Running training guides
Straight answers, grounded in published sports science.
Common questions about training for a 5K, 10K, half marathon, or marathon — answered briefly and honestly. Every answer reflects the same principles Crawl2Sprint uses to build your plan; for the full evidence and citations, follow the links into the Methodology & research page. When you're ready, build your free plan.
How many days a week should I run?
Most runners do well on 3 to 5 days a week. New runners build durability fastest on 3–4 days with rest or cross-training between them; more experienced runners can handle 5–6. What matters more than the exact number is consistency and keeping most of those runs easy. The builder lets you set your available days and shapes the week around them.
What is the 80/20 (polarized) running rule?
Roughly 80% of your running should be easy (conversational effort) and only about 20% hard. Studies of endurance athletes find this polarized distribution produces better fitness gains than spending more time at moderate-to-hard "threshold" effort — easy running builds your aerobic base at low injury and fatigue cost, while the smaller hard portion supplies the sharpening stimulus. See the research →
How fast should I increase my weekly mileage?
Build gradually, not in big jumps — large week-to-week spikes in running distance are associated with higher injury risk. The popular "10% per week" figure is a reasonable ceiling rather than a proven law; the safer principle is small, steady increases punctuated by regular cutback weeks. Crawl2Sprint caps each build and inserts cutback weeks for you. See the research →
How long should my long run be?
The long run is sized to your race distance and current fitness, not pushed to an arbitrary number. It grows gradually as part of your overall weekly volume and is capped so it doesn't dominate the week or carry excessive recovery cost. For most plans it's the single biggest run of the week — but still run easy. See the research →
How should I taper before a race?
Reduce volume over the final one to three weeks (longer for longer races) while keeping some intensity, so you arrive rested but not flat. Meta-analyses of tapering find that cutting volume substantially while maintaining frequency and a little intensity improves race-day performance. The builder scales the taper to your race distance. See the research →
Does strength training help running?
Yes. Systematic reviews show strength training improves running economy and the physiological determinants of distance-running performance, and exercise programs that include strength work reduce sports-injury risk. A small amount of consistent strength work complements running rather than competing with it. See the research →
Build your plan
These principles are baked into every Crawl2Sprint plan — gradual progression, mostly-easy running, cutback weeks, a right-sized long run, and a proper taper, timed to your race day. Build your free plan in about 30 seconds → No account needed.