Couch to 5K

Evidence note: Completion varies widely by baseline capability and injury risk; treat single-program completion rates as cohort-specific.

BS-0063

Key Result (study): One reported program completion rate is 27.3% (n=110; single-site UK study).

BS-0063

Case snapshot (schema) 

context: "Couch‑to‑5K improves adoption by matching the starting behavior to beginner capability, but still shows a long tail of users for whom the program is too aggressive."
company: "Various implementations"
industry: "Fitness"
confidence: "working"
population: "Users in the relevant population"
target_behavior: "Follow an interval running plan 3×/week"
constraints:
  - "Identity: moderate (some see themselves as “non‑runners”)."
  - "Capability: intentionally starts low, then ramps; for some users the ramp still exceeds capability."
  - "Context: requires protected time and safe running environment multiple times per week."
measurement:
  denominator: "program enrollees"
  window: "9 weeks (program duration)"
  metrics:
    key_metric: "One reported program completion rate is 27.3% (n=110; single-site UK study)."
results: "Couch‑to‑5K improves adoption by matching the starting behavior to beginner capability, but still shows a long tail of users for whom the program is too aggressive."
limitations:
  - "Injury history and baseline fitness create distinct sub-segments; a single progression will be too aggressive for some."
sources:
  - "See Sources section"
evidence_ids:
  - BS-0063

Summary

“Just start running” fails because it assumes capability that many beginners don’t have. Couch‑to‑5K succeeds more often by selecting a behavior that matches actual capability: short run intervals with walk recovery and a clear progression.

Target behavior (operational)

  • Population: Users in the relevant population
  • Behavior: Follow an interval running plan 3×/week
  • Context: (see case narrative)
  • Window: 9 weeks (3 sessions/week)

Constraints (behavioral)

  • Identity: moderate (some see themselves as “non‑runners”).
  • Capability: intentionally starts low, then ramps; for some users the ramp still exceeds capability.
  • Context: requires protected time and safe running environment multiple times per week.

Fit narrative (Problem → Behavior → Solution → Product)

  • Problem Market Fit: People want better fitness and a clear entry path.
  • Behavior Market Fit: “Run for 60 seconds, then walk” is a higher‑fit behavior than “go run 30 minutes.”
  • Solution Market Fit: A structured program scaffolds capability and reduces uncertainty.
  • Product Market Fit: Completion varies by baseline capability; drop‑off is predictable when progression exceeds some users’ constraints.

Behavior Fit Assessment (example)

Target behavior: “Follow an interval running plan 3×/week.”

  • Identity Fit: moderate (some see themselves as “non‑runners”).
  • Capability Fit: intentionally starts low, then ramps; for some users the ramp still exceeds capability.
  • Context Fit: requires protected time and safe running environment multiple times per week.

What this illustrates

  • Capability Fit is often the bottleneck in physical behaviors.
  • “Beginner” is not a single segment; true behavior matching often requires multiple starting paths.

Measurement (window/denominator stated)

  • Window: 9 weeks (program duration)
  • Denominator: program enrollees
  • Completion: 27.3% in one reported program cohort (single-site).

BS-0063

Results

  • Outcome: Couch‑to‑5K improves adoption by matching the starting behavior to beginner capability, but still shows a long tail of users for whom the program is too aggressive.

Limitations and confounders

  • Metrics may be company- or press-reported; isolate the target behavior and window where possible.
  • Effects are context-dependent; avoid generalizing beyond the population and constraints described.

Sources

BS-0063

See also