Inner Workings of Energy Systems During Tactical Operations

By, Carson Fralin– O2X On-Site Specialist

It is a falsehood to say that only one system contributes to the production of energy for an activity at any given time. Depending on the intensity and duration of the activity one energy system will provide a majority of energy during that time. This article will breakdown and highlight the differences between these energy systems, how they are used, and how to train them.

First, let’s do a brief breakdown of the three energy systems:

1. Phosphagen System (ATP-PC):

Here the PC stands for “Phosphocreatine” which is a familiar term given the popularity and efficacy of creatine supplementation for both power development and strength training (pre), reducing muscle soreness and improving recovery (post) from training sessions. PC is stored in the muscle and is ready to provide energy for high intensity activities such as jumping, sprinting, and quickly lifting light or heavy weights. Basically, your body splits creatine and phosphate apart releasing a large amount of energy without the need for oxygen. In a nutshell, this energy system can provide maximal effort for up to 8 seconds.

2. Glycolytic System (Anaerobic):

This energy system is often referred to as the lactic system in that it produces lactate as a by-product from glucose metabolism. What often limits this energy system is bioavailability of carriers to remove and/or utilize lactate for energy. When lactate accumulates in the muscle the pH drops and at a certain threshold will shut down these pathways from continuing to produce energy. This pathway provides energy for activities ranging from 20 seconds to 2 minutes in duration.

Examples include lifting weights, shuttle runs, etc.

3. Oxidative (Aerobic):

This pathway involves the use of oxygen in the production of energy, which produces energy at a slower rate. Activities that fall in this category consist of low intensity and longer duration activity such as ergometric activity (rowing, running, swimming, etc.) performed for more than 5 minutes.

The following lists breakdown the energy systems used in fire survival tasks (Abel, et al. 2011):

1. ATP-PC: Hose pull, ladder raise, hose hoist, forcible entry, lifting a victim.
2. Glycolytic (anaerobic): Using heavy tools, load carriage, victim removal.
3. Oxidative (aerobic): VES (searching a room), climbing stairs, hose line maneuvering.

Another conditioning factor that is important to consider is operating in hot environments, or heat acclimatization. Firefighters can expect an average rise in core temperature of 1.9 ◦C over a 3-hour firefighting period (Morris, et al. 2018). Acclimation to hot environments using bunker gear is important for preventing unnecessary heat related injuries. Cardiovascular fitness or aerobic capacity has a huge impact on heat tolerance, especially in firefighters wearing bunker gear in a hot environment (Larson, et al. 2015).

How can training be optimized to improve these energy systems?

A common constraint in most fire departments is time and thus the need for optimizing time for conditioning is crucial in keeping firefighters in shape. A simple solution is circuit training, since one can train both aerobic and anaerobic energy systems simultaneously. This uses the concept of concurrent training, where you train more than one physiological adaptation at a time. Practically speaking it can be an effective use of time to work on different training characteristics at once.

Here are a few simple examples of whole-body circuit training that requires little equipment:

Option #1:EMOM (Every Minute On The Minute); every odd minute perform a 40-50 yard Shuttle Run for the whole minute. You can find space by moving the trucks out of the bay or running around the station for a lap(s). Every even minute perform 10 x Bent Over Dumbbell Rows (weight that is a good challenge), 10 x Push Ups, & 5 x Reverse Lunges for each leg at body weight or hold weight for an added challenge. Do this for 10-16 minutes. This can also be a great workout to do in turnout gear. Therefore, you can omit the boots and use normal workout shoes.

Option #2: Perform the following exercises for 40 seconds then rest for 15 seconds as you get ready for the next exercise: Mountain Climbers, Air Squats, Plank, Burpees. You would perform this circuit for 7-8 rounds total (5-6 rounds if performing in bunker gear).

Option #3: Requires more equipment but works well whether you’re in gear or not. Pick a time between 30-40 minutes (20-25 minutes if in gear), and three different stations:

Station #1: Farmer’s Carry (Dumbbells, Kettlebells, Hex Bar) x 1 minute.

Station #2: Single Arm Kettlebell or Dumbbell Front Rack Shoulder Carry x 30 seconds each arm.

Station #3: Sled Drag or Pull x 1 minute, if you don’t have a sled perform a plank or weighted plank instead. The idea is to rotate from exercise to exercise without resting and to perform the workout unbroken for the allotted time.

Training on shift is a great way to build comradery and keep crew members in shape. However, firefighters should keep in mind the energy cost of certain types of training and the effect it would have on their physical state for the rest of their shift.

References:

1. Abel, M, Sell, K, and Dennison, K. Design and implementation of fitness programs for firefighters. Strength and Conditioning Journal 33(4): 31-42, 2011.
2. Larsen, B., Snow, R., Vincent, G., Tran, J., Wolkow, A., & Aisbett, B. (2015). Multiple days of heat exposure on firefighters’ work performance and physiology. PLoS ONE, 10(9), 1–16. https://doi.org/10.1371/journal.pone.0136413
3. Morris, C. E., & Chander, H. (2018). The impact of firefighter physical fitness on job performance: A review of the factors that influence fire suppression safety and success. Safety, 4(4). https://doi.org/10.3390/safety4040060

About O2X On-Site Specialist Carson Fralin:

Carson Fralin is an O2X On-Site Human Performance Specialist specializing in Strength and Conditioning with the West Palm Beach Fire Department. In this role, Carson designs and implements performance programs that enhance the physical readiness and resilience of first responders, ensuring they are prepared to meet the demands of their critical work while reducing the risk of injury. Before joining O2X, Carson served under the U.S. Army’s Holistic Health and Fitness (H2F) program with the 82nd Airborne Division. Embedded as a Strength and Conditioning Coach within the 2nd Battalion of the 504th Paratrooper Infantry Regiment, he advised officers and NCOs on optimizing physical training for combat readiness. Carson also specialized in preparing soldiers for selection schools, including SOAR 160th, SFAS, Ranger, Civil Affairs, and PSYOPS, while developing recovery programs to rehabilitate and reintegrate soldiers after their selection processes. Earlier in his career, Carson was the Head Strength and Conditioning Coach at Midlothian Athletic Club, where he worked with FC Richmond Soccer, the Richmond Generals Ice Hockey teams, and local fire stations in Chesterfield County, VA. Carson earned both his Master’s in Kinesiology and Exercise Physiology and his Bachelor’s in Exercise Science from Virginia Commonwealth University.

About O2X Human Performance:

O2X Human Performance provides comprehensive, science-backed programs to hundreds of public safety departments, federal agencies, and the military. O2X works with clients to elevate culture, improve mental and physical wellbeing, support healthy lifestyles, and reduce healthcare costs associated with injuries and illnesses. Driven by results and cutting edge research, O2X programs are designed and delivered by a team of Special Operations veterans, high level athletes, and hundreds of leading experts in their respective fields of human performance.