Frequently Asked Questions

The questions runners actually ask, answered directly. Each one starts with a short answer, then the nuance. Where the evidence supports a position, this page takes one rather than hedging.

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Training Structure

How many days a week should I run?

Short answer: 3 days if you are new, 4-5 for most people, 6-7 only if you are chasing performance and can stay healthy doing it.

Frequency exists to serve weekly volume and consistency, not the other way around. Three quality days a week, done for a year without injury, beats six days a week done for two months and then abandoned to a stress fracture.

The jump from 3 to 4 days is the highest-value change most runners can make. The jump from 6 to 7 is the lowest.

See Training Principles.

Why are my easy runs supposed to be so slow? How slow is too slow?

Short answer: because moderate-effort running builds fatigue without building much fitness. And you almost certainly cannot run too slow.

Easy running triggers the adaptations that actually matter for distance racing - mitochondria, capillaries, fat oxidation, tendon resilience - and it does so at a fatigue cost low enough that you can do a lot of it. Push those runs into the moderate "gray zone" and you get less aerobic benefit and you arrive at your hard workouts too tired to hit the paces that drive the rest of your fitness. You lose twice.

Practically: easy pace is conversational (full sentences), 60-90 seconds per mile slower than 5K pace, roughly 65-79% of max HR, RPE 3-4. For most amateurs it is slower than their ego permits.

Is there a floor? A soft one. If you are running so slowly that your form falls apart or you are walking-shuffling, you are getting less benefit per minute. But that is much slower than where almost anyone stops. The overwhelmingly common error is easy runs run too hard, not too easy. When in doubt, slow down.

See The Easy/Hard Rule and The Aerobic System.

Do I really need to run 80/20?

Short answer: yes, approximately - and if you get it wrong, err toward more easy running, not less.

The 80/20 (polarized) distribution shows up consistently in studies of elite endurance athletes across running, cycling, rowing and skiing, and controlled trials generally favor it over threshold-heavy training. It is about as close to a settled finding as endurance training has.

But do not be precious about the number. The point is not that 82/18 fails where 80/20 succeeds. The point is the shape: the large majority of your running is genuinely easy, a small minority is genuinely hard, and very little sits in between. If you run 4 days a week and one of them is a workout, you are already close enough.

The one caveat: at very low volume (3 runs a week, 15 mpw) a strict 80/20 leaves you almost no quality at all, so most low-volume plans run closer to 70/30 by necessity. That is fine. The 80/20 rule matters most as volume rises.

See The Easy/Hard Rule.

How do I know my training paces without a lab test?

Short answer: race, or run a time trial, and read your paces off a table. Nobody needs a lab.

Take a recent hard effort - a 5K race is the best single input - and plug it into a VDOT table or the McMillan calculator. Out come your easy, marathon, threshold, interval and repetition paces. This works because a race performance already accounts for VO2max, threshold and running economy together, which is exactly what a lab test has to combine anyway.

No recent race? Run a time trial: a 5K on a flat course or track, on a rested day, run honestly. Or a 3K if 5K feels like too much. Then subtract a little conservatism - time trials without competition usually come in slightly slow, and it is better to have your paces set a touch easy than a touch hard.

Re-test every 6-10 weeks in a training block. Paces should move.

See VDOT and Pace Tables, Jack Daniels and McMillan.

Should I run every day (run streaks)?

Short answer: no. Streaks optimize for a number that is not fitness.

A streak removes your ability to take a rest day when your body is asking for one, which is exactly the decision that keeps runners healthy. It converts "should I rest today?" - a good question - into "do I want to end my streak?" - a bad one. Plenty of runners maintain streaks without harm, but they succeed despite the streak, by making the minimum days trivially easy.

If the streak is what gets you out the door, keep it, but make the rule "run or do something" rather than "run", and let the minimum day be 15 genuinely easy minutes. Rest days are training. See Recovery and Adaptation.

What if I miss a week?

Short answer: nothing bad happened. Pick the plan back up roughly where you left off and carry on.

One week off costs you very little - fitness declines are only just becoming measurable at around two weeks. Do not try to make up the missed mileage: cramming a lost week into the next one is how a missed week becomes a missed month.

Rough guide:

If the week was missed because of illness or injury rather than life, be more conservative, not less.

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Pain, Injury and the Body

Should I run through pain?

Short answer: no for pain, yes for discomfort - and you need to be honest about which one you have.

Use this test:

• Stop. Sharp pain, one-sided pain, pain that changes your gait, pain that gets worse as the run goes on, or any pain in a bone (shin, foot, hip, femur) that is tender to press on a single point. Bone pain is a stress fracture until proven otherwise, and running through it turns a 3-week problem into a 3-month one.
• Proceed with caution. Dull, symmetrical muscle ache that warms up and fades within the first mile and does not worsen. Reduce volume, keep it easy, watch it.
• Ignore. DOMS after an unfamiliar session, general tiredness, the ordinary complaints of a body doing work.

The asymmetry matters: the cost of taking three unnecessary rest days is trivially small. The cost of running six more days on a developing stress fracture is your entire season. Given that asymmetry, when you are genuinely unsure, rest.

See Injury Prevention.

Do I need to stretch?

Short answer: not for injury prevention - the evidence for that is poor. Static stretching before a run is actively counterproductive.

The best available evidence does not support static stretching as an injury-prevention strategy for runners. It does not meaningfully reduce injury rates, and it does not prevent DOMS. Stretching immediately before hard running has been repeatedly shown to temporarily reduce force output, which is the opposite of what you want at the start line.

What to do instead:

• Before running: an easy jog, then dynamic movements (leg swings, skips, drills) and, before a hard session, strides. Warm up rather than stretch.
• After running / separately: stretch if you want mobility for its own sake, if a range-of-motion limitation is affecting your form, or simply because it feels good. Those are legitimate reasons. "It will stop me getting injured" is not one.

The things that do reduce injury risk are unglamorous: sensible load progression, adequate sleep, adequate fuel, and strength training.

Do I need to strength train?

Short answer: yes. This is one of the few "extras" that clearly earns its time.

Two effects are well supported. First, heavy resistance training and plyometrics improve running economy - the same pace costs less oxygen - and this shows up in endurance performance without adding bulk when volume is kept low. Second, strength work builds tissue capacity, which is a direct hedge against the tendon and bone injuries that end training blocks.

The dose is smaller than people fear: two sessions of 20-40 minutes a week, focused on heavy compound work (squats, deadlifts, lunges, calf raises, single-leg work) plus some hopping/plyometrics. Do it on hard-run days, not on easy days, so easy days stay easy.

Do not do high-rep, light-weight "toning" circuits and call it strength training. The adaptation you want comes from meaningful load.

See Strength Training.

Can I lose weight and build fitness at the same time?

Short answer: partially, and not aggressively. In a hard training block, pick one.

A modest deficit (roughly 200-400 kcal/day) alongside training is workable, and many runners get leaner over a block without trying, simply because volume rose. But a large deficit and hard training fight each other directly. Under-fuelling degrades workout quality, blunts adaptation, impairs recovery, and raises injury risk - most seriously through low energy availability (RED-S), which is associated with reduced bone density, hormonal disruption and stress fractures. Amenorrhea, ongoing fatigue, and repeat bone injuries are not signs of dedication; they are signs of not eating enough.

The productive sequence is: lose weight in the off-season or in an easy base block, then eat properly through the hard training that precedes your race. Fuel the work, especially around long runs and quality sessions.

See Fueling and Nutrition.

Is it too late to start? Am I too old?

Short answer: no.

Endurance responds to training at every age that has been studied. Masters runners set personal bests routinely, particularly at the marathon, where the accumulated aerobic base and pacing judgment count for more than raw speed. VO2max declines with age, but far more slowly in people who keep training, and threshold and economy - the two things that actually move race times in trained runners - remain trainable.

What genuinely changes with age is recovery. Adaptation is not slower; it takes longer to clear the fatigue. So: the same principles, a day or two more between hard sessions, more attention to sleep, and strength training becomes non-optional (it defends against age-related loss of muscle and bone).

The best time to start was ten years ago. The second best time is this week.

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Gear and Tools

Do I need a GPS watch or a heart rate monitor?

Short answer: a GPS watch is genuinely useful. A heart rate monitor is optional. Neither is required.

GPS watch: worth it. It answers "how far and how fast," it makes pace-based workouts possible without a track, and it logs your training automatically - which matters, because you cannot analyze a training load you never recorded. A cheap one does 95% of what an expensive one does.

Heart rate monitor: useful for one job in particular - forcing your easy runs to stay easy, which is the hardest discipline in training. Beyond that it fades: HR lags at the start of intervals, drifts upward in heat and dehydration, and is affected by caffeine, sleep and stress. If you use one, use a chest strap; wrist optical HR is unreliable at exactly the intensities where you would want accuracy.

Note that RPE - free, batteryless - already self-corrects for heat, hills, sleep and stress in a way that neither pace nor heart rate does. Experienced runners keep using it after they own everything else.

See Heart Rate Zones.

What shoes should I buy?

Short answer: whatever is comfortable when you run in them. That is close to the whole of the honest advice.

This will disappoint anyone who wants a matrix. The evidence for prescribing shoes by foot type or gait - the classic "you overpronate, so you need a stability shoe" model that shoe shops are built around - is weak. Studies assigning shoes based on foot arch or pronation have generally failed to show a reduction in injury rates, and some have found more injuries in the prescribed group. Comfort, by contrast, is the one variable that has held up as a reasonable predictor of doing well in a shoe.

Workable guidance:

• Buy for comfort. Run in them in the shop if you can. If your foot argues with the shoe on the first run, it will keep arguing.
• Rotate two pairs if you can afford it. Varying the shoe varies the loading, which is plausibly protective and certainly makes each pair last longer.
• Replace by feel, not by odometer. The "300-500 miles" figure is a rule of thumb, not physiology. When the shoe feels dead or new aches show up, replace it.
• Carbon-plated racing shoes genuinely do improve running economy by a few percent - this one is real and well measured. They are also expensive and less durable. Race in them if you want the time; do not train exclusively in them.
• Do not change several things at once. If you switch to a much lower drop or a much lighter shoe, transition over weeks, not overnight. Sudden changes to how load distributes are how calves and Achilles tendons get hurt.

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Progress and Expectations

How long until I see results?

Short answer: 4-6 weeks for a noticeable change, 3-6 months for a meaningful one, years for your real potential.

Different systems adapt on different clocks, and this mismatch explains most training injuries:

Your heart and lungs get fit far faster than your tendons and bones get strong. That is precisely why you feel capable of more running than your body can safely absorb at week six, and why the 10% rule exists.

What is a realistic improvement rate?

Short answer: beginners can take huge chunks off. Trained runners fight for 1-3% a year. Both are normal.

• First year of structured training: dramatic. Five to fifteen percent off race times is common, sometimes far more from an untrained start.
• Years 2-3: meaningful but slower. A few percent a year - for a 25-minute 5K, roughly 30-60 seconds a year.
• Experienced, well trained: 1-2% a year, and eventually you are working hard for seconds.

This is diminishing returns, and it is not a sign you are doing anything wrong. The runners who keep improving into years five and ten are almost never the ones who trained hardest; they are the ones who trained continuously, because the biggest single predictor of long-run improvement is years of uninterrupted consistency.

See Training Principles.

Why did I get slower?

Short answer: usually fatigue, not lost fitness. Check that before you check anything else.

In rough order of likelihood:

1. You are tired, not unfit. Deep in a training block, you are supposed to be running on tired legs. Fitness is masked by fatigue until the taper lifts it. Take 3-5 easy days and re-test.
2. Your easy runs are too hard. The classic. It flattens every hard session and every race. Check your HR distribution or your honest RPE.
3. You are under-fuelled. Chronic low carbohydrate intake makes hard running feel disproportionately awful.
4. Sleep. Sustained short sleep degrades performance and recovery, and no supplement compensates.
5. Conditions. Heat, humidity, wind, hills and altitude all cost real time. A pace that feels the same effort will be slower on a hot day, and that is correct behavior, not decline.
6. Life stress. Your body does not distinguish training stress from work stress. Both draw on the same recovery budget.
7. Actual overtraining. Consider it if performance is down and resting HR is elevated and sleep and mood are degraded. That combination needs weeks of real rest, not a lighter week.

See Recovery and Adaptation.

How do I pick a goal time?

Short answer: derive it from a recent race, do not invent it from a round number.

Take a recent result, convert it with a VDOT or equivalence table, and that is your realistic goal on race day if training goes well. Then adjust: nudge it faster if you are early in your running life and volume is climbing, and nudge it slower for heat, hills, or a plan you only partly completed.

Two failure modes to avoid:

• The round number. "Sub-4 marathon" is a nice story, but if your half marathon says 4:20, sub-4 is a fantasy that will wreck the first 10 miles of your race and cost you the 4:15 you were actually capable of.
• The stale PR. A goal built on what you ran three years ago is a goal built on someone else's fitness.

The honest test: could you hold this pace for a well-executed half of the race distance and still feel controlled? If not, the goal is too aggressive.

See Race Day Execution and VDOT and Pace Tables.

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Practicalities

Is treadmill running as good as running outside?

Short answer: yes, near enough, and it is far better than skipping the run.

Physiologically, treadmill running is close to outdoor running. The commonly cited fix - setting 1% incline to offset the absence of air resistance - matters mostly at faster paces; for easy running it makes little practical difference.

What differs:

• Effort feels harder for many people (heat, no airflow, boredom). Run by effort, not by the belt's numbers.
• No terrain variation, so the same tissues get loaded the same way every stride. Do not do all of your running on one.
• No pacing skill is developed, because the machine does the pacing. Race pacing is a skill you have to practice outside.
• It is superb for control: precise pacing on quality sessions, hill work without hills, and running safely in ice, dark, heat or pollution.

Use it freely. Just do not make it your only surface, and get your long runs and your race-pace work outdoors where you can.

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Next: Weekly Training Log Template