Breakthrough Endurance

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...

The "big three" determinants of endurance exercise performance are VO2max, pH threshold (sustainable pace) & exercise economy. We could also include anaerobic capacity and maximal speed/power as components that could determine the outcome of a sprint finish. The importance of running economy has been documented many times, and is often regarded as a strong predictor of performance, especially between individuals with similar VO2max values (Saunders et al. 2004; Daniels 1985). I've written on training for economy in the past. Training strategies such as hill sprints, resistance training, plyometrics or high intensity intervals have all shown improvements in economy.  In two studies, Saunders et al. (2004, 2009)  have also shown improvements in running economy following altitude acclimation. A study by Czuba et al. (2014) produced similar results in elite level biathletes and Latshang et al. in mountaineers (2013). Potential mechanisms? Stays at altitude are...

Lower peak lactate levels at high altitudes Oxidative phosphyorlation is a consumer of NADH + H+. But at altitude or under hypoxic conditions, an individual's ability to utilize oxidative phosphorylation is negatively affected by the decreased availibility of O2. Consequently, NADH + H+ accumulates and acidosis occurs. H+ accumulation inhibits glycolysis. Inhibition of glycolysis = decreased pyruvate and lactate production. Further, at altitude respiration rate increases at rest. This increases blood pH. This increase in pH at rest causes bicarbonate to be excreted from the kidneys. Loss of bicarbonate reduces the athlete's ability to buffer H+. H+ accumulation ---> acidosis ---> inhibition of glycolysis ---> decreased lactate production. Again, could supplementation with beta-alanine limit acidosis, offset the lactate paradox, and maintain work capacity at altitude?

Around 2009, I discovered the supplement beta-alanine and at that time I was intrigued by something that could potentially improve H+ buffering capacity and exercise performance. In the summer of 2011, I went to a symposium at the ACSM's annual meeting that discussed (as well as promoted PowerBar's) beta-alanine supplementation for performance enhancement. Below is a presentation I gave later that summer as an intern at Carmichael Training Systems. Since 2011, we've had more literature published and I'll try to discuss a few of those below the posted presentation as well as provide some food for thought and suggestions for future research. In short - beta-alanine supplementation has consistently shown that it increases carnosine in skeletal muscle and carnosine is understood to be an effective intracellular buffer. What's not clear is if that leads to increases in performance - but there is potential. Since the time of this presentation, we've had ...