Athletes continuously balance injury risk with optimal performance. Training load is at the core of this balance; it is a crucial idea that controls the physical and physiological stress an athlete goes through.
Internal load and External load are two key components that make up the overall training load (Impellizzeri et al., 2005) of an athlete. Internal Load reflects the body's unique response to training, by using multiple parameters, such as Heart Rate, Heart Rate Variability (HRV), or Rate of Perceived Exertion (RPE). On the other side, External load measures physical stresses exerted on the athlete, using different, objective parameters like total distance, number of accelerations and decelerations, amount of work done during training, etc.
Optimal management of training load is key in modern sports, as it can help maximize performance, lower injury risk, and improve recovery. However, if overlooked or not accurately managed, it can lead to overtraining, injury and burnout (physical and mental).
How is Training Load Used in Sports?
Training load changes with an athlete's fitness, fatigue, and competition schedule; it is not a fixed value. Using training load, coaches, sports scientists, and rehabilitation teams can:
Prescribe Training: Workouts are designed to improve performance without pushing too far (Gabbet, 2016). Monitoring workload ratios, for instance, guarantees slow growth instead of too sharp increases in intensity. Overall, the goal is to understand the preparedness of an athlete and the relative injury risk, to plan accordingly.
Reducing Injury Risk: sudden increases in external load (e.g., doubling training intensity in a week) significantly elevate injury risk (Blanch & Gabbett, 2016). Load monitoring ensures a gradual, sustainable progression. Training in safe zones while ensuring enough stress to allow super-compensation is key.
Guide Injury Rehabilitation: Returning to play too soon is one of the biggest causes of re-injury. Load monitoring provides objective data on when an athlete is truly ready to return to competition (Drew & Finch, 2016).
Where is Training Load Management Most Common?
In several sports, load monitoring is vital. In top football and rugby, it helps avoid soft-tissue injuries costing clubs millions in missed player availability (Windt et al., 2017). Load tracking is crucial in endurance sports such as cycling and marathon running to help reduce burnout and overtraining disorders (Petersen et al., 2021). Progressive load regimens also help injured athletes safely regain strength and mobility, therefore guaranteeing a controlled return to play (Drew & Finch, 2016). Training load management can therefore be helpful in multiple sports, assisting practitioners to assist their athletes effectively and tailor it to the specific needs and objectives of that sport.
Load: Internal vs. External Two Sides of the Same Coin
Internal Load
Internal load is impacted by various physiological factors such as stress, sleep, fatigue, recent training history, illness, non-competition stressors etc. which is why it varies from one individual to another. Hence, utilizing different measures alongside RPE like Heart Rate variables, sleep, and perceived stress is beneficial.
External Load
External load is the ‘’real labour’’ an athlete does, it is determined by the quantity, quality and organization of the training session(s) performed. External load is measured through distance run, weights lifted, speed, and duration for instance. Modern technologies help measure external load (Akenhead & Nassis, 2016) including accelerometers and GPS tracking.
The Science of Smart Training: Finding the Balance
Each athlete bears a load during training and also has a load capacity. To ensure that the load is in balance with the load capacity, a widely researched parameter for controlling injury risk is the Acute:Chronic Workload Ratio (ACWR). This is the ratio between how much workload has been done in the last 7 days (acute workload) versus the average weekly workload that has been performed over the previous 28 days (chronic workload). Studies indicate that while reaching 1.5 greatly increases injury risk, a 1.0–1.3 ACWR (steady increase in load) is safe (Blanch & Gabbett, 2016). Managing this balance helps to distribute loads strategically, therefore avoiding overtraining and undertraining, both of which have detrimental effects.
How can we create the right balance? An Enhanced Method of Instruction
Training load is about strategic management. Examining the long-term relationship between an athlete's internal and external metrics and stressors allows for deeper analysis of these datasets, enabling the establishment and monitoring of subjective measures of internal and external loads. This approach enhances performance, reduces injury risk, and supports a safe return to play after injuries.
In order to implement this approach, balancing internal and external loads is no longer optional in elite sports—it is a necessity. By leveraging new-age holistic management platforms like PULSE Sport, athletes and coaches can pave the way for sustainable performance and longevity in sports.
The question is: Are we ready to embrace the science behind holistic athlete management?
Bibliography
Akenhead, R., & Nassis, G. P. (2016). Training load and player monitoring in high-level football: Current practice and perceptions. International Journal of Sports Physiology and Performance, 11(5), 587-593. Available at : https://pubmed.ncbi.nlm.nih.gov/26456711/
Drew, M. K., & Finch, C. F. (2016). The relationship between training load and injury, illness, and soreness: A systematic and literature review. Sports Medicine, 46(6), 861-883. Available at: https://pubmed.ncbi.nlm.nih.gov/26822969/
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. Available at: https://bjsm.bmj.com/content/50/5/273
Halson, S. L. (2014). Monitoring training load to understand fatigue in athletes. Sports Medicine, 44(S2), 139-147. Available at: https://pubmed.ncbi.nlm.nih.gov/25200666/
Impellizzeri, F. M., Rampinini, E., & Marcora, S. M. (2005). Physiological assessment of aerobic training in soccer. Sports Medicine, 35(9), 837-865. Available at: https://pubmed.ncbi.nlm.nih.gov/16195007
Windt, J., Zumbo, B. D., Sporer, B. C., MacDonald, K., & Gabbett, T. J. (2017). Why do workload spikes cause injuries, and which athletes are at higher risk? Medicine & Science in Sports & Exercise, 49(11), 2310-2318. Available at: https://pubmed.ncbi.nlm.nih.gov/28274916/
Top Stuff!!!
good differenciation between the two! Because internal and external are two load measurements but quantified using different paramaters, it is a necessity to look at both of them. I think the best-case scenario for any sports scientist is to (ideally) look at their relationship and how they affect each other. That would probably be the million dollar question!