The one number that tells you if you’re ramping training too fast

The most common way people get hurt in training is not by working hard in absolute terms — plenty of athletes handle enormous workloads safely. It is by increasing their workload faster than their body has adapted to. The classic pattern is a motivated week: an extra run, a heavier block, a jump from three sessions to five. The body was ready for what it had been doing; it was not ready for the sudden step up.

A number built for exactly this problem

Sports science has a metric designed to catch that step-up: the acute:chronic workload ratio (ACWR), popularised by Tim Gabbett's 2016 work in the British Journal of Sports Medicine. The idea is simple. Your acute load is what you've done recently — the mean daily training load over the last 7 days. Your chronic load is your established baseline — the mean daily load over the last 28 days. The ratio of the two tells you whether this week is in line with what your body is prepared for, or a spike beyond it.

Where the danger zone actually is

The research maps the ratio onto risk bands. A ratio between 0.8 and 1.3 is the sweet spot — the range associated with the lowest injury risk, where you are training enough to keep adapting without overreaching. From 1.3 to 1.5 is a caution zone where risk starts creeping up. Above 1.5 is the danger zone, where Gabbett's original cohort saw overuse injury risk roughly double. Below 0.8 is detraining — you're losing fitness faster than you're building it, which matters if you've backed off too hard. Misi maps your live ratio onto exactly these bands.

The goal is not to train less. It is to add load at a rate your body has already shown it can absorb — roughly no faster than your recent 28-day average supports.

How Misi calculates yours

Every logged session is converted into a training load using the Foster session-RPE method — session duration multiplied by perceived effort — which is a validated way to quantify load without any special equipment. Misi sums those loads across the trailing 7 and 28 days, takes the daily means, and divides. The same ACWR figure powers both the training-load view and the daily readiness tile, so the two surfaces never tell you contradictory stories. It also holds back a verdict until there's enough history — fewer than about two weeks of logged sessions returns 'insufficient data' rather than a misleading ratio built on noise.

What to do when it climbs

A ratio drifting toward 1.5 is not a reason to panic — it's an early-warning flag that this week has ramped hard relative to your baseline, and the sensible response is to hold or slightly pull back load for a few days rather than adding more on top. Used consistently, it turns 'I feel like I might be overdoing it' into a number you can actually watch, and it's especially valuable in the weeks after a layoff, when motivation to catch up is exactly what pushes the ratio into the red.

Misi is a coaching and wellness platform, not a medical service. ACWR is a population-level risk indicator, not a personal guarantee — sharp or persistent pain always warrants a professional assessment regardless of what any ratio says.