German scientists have collected data from six professional road cyclist´s during a multi stage race. The riders used the SRM system to measure power outputs and heart rate monitors to record heart rates. This study got my attention, because it shows the benefits of using a power meter in the races instead of just a heart rate monitor. It was published in Medicine and Science in Sports and Exercise, January 2006. Before I start advertising more for using a power meter system, I will tell you a little about the study setup.

Before the stage race the six riders performed an incremental cycling test in the laboratory. Peak power output, power output, and heart rate at the lactate threshold and at a lactate increase of 1mM above the lactate threshold were assessed. Based on the test results there were made 3 different intensity zones for both heart rate and power output. Zone 1 was below LT, zone 2 was LT to LT+1mM and finally zone 3 was above LT +1mM. After the testing session the riders were ready to compete in the stage race.

The scientists analyzed the time spent in the three target zones during the 6 stages. There were five mass-starts where the riders averaged 220 Watts and one uphill time trial with an average power output at 392 Watts. This is not breaking news for experienced power meter users. In an uphill time trial riders prefer to ride with a slower cadence and are therefore able to maintain a higher average power output and they have to go fast all the time which also adds Watts to the average power output. In the mass-starts the heart rate monitors over-estimated the time spent in Zone 2, and I am not surprised at all. The heart rate monitors recorded that the riders spent 38% vs. 14% recorded with the power monitor. Heart rate monitors are still valuable, but it is important to know the physiology behind to understand how it works. There is a delay in the heart rate due to oxygen deficit or repayment of oxygen debt. A professional cycling race is either slow or very fast, there is almost nothing in between. But when they ride this stop and go way, the average heart rate will be somewhere in between, in this case this will say Zone 2. This could lead to the wrong conclusion that training in heart rate target zone 2 is optimal for preparation to stage races. Listening to the power meter makes more sense to me, since it tells me instantly what the power output is and therefore gives a much more precise description of the effort.

Reference:
Vogt S, Heinrich L, Schumacher YO, Blum A, Roecker K, Dickhuth HH, Schmid A.
Power output during stage racing in professional road cycling.
Med Sci Sports Exerc. 2006 Jan;38(1):147-51.

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Power meters are very expensive and for many people it is a big decision to buy one. Polar offers one of the cheapest power measurement systems on the market, so it was interesting for me to see how it performed compared to the much more expensive SRM crank system. SRM crank system uses torque and angular velocity to measure power output, while Polar uses the vibration and speed of the chain to calculate power output.

British scientists made a study with 12 trained men who made 12 all-out efforts separated with short recovery periods. This study setup is very demanding for the power meters, since the stress on the bike is very high. The purpose of the study was to compare the agreement between these two different systems. The results were published in Journal of Sports Science, August 2006.

Polar underestimates power output

The main finding was that Polar underestimated the power output and did not agree with the power output from SRM. One of the great problems with the Polar was that it was greatly influenced by chain vibration and sampling rates.

These findings agree with the experiences I have been told about Polar. If you ride on cobble stones it is not reliable at all and it is necessary to change chain often. It is obvious that you can not get a precise system like SRM and only pay 1/10. For me Polar offers a cheap entry level for riders who would like to explore power outputs without spending all their money. I believe that you can make analyzes of races and get a good feeling of how races are. But I am not sure, that Polar is good enough for pacing in intervals. Maybe I should go try one?!

Reference:
Hurst HT, Atkins S. Agreement between polar and SRM mobile ergometer systems during laboratory-based high-intensity, intermittent cycling activity.
J Sports Sci. 2006 Aug;24(8):863-8.

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Inspiratory muscle training is done against an external resistance when you breathe. There are several products (POWERbreathe, PowerLung, Ultrabreathe etc.) on the market claiming they can significantly improve your endurance. I have done some studying in Cochrane Library and Pubmed to figure out what we know about inspiratory muscle training for trained cyclists.

Inspiratory resistance training improves maximum inspiratory pressure

Nearly all studies find that it is possible to improve the maximum inspiratory pressure, but it remains uncertain whether this improvement actually affects cycling performance. Most studies have in common that they have used very small study groups with less than 10 participants in each group in the randomized placebo controlled studies. I am pretty sure that inspiratory muscle training does affect maximum inspiratory, but these respiratory muscles are also trained during hard aerobic exercise.

Respiratory muscles get exhausted during hard exercise
The first time I was introduced to exhausted inspiratory muscles was after a long race with a very high intensity. When I took a deep breath afterwards, I could feel pain in my inspiratory muscles. My conclusion was that vo2 intervals and racing probably gives your respiratory muscles a great stimulus.

Inspiratory muscle training - Yes or no?

As I have previously discussed, it remains uncertain whether strength training improves aerobic endurance. It seems like we have a similar problem with respiratory resistance training: Strength training for inspiratory muscles and skeletal muscles both increases maximum strength, but it remains unsure if there is a benefit for you in a competition.In a Cochrane review it is concluded that “Currently there is insufficient evidence to suggest that inspiratory muscle training with external resistive breathing devices provides any demonstrable clinical benefit in patients with asthma.”

So until we get more scientific evidence, I can not advice you to use respiratory resistance training regularly because there is not (enough) evidence for its benefits. On the other hand there is no doubt that instruments like Powerbreathe, PowerLung or Ultrabreath can train your respiratory muscles in a way you can’t train them during endurance training. I can’t think of any unwanted side effects to respiratory training, so if think it sounds interesting you can give it try. They are non-invasive and inexpensive, so it might be a cheap improvement for your performance.

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When Lance Armstrong won the Tour de France back in 1999, he showed us a pedalling style with a very high pedalling rate, even in the mountains. Many experts have referred to this technique as one of the main reasons that Armstrong could beat his opponents so easily. With a high frequency it is easier to remove lactate from the legs, but it requires a high degree of special training to be able to maintain a high pedalling frequency.

There is no definitive answer
For me, cycling pedalling rate has always been some kind of a controversial topic. I am not sure that is possible to change riding style significantly. Nevertheless, I have tried to adapt some of my riders pedalling frequency to a faster one, believing that this would help them to save energy for the final parts of the races. My conclusion until now is that it is not possible to make big changes, probably in the area of on average 0-5 rpm higher pedalling frequency. So special training at high frequencies can probably not explain why some riders are able to do it and others are not. It is also worth to remember that a couple of riders who prefer slow frequencies also perform at world class level (e.g. Serguei Gonchar). Thus, a high pedalling rate per se is not

Slow pedal rate might be a better choice
I found an interesting study that is made of Ernst Albin Hansen, who is a scientist and previous elite cyclist that have been studying choice of cycling pedalling rate for more than 10 years. In the study 9 trained cyclists rode two rides of 2½ hours at 180W followed by a 5-min all-out trial.

Test setup:
• 180W, freely chosen pedalling rate (avg. 95rpm) followed by 5min all-out.
• 180W, calculated pedalling rate (which averaged 73rpm) followed by 5min all-out.

The calculated pedal rate was supposed to result in a minimum oxygen uptake.

Results
When comparing the two setups, some interesting results were found:
• Peak VO2 was lower after riding with freely chosen pedal rate
• Perceived exertion were higher with freely chosen pedal rate (7-9%)

These results indicate that riding like Armstrong might not be the answer for optimal cycling pedalling rate. If some of you think this study is interesting, you could consider trying the tests mentioned above in the gym during the winter. It is guaranteed a good workout for you. Tell us about your experiences!

Source:
1: Hansen EA, Jensen K, Pedersen PK. Performance following prolonged sub-maximal cycling at optimal versus freely
chosen pedal rate. Eur J Appl Physiol. 2006 Oct;98(3):227-33. Epub 2006 Aug 12.

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Exercise-induced muscle cramps are common among cyclists in the end of hard races. Some riders seem to have more frequent episodes of muscle cramps than others, but most cyclists have experienced the phenomena.

It is often written that hydration with water and different electrolytes may protect riders from muscle cramps, since dehydration and electrolyte imbalance is very close related to these involuntary, painful muscle contractions. One of the potential risks is exercising in hot environment because of dehydration and massive loss of sodium, potassium, magnesium and other electrolytes. When this water loss is recovered with plain water, there will be a net loss of electrolytes. In old days hard working people who worked in mines died because of an excessive water intake that diluted the concentration of electrolytes. This was called ‘Minors Cramp’.

Scientists from the University of North Carolina have published an article in Journal of athletic training, June 2005: Influence of Hydration and Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle Cramps.

In this study 13 men with a history of exercise-induced muscle cramps performed two tests that were made to provoke muscle cramps in the calves. One test was done with supplementation of water, carbohydrates and sodium, while the other test was done without any supplementation. The findings were that 9 people developed muscle cramps in the hydration/supplementation trial and 7 people did in the dehydration trial. These findings do not indicate that hydration and supplementation with carbohydrates and electrolytes protect against muscle cramps. It tells us that there are other factors implicated in development of exercise-induced muscle cramps. However, in the hydration/supplementation trial, the time to onset of muscle cramps were prolonged (36.8 minutes completed before onset, compared to only 14.6 minutes in the dehydration trial.)

In my opinion, the study should have included a trial with plain water only. This should be done to see if it was the water or the supplementation that prolonged the time to onset of muscle cramps.

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Many heart rate monitors and bike computers has a feature to measure the energy cost of the exercise. But can we believe these numbers? I have always been sceptical to these calculations since they are based on very few variables (percentage of maximum heart rate and total time). I have always said to my riders that they can use these numbers for fun, but don’t count on them when they cook dinner. There is probably huge variability in the quality of calorie metres, some gives a rough estimate and some doesn’t.

Can heart rate monitors be used to calculate energy expenditure?

Yesterday I found a study published in Medical Science of Sports and Exercise that tried to figure out how accurate the energy expenditure calculator of the Polar s-410 heart rate monitor was. They used three different calculations of the energy expenditure: 1) Polar s-410 using predicted values of VO2 max and maximum heart rate. 2) Polar s-410 using actual values of VO2 max and maximum heart rate. 3) Indirect calorimetry (You might have heard about this one in school…)

The results showed that the Polar s-410 did a quite good job for the men with no significant differences between the three calculation methods. The women’s numbers were overestimated when using predicted values of VO2 max and maximum heart rate. The estimation was better when they used the actual values but still overestimated with 12%.

Read the full article about Polar S-410

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