Part 3: Energy System Development
Physical preparation is pretty straightforward with respect to strength (producing force) and power (producing force quickly). Conditioning, or energy system development (ESD), on the other hand is far more complex. Let’s start the conversation by establishing a point of differentiation between complex and complicated within the context of physical preparation. Processes that are linear, with multiple moving parts, but that come together to form a whole, are complicated; pieces are identifiable and the outcome is fairly predictable. Processes that are non-linear, with parts that may not even be visible, and which only elicit a desired outcome under specific conditions, are complex. Strength and power are complicated, energy system development is complex.
The Systems
Most seasoned trainees can probably identify the two primary systems: anaerobic and aerobic. Anaerobic metabolism works primarily without dependence on oxygen - although never completely - and aerobic metabolism is oxygen-dependent. Although from a functional perspective, both are oxygen-dependent. Within the anaerobic system, there are two subsystems: alactic and lactic - also called glycolytic. The alactic system produces the highest output and can only provide energy for limited periods of time - sub 10s for most tactical athletes. The lactic system is also a high output system but produces lactate, which is indirectly responsible for the “burning” in muscles during high intensity, longer duration exercise - > 45 seconds to about 5 minutes in tactical populations. The aerobic system provides some oxygen to support lactic system function in proportions inverse to intensity - higher intensity, less oxygen; lower intensity, more oxygen. As duration increases, intensity decreases and the aerobic system provides the majority of energy.
Practical Function
The alactic system is not active frequently because of other environmentally limiting factors and is primarily trained through strength training. During most tactical training and combat scenarios, the lactic/glycolytic system is heavily taxed by fast movement over ground and under load or from moving from cover to cover. Many tactical athletes spend a good deal of time training the lactic/glycolytic system at > 90% of maximum heart rate. The aerobic system supports the majority of other activity - running, rucking, swimming, general movement over ground, while also supporting the recovery of the lactic system. Oxygen helps cells metabolize lactate in order to prepare for another high intensity bout of activity.
80/20
Much like a weapons system, it takes much more time to prepare for its use than it does to actually use it. From being in a firefight, to fighting an actual fire, to pursuing a perpetrator on foot: these outputs are only a fraction of a percentage of time spent training for them. With that in mind, we advocate a “polarized” training model where athletes spend about 80% of total training time at lower, primarily aerobic, intensities and 20% of their time at very high, primarily glycolytic intensities.
In the above scenarios, fatigue is rarely the reason tactical athletes are forced to slow down - adrenaline notwithstanding - lactate tolerance is usually the rate-limiter. From a training perspective, high volumes of aerobic capacity work allow muscle cells to convert lactate into a fuel source during higher intensity outputs and high intensity glycolytic training improves the ability to “tolerate” higher levels of lactate without decreasing output.
Circling back to the weapons system analogy, tactical professionals spend an inordinate amount of time preparing their weapons systems for their use - this is equivalent to aerobic capacity work. Tactical professionals then spend a good deal of time on the range perfecting marksmanship skills, probably around 1/4 of the time they spent on maintenance of the weapons system - this is equivalent to glycolytic work.
All of this preparation for a few cumulative minutes of contact in a firefight…