Part 1
Firefighting is a physically and mentally demanding profession that requires individuals to perform under intense conditions, often while managing high levels of cognitive and physical stress. The dynamic and unpredictable nature of firefighting poses unique challenges for maintaining optimal fitness, resilience, and injury prevention. Effective training programs are critical to ensuring that firefighters are prepared for the rigors of their work, yet developing effective programs requires a nuanced understanding of the dynamic interaction between physical and cognitive workloads.
Intentional planning of training programs that balance physical and mental stress is widely considered to be best practice. Implementation of these best practices typically requires a financial investment to provide the resources (technology, systems, platforms, personnel, and expert vendors) needed to deliver the desired outcomes. The periodized model to fitness programming presented here is a no-cost solution to begin implementation with a training staff of minimally qualified fitness generalists.
This series will address a novel approach using the role of “training load” in the development of a planned, progressive fitness training program for firefighters, integrating concepts like the acute-to-chronic workload ratio (ACWR), “cognitive fatigue,” and available tools to aid implementation. In part one, we will explain the calculation and applications of training load and its implications for your physical training program.
Training Load: Definition and Components
“Training load” refers to the overall stress imposed on the body during physical activity and is a critical factor in designing fitness programs, especially for demanding professions like firefighting. It encompasses both external and internal loads, which together provide a comprehensive understanding of how the body responds to training stimuli.
External Load
External load represents the objective measures of physical work completed during a session. These include quantifiable metrics such as:
- Distance: How far an individual moves during a session, typically tracked in meters, feet, yards, or miles.
- Speed or velocity: The pace at which the distance is covered, often measured in meters per second or miles per hour.
- Duration: The total time spent in activity, expressed in minutes or hours.
- Power output: The amount of force exerted over time, commonly measured in watts (e.g., in cycling, rowing, or weightlifting).
- Repetitions and sets: In resistance training, external load can also be quantified by the number of repetitions, sets, and the weight lifted.
- Intensity: The relative percentage of work performed compared to a maximal effort for that exercise.
Internal Load
Internal load reflects the physiological and psychological response to the external load. This can vary greatly between individuals, depending on their preexisting fitness levels, fatigue status, mental resilience, and musculoskeletal injury history. Key indicators of internal load include:
- Rate of perceived exertion (RPE): A subjective measure of how hard an individual feels they are working, typically reported on a scale of 1-10.
- Heart rate (HR): A common measure of cardiovascular response, expressed in beats per minute (BPM). Training sessions can be categorized based on intensity zones corresponding to percentages of maximum heart rate (HRmax).
- Blood lactate levels: Reflecting anaerobic metabolism, lactate concentration can indicate the intensity of exercise and whether the individual is operating above their lactate (anaerobic) threshold.
- Oxygen consumption (VO2): The rate at which oxygen is utilized during activity, often expressed as a percentage of VO2max, a key indicator of aerobic capacity.
- Psychological responses: These include mood states, motivation, perceived fatigue, fear of negative performance evaluation, and personality conflicts that can affect both training performance and recovery.
In simple terms, the external load describes what you did, whereas internal load describes your response to that training stimulus.
Measuring and Monitoring Training Load
The combination of internal and external load metrics provides a holistic picture of an individual’s response to training. Monitoring these variables allows practitioners to optimize training interventions, ensuring adequate stimulus for adaptation while minimizing the risk of overtraining or injury.
- Session RPE (sRPE): A widely used method that multiplies the RPE score by the session duration (in minutes). This sRPE provides an overall load score that combines internal perception with session length. If multiple training sessions are performed in a single day, use a separate RPE for each session. The sum of these session RPEs will be tracked for load monitoring purposes.
- Heart rate monitoring: Used to gauge training intensity in relation to cardiovascular response, ensuring that firefighters are working in the appropriate heart rate zones based on their fitness goals.
- Work-to-rest ratios: Commonly used in high-intensity interval training (HIIT), work-to-rest ratios help balance training load by regulating the recovery between high-effort bouts and promotes development of specific energy systems (e.g., phosphogen-ATP, glycolytic, oxidative) to sustain that activity.
Importance of Balancing Training Load
Balancing training load is crucial for enhancing performance while minimizing injury risk. Overloading the body too quickly without proper adaptation can lead to overtraining syndrome or acute injuries, while underloading can result in suboptimal performance improvements. Therefore, intentional planning and progressively increasing training load over time allows firefighters to improve their fitness while maintaining their ability to perform under high physical and cognitive stress. This systematic approach will also directly support efforts to lower musculoskeletal injury risks—one of the primary contributors to firefighter injuries and work-loss annually.
In subsequent installments, we will consider concepts like the ACWR, “cognitive fatigue,” and available tools to aid implementation.
REFERENCES
Abel, M. G., Langford, E. L., Lanham, S. N., Thruston, J. L., Eastman, A. Q., Miller, J. B., … & Melton, B. (2023). Influence of call volume on firefighters’ physical activity level and training load. In International Journal of Exercise Science: Conference Proceedings (Vol. 16, No. 2, p. 378).
Blanch, P., & Gabbett, T. J. (2016). Has the athlete trained enough to return to play safely? The acute:chronic workload ratio permits clinicians to quantify a player’s risk of subsequent injury. British Journal of Sports Medicine, 50(8), 471-475. https://doi.org/10.1136/bjsports-2015-095445
Cross MJ, Williams S, Trewartha G, et al. (2016). The influence of in-season training loads on injury risk in professional rugby union. International Journal of Sports Physiology & Performance, Apr;11(3):350-5. doi: 10.1123/ijspp.2015-0187.
Eckard, T.G., Padua, D.A., Hearn, D.W. et al. (2018). The Relationship Between Training Load and Injury in Athletes: A Systematic Review. Sports Medicine, 48:1929–1961. https://doi.org/10.1007/s40279-018-0951-z
Gabbett, T.J., Jenkins, D.G. (2011). Relationship between training load and injury in professional rugby league players. Journal of Science and Medicine in Sport, 14:204-9.
Gabbett, T. J. (2016). The training-injury prevention paradox: Should athletes be training smarter and harder? British Journal of Sports Medicine, 50(5), 273-280. https://doi.org/10.1136/bjsports-2015-095788
Mason, M. R., Heebner, N. R., Abt, J. P., Bergstrom, H. C., Shapiro, R., Langford, E. L., & Abel, M. G. (2023). The acute effect of high-intensity resistance training on subsequent firefighter performance. The Journal of Strength & Conditioning Research, 37(7), 1507-1514.
Alan Russell, MS, LAT, ATC, PES, CES, a resident of Little Elm, Texas, is a sports medicine clinician with more than 30 years of experience working with elite, collegiate, youth, recreational, and tactical athletes. As the education coordinator for the Public Safety Athletic Trainers’ Society, he is an internationally invited presenter, educator, and author. The spouse of a firefighter, Alan is driven by a deep commitment to providing first responders with the same level of care given to elite athletes, understanding that their critical work leaves no opportunity for an off-season
