Thursday, January 22, 2009

Less is More, More or Less

Much of our decision making process in based on our perception of reality. We may have a “gut” feeling about something one way or the other but what exactly causes this? Gerd Gigerenzer describes simple rules of thumb which become the basis for our decisions . The rules of thumb ignore other information. For example, we have a recognition rule of thumb or heuristic that enables us to process something familiar to us very quickly. Studies have shown that many times keying in on a couple of the most important variables is a much more valuable predictor of a future outcome than many weighted variables. The art is knowing which information to ignore.
An example is an ingenious study design in which used a very sophisticated set of computer generated variables to try and predict which Chicago schools would have the highest rate of dropouts. The data from the first half a of schools were used as a predictor for the second set of schools. It turned out that asking two questions fared better as a predictor of the future “What was the attendance rate” and if that was more or less the same moving on to the next question which was “what were the test scores”.
The healthcare arena has many examples. One of the most compelling was some research done at the University of Michigan on coronary care. It was found that predicting heart attacks as a basis for ICU admission was no better than chance. Much of this was attributed to the spector of malpractice ans so called “defensive medicine”.This meant that you had a 50/50 chance of being placed erroneously in the ICU with the associated risks of infection etc. It was discovered that too much emphasis was place on medical history questions such as a history of diabetes or hypertension. After constructing a very elaborate logistical regression instrument results improved as expected. Many of the doctors did not like using this method because they found the charts cumbersome. When the instrument was taken away surprisingly doctors were able to predict about as well because they were armed with a better internal algorithm for making a choice after being exposed to the more complex instrument.
It turned out that the most important question was whether or not there were ST segment changes on the EKG and if so the ICU was statistically the right choice.. The next most important question was whether the admission complaint was chest pain and if not a regular nursing unit bed was more appropriate.

Monday, January 19, 2009


Sunday, January 18, 2009

Fatigue and Injury

We all know the effects of individual muscle fatigue on injuries, your leg muscles get tired and all of a sudden you injure your knee. EMG studies have shown that the anterior shin muscles fire 85 % over their fatigue threshold in running. Hence it is no surprise that many runners develop shin splints. It turns out that over all fatigue plays an important role just as localized muscular failure to an area. No one has been able to prove decisively why this happens but it is probably multifactorial. As our
form degrades with fatigue we are in a less stable position to prevent injury. It is also reasonable to assume that as you fatigue the brain's ability to execute precise movement patterns also degrades. What to do? Develop the core and support muscles. Heighten the body's spatial awareness with agility drills. This is why track work deconstructs the running stride and uses drills to help perform more efficiently.

Lost In Space

Recent research has now confirmed how we process are movements. We have two ways we measure where we are in space without thinking about it. The first way is with something called plate cells. Plate cell are neuron's connected to the hippocampus. If you are in your kitchen and you are navigating to the refrigerator in the dark you are activating the plate cells, Grid cells help place where your body is regardless of context.The cells allow you to triangulate where you are in space.

The ability to tap into practiced movement patterns works a little differently. While we are learning the movement we are using the conscious part of the brain known as the I-function. Once we have learned the movement pattern we can access the practiced
movements and go on auto pilot. The I-function does not have to be burdened. When
we have learned a movement sequence it becomes more difficult to consciously think
about the movements versus just doing it. Imagine thinking about each key stroke while you were playing the piano. Much of coaching performance revolves around not over thinking movements.

We use this knowledge to retrain our body after injury. A good example is how we rehab
after an ankle sprain. A wobble board stimulates the vestibular cortex. People adapt quickly. This helps recalibrate your ankle balance after an injury.

Friday, January 16, 2009

Resistance (Strength) Training for Cyclists

This submission is from Dr. Paul Glodzik:

I decided that this would be a good topic to cover since I recently attended a very good seminar on Olympic lifting. I also just started to interact with some fairly high- level racing cyclists. One of them asked me how resistance training could benefit a cyclist. I had to stop and think because there are multiple answers, which led me to write this article. I need to explain some concepts that the average cyclist or person in general doesn’t know or correctly understand about resistance training. It is unfortunate that most people think about resistance training and someone like Arnold Schwarzenegger immediately comes to mind. There are many styles of resistance training that have completely different effects on the body than bodybuilding, the method Arnold used. Never mind the large doses of steroids he did as well. Bodybuilders are interested in increasing the size of their muscles without any regard for function. The increase in muscle size and mass is a concept known as hypertrophy. Most cyclists know that this extra size and weight is not advantageous when on their bike. Fortunately, there are other ways to resistance train and get stronger with little to no hypertrophy.
The types of resistance training that can be used by cyclists can be broken into three major categories - endurance, strength, and power. Of these the easiest to explain is endurance training. By endurance I am speaking of muscular endurance. This is something most cyclists have experience with. Muscular endurance can be increased in many ways. You can cycle for long time periods at lower energy outputs, run distances, perform aerobics, or resistance train using lighter weights with higher repetitions. If you are training for a century ride with the goal of only finishing this is the type of training you need to perform the most. That doesn’t mean you should neglect the other types of resistance training, however.
To understand strength training you need to know the definition of strength. Strength is the ability to exert a force against an object. When you are trying to increase your strength the object is to be able to produce more force. This can be accomplished in different ways in the body. Increasing the cross sectional size of the muscle (hypertrophy) is one way. However that is not what a cyclist wants. You can increase the amount of muscle fibers recruited within a muscle to make that muscle more efficient and you can increase synchronization of muscles that work together. Exercises such as squats, dead lifts or pull-ups are examples of this type of exercise. When performing exercises for strength you should work yourself up to a point where you are using very heavy weights but with only a few repetitions. By doing so you will minimize the hypertrophy but still increase your strength. One example of the effects of strength training would be the effects on your quadriceps. By performing strength exercises a cyclist will have more efficient quadriceps muscles that can keep a consistent pedal rate over a longer time. The muscle doesn’t need to recruit as many fibers to produce a certain force at first and then can recruit more fibers as fatigue begins to occur.
The final category is power training. To understand this, power needs to be defined as well. Power can simply be defined as follows: Power = Force x Rate. This means that a force is exerted on an object just like true strength training but there is a time component to it. Power exercises are also known as Olympic lifts because they are in the Olympics. The exercises that fall into this category are the clean and jerk and the snatch. These exercises are extremely explosive and they produce huge amounts of force over a very small time frame. Most cyclists would believe these exercises have no real benefit to them. I would have agreed until I went the seminar I mentioned earlier. There is research that proves that anaerobic exercise, which power exercises are, can actually increase aerobic capacity but not the other way around (Paavolainen). I wouldn’t advocate that cyclists start performing Olympic lifts without professional help, however. It is not say these exercises wouldn’t benefit a cyclist’s power output, but because they are very technical and hard to teach. There are power assistive exercises that can be used instead. Think of it this way - if you are in a race and suddenly someone jumps out of their saddle to try and break away, in many cases you want to be able to follow them. If you are 100 meters from a finish line, you may need to sprint. By performing power exercises, you would be able to increase your power output very quickly and be able to catch that rider or out-sprint the other riders.
A type of training that has become very popular, and in my opinion, most important, is core training. To truly tie together all of your training, you must train your core. Most core exercises are performed with the main goal of stabilizing joints, have fairly low force production, and can be held for long periods of time. A plank or side bridge is a good example of this type of exercise. Core exercises are usually performed with only your own body weight or a medicine ball. When you are riding for three or four hours in a row do you ever notice that your back starts to ache? There are many reasons for this, but a major one is that you are in a tucked position and your core muscles are not working to stabilize your spine. If you perform exercises to strengthen your core muscles, the increased stabilization will allow you to withstand the tucked position for longer periods of time on rides.
Now that I have explained the different types of resistance training, most people will want to know what exercises to do. That is a bit extensive for an article like this, but I can at least start you off in the right direction. To begin with, decide what you are attempting to gain from your resistance training. Are you looking to increase your leg strength, or decrease the effects of a long ride? Maybe you have been training using wattage and realize that you are not producing the output you would like so you want to increase your power. Once you have decided on what it is you are attempting to accomplish, you need to figure out how often, where, and with what equipment you are going to train. If you don’t have these questions answered you will never stay with your training program. I am not a fan of using machines to resistance train. When you are using a machine only one specific movement or muscle is being trained. Have you ever tried to ride by using your quadriceps only? It doesn’t work that way! By using free weights (dumbbells and barbells) you are training multiple muscles and also forcing yourself to stabilize joints. When you use a machine, stabilization is already done for you.
This is the point at which things become difficult because of the specificity of training for each person. Two riders may want to accomplish the same thing but are starting at totally different points in training. The easiest way to figure out what you should be doing is to know how much training you have had and how advanced you are with different exercises. If you have never touched a weight in your life, any basic exercise routine that works the major muscle groups will help. If you have trained for years and are proficient at many exercises, it may be time to find yourself a strength and conditioning coach. If you are looking for a trainer, your best bet is to talk to the other people you ride with or talk to the riders you would like to be more like about coaches (trainers) that they trust.
I feel I should discuss safety a little. Resistance training when performed properly has very little chance of injury (Stone). Having said that, you need to learn how to perform the exercises correctly and listen to your body. No one would get on a bike and ride 100 miles if they hadn’t trained for a while. The same concept applies to strength training. Don’t use weights that are too heavy and cause you to break technique. Remember that a good training regimen should always have rest periods or decreased training loads built into it. That way, over-training doesn’t occur.
If you have any questions feel free to contact

Paavolainen L, Häkkinen K, Hämäläinen I, Nummela A, Rusko H. “Explosive-strength training improves 5-km running time by improving running economy and muscle power.” J Appl Physiol. 1999 May;86(5):1527-33.

Stone, M., et al. "Injury Potential and Safety Aspects of Weightlifting Movements" Strength and Conditioning 16(3):15-21, 1994.