Breakthrough Endurance

I usually try to avoid writing about myself. But after racing last week, I wanted to take some time to reflect upon my experience at ITU's World Championships. But first, let me explain what happened last year... Last year was a son of a bitch (I'll give a cookie to whoever gets that reference). It started well -- I raced well at the Kickstart Duathlon in Georgia and the Mount Rainier Duathlon in Washington. My fitness was good heading into Long Course Duathlon Nationals; I had set several PB's for 10-30:00 power on the bike and run some good track workouts. But after the Mount Rainier Duathlon, I had a sharp pain in my low back. Despite rest and chiropractic treatment, the pain persisted for two weeks leading up to Long Course Nationals. And during the race, the shit hit the fan. I got off the bike and struggled to start running. I had a really sharp pain in my back/glute with every step. I contemplated dropping out sever...

Some coaches will speak of the elements of performance as exclusive concepts. Aerobic and anaerobic metabolism for example. Traditionally, the two could be separately defined, but we've known for some time now that the two are essentially bound in a symbiotic relationship. They're both a piece of the pathway that creates ATP. A typical physiological response from high intensity intervals, sprints, a finishing kick or a high intensity (<30 min) race is an accumulation of lactate and H+ ions. We know an accumulation of H+ ions (acidosis) will decrease performance capacity. The table below from Cairns, 2006 lists some proposed mechanisms through which acidosis inhibits performance. If only there were a mechanism in place to remove these pesky ions... Then, we could perform at a higher intensity for a longer period of time. But wait, there is! Oxidative phosphorylation, more commonly known as the electron transport chain or "aerobic metabolism," consum...

Below, I've started creating a list of factors that influence running economy. Here, I'll define economy as the steady state O2 consumption required to maintain a given running velocity. This list is more of an open note that I intend to periodically update and modify as I, and we, learn more about running economy. As you can see, there are quite a few factors that can influence economy. Let me know if you think of any others! Training Strength/plyometric training Stiffness/flexibility Training volume Altitude training Pace/Power output Substrate utilization Training specificity Running Form Mitochondrial quality Uncoupling proteins Influence of training Heritable Substrate availability (O2 & CHO) More economical to burn CHO More economical when O2 availability is limited Fatigue VO2 slow component Motor unit activation - number and "type" Fatigue VO2 slow component Anthropometrics Body mass distribution Ankle/wrist circum...

I don't imagine this post will be relevant to many of you. Maybe you'll find it to be an interesting topic in physiology and medicine. But I want to put it out there to increase awareness, just in case any one has concerns over Warfarin use or is looking for answers. This past fall, I had a pulmonary embolism. This was my second, unprovoked episode -- the first occurred in 2011. Usually after the first event, you leave the hospital with a prescription for an anticoagulant (blood thinning) medication and you'll take it for anywhere between 3 and 12 months. After the second episode, your doctor will likely suggest you stay on anticoagulants indefinitely (or until gene therapy becomes avalable). There are a few anticoagulant options out there now -- Coumadin, Eliquis, Xarelto, and Pradaxa to name a few. So, how did I choose Warfarin? Coumadin, generically known as Warfarin, is the oldest of these anticoagulants. Having been around since the 50's we've had a lot of ...

Fractional utilization refers to the fraction of VO2max that an athlete sustains during an event. It varies between events and between athletes. An athlete can sustain a greater percentage of VO2max for a shorter duration (5000m vs. 10,000m). Fractional utilization is sometimes referred to as lactate threshold. While the concepts are related, they are not the same. Consider an athlete with a VO2max of 70 ml/kg/min: If we find that he can average 90% of VO2max over the course of a 5000m run, he averages 63.0 ml/kg/min for the race. If he averages 86% of VO2max during a 10,000m run, he averages 60.2 ml/kg/min. Athletes may train for years, increasing fractional utilization. By increasing fractional utilization, an athlete will be able to complete a distance at a greater percentage of VO2max. For example, if that same athlete increases his fractional utilization during the 5000m to 93%, he can now average 65.1 ml/kg/min. That 2.1 ml/kg/min increase in utilization means more O2 is cons...

Potential for Improving Endurance Performance through Substrate Conservation We know skeletal muscle needs ATP to contract and there are different pathways from which ATP can be synthesized. During endurance exercise, inevitably, some combination of glucose/glycogen and fatty acids will be used for substrate. Utilizing fatty acids for ATP synthesis could be beneficial for endurance athletes because humans have a virtually unlimited supply fatty acids, whereas stored carbohydrate is relatively limited - demonstrated below: 135,000 Cal from stored fat is roughly enough energy for a 65 kg person to run 2000 km (R. Margaria et al, 1963). A decreased reliance on carbohydrate and a subsequent increased reliance on fatty acids during exercise should help to "spare" muscle glycogen. Accepting the well documented theory that low muscle glycogen causes fatigue, one can see how glycogen sparing can potentially extend performance or allow for an acceleration late in a race. ...

Training Basics Training always involves balancing stress and recovery. A stress is applied to the system, the stress results in a deviation from homeostasis, acting as a stimulus for cellular signaling that leads to adaptation. This adaptation will leave the system better able to cope with the stimulus in the future (demand for ATP, substrate transport, muscle recruitment, etc). Generally, there is a dose-response to training so that the more training stress or training load encountered, the greater the signal and response to adapt. For example, if you had two groups of college kids, one group ran 10 miles per week (mpw) and the other group ran 30 mpw - after 10 weeks, the group that ran 30 mpw will likely outperform and/or show greater improvement over the 10 mpw group. Why? Because the 30 mpw group accumulated a greater training load resulting in a greater response. Of course, that's a very simple example. When it comes to training at a higher level - more is not always be...