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Load Monitoring for Smart Trainer Owners Using Internal:External-Load Ratio

Came across this paper... ... .2017-0208

...and the following regarding using internal:external-load ratio as a method of load data analysis caught my eye...

However, while practically attractive, the implementation of this approach is limited unless care is taken in controlling and quantifying the athlete’s external loads and the environment in which the exercise is completed.

...because for the past year I've been using internal:external-load ratio indoors on smart trainer (where both external load and environment can be controlled) with great success.

Here are some of my favorite quotes from the paper:

The integrated internal:external-load ratio assesses the psychophysiological stress experienced by the athlete (ie, heart rate, RPE, blood lactate, etc) during training in the context of the external training load completed and can be used to infer on athlete training status. For example, an increase in the internal load to a standard external load may infer athlete fatigue or decreased fitness, while a reduced internal load (a lower heart rate or perception of effort to a standard external load) indicates that an athlete is gaining fitness and coping with training. Furthermore, this may inform on the consequences of training programs, identify fatigue during team-sport competition, and identify changes in fitness or fatigue status. However, while practically attractive, the implementation of this approach is limited unless care is taken in controlling and quantifying the athlete’s external loads and the environment in which the exercise is completed.

Monitoring athletes’ training load is essential for determining whether they are adapting to their training program, understanding individual responses to training, assessing fatigue and the associated need for recovery, and minimizing the risk of nonfunctional overreaching, injury, and illness.

Measures of training load can be categorized as either internal or external. For the context of this paper internal training loads are defined as the relative biological (both physiological and psychological) stressors imposed on the athlete during training or competition. Measures such as heart rate, blood lactate, oxygen consumption, and ratings of perceived exertion (RPE) are commonly used to assess internal load. On the other hand, external training loads are objective measures of the work performed by the athlete during training or competition and are assessed independently of internal workloads. Common measures of external load include power output, speed, acceleration, time–motion analysis, global positioning system (GPS) parameters, and accelerometer-derived parameters.

An integrated approach to training load is also important, and for this reason internal and external training loads should be used in combination to provide greater insight to training stress. For example, athletes repeating the exact same session on different days may maintain the same power output for the same duration (ie, same external load) but experience quite different internal loads (heart rate, blood lactate, RPE, etc) depending on their state of fatigue, emotional disturbances, recent training history, or illness. This uncoupling of internal and external loads may aid in determining if an athlete is fresh or fatigued.

Concurrent assessment of specific load measures (external and internal) allows an assessment of combined physiological and psychological stress and also allows applied researchers and practitioners to evaluate fatigue/recovery status, adjust individual training prescription, and determine relationships between these loads and performance. Furthermore, such metrics allow the categorization of training stimulus into relative zones of intensity (low, moderate, high).

Interindividual and intraindividual differences in recovery potential, exercise capacity, nontraining stressors, and stress tolerance may explain the different degrees of vulnerability experienced by athletes under identical training conditions. The key is to evaluate athletes individually, monitor them regularly, and compare the obtained data longitudinally. Overtraining studies have demonstrated that psychological indicators are more sensitive and consistent than physiological indicators.

SSM practitioners should select both internal and external monitoring tools that suit their specific situation. Note that a combination of work performed (external load) and impact of work performed on the player (internal load) provides an assessment of the athlete’s/team’s capacity to handle the session delivered. If implemented longitudinally, a combination of internal and external monitoring can also provide information on training-load adaptation for both individuals and teams. Ideally, a combination of objective and subjective tools should be employed. This ensures an equal balance between athlete perception and quantifiable practice.

...standards for applied practice should be similar to those expected in research...

The use of composite or derivative methods, typically measured in arbitrary units (eg, TRIMP derived from heart rate), metabolic power (derived from locomotor acceleration and deceleration), player load (derived from accelerometer acceleration), and sRPE (derived from perception of effort) adds more complexity to the interpretation of results but may bring more insight if analyzed correctly.

The objectives of a load-monitoring system and the context in which it will be applied may determine whether certain limitations are acceptable or not. A consistent and rigorous approach in a program over an extended period, even with a method that has some limitations, may provide meaningful data and influence practice, particularly if used in conjunction with other objective and subjective measures.


  • joey54321joey54321 Posts: 1,297
    Interesting, I became aware of limitation of powermeters while doing some heat adaption training. I'd do sweetspot sessions on the turbo and close the window for the last ~30 minute. My PE and heart rate started climbing significantly when I did this but my power was still rock solid. Powermeters don't measure everything.
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