Vitamin D

March 2, 2009

vitaminsI started feeling a lot better lately. It also happened to coincide with my taking my cod liver oil supplements once again, which, as we all know, are rich in vitamin D. Living in a Northern clime, it’s not a bad idea to take these during the winter.

Understanding Interval Training

February 19, 2009

Stephen Seiler has a nice description of what happens in your muscles when you undergo interval training. It really serves to illustrate the differing physiological responses that come about with different durations at any given intensity. It also serves as a reminder as to why you don’t want to go 110% all the time (hint: optimal stimulus for cardiac stroke volume improvement is not the same as that required for widespread capillary growth and oxidative enzyme upgregulation.)

One interesting take on the article, if you look at the data he presents, is that you can have your cake and eat it too, if you exercise strict discipline. If interval duration is kept short enough, you can accumulate many minutes of time at faster than race-pace velocities while keeping the concentration of lactic acid in your muscles about what it would be at a more moderate, steady-state pace. The advantage of introducing that sort of training is that you work on neuromuscular efficiency as well as increasing oxidative capacity of type IIa muscle fibers.

Notice from the data, however, that if you ‘overcook’ the interval duration by even 60 seconds, the lactate concentration can almost double. You cross from a zone where you are training your cells to upregulate pyruvate dehydrogenase, an enzyme that aids in speedy aerobic metabolism, to a no-man’s land where you neither optimally stimulate aerobic or anaerobic metabolic pathways.

Cycling (and cross-country skiing for that matter) are aerobic sports, so next time you work out, give some thought about your specific goals for the day. Are you trying to improve stroke volume? Then go flat out for 3 minute intervals that hurt like the dickens. Do you want to raise your velocity at LT, the number one determinant of endurance performance? Then remember the lessons from the Seiler article and give your muscles the conditions they need to adapt.


February 11, 2009

I haven’t posted here in a while because I’ve been sick. Rather than encourage further fatigue from developing, I’m taking a short break from the bike and skis. That is easier said than done, since we know that mitochondrial enzymes seem to have a half life of about 7 days, so I am detraining. Alas, that’s better than the alternative, which is getting really sick.

5 Minute Barrier

February 8, 2009

Today marked my achievement of getting to the 5 minute barrier. The last minute hurt, and my legs were getting ready to shut down by the end. I’m thinking that I may do additional 5 minute reps at this power output until the duration starts to feel a little easier. It’s probably not realistic to expect one minute improvements every time I get on the bike.

It does feel great to set a goal and then meet it, even if it does represent a baby step towards my overall goal.

Getting to Five

Getting to Five

Power Training To Increase Performance

February 6, 2009

This paper, by researchers in Finland, examines the link between neuromuscular power and running economy. What’s interesting to note here is that runners improved 5k performances without a corresponding increase in VO2max. However, the neuromuscular improvements associated with power training made them more efficient runners at race paces, and thus faster overall.

It seems that any quality training program should include some emphasis on power development. This would be especially true for cycling, which requires a high loading of the vastus lateralis and the ability to maintain high power for long periods of time.


Paavolainen, Leena, Keijo Ha¨ kkinen, Ismo Ha¨ – 

ma¨ la¨ inen, Ari Nummela, and Heikki Rusko. Explosive- 

strength training improves 5-km running time by improving 

running economy and muscle power. J. Appl. Physiol. 86(5): 

1527 – 1533, 1999training, whereas the development of maximal O2 

uptake (V˙ O2 max) is not influenced as much (e.g., Refs. 

10, 16, 18, 22). These observations are mainly based on 

experiments in which heavy-resistance strength train- 

What makes this study interesting is that it deals with trained athletes whom presumably have already attained a fairly high VO2max as a result of prolonged training. It would be interesting to compare the training program used in the study with a control group that performed short intervals at slightly faster than race pace for comparison. If neuromuscular adaptations are most specific to both the force and frequency of movement, then it would stand to reason that intervals at slightly higher than race pace would be at least as effective, perhaps even more, at decreasing 5k times.


February 5, 2009

Here’s a Paleo lunch. If you haven’t heard of Dr. Loren Cordain yet, you should definitely check out his work. He wrote both “The Paleo Diet” and “The Paleo Diet for Athletes.”

Prep time: about 120 seconds.

Paleo Lunch

Paleo Lunch



1 Avocado, 1 Tomato, Smoked Salmon Trim.

Muscle Fiber Adaptation Varies Depending on Workload

February 5, 2009

This article goes more in depth regarding the adaptations you see in skeletal muscle with various workloads. Notice the principle of specificity at work.

Human skeletal muscle fiber type adaptability to various workloads

RS Staron, RS Hikida, FC Hagerman, GA Dudley and TF Murray

Muscle biopsy specimens were removed from the vastus lateralis muscles of three groups of human subjects: controls, weight lifters, and distance runners.

A Must Read

February 5, 2009

When possible, it’s always better to read the original paper rather than just the abstract. Here’s a link to a must read paper on endurance by JO Holloszy and EF Coyle. Taken by itself, it could provide fuel for the ‘more is better’ approach, but remember to take everything with a grain of salt. After all, we are people, not rats, and there’s more to life than the number of mitochondrial enzymes in your quadriceps.

Here’s the abstract

Regularly performed endurance exercise induces major adaptations in skeletal muscle. These include increases in the mitochondrial content and respiratory capacity of the muscle fibers. As a consequence of the increase in mitochondria, exercise of the same intensity results in a disturbance in homeostasis that is smaller in trained than in untrained muscles. The major metabolic consequences of the adaptations of muscle to endurance exercise are a slower utilization of muscle glycogen and blood glucose, a greater reliance on fat oxidation, and less lactate production during exercise of a given intensity. These adaptations play an important role in the large increase in the ability to perform prolonged strenuous exercise that occurs in response to endurance exercise training.

Why No Watts/kg?

February 5, 2009

Astute readers may ask why I haven’t set a target for watts/kg. It’s a good question, and an issue for which I have a healthy respect. One oft-heard statistic states that if you can maintain 7w/kg for 30 minutes, you can win the Tour de France. In theory.

I’ve witnessed first hand what can happen when an obsession with the weight side of the equation leads to unhealthy behaviors. Through my own and others’ trials, it’s easy to see that there is so much more to enjoying your sport than the number reported by a scale.  Focusing on weight also disregards much more important parameters, such as your actual metabolic fitness and how you feel. As such, I’m purposely leaving out any discussion of weight when measuring performance in this blog.

Having said that, I’m about 5’6″ and a solid mesomorph. My dad is a really good sprinter, and my strength is doing out of the saddle uphill efforts that last 2-4 minutes in a huge gear. I have no idea what I weigh, and I don’t really care at this point, because it doesn’t matter.

Interesting article by Kirk Willet

February 5, 2009

This article by Kirk Willet has been around for a few years, but still merits a read.

This result suggests that mitochondrial density adaptations can be achieved in a reasonably duration independent manner (Dudley et al., 1982).  The overall higher mitochondrial densities associated with the higher intensities outlines the potential need for mitochondrial uncoupling and the AMPK signaling, at least beyond the completely untrained state.

-Kirk Willet