As athletes, we are constantly striving to push our limits, challenge ourselves, and achieve new goals. This desire drives us to work hard during our training and creates the stimuli needed for positive change and adaptation. But there is a limit to the amount of stress our bodies can handle and it’s therefore vital that we understand how to quantify and manage this stress, so that we can balance our pursuit of performance with our need for good health. . Monitoring and optimising training load is central to this.
What is Training Load?
Training load refers to the total amount of stress placed on a body through exercise. It encompasses multiple factors, including the intensity, duration, and frequency of our workouts. There are two types of training load:
- External load is the quantity of work placed on the body (eg distance run, weight lifted etc)
- Internal load is the psychological and physiological response to the external load. Internal load can be affected by factors like baseline fitness level, environmental conditions (temperature, altitude, humidity), lifestyle stressors (work and family commitments) and recovery status.
Why is Training Load Important?
Understanding and managing your training load is essential for several reasons:
Optimal Performance: By carefully monitoring and adjusting your training load, you can optimise your performance and progress towards your fitness goals more efficiently and with less risk of illness and injury. Monitoring load enables you to progressively increase your training stimulus whilst ensuring you’re recovering well and adapting positively to the stimulus.
Injury Prevention: Overloading your body with too much training stress without adequate recovery can increase the risk of injuries and burnout. By balancing your training load, you can reduce the likelihood of overuse injuries and maintain long-term health and fitness. Remember the story of the tortoise and the hare?!
Recovery and Adaptation: Adequate rest and recovery are crucial for the body to adapt to the stress of exercise and deliver the desired enhancements. By managing your training load, you can ensure that you’re giving your body enough time to recover and adapt between workouts so that you maximise the return you get for your hard work during each training session. This often requires real time adjustment which is only possible if you are monitoring your load and response.
Personalisation: Training load will vary from person to person based on factors such as fitness levels, training experience, age and lifestyle. By understanding your own training load requirements, you can tailor your workouts to suit your individual needs and capabilities. In other words your optimal training load may differ from your team mates or training partner. A personalised approach is always best.
How to Calculate Training Load
There are various methods for calculating training load. One common approach is to multiply the length of the session in minutes (session duration) by the intensity of the session, measured with a Rating of Perceived Exertion (RPE) scale. This is the formula we use:
Training Load = Session Duration (in minutes) x RPE (perceived exertion)
Whilst there are multiple RPE scales, we typically use the modified Borg scale. This is a tool used to subjectively measure the intensity of physical activity based on how hard you feel you’re working. Originally developed by Gunnar Borg in the 1980s, the scale has been adapted and modified over time to better suit general populations, ie the everyday athlete.
The modified Borg uses a scale ranging from 0 to 10 to subjectively measure the intensity of an exercise session. It’s important to understand the definitions of each number within the scale to ensure consistency when assessing the intensity of a session
Here are the definitions of the modified Borg scale ratings:
- 0. Rest: No effort
- 1. Very, very easy: Minimal effort required. You feel almost no exertion
- 2. Easy: Noticeable effort, but still easy to maintain
- 3. Moderate: Moderate effort, somewhat challenging but sustainable
- 4. Somewhat Hard: Increased effort, starting to feel more challenging
- 5. Hard: Hard effort, challenging but manageable
- 6
- 7. Very Hard: Very hard effort, challenging to sustain
- 8
- 9
- 10. Maximal: maximal effort, impossible to sustain for extended periods
Example: If you rate your workout as a 5 (hard exertion) and it lasts for 45 minutes:
Training Load = 45 (minutes) x 5 (RPE) = 225
Acute to Chronic Work Ratio
In order for the training load of an individual training session to be useful, you need to understand it in the context of your recent sessions. Fortunately sport scientists have a simple term and formula to help us understand and monitor this: Acute to Chronic Work Ratio (ACWR). ACWR compares your total training load over the past 7 days (acute) against your average weekly training load over the past 28 days (chronic). It is a moving ratio and will change over time. Don’t worry, we share all this to simply give you some background, the good news is we take care of all these formulas for you with a simple training load tool which you’ll find on your home screen.
Many elite athletes and sports teams use this a similar tool to guide their training on any given day. Once you complete a strength or conditioning session, simply use our training load tool to capture how long the session was and how hard you felt it was – this takes less than 5 seconds. Your ACWR will be instantly captured and presented to you with the following traffic light system to help guide your training:
<0.8 (amber) = Low immediate risk. Your training load is comparatively low and you may wish to consider exercising with either more frequency, duration or intensity to build physical resilience for future training sessions
0.8 to 1.5 (green) = Optimal training load, low injury risk. This is your optimal zone and you should continue with your current level of exercise
1.5 to 2.0 (amber) = Slightly elevated injury risk. Your training load is comparatively high. You may wish to consider slightly reducing your exercise duration or intensity in the short term to lower your training load to the optimal range (0.8 to 1.5)
>2.0 (red) = Elevated injury risk. Your training load is comparatively very high, placing you at an increased risk of injury. We suggest you reduce your exposure to riskier forms of exercise today eg. sprinting, heavy lower body weights. We also suggest you reduce your exercise frequency, duration or intensity in the short term to lower your training load to the optimal range (0.8 to 1.5)”
Use this guidance to adjust your training throughout the week – it will help you understand when you can push harder and when you should ease off. It’s one of the most effective tools we have for reducing injury risk. Used consistently, this tool can help you train more intelligently so you can get the most out of your mind and body.
References
Griffen et al (2019) The association between acute:chronic workload ratio and injury and its application in team sports: a systematic review
Gabbett (2016) The training-injury prevention paradox: should athletes be training harder and smarter?
Hulin et al (2015) The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players
