01/06/2021 # Home
Biking, running, swimming, rowing, speed skating, and cross-country skiing are collectively known as “metabolic conditioning.”
In the common vernacular they are referred to as “cardio.” CrossFit’s third fitness model, the one that deals with metabolic pathways, contains the seeds of the CrossFit “cardio” prescription. To understand the CrossFit approach to “cardio” we need first to briefly cover the nature and interaction of the three major pathways.
The Metabolic Pathways (Aka CrossFit’s Third Fitness Model):
There are three metabolic pathways that provide the energy for all human action. These “metabolic engines” are known as the phosphagen (or phosphocreatine) pathway, the glycolytic (or lactate) pathway, and the oxidative (or aerobic) pathway.
The first, the phosphagen, dominates the highest-powered activities, those that last less than about 10 seconds. The second pathway, the glycolytic, dominates moderate-powered activities, those that last up to several minutes. The third pathway, the oxidative, dominates low-powered activities, those that last in excess of several minutes.
Total fitness, the fitness that CrossFit promotes and develops, requires competency and training in each of these three pathways or engines. Balancing the effects of these three pathways largely determines the how and why of the metabolic conditioning or “cardio” that we do according to CrossFit’s methodology.
Favoring one or two to the exclusion of the others and not recognizing the impact of excessive training in the oxidative pathway are arguably the two most common faults in fitness training.
Of the three metabolic pathways the first two, the phosphagen and the glycolytic, are “anaerobic” and the third, the oxidative, is “aerobic.” We need not belabor the biochemical significance of aerobic and anaerobic systems; suffice it to say that understanding the nature and interaction of anaerobic exercise and aerobic exercise is vital to understanding conditioning. Just remember that efforts at moderate to high power and lasting less than several minutes are predominantly anaerobic and efforts at low power and lasting in excess of several minutes are predominantly aerobic. As an example, the sprints at 100, 200, 400, and 800 meters are largely anaerobic and events like 1,500 meters, the mile, 2,000 meters, and 3,000 meters are largely aerobic.
Aerobic training benefits cardiovascular function and decreases body fat–all good. Aerobic conditioning allows us to engage in low-power extended efforts efficiently (cardio/respiratory endurance and stamina). This is critical to many sports. Athletes engaged in sports or training where a preponderance of the training load is spent in aerobic efforts witness decreases in muscle mass, strength, speed, and power.
It is not uncommon to find marathoners with a vertical leap of only several inches! Furthermore, aerobic activity has a pronounced tendency to decrease anaerobic capacity. This does not bode well for most athletes or those interested in elite fitness.
Anaerobic activity also benefits cardiovascular function and decreases body fat! In fact, anaerobic exercise is superior to aerobic exercise for fat loss! Anaerobic activity is, however, unique in its capacity to dramatically improve power, speed, strength, and muscle mass. Anaerobic conditioning allows us to exert tremendous forces over brief time intervals. One aspect of anaerobic conditioning that bears great consideration is that anaerobic conditioning will not adversely affect aerobic capacity. In fact, properly structured, anaerobic activity can be used to develop a very high level of aerobic fitness without the muscle wasting consistent with high volumes of aerobic exercise! The method by which we use anaerobic efforts to develop aerobic conditioning is “interval training.”
Basketball, football, gymnastics, boxing, badminton, tennis, track events under one mile, cricket, swimming events under 400 meters, volleyball, wrestling, and weightlifting are all sports that require the vast majority of training time to be spent in anaerobic activity. Long Distance and ultra- endurance running, cross-country skiing, and 1,500+ meter swimming are all sports that require aerobic training at levels that produce results unacceptable to other athletes or the individual concerned with total conditioning and optimal health.
We strongly recommend that you attend a track meet of nationally or internationally competitive athletes. Pay close attention to the physiques of the athletes competing at 100, 200, 400, and 800 meters and the milers. The difference you are sure to notice is a direct result of training at those distances.