Category Archives: Running

How does age affect running performance?

  1. Go the Runner’s World Age Graded Calculator to see your running speed less your age handicap
  2. Smile 🙂
  3. Read on to see how your handicap was calculated

It starts with the World Masters Association’s extrapolation of World Record (WR) race times for runners of all ages, at distances from 5k to 200k. A subset of the WMA’s numbers look like this: 

Running Race Times by Age

As runners grow up and mature, they tend to get faster in all races, until they peak around 22 years old. Up to the age of 28 they stay at peak for the 5k and 10k, up to the age of 32 for the half marathon, and up to the age of 35 for the full marathon. Then runners get slower, the effect increasing with age, and dramatically slowing after 70.

Running Pace by Age

The difference between World Record paces for the 5k, 10k, half marathon and marathon stay surprisingly consistent across runners’ ages. 10k pace is, on average, 11 seconds per mile slower than 5k pace, from ages 18-60. Half marathon pace is 10 seconds per mile slower than 10k pace, and Marathon pace is 13 seconds slower than half marathon pace.

If you aren’t a world record holder expect your pace differences to be larger. If you run a two-hour half marathon, roughly double the WR time, expect your pace differences to also be double that of the WR holders, so your best marathon pace (if you’re well trained) might be about 26 seconds per mile (13 x 2) slower than your best half marathon pace, your half marathon pace about 20 seconds slower per mile than your 10k pace, and your 5k pace about 22k seconds per mile slower than your 5k pace.

To make the effect of age more obvious, instead of viewing the time to finish a race by age, let’s look at how much longer (or shorter) it takes to do various races with each passing year.

Running Race Times Change by Age

You can see how much faster, world-class, young runners can expect to get in a year. 5k times shrink by 29 seconds between ages 10 and 11, 13 seconds between ages 15 and 16, and 9 seconds between ages 18 and 19. Longer races quicken even more dramatically. Between ages 20 and 21, 5k times will decrease by only 5 seconds, but 10k times will decrease 11 seconds, half marathon times by 27 seconds and full marathon times by 61 seconds.

We see that runners reach their full potential at 22 years old. The performance spike at 22 may reflect the age that many ‘amateur’ athletes turn pro. I suspect the drop in marathon performance at age 35 reflects the decision of many pros to retire on this nice round birthday.

The steady, linear decline after the age of 35 is clear. From ages 39 to 67, 5k WR times increase 6-10 seconds a year, 10k times 13-20 seconds per year, half marathon times 29-47 seconds per year, and marathon times increase from 63-105 seconds per year.  Again if you’re twice as slow as the world record holders expect your times to increase twice as fast.

Finally it’s easiest to see what’s going on when we look at pace changes per mile per year for various races at various ages. Surprisingly our paces speed up nearly identically across all race distances as we mature, then equally consistently slow down as we age. World class runners speed up about 10 seconds per mile between the ages of 10 and 11, whatever the distance, 5 seconds per mile between the ages of 15 and 16, 2 seconds at 20, 1 second at 21, then stay at peak until 28 for the 5k and 10k, 32 for the half and 35 for the full marathon. Finally we begin to slow, roughly 2 second per mile per year until our mid forties, then 3 seconds per mile until about 65.

Running Pace Change by Age

Our charts plot the numbers in the WMA 2010 spreadsheet. This sheet extrapolates World Record (WR) times and speeds for running races from 5k to 200k, for men and women, from age five to one hundred. WMA stands for World Masters Athletics, the organization designated by the IAAF to run the worldwide sport of Masters (Veterans) Track and Field. These estimates are used to drive Age Grade, the WMA’s method of handicapping* runners by age and sex.

* Handicapping, in sport and games, is the practice of assigning advantage through scoring compensation or other advantage given to different contestants to equalize the chances of winning


Why run? Live 6 years longer. How to run? Read on …

Why run? Live 6 years longer. How to run? Read on …

A runner friendly summary of the best new running science from Runner’s World, The New York Times, Running Science by Dr. Owen Anderson, and the latest academic research.

How much to run?

Run 20 miles a week for health, 40 miles a week for fitness, 60+ for serious competition. Of course 99.9% of us are never going to run 40 miles in a week, let alone every week. The important thing is to get moving. It pays off in health and happiness, with 14 hours more life for each hour of running!

If you’re a new runner please don’t start with a hard run. That’s an easy way to get hurt before you get into shape. While we’re designed to run, we’re capable of running more than an un-practiced body can handle. (Better than getting eaten by a lion, I suppose). If you haven’t exercised in years, give your body months to catch up.

Decide how much time you want to exercise a week. 15 to 30 minutes a day is great. Even 5 or 10 minutes a day works. If you’re starting out of shape, walk briskly most of the way, then run gently for a few minutes, then walk some more, then run a few minutes more. Every couple of days add a few more minutes of running. Gradually ramp up so that after a few months you can run the whole way. If you want extra motivation, sign up for a 5K race a few months down the road.

A little sore is OK. A lot sore is not, except after a race. If you feel like you need to recover, walk or do something else active that day. Don’t run (at least) one day each week. This will refresh you for the next week. Taken a few days off and still tired? Get out and run, even if just for 5 minutes. It won’t ruin your sleep. Running gives insomniacs 45 minutes more sleep!

Don’t just run. Strengthen your whole body.


How fast to run?

  • If your goal is health, then pick any pace you like. Anything is better than sitting at a desk or watching TV.
  • If your goal is to maximize fitness then faster is better. Up to 20% or 25% of your training time should be ‘quality’ running, that is running fast. According to the graph above, elites go fast a lot more.
  • If your goal is a specific race time or pace, then some time running at that race pace and some time running even faster than that every week. The more you run at a pace, the more efficient you get at running at that pace. Running faster makes you stronger.
  • To train to run faster, run faster (in shorter intervals). Purposely alternate between slow and fast. This is called interval training. Fast is as fast as you can run and keep running, for up to half of your workout time. Slow is slow enough to recover so you can go fast again. Start small, with a couple 20 or 30 second intervals over the course of a whole workout. Gradually add more or longer intervals.

Running Gear


Running shoes

The lighter the shoes, the faster you go: 1% speed up per 100 grams. Humans, like other mammals, are designed to run barefoot. If you want to try lighter shoes, be careful! It’s easy to get hurt when you make a sudden, big change to your training. Buy a slightly lighter pair. Spend a few months getting used to them and then repeat. If your foot or leg starts to hurt, immediately go back to your old shoes. Give your body months to adapt to big changes. If you didn’t grow up running barefoot, sorry, you missed your chance.

Cushions on your feet?

If you’ve ever thrown a ball against a wall you know that hard rubber balls bounce more than soft rubber balls. The perfectly designed bounce of the (trained) human foot and leg are unbeatable. Adding spongy stuff to your feet weighs them down and absorbs their energy. Not only do you have to bounce, you have to balance. Try balancing yourself on one foot on a hard surface in bare feet. It’s easy. Now try balancing yourself on a soft cushiony surface. It’s hard. Unfortunately safely changing a lifetime habit may take years.


Running apps, watches, heart rate monitors and fitness bands.

I like to see how far and fast I ran and how hard I worked. If you’ve got a smart phone, my favorite running application is Strava with Veloviewer. As for fitness bands, save your money. They’re toys compared to a GPS phone or watch or a heart rate monitor. If you want the best get a Garmin 620 with a heart rate monitor.


A cotton t-shirt is great dry but terrible sweaty. Spend some dollars and buy a running shirt. You’ll never go back to t-shirts. If it’s cold wear gloves. If it’s colder wear a hat, then a light jacket, then tights… Take them off as you warm up. Don’t over dress. Getting hot isn’t making you fit, just dehydrated faster.

Breast and Nipple Protection

Females need a good sports bra. Males, when cold and wet, need to make sure their nipples don’t get abraded. The cold makes them hard and the wet makes their shirts rub. Cover them with Bodyglide or 3M Transpore Tape before they hurt.

Weight, diet, calories, food and drink



You lift your entire body weight on every running step. Within reason, the less you weigh the easier and faster you can run. Every 1% weight loss is a 1% to 1.4% speed up, down the point you look like a fitness model (male ~8% body fat, female ~15% body fat). Thinner than that and you’ll look and feel unhealthy.



Running Science: “The best endurance athletes in the world – the Kenyan runners – follow a diet that is extremely rich in carbohydrates, moderate in protein and low in fat.” And up to 15% sugar!  Of course they also stay extremely skinny (5% body fat for male champions, 10% for female) by exercising much without eating too much. Based on victories, their diet, not some fad, is the best for runners.

Calories (during and after a run)

Runner’s World estimates calories burned by running:
Calories = Runner’s Weight in Pounds * Miles Run * .63

That’s 95 calories a mile for a 150-pound runner.  .63 is just the net calorie burn of running. If you want the total calorie cost (including the normal cost of being awake) use .75 k-calories per pound per mile (most published calorie calculators use this higher number).

Add more for climbing:
Climbing Calories = Runner’s Weight in Pounds * Height Ascended in Feet * .001

If a 200 pound runner climbs 1000 feet that’s an additional 200 calories. Of course if you come back down you’ll gain half of the energy back.

Subtract for descending:
Descending Calorie (savings) = Runner’s Weight in Pounds * Height Descended in Feet *.0005

Add more for air resistance:

Economy of running: beyond the measurement of oxygen uptake Jared R. Fletcher, Shane P. Esau, and Brian R. MacIntosh

Air resistance goes up with the square of speed. Running 12 minute miles has only ¼ the air resistance (1.5%) of running 6 minute miles  (5.5% energy cost). Running calorie calculators ignore air resistance as “small and may be neglected.” If you’ve ever run into a 10 mph headwind, you know wind isn’t so easy to ignore. The reason most exercise studies ignore air resistance is because wind tunnels are expensive. Since the wind (earth’s average wind speed is 7.4 mph) combines with our running speed, even a slow runner can be fighting a 20 mph headwind (~20% extra energy cost).

Here’s my simple formula for wind calories.
Speed = Higher of either Wind Speed (in mph) or Running Speed = Miles Run/Time to Run in Hours
Air Resistance Calories = .05 * Miles Run * Speed * Speed

Add more for after-burn:
After a run, your body must repair itself. That’s why you feel warm at night after a long, hard run. Since earlier calorie research did not extend past the actual workout, these calories have been ignored. To add them in:
After-burn calories = Workout Calories * .01 * Miles Run/Time to Run in Hours

Total Calories = Running Calories + Climbing Calories – Descending Calories + Air Resistance Calories + After-Burn Calories

Click on a yellow box to enter your numbers

Screen Shot 2014-03-09 at 3.57.45 PM

Heat makes it harder to run fast and far, ~3% per 10 degrees fahrenheit above 40. Assuming calorie research is done at room temperature (~70°) you’ll burn more on a hot day, less on a cool day than what’s calculated above.

Food (just before, during and just after a run)

Don’t expect to digest food during a fast run; expect to burp. Even at a slow run 65% of the blood flow to your gut is redirected to power your legs. So eat your last meal a couple hours before you run. The bigger the meal, the longer you’ll need to digest.

If you eat just before or during a run, you won’t digest even running ‘food’ like sport goo’s or gels without an appropriate amount of water to dissolve them.

Of course the sooner you eat after a run, the sooner those nutrients aid your recovery.


You sweat a lot running (even when it’s cold). As you dehydrate you lose blood volume and its ability to move oxygen. You need to replenish three things:

  1. Water
  2. Electrolytes
  3. Energy (simple carbohydrates, if you’re running more than an hour)

The easiest way to do this is to drink sports drink – they have what you need in the right proportions. Yes, they really are better than water. Bottled or powder, they all work. (I like powder, it’s cheaper and easier to store).

Water doesn’t have electrolytes, so when you drink water, homeostasis will pull electrolytes from your body (bad while running). To avoid that, when you need to drink water (because there is no sports drink handy) eat just enough sports gel or goo to add the electrolytes back in (one 100 kCal goo per twelve big swallows, or 12 ounces of water).

As soon as you finish a run, weigh yourself and figure out how much water you just lost and replenish it. If you lost a pound, drink a at leastpint (a pound) of water, beer or chocolate milk.

Glycogen & sports drinks

Your legs (and liver) should have enough ready energy (called glycogen) in them to run at least 10 miles or 1 hour. You don’t need to fuel up unless you’re going longer.

Sports drinks are designed to give you as much glycogen as possible. They include maximum amount of energy you can absorb while running. That’s ~8% carbs [8 grams of carbohydrates per 100 grams (3.4 ounces) of water.] [8 grams of carbohydrates yields 31 kilo-calories, enough for ~1/3 a mile of running.] If you eat food with your sports drink you won’t increase energy absorption, just your chance of an unhappy tummy.

Drink to replenish what you sweat (if not during the run, then just after). Sweat depends on the weather and your speed, from 12-36 ounces per hour. The slower you run, the less you need to drink per hour. Don’t drink too much.

I should drink ~32 ounces per hour. That’s 32 gulps (or 12 tiny race cups) per hour, which is about triple what I actually drink in a race. Dehydration of 2-3% of body weight is considered normal. Elites lose up to 10%! I drink a big (28 oz.) bicycle water bottle filled with sports drink just before a long race, and drink more when I can.

Beware: A couple pounds of liquid in your stomach can be uncomfortable, so test this out (or anything else) before you race. You may have to train your stomach or come up with your own plan.


Predictors of Running-Related Injuries Among 930 Novice Runners A 1-Year Prospective Follow-up Study Rasmus Oestergaard Nielsen, MHSc*,†‡ Ida Buist, PhD§ Erik Thorlund Parner, PhD|| Ellen Aagaard Nohr, PhD¶ Henrik Sørensen, PhD† Martin Lind, PhD# Sten Rasmussen, MD‡

The average runner gets injured once every ~100 to ~200 hours of running. Novices get injured 5x more frequently than marathoners! Minimize your risk:

  1. Ramp up gradually.
  2. Follow Runner’s World‘s advice and strengthen your 5 spots most likely to get hurt.
  3. To better absorb shock, strengthen your core muscles.
  4. Try Pilates or Yogacarefully
  5. Make your miles count. There is a 0.1% – 0.2% chance of injury each mile.

The big risk factors:

  • High body mass index >30 kg/m2
  • Previous injuries. “50% of injuries occur in the exact spot where a prior injury occurred”
  • Miles (~0.1% per mile!)
  • Novice runner. Bad form
  • Physical limitations. Imbalances. Poor strength. Poor flexibility. Weak core.
  • Rear Foot Strike (5.8 injuries per 10,000 miles)
  • Sudden changes to your training

To decrease risk (while maintaining fitness):

  • Lower body mass index <20 kg/m2
  • Fully rehabilitate from any previous injuries
  • Shorter but faster runs or intervals
  • Practice running smoothly. Improve form
  • Find and correct inflexibility or imbalances. Running specific strength training. Core training.
  • Fore Foot Strike (2.19 injuries per 10,000 miles)
  • Gradually introduce changes

What if something gets hurt?

Runner’s World has a nice summary of the common running injuries, and what to do if they strike you. Injuries have causes: A previous injury or imbalance, bad running form, asking your body to do too much too soon; too many miles, too little rest, pounding down hill without enough strength, a sudden, big change in training habits … No amount of rest, ice, painkillers, cortisone, etc. will prevent reoccurrence of an injury. You’ll need some good physical therapy to find and then correct the root cause of the injury.

Medical science has limited therapies for many running ills, including the runner’s bane, Plantar Fasciitis. Doctors are quick to prescribe a pill or a cortisone shot even though these are more placebos than cures. If the doctor wants to cure the symptom and not the cause, find a sports medicine clinic, or ask your local track coach whom they recommend. Then work diligently with your physical therapist until you are fully rehabilitated. Don’t go back to running too soon, or face a quick trip back to square one.


Runners World: The Pros and Cons of Massages for Runners
Research finally reveals just what massages can—and can’t—do for runners.

Stretching, Warming Up, Cool-downs and Massage

Despite what your old coach said, don’t stretch before a run. This increases your risk of injury. There is also little or no evidence stretching helps after a run (if you have a good range of motion).

You still need to warm up. Run slowly for a couple minutes.

Cool-downs are in most coaching plans, but have little research to support them.

Pro’s massage regularly. Treat yourself if you can.

If you have an injury, stretching will be part of your physical therapy. If you don’t full rehabilitate from one injury you’re likely to get another (as one part of your body tries to do the job of the injured part), so massage out the scar tissue, stretch and strengthen religiously until you’re better and stronger than before.

Running technique



Heart rate

A heart rate monitor (HRM) measures how hard you are exercising. Your HRM can coach you on how hard to push.

heart rate

Measure your level of effort relative to your maximum heart rate (MHR). An easy, but unreliable way to estimate maximum heart rate is to use the latest (Dec 2013) aged based formula:

Maximum Heart Rate = 211 – (Age * 0.64), plus or minus 11. Example: If you’re 54 years old, your maximum heart rate typically should be within 11 of 176 beats per minute.  The standard Maximum Heart Rate = 220 – Age formula is obsolete.

The hard (but accurate) way to measure heart rate is to warm up and then run up stairs faster and faster until you think you are going to die. Please check with your doctor before trying to kill yourself.

It takes about 10 minutes for your heart to ramp up to match your level of effort.

Once your heart rate is stable it can guide your training. Runners World has a nice summary, if you’re already a runner. If not, Table 6.1 (above) from the American College of Sports Medicine will get you started.

Cadence or Stride Frequency

Factors Related to Top Running Speed and Economy Authors A. Nummela1, T. Keränen1, L. O. Mikkelsson2

Some runners, particularly new runners, run with a bit (~3%) too low cadence (too few steps per minute = too long a stride) for maximum efficiency. Coaches recommend at least 180 steps per minute, even going uphill. This may be too high if you run slowly, as optimal cadence increases slightly with speed. Buy a foot pod or count how many times your left foot hits the ground in 10 seconds. If it’s less than 9, your cadence may be too slow. Try a few runs with quicker, shorter steps.

Smooth running

This video is a nice introduction to efficient running.


The more stable you are running the safer and more efficient you are. Strengthen. Smooth out your bumps with a faster cadence. Some runners have strange movements as they run. Have someone check that you’re running smoothly.

A checklist for efficient running:

  • Don’t reach ahead with your foot. Stepping too far ahead acts like a little brake – as you can feel when you run down hill.
  • Lean a tiny bit (a couple degrees) forward from the ankles (not from the hips, back or neck). Don’t bend from your hips when you go up hill.
  • Run with shoulders square (not hunched). This is called opening your chest.
  • Run with a straight back and long neck (spine and neck that feels straight and as strong as a board). Keep your hips fully forward (by engaging the glutes). Coaches call this running tall.
  • Look straight ahead.
  • Minimize the amount of bouncing up, down or side-to-side.
  • Arms balance each foot strike. Don’t swing them past your mid-line.
  • Relax! Muscle tension burns calories.

It takes time to smooth out your running form, for me five years. Focus on one improvement at a time.

Hills and Strength training

Good runners use hills to improve their fitness. Hills are a natural form of interval training. When you run up a hill shorten your stride to keep your cadence the same as it was on the flats. Don’t increase your forward lean. Ultra-marathoners walk on long steep hills  (>10% grade). It’s faster than running them. Top runners also do strength training. It increases speed and reduces injury.


To simulate air resistance, incline your treadmill at 1%. Make your treadmill time interesting. Try running barefoot. The treadmill is soft and safe. Try running at 5%, 10% or maximum slope. Try various paces and intervals. Plodding at the same speed and distance won’t maximize your brain or legs.


Many runners have difficulty breathing. While you might have asthma or allergies*, the main cause is being out of shape. Learn to breathe deeply to get into shape faster.

[Video]. Put your hand on your stomach. Take a deep breath. Your stomach should push out when you breathe in. Now put you hand on the side of your back at the same height as your stomach. Take a deep breath. Your back should push out a bit. Take Yoga to open your chest. Open your throat so the air goes in and out easily. Synchronize your breath with your step.

Give yourself a few months to learn to breathe deeply.  Unplug your headphones and concentrate on breathing as you run. Focusing on your breath is very meditative and surprisingly rewarding.

Breathing deeper won’t instantly cure the awful feeling of being out of breath, but with a couple months of practice you’ll pull in more oxygen and enjoy your runs more.

* I found I had a problem with dust mites – the day after I replaced my mattress – and could breathe!

Side stitch

Too much food or drink in your belly, dehydration, a weak or tired core, or prolonged rapid, shallow breathing can cause cramps. If you get a side-cramp, exhale when the leg on the opposite side from the stitch strikes the ground. Your cramp is generally on your right, near your liver, which can tug your diaphragm.

Running clubs, running with friends, coaches


Though I have no data, most runners seem happier and faster in a group. The easiest (and nicest) way to improve your running (and motivation) is to start running with someone else. The bigger the group the better the chance you’ll find someone just your speed. If you’re serious, find a running coach. Sorry, no data on the effect of running coaches (or reading running blog posts). 🙂



A few months before Train! You can improve a lot in one month, and more in two, especially if you’re not in shape to start. If you’re game try some high-intensity interval training (HIIT).
Two weeks before Taper. Run your last long run. Reduce your miles. Keep doing some speed work.
A couple days before Your legs should feel fresh. Figure out your race pace*. This can be based on your best training runs or your previous races using a Race Calculator. Figure out your hydration plan.
The day before Don’t stay up late drinking 🙂 Lay out what you are going to use in the race. Don’t eat, drink or wear anything you haven’t run tested.
Carbohydrate-loading If you’re running a marathon or more, carb load the 36-48 hours before the race. One easy method is to warm up and sprint as fast as you can for 30 seconds the morning before your race. Then eat a pile of carbohydrates.
The morning before Make sure you are well hydrated. If you’re going further than normal, lube your toes, thighs, nipples or anywhere else that might get abraded or blistered. If you like running caffeinated (test it out beforehand) load up on caffeine, ~5 milligrams per kilogram of body mass (about 2 NoDoz), one hour before the starting gun. More doesn’t help. You’ll still have half the caffeine in your system after ~5 hours, so no need to refill. For marathons, eat a few hours before the race. Closer to race time and you’ll get an upset stomach. One 2012 study suggests a 1000-calorie meal 4 hours before.
During the race Run your race pace. Even power output is optimal, so slow uphill or into the wind, speed downwind or downhill. One exception, push harder up a climb if you’ll get an immediate rest after the crest (because the downhill is too steep to run at full race power). Don’t start too fast. For long runs drink sports drink according to your hydration plan and the day’s weather. If you’re running into a wind, find a big runner to draft (run on his or her heels).
When you’re done. You’ll quickly cool down and tighten up. Relax. Replenish your lost fluids. If you lost two pounds drink two pints (a pint is a pound) of water.  Enjoy a massage.
The next few days If you pushed yourself to your limit expect to be sore, perhaps for days. Sleep, eat and hydrate well. Walk. Massage out tight muscles and stretch out tight tendons. Easy runs may aid your recovery.  The harder the effort (and older you are) the longer to fully recover.  It might take weeks to recover from an ambitious marathon.

Race Pace

Your race pace is the speed you run when you are in a race. Since a steady pace is the most efficient way to cover ground, it helps to know what pace you can sustain during that race.

On race day try to run at an even pace, the same (fast, but not too fast) pace each (flat) mile. If you’re not sure what your race pace is, start a bit slow and speed up half way. Sustain the same level of effort, whether going flat, up or down. Slow down when you go up, and speed up when you go down. Keep your cadence up even when you slow down. If you rarely run downhill, the extra stress on your back, legs and feet can cause an injury, so be careful if it gets steep.

How fast can you run a race? Once you run one race you can use my favorite Race Calculator to estimate how fast you can run other distances. To modify for hills, each foot of elevation gain slows you down as much as running another ~4 feet, so 10 feet of elevation gain will slow you down ~3-5 seconds. Each foot of elevation loss speeds you up as much as running 2-3 feet less, so 10 feet of elevation loss will speed you up by ~2-3 seconds.

If you haven’t run a race before, you can push yourself harder than in training (say 20-60 seconds per mile faster, or a 5-15 beats per second higher heart rate) and hope for the best. If you have to slow down a lot before the end, start slower next time and keep the pace steady. Shoot to run the first and second half of your race the same speed, or the second half a tad slower (a slight positive split).

Marathons and ‘The Wall’

A marathon is different. Unlike shorter races, 40% of marathoners run out of glycogen and ‘Hit the Wall”

Metabolic Factors Limiting Performance in Marathon Runners Benjamin I. Rapoport Wall text

If you use up all your glycogen before your race is over your legs suddenly turn leaden and your body tells you to stop. To avoid the wall, set your pace or intensity just slow enough that you don’t quite run out of glycogen. Maximize your pre-race carb-loading and your in race refueling. Specialized training (fasting before long runs) may not help. However you can find your maximum fueling tolerance in training. 100 calories of sports drink or 1 gel/Gu + 8 oz. water every 3-5 miles?

New Fads and Old Myths

There are always new exercise fads. Ignore them until you see the professionals using them, and even then …



… plus old exercise fables for scientists to disprove and coaches to un-learn.

Placebos (Which work, even when we don’t believe in them!)

Science disputed

Running Science Old and New

The half life of old running science

In school we’re taught that theories evolve but facts don’t. Unless you go to medical school, where the medical school faculty are personally responsible for evolving medical science, and gleefully teach their young doctors-to-be not to kill their patients with out-of-date medical ‘facts’, we’re not taught that even facts change. The human physiology facts of 2014 are not the facts of 1964, or even 1994.  30% of medical ‘facts’ were overturned in the past 25 years. Running science will be different in 2024.

Facts have a half-life, long for clean subjects like physics, short for messy subjects like neurobiology. Any running book written before 2013 will include some ‘facts’ that have been already proven wrong, and more will be disproven next year. While running itself is timeless, running science is not. If your running coach hasn’t changed their coaching in 10 years they are out-of-date and getting more so each year.

I’ve done my best to present running science as of 2014. Unlike a book I can easily update this as the ‘facts’ change. Just let me know.

New coaching

Coaching will move into the 21st century. Today’s coaching manuals only assume one piece of technology, a stop watch. Tomorrow’s coaching mobile applications will monitor every athlete by GPS and heart rate monitor. Under or over-training will be quickly detected by regular monitoring of heart rate. Every day the app will update the coach and athlete based on yesterday’s performance, and suggest what to do today to best prepare for the next race. The app will get smarter and smarter as it collects data from around the world.

New running science

The Internet Of Things will provide running science with vast, cheap data. Instead of studies based on two dozen college athletes we’ll start seeing research leveraging millions, enough to detect small, one second per mile differences.

Experiments, instead of requiring years to submit grant proposals, collect and train volunteers, buy and set up special equipment, process and analyze data, write up results, submit for peer review and eventual publication (with the results then only available by paying a significant fee to the publisher), will be invented, run and published to the world in days, just like web A/B testing. I hope to see running science based on The Quantified Self by 2015.

Ned @nedlern

Get fast, smart


Strava, Garmin, MapMyRun, Runkeeper, Endomondo, Runtastic, Nike+, MiCoach, … you’ve pioneered the exercise app, but it’s time to Get Smart. Leverage the great data we help each other collect.

First remove the bad data. Here’s what not to do. On July 7, 1995, Hicham El Guerrouj of Morocco ran the world’s all time fastest mile of 3:43.13 in Rome.  Go Hicham!


But according to your records, on April 1, 2012, Tina Harrison ran a 1:58 mile. Go Tina!!


Let’s stop embarrassing each other. Don’t publish that I broke Usain Bolt’s world record time of 9.58 seconds in the 100-meter dash, when actually all I did was …

  1. Finish my run
  2. Didn’t turn off my watch
  3. Drove off at 60 MPH

So if my GPS reports that I’m running 100 meters in 9 seconds, don’t mess up our* records, throw out the bad data.  

* Why do I say our records, and not my records? My stats feed the global data pool. My bad data messes up everyone’s records.

After you throw out our false world records, then use our heart rate monitors to double check our (less reliable) GPS measured speeds. It’s not that hard to determine how fast a runner should be able to run, given heart rate, distance, slope and prior running history. If I’m not wearing a heart rate monitor (HRM) then sanity check my speed against segments from HRM double-checked runners who normally run like me.

Check the wind and weather data too. We both know it’s not a personal record if there is a 20 MPH tailwind. Correct for these weather effects. Your hill adjustments are also off. Uphill you should use heart rate (HR) as a proxy for effort, showing our normal speed at that HR, not some abstract calculation based on GPS speed and slope.

What we want is a RealSpeed™. RealSpeed would correct for all external effects; hills, wind, wind velocity, temperature (too hot or too cold = hard), even path roughness. The key is to use your millions of runs to generate real data, not to use simple (but false) calculations.  The HRM (heart rate monitor) is the key (except for downhill runs). If you run 7.5 MPH (8 minute miles) at a HR of 150 beats per second (bps) with perfect temperature, no wind, no hills, flat road, then whenever you see a HR of 150 you know the RealSpeed is 7.5, (at least until your running form and conditioning improve, and RealSpeed is the key to measuring this improvement).

Once you’ve got my RealSpeed you can start comparing every run I do, regardless of slope, wind, course, … Give me a cool chart that shows me, at a glance, my progress over time. We love charts – especially when we’re training and improving. Find a clear, visual way that lets me compare my last 6 months of runs versus today’s run.

Veteran runners might have a problem with Real-Speed. We eventually get slower. We might want an age-adjusted RealSpeed. Otherwise we’ll train and train and get slower. That isn’t fun. In fact any runner who works hard will be tired the next day and slow down a bit. Maybe we need a rest-adjusted RealSpeed too.

Next, stop asking us to manually create courses. There are algorithms to identify if any two paths match, that is if I (or anyone else) has run this path before. Use these algorithms to instantly acquire 100% ‘course’ coverage of every step I run, without any manual input, duplicates or gaps. A good path-matching algorithm is as important to managing outdoors activity as a good search algorithm is to managing Internet activity, and we need Google, not Alta Vista. For route names, default to the name on the map, or allow the course regulars to propose better names, which all those who have completed the course can vote on.

When I do run the same paths I’d like to see how I’m doing versus my previous steps on that path. This may sound simple, but it isn’t. Why? Look at the GPS plot below. I don’t think most GPS data this bad, but …


This GPS data is so bad you might not even realize I’m actually just doing laps in the bottom lane of the pool (the bright blue rectangle in the middle).  Before you can compare two identical runs, you’ll need some tricky DSP (digital signal processing) work to clean the GPS data, to extract simple, easy to understand feel for speed and effort.

Right now my speed graphs show a lot of random spikes, even when I’m running smoothly.

Without this clever DSP work, when you compare two or twenty identical runs you’ll get a barrage of spikes and noise, hiding the signal or ‘true’ speed.  Digest our noisy data so we can understand it.

You might be amazed how nicely a top-notch signal-processing expert can clean up noisy data, given enough data. Here’s some non-expert signal processing.


This graph looks pretty, but its smoothness is a lie. Bad signal processing, in this case smoothing data over 60+ seconds, created a false smoothness. Neither was the terrain smooth, nor was I trying to run smooth. Here’s the same run, without the fake smoothing.


  • The first, biggest spike is where I walked down some stairs.
  • The second spike is where I stopped after my speed mile.
  • The third, small but sharp spike is where I stopped to drink from a fountain.
  • The fourth spike is where I encountered a flight of (very) steep stairs (and stopped for a breath at the top).

When I got to the (obvious) very flat spot on Great Highway (along side the very flat Pacific Ocean)

great highway

I increased my pace from about a 9 minute miles to a 7 minute miles, just to see if I could run this fast, starting at the moment when I pushed my lap button (which should have been noted).  The smoothed graph entirely misses this 7-minute mile – that’s not helping me analyze my run.

While the little spikes may be noise, OK to smooth, the big spikes are not OK to smooth. When I ‘change gear’ from fast to slow (or slow to fast) the graph should jump, not connect, and certainly not blend in speeds from 30 or 60 seconds before my abrupt pace change. It might more meaningful to skip or drop non-running spots from my running graph, since I’m actually not running.

More important, you need a meters per second graph or MPH graph. The current Seconds per Mile display goes up to infinity as I slow down. This makes ugly graphs, with the ‘slow’ spikes so high they take up all the vertical space.  It’s more than a cosmetic problem. My fast sections are critical for training, the slow parts literally just junk.

Our fast sections must stick up and be emphasized. 10 MPH should be higher than 8 MPH. Anything less than a running pace (5 MPH), should be just noise at the bottom of the graph. This is exactly what a MPH graph does.


Unfortunately, the popular Minute:Seconds per Mile graphs highlights the meaningless, easy sections or our workouts, and squashes the important, hard sections of our workout.  Stops become huge spikes, sprints are practically invisible.


The blue and red graphs show the exact same speeds, but the red, Seconds Per Mile graph emphasizes all the wrong information.

Since many runners stop at the same places (a turn around point at a fence or wall, a water fountain, bathroom or traffic light, …), looking at everyone’s data will help separate what is a ‘stop’ from what is data noise. The clean up process will need to be fed, not only my GPS data, but also my lap button presses, terrain data, and places we take breaks. Big data combined with good DSP work should clean up my noise without wiping out my signal.

The most valuable thing you could do for me is to give me a Big Data-driven virtual coach. I want my big-data coach to: Tell me if I’m not warming up enough before pushing hard. Pester me when I over-train and tell me I need to take a break. Coach me when I need intervals, both how much to rest, and how much to push. Motivate me with real data on how much faster I’ll be if I run 5 miles more a week, or lose 5 pounds, or can push harder on my hardest hill. Have an expert, like Owen Anderson, PhD., author of the new book, Running Science, or another famous scientific data-driven coach co-design and endorse your big-data coach.

Maybe I’m biased after working on games, but can I get a score? How much have I improved over the last four years? Am I the 10,000th fastest half marathoner in the world? If I’m not, how much faster do I need to go? How much help was my last training run? Coach – encourage me! If I’m going to live an extra 100 minutes thanks to my 40 minute workout, let me know my sweat just bought me an extra hour of life.

For bonus credit, if more experienced runners or riders take variant courses, we’d love to see them (on your map, of course). I’ve been pounding down the steep Point Lobos Avenue hill for years.

Point Lobos Ave

I just found out there is a nice, soft (dirt) footpath hiding just across the street.

sutro heights stairs

Ideally less experienced runners of the Point Lobos hill could now benefit from my experience. If the system were paying attention it would see I’ve changed my routine (say after 5 repeats of the new route instead of the old route) and then ask me if I’d recommend this change to others.

I don’t always want to run alone. I want something like a game matchmaking service, to let me discover potential training partners: people who run where I run, who aren’t too fast or too slow.  If I run by them, send me a sign. A simple text will do. Tell us both how much faster we’ll become if we start running together. Tell me which of my coworkers (my address book), neighbors (your service), contacts (LinkedIn), or friends of friends (Facebook) might want to run with me. Let running clubs and running stores promote their weekly runs and sign up their friends. Allow coaches and trainers to monitor and message their athletes. Encourage race organizers to set up their exact courses and give out virtual prizes.

Get super smart! You have more data than any coach or exercise study in history. Look for patterns in your millions of runs to predict how we’re most likely to get hurt, and then warn us. How do you detect an injury? Look for regular runners that stop in the middle of a workout and then don’t run again for weeks. Take me as an example. If you look at my March 28th log, you’ll see me running as fast as I can down a steep hill, then stopping about two miles from home, then no running for the next ten weeks. Once you can see where we get injured, help us not get injured. If you see us running too fast down a steep hill, tell us how risky that is, and how to mitigate that risk.  I’m not the only one who would pay a virtual coach $10/month to skip one injury. That’s a lot less cost (and pain) then physical therapy.

Want to spawn a blizzard of sparkling publicity? Enlist us in mass experiments to replace old coaches’ tales and marketing puffery with hard-data backed science. Maybe start with our shoes. Do we run the same speed at a lower heart rate when we put on fancy new shoes? Do minimalist shoes actually reduce our injury rate? Find out everything: Does stretching before running increase or decrease injuries, what’s the impact of a cool down run, how much warm up do we need, do long, slow runs increase fitness, how fast is it safe to ramp up distance (particularly after certain kinds of injuries), how much faster do we get if we join a club or get a coach, does cross training help, and if so, what helps the most, …

Finally, once you gather for me all this great information, I want it nicely organized on a single page, my race readiness fitness poster. Most runners have weekly schedules; it’s fun to compare run to run, but a real coach watches progress week-to-week and race-to-race. You don’t make this easy; my progress information is scattered on bunches of pages hiding somewhere.

In conclusion: Make yourself indispensable. Look at runners who run real races. Find out which training programs actually work best, and teach them to us.

Get fast, smart, together!