Load Monitoring Series: Part 1

Load monitoring has been a topic of recent discussion with the increasing relevance of smart watches, devices, knowledge and awareness of the monitoring importance of internal training load. The measuring of internal and external training loads in a properly designed program can be used to monitor fitness/fatigue to plan for peak performance on event day. A large gap between internal and external training loads can be an indicator of fatigue in an athlete. Proper monitoring can also help athletes and coaches avoid overtraining, determine adaptation to training, and avoid illness and risk of injury. The on-going relationship between internal and external loads can aid in determining fatigue. It's important that load monitoring be individualized for athletes, there is no "cookie-cutter" program out there that can be applied to every athlete. Individualization and specificity is hugely important when devising training plans. Scientific and statistical models can and should be used to detect changes in load. Appropriate monitoring can provide insightful information to coaches and athletes about proper adaptation to training programs. 

Now that I have spoken a little bit about why it's important to monitor training loads; let's talk about what the differences between internal and external training loads are, and how to monitor them. External training loads can be physically measured separate of an athlete's internal characteristics. Internal training loads are relative physiological and psychological stressors and how the body responds. 

  • Methods of measuring External Load
    • Power output/work: average power, normalized power, TSS, kilojoules/calories, pace, speed, distance, etc. All of these measures are quantitative data that reflect the work or output of exercise.
  • Methods of measuring Internal Load
    • Rate of Perceived Exertion: most commonly used, how the body is perceiving the work placed on it, psychological measure of physical work 
    • Heart Rate and Resting Heart Rate: HR is relative and controlled by many factors such as hydration status, temperature and humidity, fatigue and/or sleep.
    • Heart Rate Variability: HRV is the variation in the timing of heart beats. High or low HRV indicates high or low control from the autonomic nervous system. HRV is a great metric to measure physiological stress on the body. In general a high resting HRV (relative to one's self) is better. High resting HRV values indicate the body's ability to tolerate stressors and recover well from activity. 
    • Questionnaires: subjective questionnaires such as sleep and stress are great ways to measure internal load and psychological perception of the current state of the body
    • Sleep: Monitoring sleep quality and quantity help with early detection to avoid detrimental decreases in performance and health. 

The incorporation of smart watches and devices have rapidly changed the game and ease of monitoring, especially for internal training loads over the past few years. Devices such as Fitbit, Apple Watches, Biostrap, Whoop, etc. have enabled athletes access to data such as Resting Heart Rate, Heart Rate Variability and Sleep Metrics. By simply wearing these devices 24/7 or just while you sleep, individuals can gain access to a multitude of these metrics (specifically sleep data) that then allows them to become a more well-rounded athlete from the ability to data monitor external and internal loads. 

Load monitoring is becoming increasingly popular among recreational and elite athletes and coaches. It can be an important key to watch and help to reduce the risk of injury, illness and overtraining. If internal and external loads are planned and periodized appropriately, athletes and coaches can get the most out of training programs to ensure adequate load and adaptation. In this day and age of smart phones, devices and constant data, it's an important time for athletes to take control of their performance and training. Athletes (and coaches) need to be monitoring internal and external loads in order to be making the most of their training. 

Tune in next week for Part Two. I'll dive more into detail about how to monitor internal training loads, and the importance of sleep quality monitoring and heart rate variability.



Reference: Monitoring training load to understand fatigue in athletes. Shona L. Hanson. 2014. Australian Institute of Sport. DOI 10.1007/s40279-014-0253-z