Cyclingnews Fitness Q&A - February 24, 2011

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Lucas Euser gets the tape treatment on the knee which was severely damaged almost exactly a year ago when he was struck by a car while training in Girona, Spain.(Image credit: Wil Matthews)

Got a question for the fitness panel? Send it to fitness@cyclingnews.com. Emails may be edited for length or clarity, but we try to publish both questions and answers in their entirety.

If you've eaten recently, more blood goes to your gut to support peristalsis and absorb the nutrients absorbed during digestion. The heart always gets the blood it needs to support it's pumping, since otherwise it doesn't pump. As you start to exercise, your muscles need more oxygen and fuel, and need to dump more CO2 and waste heat. Blood is directed to the muscles and away from the digestive system.

In order to supply blood to the skin, it has to be shunted away from muscles, so on the hotter the day, the less blood goes to the muscles at the same heart rate. To some extent, heart rate can increase so you can maintain normal power so long as that power is well below your cool-day peak, but that effect is limited. Any sustained, aerobic power that is near your LT on a cool day will be above your limit on a hotter day simply because your ability to deliver oxygen to your muscles is compromised by the need to deliver it to your skin for cooling.

Now you can probably understand why eating while riding becomes more challenging on hotter days, even for well trained athletes. Blood volume may be enough to support digestion and muscular work, but not enough to support digestion, muscular work and cooling. Endurance training in the heat will cause a further increase in plasma volume beyond that caused by endurance training in pleasant weather, but won't be enough to completely negate the effect of heat on performance.

There is one more important effect to discuss that would prevent you from performing as well on a very hot day as on a cooler day, even if you could pump enough blood to deliver normal amounts of oxygen to your muscles at all work rates: Your brain doesn't want to be boiled. Your brain only works well in a narrow range of temperatures, and completely fails (you die) if you get outside that range, so your brain has evolved some very effective safety mechanisms for keeping your core temperature in that good range.

Training in the heat, because you are making less power, is less effective than training in more pleasant conditions, so do a bit of heat acclimatisation training, but do the majority of your training in the early morning before the heat of the day. Note that you can acclimate to heat by exposure to heat, on or off the bike, and that exposure to cool undoes the effect, so dress warmly if you'll be in air-conditoned spaces in the summer. (That's one reason you see pros wearing sweaters and hats on days when you'd think they really ought not to need them).

3) Too rapid build up of volume. You are right that 8-10 hours is not that much riding in a week, but it's a lot for someone who has been off the bike for several weeks or more. Try maintaining 3-4 hours per week of pedaling during your rest period, or starting from a week of half-hour rides if you take a long break. In either case, add only an an hour per week if your knees are giving you any trouble, and only two hours if they aren't. You'll soon enough be up to real volumes again.

Unlike the other quads, the muscle fibre orientation of the VMO is oblique meaning that it is the prime muscular lateral stabliser of the knee. Unlike every other muscle in the body (except one small ankle muscle that I forget the name of) the VMO will lose strength significantly after just a few days of inactivity. I've done a bit of research on this and my best guess (and that is all that it is) is that the lateral orientation of the fibres is a relatively recent evolutionary acquisition.

To your case; based on what you say, something about your gait or footplant doesn't allow you to use your VMO well and that you have a tendency towards instability at the knee. Once on the bike, you are still unstable to some degree (pain) but the action of riding loads your VMO, strengthening it and improving your knees stablity. The initial soreness is likely to be a weak VMO being forced to work again. The pain disappears as more riding equals stronger VMO equals more stable knee.

So tell your wife that you need to ride your bike more often... It works for me. A personal example of the benefit of strong VMOs: I have a severely unstable left knee from a teenage accident. To counter this I have developed very large VMOs relative to the rest of my leg muscle development. While ever I ride regularly I can do anything on my dicky knee including a lot of things that I am not supposed to be capable of with the damage I have.

In May 2010, after a condition of exhaustion and palpitations, I have been diagnosed with thyroid thyloma CA and had an operation in July 2010. Now, I have been stabilised and taking 175 µg T4 prescription. I feel fine, I've been jogging and cycling at a light volume and doing some intensity sessions. I am not sure how far I can return to my normal training and event participation. My doctor says to "live normally" but I know that sports at higher intensity than simple weekend activities are not what he means!

I recently purchased some knicks (by the same manufacturer) for training and racing that have differing chamois thickness and shape. The racing knicks chamois have 14mm high, 120 density foam at the contact area of the pelvic region whilst the training knicks have 8mm of high density foam. Both have mid level impact foam at the frontal region however the racing knicks chamois is shorter in the front section.

I also have one pair that were given to me as a present and they are made by a well known high end brand and have an unusually thick (at least by my standards) chamois. My body weight on the seat compresses this extra thickness to some degree, but unless I drop my seat post 3mm further into the frame than normal, I struggle on the hills or when riding big gears on the flat. I'm 18kg heavier than you so the effect is probably even more apparent for you than for me.

Scott Saifer (www.wenzelcoaching.com) is head coach, CEO of Wenzel Coaching.com and has been coaching cyclists professionally for 18 years. He combines a master's degree in Exercise Physiology with experience in 20 years of touring and racing and over 300 road, track and MTB races to deliver training plans and advice that are both rigorously scientific and compatible with the real world of bike racing.

James Hibbard progressed from the junior to the professional ranks as a rider and has over 15 years of competitive cycling experience. He is a former Collegiate All-American track cyclist, trained as a resident athlete at the United States Olympic Training Center, earned international medals as part of the U.S. National Team, and was a member of the powerhouse Shaklee and HealthNet Professional road cycling teams.

Carrie Cheadle, MA (www.carriecheadle.com) is a Sports Psychology consultant who has dedicated her career to helping athletes of all ages and abilities perform to their potential. Carrie specialises in working with cyclists, in disciplines ranging from track racing to mountain biking. She holds a bachelors degree in Psychology from Sonoma State University as well as a masters degree in Sport Psychology from John F. Kennedy University.