Friday, January 18, 2008

Measuring and Improving Fitness - Concepts

Some of us exercise just to 'keep fit' while others exercise to maximize performance at a given task. Where is the line between those two things and what, really is 'fitness'? That is hard to really say, and science doesn't do a lot to help us draw the line. But I know this much-- everyone I've ever met says the same thing after they finish an event: "Next time, I'd like to do it faster..."

Science is just beginning to give us a real recipe for doing just that. The strange thing is that there is no single plan that works for everyone. We all need different things, and respond in different ways to each training session, and, ultimately, have different levels of potential. What matters isn't how we compare to others-- it's how close we are to our own upper limits. My suspicion is that most of us have no idea where our real limits lie.

But we do know this much-- improvements in fitness only come when we operate near our current limits in a particular area of fitness. It used to be thought that endurance only came from training over longer and longer distances. Science is proving that there is another way, but there is a still-bewildering relationship between the role or value of intensity versus volume, one where we are just beginning to learn the crossover between short, intense efforts and endurance. It is becoming clear that intensity matters more than total time when it comes to improved fitness, even in endurance. What is still unclear for endurance sports is the true value of (or need for) long distance, high-volume training as it relates to endurance- called for years 'LSD' or long, slow distance. Put another way- can we do it all with interval training? The science more and more seems to be pointing toward 'yes'. The science is more and more pointing toward LSD training as being 'junk miles.' Can we totally rule out LSD yet? I haven' t found that study.

But there are challenges with this idea of doing it all with intervals-- truly high intensity is hard to maintain over long periods of time-- our mental focus and accumulated physical fatigue tends to drive us in a sine wave of intensity, with periods where we can drive hard followed by periods where we don't feel as committed or able to push our limits. The good news is that science is proving this to be necessary toward our goal of higher performance. So we need periods where we maintain, along with periods where we stretch our limits.

The bottom line? We need a full menu of activity types in order to reach our potential. Easy, hard, short long in all combinations. The trick is avoiding the stuff in the middle.

I'd like to take a bit of time to establish some basic thoughts on how we measure our fitness. From there, we'll build on the tools that help us construct and guide our training program. You may not understand all of this until you live through it a few times, so keep coming back to the concepts and you'll find over time that things make more sense. You might also find a desire to incorporate more measurement into your training program. Start simple and add on. Even if you don't want to measure down to the last intra-beat ms duration of heart rate or N-m of torque over milliseconds of time, you'll be able to understand more about what you're doing and how it relates to our greater goal of what I call 'Living Fast' -- realizing our true potential in whatever we do.

The most effective fitness training involves science; it is nearly impossible to know if you are overtraining or achieving maximal training benefits without having detailed data on the kind of energy expended over time, as well as the power generated over time. It's like having an engine with gauges-- a speedometer tells you how fast you're going. A tachometer says something about the effort level of the engine, but only a dynamometer can tell us how much torque and horsepower that engine is making, in essence whether we've got a V-8 or a 4-cylinder on our hands.

Torque is a measurement of rotational force- like how much weight can you lift in a single moment in time.
Horsepower is a measurement of force over time- how much weight can you hold up in the air? And for how long? The time piece of this is as important as the force part.

Effective training improves three things:

1. Horsepower (measured in Watts for cycling - speed)
2. Torque (also known as force production- acceleration)
3. Aerobic fitness (measured in heart rate for a given speed - efficiency)

A balance of effort across these three variables is required to deliver your best fitness.

The good news is that there are simple tools that can really help us train smarter, akin to the engine tools noted above. Here they are:

- Any basic bike computer is a speedometer. Simple enough.
- A cadence counter is a simple tachometer- your car can go 30 mph in four or five different gears, so which one is best? It depends on the terrain.
- A heart rate monitor is another form of tachometer, linked directly to your heart. The bad news is that the response of the engine (your heart) typically falls between 30 and 60 seconds behind the level of effort at the wheels.
- A power meter is a dynamometer. Most relate horsepower in units of Watts. Some can also give torque, which relates more to an ability to accelerate or climb a steep hill at a low cadence.

A heart rate monitor combined with a bike computer's speed will tell us quite a bit about efficiency and power over time in the form of average speed. Higher efficiency and higher power equates to a higher average speed at a given heart rate. Higher efficiency may not always yield improved speeds- you can improve your efficiency without improving your speed if you just use long, slow distance training versus training that focuses on both power and efficiency- intervals.

A heart rate monitor combined with a bike computer's cadence on a long, steep hill will tell us lots about torque and power over time in the form of the time required to climb the same hill.

Here's what the tools I just named tell us: Relative changes over time, provided we use identical testing under reasonably identical conditions every time we test-- typically, the things we'd measure would be time to complete something (power), average speed and heart rate over a distance (power), average speed for a given heart rate (not reliable day to day but decent over long periods of time), distance achieved over time (acceleration and sprinting) or top speed in a given distance (sprinting) - using the same course and ensuring we're well rested each time we measure for comparison. Each test requires a different course and procedure.

Note that the key factor here is that we're recording relative changes, not absolute ones- how we did compared to other times versus how we do compared to a standard. This is useful data and it can help us improve our own performance. But it's really only useful to us as individuals over time unless we all do the same tests on the same course at the same time.

We call those races.

Each of these tools use data from instantaneous sources to produce a report over time, whether it's average speed or heart rate, or total time or distance.

In the same way, a heart rate monitor is critical to our performance monitoring, but it really just records instantaneous effort as opposed to overall intensity- put another way, which workout is 'harder'? Which workout gives more 'bang for the buck' of effort? If your car's engine runs wide open for 1 hour versus five hours at half-speed, which session is harder on the engine? That depends on the load it was carrying right? It also depends on what kind of fitness we're focusing on in that particular workout.

Which begins to explain the importance of having a longer-term plan.

If we want to take our fitness to its highest levels, we need absolute measurements, and tools that help us manage our training in terms of effort over time.

I plan to relate more on those tools and the science behind them in the days ahead.



Blogger GeorgeK said...

I'm looking forward to more on the subject of power vs. efficiency. Thanks for turning me on to TI swimming - I already notice a great difference and can't wait until I have more training under my belt. I'll be applying the same principles to my biking position for time trial racing and can't wait for better weather to experiment. I'll let you know how a mix of Yasso intervals and long runs works for my marathon training as well. Best of luck on Arrowhead - Ride Harder!

8:00 PM  

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