by Grace Lin

In Stimulus Part 1, we talked about workouts geared toward increasing strength and taxing the central nervous system. In this installment, we will be focusing on the second category: Metabolic Conditioning.

What is metabolic conditioning? Metabolic conditioning refers to structured patterns of work and rest periods to elicit a desired response from the body, usually to maximize efficiency of a particular energy system (or metabolic pathway). These are the types of workouts that test how much work you can do in varying time domains, from 20 seconds to 20+ minutes. The purpose of metabolic conditioning is to build upon both muscular and respiratory endurance. There are three metabolic pathways we target in CrossFit.

Phosphagen (Anearobic): High Power, Short Duration – This energy system is the meat and potatoes to CF athletes – it’s what most people crave. Within the phosphagen pathway, we focus on short bursts of explosiveness through high-powered workouts. The activities in this domain require maximal effort and are very short in duration (about 12 seconds, max). These would be short sprints, 1-3RM lifts, etc.

Glycolytic (Anaerobic + Aerobic): Moderate Power, Moderate Duration – In this pathway, we focus on moderate-powered activities that last several minutes; this occurs after the phosphagen pathway has been expended. These would include workouts that last around 2-5 minutes. Using this type of energy allows our bodies to work in increased time domains, while keeping intensity high. Some examples of workouts that fall into this pathway are Fran, Grace, and Isabel.

Oxidative (Aerobic): Low Power, Long Duration – This is probably the most dreaded pathway for the majority of CF athletes. In this pathway, we focus on low-powered activities that typically last several minutes or even hours. Long duration or endurance workouts are geared toward training this system. The most famous example (in CrossFit) would be Murph.

Training within all of these domains is imperative to increasing your overall fitness and health. Dwelling in only one or two of these systems will create holes in our fitness. The CrossFit methodology is about being well rounded in all aspects of fitness, so that we are prepared for any situation. That means being able to move heavy weight AND also running 5K. So if you know you favor one or two of these systems, then make an effort to train that third system. Working on weaknesses will always increase overall fitness.

Stimulus Part 2: Metabolic Conditioning