For the swim, the late Terry Laughlin would say forget about trying to get stronger. Focus entirely on better form and technique; the strength will happen. I think this works well for full time swimmers who can get to the pool at least five times a week. For a time crunched working triathlete like me there just isn't that kind of time to devote to any one activity. Thoughtful use of strength training can really help here. I have devoted one of my two weekly strength training sessions to upper body development, tailored by my trainer to apply to swimming and running. I hope to add in some good old fashioned arm exercises using stretch bands, like I learned from Peter Hursty.
The key to improving my bike time is to increase my Functional Threshold Power (FTP), and, right behind that, fatigue resistance. Having just finished my "A" race for this year and with nothing special until the Honolulu Marathon in December, conventional wisdom would have me drop back down to base training. I certainly do not intend to abandon those long aerobic threshold rides. My plan is actually quite simple, and follows common practice. Be sure to do one long aerobic threshold ride, one short but hard interval ride, and one or more short to medium distance recovery rides per week, with some cut back every third week. My training leading up to Honu was too focused on long and slow.
Improving my run presents the greatest mystery. I feel like I have tried all the usual stuff, without success. This could be an example of training response outliers, how some individuals do not respond to training stress the way average bodies do.
I am lucky enough to be able to afford most of the available training gizmos. I try to restrict myself to reasonably sane stuff -- no crazy thin shoes, no drag chutes, no copper mesh knee braces. One slightly crazy gizmo I have is a Stryd running power meter, and I find it extremely valuable. This is still a young field, not nearly as well understood as bike power meters. The well respected Dr. Andrew Coggan did a nice presentation on the subject back in 2016, when it was just getting started. This video is a must-see for anyone even slightly curious about running power.
In order to run faster there are two, and only two, physical actions to address. One is stride length. The other is stride rate. It is important to look at many other factors, from head position to foot turn-out, but only stride length and stride rate make any significant contribution to speed. From what I have gathered, a focus on increasing stride rate -- otherwise known as cadence -- is far more likely to produce a useful increase in speed.
The key to increasing stride length is to increase vertical oscillation. As the body moves forward over the planted foot the leg pushes up through the hip and lifts the runner toward the sky. For a brief moment after the planted foot leaves the ground the runner is flying through the air. Both feet are off the ground. Technically this is called the flight phase. Makes sense. A moment later, the recovering foot makes first contact with the ground, starting the cycle again on the other side of the body.
Unless the runner has attached helium balloons to their shorts, or added wings to their arms, when they are flying they are also falling, at a rate of 32 feet per second, squared. During every foot plant push up cycle the body must rise exactly as much as it falls during the flight phase. If it were possible to increase how high the body goes with each push upward without changing anything else, the runner's speed will increase. Or, it may be more useful to look at it the other way around. If the rate at which the feet hit the ground remains constant, the higher the runner goes the longer the round trip up and down will take, therefore the distance traveled with each stride will increase, and this can only happen when the speed increases. As good as this sounds, it comes with a high price. It takes a lot of energy to launch a body up into the air. The heavier the body, the more energy it takes, and to me this feels like an exponential increase.
In order to run, the body must experience some vertical motion. Increasing cadence is a way to minimize vertical motion. Remember, the body falls at a fixed rate 32 ft./sec2. The shorter the time the body is falling, the shorter the distance it falls, and therefore the shorter the distance it must be pushed upward with each stride. While keeping speed constant, a faster cadence can result in a smoother, less bouncy stride.
Another, somewhat related, aspect of running with increased cadence is better use of tendon elasticity. As the foot plants and starts to bear weight, a whole bunch of tendons spread throughout the feet, and more impotently the legs, start to stretch. The foot should land just in front of the runner's center of gravity, and as the body moves forward over the foot the stretch increases as the tendons absorb the shock of landing. As the body moves past the center of gravity the energy stored in the tendons is released, contributing significantly to upward and forward motion. When a runner jogs at a slow cadence the bounce is wasted. By the time the body is ready to shoot upward, the stored energy has already been released, leaving most of the work to the muscles. At right around 80 RPM (some call this 160 because they count every foot strike) the timing of the energy release begins to align well with the body motion. I think of this effect as resonance, but that might be wrong. What I feel is best described as flow. The word float also comes to mind, but flow is more descriptive. I have no idea where the upper limit is, but the effect seems to continue well past 90 RPM.
I am sure there are other benefits to running with a faster cadence, but I will stop here. It is obvious to me that this is something to look into. So, why is this even an issue? Because when I run at a cadence of 80+ my heart rate climbs steadily up into the red zone. The only way I have been able to sustain a long run is by running at around 75 RPM. That slogging pace is too inefficient.
Last year I assumed that if I ran more I would improve. I ran more, and saw no improvement. It was right after Honu, where I never even got the chance to run, that I found inspiration. A friend had expressed an interest in getting started running. I recited the usual stuff, about starting easy, being consistent, gradually increasing the distance of each run and avoiding the temptation to go right out and run a 10K. I recalled how it was for me, running thirty minutes a day, at lunchtime. Run as long as possible, then walk until I could run again. For months I was envious of the runners who flew past me and kept on going. I could only sustain a run for a minute at most, and would need to walk two or three minutes before I could run again. Gradually the run interval got longer, but then it plateaued. I could run for as long as three minutes, but sooner or later I just had to stop and walk. I was sure I could never get past this point, that I was never going to be able to run a marathon. Then, one day, it happened. I did not have to stop. I don't think I ran thirty minutes non-stop, but it was a whole lot longer than I had been doing.
In order to teach my body how to run, I had to run, even though I could not run. By pushing my body to a higher intensity than it was accustomed to and holding that level for as long as possible I was able to develop the strength and neuromuscular ability to run. My inspiration? Use the same approach to increase my run cadence.
Those beginner runs were limited to thirty minutes. Just enough time to impart a little training stress without causing injury. I already have good endurance, so there was no need to start completely over. A good rule of thumb for long runs is to limit the duration to two hours. Anything lasting longer invites over-use injuries, and at the very least generates so much fatigue that effective workouts are impossible for the rest of the week. The rules I came up with are simple:
- After warming up, aim to keep cadence above 80 RPM.
- When candence drops to 75, or heart rate goes well into zone 3, walk.
- When heart rate falls back to zone 1, start running again.
- Continue for two hours.
This approach is based on my belief that over the course of several years focused on slow running my body -- nerves, muscles, cardio-vascular system -- has learned to run comfortably -- if it can be called that -- at a slow cadence. Even though the strength is there, the muscles and nerves have not had sufficient practice at moving fast to be able to move fast smoothly and efficiently. In the same way that run/walking got me to where I could run continuously, run/walking at a faster cadence will get me to where I can sustain that effort for long periods of time.
Here is an example of a recent run using this method (click to enlarge). The gray horizontal line marks the top of HR zone 3. What you may not be able to see is how often I struggled to keep my cadence at or close to 80. If it feel to 75 and my heart rate was already high I would start walking. I do not want to reinforce the feeling of running with a slow cadence.
It is too soon to say how this is working. In upcoming posts I will follow up on how this is going, and go into more detail on what I am doing on the bike.