Monday, March 22, 2010

Physiological Fitness - Economy

It's been a long time since I lasted posted anything here. Putting on a camp in Majorca wih all of the travel and time zone changes has made things a bit challenging this past few days. And then a flu bug on top of all of that really did me in. But I'm much better today and managed to find time between camp activities to do some writing.

The last of the big three physiological fitness determiners is economy. Sport science understands less about this one than the other two, but it may be the most important. It has to do with how efficiently you use oxygen while exercising. Measuring oxygen used is just another way of measuring energy during exercise since in the human body how much oxygen you use also tells you how much energy you’re expending. Your economy is much like the economy rating for a car. – how many miles per gallon of gas. Only in the case of exercise it’s how many milliliters of oxygen per mile.

The longer the race is the less important aerobic capacity becomes and the more important economy is. This is because at the longer distances you exercise at a lower percentage of your aerobic capacity. So having a big VO2max won’t be of great benefit. But wasting even a little energy per stroke or stride due to poor economy will add up to a lot of wasted energy – and a slow performance – in a long race.

We know what can be done to boost your aerobic capacity. You can do lots of miles and mix in high-intensity intervals. Economy is a bit different. There are some things you have control over, but many you can do nothing about. For example, we know that for swimming being tall with long arms and legs and big feet improves economy. Unfortunately, you can’t change those. In the same way, for cycling having a long femur bone relative to your total leg length improves economy. For running being short and small are good for your economy. As an endurance athlete economy is improved by having a greater percentage of slow twitch muscle fibers. And there are other improvements to our physiology we would also make if we had control over them such as increasing the number of mitochondria we have (these are the little powerhouses in the muscle cell that produce energy). These are all things we have little or no control over.

So what things can you control to improve your racing efficiency and use fewer milliliters of oxygen per mile? The most common technique. You must realize that if you decide to go this route and make changes to your current technique that there will be a period of time during which you become less efficient. This will show up as a higher than normal heart rate at any given speed or power. And it may take weeks if not months to make the new technique your normal. At that point you should be faster at the same heart rates as before.

Others that are beneficial for the bike and run are reducing excess body weight and using lighter equipment. Then there are sport-specific efficiency improvers. The most notable is aerobars on the TT or tri bike along with other aerodynamic equipment such as wheels, helmet and bike frame. As a swimmer you can improve economy by improving the flexibility of your shoulders and feet, especially the ability to point your toes. Interestingly, the research shows that having less flexibility in the ankle joint makes for more economical running as this appears to improve the release of energy stored in your calf muscle with each footstrike.

Training components that improve economy are intensity and frequency. Training at a high speed or power has been shown to make athletes more economical at all speed and power outputs including the lower range. But it doesn’t work both ways. Going very slowly doesn’t pay off with greater economy at the high end of speed and power.

One of the best ways to improve your technique and therefore your efficiency is to do your sport frequently even if each session is very brief. For example, for a triathlete to become a more efficient swimmer with only two hours a week to devote to it, swim four times a week for 30 minutes each time. That will improve your efficiency sooner than doing two, one-hour swims each week.

Plyometric exercises have also been shown to improve economy in both runners and cyclists. This involves doing explosive jumping, bounding and hopping drills. For the run brief, powerful hill repeats are much like plyometrics.

There is still a great deal of debate about whether or not traditional strength training with weights improves economy. I believe it does as I have seen so many of the athletes I’ve coached over the years improve their performances remarkably after a winter of lifting weights – provided they did exercises which closely mimic the movements of the sport. Doing curls is unlikely to make you a better runner. But doing step ups may help.

In summarizing the three physiological fitness determiners remember that aerobic capacity is largely the result of your genetics as optimized by steady training over many years. And the longer your race is the less significant this is to performance, even though it wouldn’t hurt to have a high VO2max. Lactate threshold is highly trainable and you should see a steady improvement in your speed or power when you reach this threshold. Economy may be the best determiner of performance of the three. But, as mentioned, we don’t know a whole lot about it and much of what is known to be important is out of your control. The things you do have some measure of control over often take a long time to accomplish (e.g., changing your technique), are difficult to achieve (e.g., lower body weight) or are expensive (e.g., lighter bike).

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8 Comments:

At March 22, 2010 12:09 PM , Blogger mehdi said...

"having less flexibility in the ankle joint makes for more economical running as this appears to improve the release of energy stored in your calf muscle with each footstrike."

I have been running for years and that's the first time i hear not being flexible could be a could thing.

Great blog.

 
At March 22, 2010 4:11 PM , Blogger Pete F said...

"So what things can you control to improve your racing efficiency and use fewer milliliters of oxygen per mile? The most common technique."

Ok now you're just teasing! Which is ...? Or is there an "is" missing?

A terrific post as usual Joe. It appears to me that there are two definitions of "efficiency"; intra-muscular efficiency (ie how efficiently an athlete's muscles utilise components, one of which is oxygen), and mechanical efficiency (the full and appropriate use of muscles). Would this assumption be accurate?

If "technique" is the most trainable in improving efficiency hopefully you'll cover some techniques in doing so. I know I'm terribly guilty of not being disciplined in consistently doing drills on the bike and stretching when off it to improve my efficiency.

Thanks for sharing you knowledge, and hope you get well soon.

Pete

 
At March 22, 2010 4:12 PM , Blogger Pete F said...

"So what things can you control to improve your racing efficiency and use fewer milliliters of oxygen per mile? The most common technique."

Ok now you're just teasing! Which is ...? Or is there an "is" missing?

A terrific post as usual Joe. It appears to me that there are two definitions of "efficiency"; intra-muscular efficiency (ie how efficiently an athlete's muscles utilise components, one of which is oxygen), and mechanical efficiency (the full and appropriate use of muscles). Would this assumption be accurate?

If "technique" is the most trainable in improving efficiency hopefully you'll cover some techniques in doing so. I know I'm terribly guilty of not being disciplined in consistently doing drills on the bike and stretching when off it to improve my efficiency.

Thanks for sharing you knowledge, and hope you get well soon.

Pete

 
At March 23, 2010 9:37 AM , Anonymous Ethan said...

Joe- Question about femur length. As a short-femured road cyclist do you know of any special concerns I might face in trying to get an optimal fit on a bike? My fit guy recommended the possibility of buying a TT frame for my next road bike. Any other concerns that you've heard of or come across over the years?

Thanks

 
At March 24, 2010 2:03 AM , Blogger Bahzob said...

Thanks Joe. Very much due to your emphasis on efficiency as something that can be worked on and improved, I have spent much of the winter working on this aspect. Done 4
things:
- train in race position: First year TT last year found a big loss in power in aero vs upright. So most every session now in aero. It was a bit depressing seeing lower power at first but sticking with it power is now not too different to up on the bars/
- get a wind tunnel session to find right compromise between power, position and comfort
- weights: main drill is the one from Training Bible: Single leg step up to bench 2xcrank length. I find this works the big muscle at the top of the leg in a way that feels very much like cycling.
- Get as much time as possible on a Wattbike. Don't know if u have come across these. Its an exercise bike thats different: it feels like a real bike and it gives unique real time feedback on how you are pedaling. It's really good. What's especially impressive is when doing really hard intervals I can keep power up and feel more comfortable simply by concentrating on keeping the display smooth. This translates very well onto the real bike.

 
At March 25, 2010 12:40 AM , Anonymous Coach Training said...

Nice post. You highlight something new regarding coaching. It is really informative....thanks for sharing.
Coach Training

 
At March 26, 2010 5:31 AM , Anonymous Rich said...

Do you think treadmill running can compromise form? No matter how much I focus on form I only go as fast as the belt so I am not getting the high turn over rate I want.

Also, if one throws "pick-ups" into a long run is that equivalent to a dedicated speed day?

Thanks for sharing your wisdom.

 
At March 26, 2010 8:31 AM , Blogger Joe Friel said...

Rich--There's both good and bad about TM running when it comes to run technique. Haven't got time to get into it here, unfortunatly. Camp going on in Majorca.

 

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