The article will introduce the principles of internal and external training load. By the end of this article you should understand why it is important and how to monitor internal and external training loads for Track and Field athletes.

Why Monitor Training Load?

Increased Understanding of Performance Changes
Monitoring training load can provide a scientific explanation for changes in performance. It allows the coach to retrospectively examine the relationship between load and performance of their athletes and to adjust the training program based on the optimal load for the individual (Foster et al., 1996).

Planning for Competitions
Monitoring training load can assist the coach to prepare their athletes for major competitions by ensuring that they are at an optimal condition (Franceschi et al., 2020).

Injury and Illness Prevention
Monitoring training load can provide coaches and medical practitioners with important information for reducing the likelihood of injury (Impellizzeri et al., 2020). It assists coaches in avoiding large fluctuations in training loads, which have been associated with higher risk of injury.

Athlete Confidence and Empowerment
Involving athletes in their own monitoring can enhance their feelings of involvement in the training program and increase their sense of ownership of their performances (Halson, 2014).

Internal versus External Load

External load is the training work completed by an athlete, independent of their internal characterstics. For example:

a distance coach may measure the total distance covered in a session.
a sprints coach may measure the total number of accelerations in a session.
a jumps coach may measure the total number of takeoffs in a session.
a throws coach may measure the total number of full effort throws in a session.
a strength coach may measure the total number of reps during a gym session.

Internal load is the unique physiological and psychological stress experienced by the athlete during or after a training session. For example:

Two distance athletes running the same distance may report different perceptions of effort.
Two sprinters performing the same number of accelerations during a session may be operating at different percentages of their maximum heart rate.
Two jumpers performing the same number of takeoffs in a session may have different blood lactate concentrations.
Two throwers performing the same number of throws in a session may subsequently experience different quality and quantity of sleep.

Monitoring Internal and External Load

An effective scheme to monitor load should incorporate external and internal load measurements. By analysing the relationship between the two, the coach may be able to identify fatigue and/or adverse training responses.

For example, a thrower may perform the same number of back squats using the same weight in subsequent sessions (identical external load) but report signficantly higher perceptions of effort (higher internal load) in the second session due to fatigue. The coach can use this information to adapt the training program and schedule more recovery between sessions.

Figure 1: Revised Borg Scale of Perceived Exertion

Monitoring Internal Load

The most important element of an effective monitoring system for Track and Field athletes is that it is simple to use for both the athlete and the coach.

The ‘Session Rating of Perceived Exertion’ (s-RPE) is the most recommended tool for monitoring internal load. This method has been found to be valid, reliable, and easy to use (Foster, 1998; Borresen & Lambert, 2008). This measurement asks the athlete to quantify their rating of perceived effort on a 1-10 scale (see figure 1) and multiplies this number by the duration of the session.

This gives the coach an s-RPE value, which they are able to monitor alongside an external load recording and other variables of interest. In the example below (figure 2), you can see the example of an 8-week monitoring program of a Long Jumper (you may need to click on the table to open it in full screen mode). Using the s-RPE, the coach can observe a gradual increase in training load, despite no obvious increase in the external loading measurements recorded.

Figure 2 - Recording of s-RPE example for a High School Long Jumper. Click to open in full screen.

Monitoring Exernal Load

Measurements of external load will vary depending on the training activities and the personal preferences of the coach. The most important element in choosing an appropriate external load is finding variables that can be measured consistenly, easily, and are relevant to the athlete’s training effort.

For example, a distance coach will usually monitor weekly running mileage as it is easy to calculate and relevant to the athlete’s overall training effort. However, total running mileage is less likely to be correlated to the training effort of a thrower in the middle of a strength block.

An example of commonly used external loads for each event group are included below:

All Athletes
Session Duration, Repetitions

Sprinters
Distance, Speed, Maximum Intensity Efforts, Starts/Accelerations, Jump Test (squat jump), Sprint Performance

Endurance
Distance, Speed

Jumps
Sprints/Accelerations, Ground Conacts, Short Approach Jumps, Full Jumps, Jump Test (squat jump), Jump Performance

Throws
Releases, Full Throws, Implement Weight, Jump Test (squat jump), Throwing Performance

Further Information

Watch the video below to learning more about the differences between internal and external training loads and the pros and cons of common technologies used to measure/assess each.

Monitoring Training Load for Track and Field Athletes