Why 'Start Slow' Is Terrible Injury Advice

Ask a physio, a coach, or a running forum how to come back from injury, and you'll hear the same thing: "Just start slow and listen to your body."

This advice has three problems:

1. It's not quantified. Slow compared to what? Your pre-injury pace? Your current fitness? Everyone's "slow" is different, and without a reference point, the advice is meaningless. A runner whose easy pace was 5:00/km might think 5:30/km is "slow." It might still be too fast for their current tissue tolerance.

2. It addresses pace but not load. Pace is only half the equation. Running 3km "slow" is very different from running 15km "slow." The cumulative load (volume x intensity) is what drives overuse injury, not pace alone. You can run slowly and still overload your tissues by running too far, too often.

3. "Listen to your body" fails at the margin. By the time your body sends a clear pain signal, tissue damage has already accumulated. Overuse injuries build subclinically. Micro-damage stacks over days and weeks before symptoms appear. When you finally "feel something," you're past the prevention window.

Replace "start slow" with specific, quantified guidance:

"Start at 30-40% of your pre-injury weekly volume, at conversational pace, with walk breaks."

This addresses volume (30-40%), intensity (conversational = RPE 2-3), and structure (walk breaks reduce cumulative loading per session). It's specific enough to act on and conservative enough to be safe for most injuries.

"Increase by 10-15% per week only if your ACWR stays below 1.2."

This replaces the vague "build gradually" with a measurable constraint. ACWR below 1.2 means your increase is within your body's adaptation capacity, not just your willingness to push.

"Monitor morning symptoms, not mid-run feelings."

For tendon and bone injuries, the best predictor of overload isn't how you feel during a run. It's how you feel the next morning. Morning stiffness lasting more than 10 minutes, next-day soreness at the injury site, or increasing resting heart rate are earlier warning signs than mid-run pain.

The sports science literature is unambiguous: progressive, quantified loading produces better outcomes than subjective guidance.

Blanch & Gabbett (2016) showed that athletes who used ACWR-based load management had 50% fewer injuries than those following traditional periodization alone. Silbernagel et al. (2007) demonstrated that a structured pain-monitoring model for Achilles tendinopathy outperformed "rest until pain-free" protocols.

The pattern is consistent: more data, better decisions, fewer injuries.

This is exactly why injury.vision exists. Not because "start slow" is wrong in spirit (it's directionally correct), but because it's not enough. Runners coming back from injury deserve a daily risk score, not a platitude. They deserve to know their ACWR, not just that they should "be careful." They deserve a week-by-week protocol calibrated to their injury type and time off, not a generic suggestion to "build gradually."

Here's what a runner returning from Achilles tendinopathy sees in injury.vision:

Day 1: Risk score 28 (low/green). RTR protocol says 4.8km easy with walk breaks. What-If Planner confirms this run keeps risk in the green zone.

Week 2: Risk score 31 (low/green). Protocol advances to 5.5km continuous. ACWR is 0.95, well within the safe zone. Confidence building.

Week 4: Risk score 38 (moderate/amber). Protocol says 8km, but the What-If Planner shows this would push risk to 45. The limiting factor is TSS spike: this would be the longest run in 6 weeks. Suggestion: split into 6km + 2km with a rest day between.

Week 6: Risk score 29 (low/green under Shield mode's tightened thresholds). Back to pre-injury mileage. Shield mode reminds the runner that tissue is still adapting. ACWR is 1.08, stable.

At no point did this runner need to "listen to their body" or guess at what "slow" means. Every decision was backed by a number.