Friday, April 15, 2011

Are heart monitors still useful for cycling?


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Q.Dear BCSM,
I recently read about a study that brought heart rate monitors into question. The study said that there was a disparity between anaerobic thresholds when cycling vs. running. It basically brought the whole concept of heart-rate training into question. This concerns me because I cannot afford a power meter and I use a heart rate monitor cycling computer to measure my progress. Is this a good study, and are there other pitfalls with heart rate training we need to know? Should I dump the HR monitor?
— Peter
A.Peter,
The term anaerobic threshold is a bit dated, though unfortunately many people still use this term. If you could provide the specific article that you read, then I could comment further on that specific study. But the idea of the existence of a threshold intensity above which exercise capacity is limited can be measured in an exercise physiology laboratory in various methods such as using blood lactate concentration or measuring oxygen consumption and CO2 production relative to respiratory rate. Most tests used to evaluate a breakpoint in these physiological responses will then reference the value obtained relative to the testing method, such as lactate threshold or ventilatory threshold.
2008 World track championships, Neal Henderson and Taylor Phinney
The author coaching Taylor Phinney at the track world championships. Photo: Casey B. Gibson
In our physiology lab at Boulder Center for Sports Medicine, we use both methods but most importantly look at the associated power (watts), heart rate, and perceived effort at not only the breakpoints (or thresholds) but also across the continuum of effort from easy to threshold and to maximum effort. As a coach, I also like to establish not only laboratory threshold values, but also real world power output using tests such as constrained heart rate efforts as well as maximum power output tests from short duration (1-5 seconds), all the way to 1-hour maximum efforts. I usually have my athletes who are undergoing physiology testing also perform power output testing on their bike to look at the correlation between lab results and performance capacity.
When looking at different sports such as cycling and running, there are typically differences observed in peak or maximum heart rate in each activity — as well as the corresponding threshold heart rates. Generally speaking, running and cross-country skiing yield higher maximum and threshold heart rate values with respect to cycling. Swimming, on the other hand, is typically lower than cycling, though your training history and experience in a given sport can influence this. I also encourage the combined use of heart rate and perceived effort, in addition to some sort of output (power for cyclists, pace/speed for runners & swimmers) to evaluate training responses with my athletes.
The heart rate, though different from sport to sport, can still be a useful tool for training. The use or lack of a power meter does not mean that you should ditch your heart rate monitor; ideally you should integrate whatever tools you have available to track your progress. Without using a power meter, you could evaluate your progress occasionally (every month or two) by performing a trial effort from Point A to Point B while holding a constant heart rate and track your speed. I like to use a sustained climb of 15-30 minutes if possible, as this reduces the effects of differences of wind speed from trial to trial.

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Boulder Center for Sports Medicine was founded by Andrew Pruitt, EdD, PA-C, in 1998. For the past 12 years BCSM has been providing athletes from around the world with the highest possible level of care. BCSM offers a wide range of services, including Orthopedic Clinics, Physical Therapy, Expert 3D Bike Fitting, Running Gait Analysis, Coaching & Training, Nutrition Services, Performance Testing, and more. For more information, visit www.bch.org/sportsmedicine, or call (303) 544-5700.

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