal was to excel in road racing, so his goals were increasing FTP and losing weight.  In October, he was 10kg heavier, with a 1400w Pmax, 700w 1 minute power, and 280w FTP (not shown in graphic).  His Pmax dropped to 1200w, but his w/kg at FTP went from 3.8w/kg to 4.7w/kg.  This is the power curve not normalized to weight (the w/kg graph is a bit muddy with several lines on it, but this is clearer).

For the long road races he'll be doing, this is what I wanted to see.  Would he have 10-20w greater FTP if he hadn't lost the weight?  Probably, but a 345w FTP at 80kg that would only leave him at 4.3w/kg.  Fortunately his Pmax hasn't suffered as terribly as I expected, and will serve him well in reduced bunch sprints.  We've done some 3' VO2max work, but no anaerobic or sprint work yet.  It's just been burning calories and increasing threshold, and this is reflected well in this graph.  In fact, despite regular rest weeks, he spent from October through Christmas with a negative TSB, having ridden 6000 miles.  There's been reduced workload since, but it's the foundation of a successful season.