Layer 3 · Derived indicators

Coming soon. This layer is described here as a conceptual reference for the full framework, but the ACWR, monotony and strain indicators are not yet implemented in the product. The first version exposes Layers 1 and 2; Layer 3 will arrive once there is enough accumulated load history per client for the ratios to make statistical sense.

Derived indicators are what sports scientists use to decide when to deload or when injury risk goes up. They are not calculated directly — they are derived from AU load accumulated over the weeks.

ACWR (Acute:Chronic Workload Ratio)

The ratio between acute load (last week) and chronic load (average of the last 4 weeks). Proposed by Gabbett (2016) and considered today the main injury-risk indicator.

ACWR = current_week_load / average_load_4_weeks

Monotony

It measures the variability of daily load across the week. Flat loads (with no variation) lead to worse adaptation than varied loads.

monotony = average_daily_load / standard_deviation

Values below 1.5 indicate healthy variety. Above 2.0, the programming is too uniform.

Strain

It combines volume and monotony. An athlete can accumulate a lot of load without risk if there is variety, or little load with high risk if the programming is flat.

strain = total_weekly_load × monotony

It is a combined indicator: watch week-to-week jumps in strain, not the absolute value.

What to read next

These indicators are fed by AU load, so their reliability depends on logging each set's intensity properly: see Intensity sources and how to interpret load.