Why we spin – High cadence training for triathletes.
Alan Couzens, MS (Sports Science)
Jan 25, 2016
In previous posts I’ve sung the praises of low cadence training for triathletes. Specifically as a tool for increasing the size and strength of an athletes FOG (fast oxidative glycolytic) muscle fibers. For triathletes, having sufficient muscle for the task at hand is an important consideration. However, especially for long course triathletes, it’s not the only consideration.
Ironman is, fundamentally, a metabolically limited event. Even the best athletes perform the event at an intensity significantly below the onset of blood lactate accumulation. In other words, it is not a rise in acidity within the muscles that prevents an athlete from going faster. There is another muscular limiter at play.…
No, the key factor that slows an Ironman athlete down is running out of that critical fuel source – glycogen. Consequently, anything we can do to slow this process is directly beneficial to Ironman performance. Enter high cadence training…
The central v peripheral demands of different pedaling cadences has been investigated in a number of studies that have arrived at a similar conclusion: While absolute ‘whole body’ metabolic cost is higher in the high cadence condition, the peripheral cost within the ‘prime mover’ muscles is lower. This results in improved hemodynamics (O2 in, lactate out), decreased muscular stress, AND decreased metabolic stress (glycogen use) (e.g. Ahlquist et al., 1992, Faria, 1992, Gotshall et al., 1996, Takaishi, 1996). For example, The Ahlquist study showed 28% less total muscle glycogen used by cycling at 100rpm vs 50rpm at the same power output! The bulk of this difference was in the less economical Type II fibers, indicating less reliance on these with the high cadence approach.
In the world of Ironman racing, most athletes can afford to spend a little more O2 to save a little more glycogen. In performance terms, it’s a good deal. However, it is also a technique that goes against our natural tendencies: If you put a complete novice on a bike erg, the average pedaling cadence will fall in the ~60rpm range, i.e. high cadence cycling is something that must be practiced & trained for, especially if your plan is to hold a high cadence for 5ish hours under conditions of increasing fatigue.
In practical terms, there are 2 elements here worthy of attention within the training plan…
As I stated above, if you pluck an unsuspecting college student out of their classroom and throw them on an erg, they’ll tend to pedal at around 60rpm as their default. Similarly, if you put a semi-trained cyclist on an erg and have them pedal to a good level of fatigue, their cadence will progressively fall in the same direction. Fatigue makes plodders of us all!
Moving away from these tendencies takes time and practice.
There are 2 types of cadence practice that I use with my athletes…
a) Fresh to the max!:
Cadence work under low fatigue conditions that builds to maximal cadence & raises the athletes ‘neuromuscular ceiling’. When an athlete is comfortable at 120rpm plus, sustained work at 100rpm becomes much less 'neuromuscularly' taxing. For example…
A favorite max cadence set is...
10min ladders (all at easy watts) as...
- 4min @ 90+rpm
- 3min @ 100+rpm
- 2min @110+rpm
- 1min @120+rpm
b) Cadence under fatigue:
For example: A 4hr ride on a 4 loop course that incorporates a sustained flat section of 20min on each loop. Every time the athlete hits the flat section they do that 20min @ 100+rpm. This becomes more challenging as the athlete fatigues.
Contrary to popular belief, not all watts are created equal. Power = Force x Speed of movement. Therefore we can achieve the same power in different ways & with different physiological consequences. While well known and exploited in the world of cycling, this fact hasn't really trickled down to training prescription for long course tri - an event where it is even more directly applicable! Let's delve into the physiological consequences of cadence manipulation in a little more depth...
Despite the terminology of Fast Twitch, Slow Twitch etc, it is not the speed of movement that determines fiber recruitment. Rather, it is the load demand placed on the muscle. More load = larger (fast twitch) fibers recruited. Less load = smaller (slow twitch) fibers recruited. By altering the force component for a given power output (i.e. by increasing the rpm) we can actively select the muscle fibers that we are emphasizing. Going back to the differences in metabolic efficiency between fiber types, it is clear that as athletes involved in a metabolically limited event, we want to highlight the slow twitch fibers … a lot!
For this reason, in addition to very low intensity/lactate levels <2mmol/L, effective base training incorporates a lot of relatively high cadence work.
Some time ago when the inter-web was in its infancy, Chris Carmichael was posting the workouts of a certain cyclist by the name of Lance Armstrong. As a relative noob to the world of triathlon/cycling, I was intrigued by the emphasis placed on high cadence work. There was a lot of very low intensity, very high cadence 100+rpm work performed over very long durations. While other factors were clearly at play, this type of training led to a remarkable increase in economy (from 75-81 watts per liter of O2) over the course of 7 years & was touted by many as the differing factor in Armstrong’s performance vs his (similarly doping) rivals.
I was exposed to this new world of elite cyclist base training myself when a buddy of mine, who was one of the top track cyclists in the U.S. decided to make a comeback as a road cyclist. As a typical triathlete, I was dumbfounded during our first base ride together at a) just how easy and conversational the pace was. b) just how relaxed he was spinning his legs over at ridiculously high cadence for hours on end. This same buddy would soon go on to make the move from elite anaerobic guy to elite aerobic guy by securing a team RadioShack contract and achieve his dream of racing side by side with some of the top cyclists in the world. So what did these transformative base rides look like?
c) Sustained low load, high cadence endurance
Frequent 'conversational' 4-6hr rides on very flat terrain with cadence of 90-110rpm and HR <70% max
...and, just as importantly, with the 'long, slow (conversational) distance', we stayed healthy, we had wonderful long chats (we were both into Tony Robbins at the time), we leaned out like crazy & we both got really, really fit!
Beyond the pleasant anecdotes, there is clear scientific backing for an emphasis on LSD (low load, high cadence) Type I fiber training leading to an increase in economy. Ed Coyle has spent years researching this relationship & while it’s a tough one to study longitudinally (due to the slow time course of fiber change), it is clear that those athletes with a higher % of Type I fibers are also those athletes with the highest economy numbers (Coyle et al., 1992). In fact, the relationship between Type I fiber % and delta (metabolic) efficiency resulted in an r value of 0.85 – a very high correlation between the 2.
But don't take my word for it! You can (& should) monitor changes in your own economy numbers over time in response to different training protocols. With the use of a progressive metabolic test you can get a number for your own economy (in watts per liter) that you can attempt to shift over time. The direct benefit to your event from becoming more economical with the 'fuel' that you have at your disposal, for a metabolically limited event like Ironman is nothing short of crucial. A shift from 70-75W/L represents an addition of ~20W of power for the same metabolic cost for competitive level athletes!
In short, if economy is important to your event (if you’re an Ironman triathlete, it is) then a good chunk of your training should focus on its improvement. My own experience & the literature to date suggest that this is best accomplished with low load, high rpm work designed to target your Type I fibers. This means a lot of relatively high (90+rpm) cycling at easy intensities on flat terrain during your base training.
Increasing metabolic efficiency is a key component of performance for all endurance athletes, but especially so for those athletes for whom it is a specific event limiter, i.e. Ironman triathletes. High cadence emphasis work is critical here both in developing race ‘practices’ that lead to the highest levels of economy during the race and in ‘training’ that Type I fiber base that will lead to continued economy development for years to come.
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