The Most Efficient Way to Run (According To Science)

I came across a recently published (6/3/24) systematic review on what is the most efficient way to run, according to science (Van Hooren et al, 2024). 51 studies were reviewed in this systematic review.

It's a long review paper, key findings in the pictures attached. Let me highlight some of the important points. The paper does lend some support for increasing your cadence or step rate to improve running economy as this increases leg stiffness and reduces vertical oscillation. When you watch some runners run, you can see that they tend to 'bounce' up and down while running, that is vertical oscillation. 

Initial Contact

At Initial Contact (or foot flat) phase, higher cadence (step rate) may be associated with a lower energy cost of running. Decreased trunk flexion and knee flexion during swing phase may also be associated with better running economy.

Mid stance 

During Mid Stance phase, decreased trunk flexion and reduced vertical oscillation may be associated with improved running economy. Increased vertical and leg stiffness may also be associated with lower energy cost.

Toe off

At the Toe Off phase, if trunk flexion and ankle plantarflexion are reduced, running economy may be improved.

Those metioned above are just he key findings which I have summarised. However, there are many more details and applications in the paper itself. You can read the free paper here.

I have previously written before on running cadence and running form if you wish to read further.

Reference

Van Hooren B, Jukic I, Cox M et al (2024). The Relationship Betwen Running Biomechanics And Runnng Economy : A Systematic Review And Meta-Analysis Of Observational Studies. Sports Med. DOI: 10.1007/s40279-024-01997-3

Summary

Can Your Sports Bra Restrict Your Breathing?

Excellent post by Aized on whether your sports bra can restrict your breathing when you exercise in our Physio Solutions blog. Have a read here.

Simple Hopping Exercise Improves Running Performance

Last week's topic was on when to change your running shoes, with a key finding showing that energy consumption while running with newer PEBA midsoles was 1.8 percent less compared to EVA misoles. And using less energy means we can run further and faster. Running performance is thus dependent of how efficiently we move, which is defined as running economy  (RE).

In case some of you are not willing to shell out a few hundred dollars for a new pair of PEBA midsole running shoes, let me suggest another way to improve your RE without spending any money.

Here is what authors who investigated the effects of spending just 5 minutes daily doing double leg hopping (similar to plyometrics) over 6 weeks (Engeroff et al, 2023). 

34 amateur runners (29±7 years, 27 males) were assigned to a control group or a hopping exercise group. Those in the control group did not do the hopping exercises but continued with their own exercise. 

Those in the hopping exercise group did the regular exercises plus the hopping. The hopping bouts lasted 10 seconds each initially, (they did 5 times with 50 seconds rest) with the bouts gradually increasing and the rest periods shortening (pictured above). Each week after, they added an additional set of hops and reduced the rest times by 10 seconds to have a total training time of 5 minutes.

RE, peak oxygen uptake (VO2 peak) and respiratory exchange ratio (RER) were measured at 3 running speeds (10, 12 and 14 kmh) before and after the hopping program.

The authors found that the simple double legged hopping exercise can enhance running economy (RE) at higher speeds (12 and 14 km/h) in the subjects. The benefits are pronounced even when the hopping regimen is kept simple and done for 5 minutes daily. Maximum aerobic capacity was unchanged if their regular running and exercise habits were maintained.

The authors sugested that the increase in Achilles tendon stiffness improved RE since stiffer tendons are more capable of transferring energy to help movement. Their data showed significant improvements in RE while the subjects were running at 12 and 14 km/h but not at 10 km/h which provides support that Achilles tendon stretch and recoil increases with running speed (Lai et al, 2014).

What I felt was important was that there were no reported injuries nor side effects from the hopping exercise protocol. It is also not known if the hopping can be done in a fatigued state? Would that then lead to possible injuries? 

The hopping described in this study is really simple. The subjects hopped as high as they could using both legs with both legs either straight or slightly bent. So no need to do box or squat jumps! Other than packing my skipping rope with me when I'm traveling later this month, I'm going to try this as well.

References

Engeroff T, Kalo K, Merrifield R et al (2023). Progressive Daily Hopping Exercises Improves Running Economy In Amateur Runners: A Randomized And Controlled Trial. Sci Rep 13, 4167. DOI: 10.1038/s41598-023-30798-3

Lai A, Schache AG, Lin YC et al (2014). Tendon Elastic Strain Energy In The Human Ankle Plantar-Flexors And Its Role With Increased Running Speed. J Exp Biol. 17: 3159-3168. DOI: 10.1242/jeb.100826

Super Pants Instead Of Super Shoes?

When someone mentions exoskeletons, I immediately think of 'Robocop', a film from 1987 (film poster below). Those of you who are old enough to remember watching Robocop starring Joel Kinnaman will understand what I'm trying to write. 

Why am I writing about exoskeletons? Well, it seems they may be the next big thing for runners after super shoes like Nike's Vaporfly came onto the market in 2017.

Wearable exoskeletons were invented to assist walking or running, especially to help carry heavy loads. Here's an early invention from a paper published in 2018 (Nasiri et al 2018). A spring loaded exoskeleton (pictured above the movie poster) worn around the waist and clamped to the upper legs that helps the rear leg forward with each stride. The researchers showed an improvement of 8 percent (compared to 4 percent with the Vapourfly).

However, if you looked at the design, it looks too cumbersome to run with. Probably it would be banned by World Athletics too.

A more recent paper published last year by South Korean researchers showed how a relatively simple design can improve running economy by 2.5 to 4.7 percent. 

There is a band around your torso, held up by suspenders (pictured above).There is also one compression band around each thigh, which is connected to the torso by an elastic. It weighs just 1.3 pounds and sticks out from your body by not more than an inch. Surely that can pass off as a pair of compression tights that will not be deemed illegal by World Athletics standards?

There was also another paper from a group of researchers in China that studied a unpowered exoskeleton that improved running economy by 7.2 percent (Zhou et al, 2021)

Rememeber so many world swimming records were broken after the now infamous polyurethane Speedo Fastskin LZR 'super suits' were introduced in 2009 and FINA (World Swimming Federation) subsequently banned them. Well, some of those timings still stand. 

Similarly, road running/ racing shoes cannot be used (for World Athletics races) if the midsole is thicker than 40 mm or if the shoes contain more than 1 carbon plate. Running spikes can only be 20 millimeters (mm) thick (down from 25) with effect from 2024. 

This may have led to the 400m hurdles men's world record By Karsten Warholm at the Tokyo Olympics last year. That world record and any other records set by these super spikes may last a whole lot longer when the super spikes are outlawed in 2024. Just like the swimming world records set wearing those 'super suits'.

Perhaps World Athletics should write some rules with these soon to be developed super pants. Remember you read about the 'super pants' here first.

References

Nasiri R, Ahmadi A and Ahmadabadi MN (2018). Reducing The Energy Cost Of Human Running Exoskeleton. IEEE Trans Neural Sys Rehab Eng. 26(10): 2026-2032. DOI: 10.1109TNSRE.2018.2872889

Yang JH, Park JI, Kim JH et al (2021). Reducing The Energy Cost Of Running Using A Lightweight, Low-profile Elastic Exosuit. J NeuroEngineering Rehab. 18, 129. DOI: 10.1186/s12984-021-00928-x

Zhou T, Xiong C, Zhang J e al (2021). Reducing The Metabolic Energy Of Walking And Running Using An Unpowered Hp Exoskeleton. J NeuroEngineering Rehab.18, 95. DOI: 10.1186/s1298-021-0093-5

Are You Choosing Running Shoes Based On Comfort?

Picture by Oyvind Solstad from Flickr

Don't we all love shoes that are comfortable? Especially when it comes to our running shoes. As runners, we all love that ahhhh sensation of our first steps in an exceptionally soft and comfy shoe. I couldn't believe how soft an Adidas NMD (not really running shoe though) felt when I first slipped it on. 

A more comfortable (or cushioned) shoe is usually preferred by new runners or for runners who are prone to injury and want extra protection and support.

The shoe companies know that subjective comfort is an essential factor in sport shoe development since this definitely helps them sell shoes. This comfort paradigm is based on an assumption that perceived comfort will lead to a path of least resistance (while running) and potentially reduce injury and improve running economy. (Luo et al 2009; Mundermann et al, 2001).

We've definitely been sold on advertisements selling us the softest, bounciest and energy return shoes that propel us forward and saves us energy and prevent injuries.

One study showed reduced oxygen consumption levels during running at submaximal speed while running in shoes that were rated subjectively as most comfortable (Luo et al, 2009). This may support the fact that running economy improves due to reduction of muscle activation (which decreases oxygen consumption or metabolic demand). 

Another study on military personnel showed some evidence supporting the use of comfortable shoe inserts (or orthotics) reduced injury rates of the foot, ankle, hip, knee and lower back compared to a control group.  However, two studies are not credible enough to know what actually helps and what are the mechanisms of reduction in oxygen consumption and preventing injuries. (Both studies count Professor of Biomechanics Benno Nigg, known for his work of running shoes as one of the authors).

In this latest paper I read, the authors aimed to investigate how shoes of differing comfort affects differences in oxygen demand along with potential mechanisms associated with injury risk. 

Fifteen male runners who ran at least 20 km per week with treadmill experience were recruited for the study. Testing includes an incremental lactate threshold test, a comfort assessment and treadmill running trials for biomechanical and physiological assessments. 

The researchers did not find any decrease in oxygen consumption in the most preferred shoe. Potential biomechanical contributors to changes in oxygen consumption (or metabolic demand) showed some differences in stride rate between the most preferred and least preferred shoe. Personally, it was interesting for me to note that stride frequency was actually lower in the most preferred (or comfortable) shoe compared to the least preferred (or least comfortable).

Based on the findings of this study, previous suggestions (derived from two other studies) regarding positive effects of enhanced footwear comfort during running cannot be supported. Neither on running economy nor on preventing injuries.

Should we then choose our running shoes based on comfort alone? This study suggest maybe not since the most comfortable shoes were not better or worse off with regards to oxygen consumption and not enough data to show any real change on injury risk.

Comfort is just one of many factors when we choose running shoes (compared to the more common foot type option like overpronators, supinators etc). Of course I definitely would not suggest running in shoes that are uncomfortable. 

I'm also feeling appalled that only 15 male runners (and no female  runners) were selected for the study. Remember I write previously how difficult it is to recruit runners to participate in a running research.

Athletes will want shoes that give them absolute efficiency that helps that run faster while your average runner would want the least discomfort while running to get fit.  

Of course there are some runners that will choose based on colour! *facepalm*

References

Lindorfer J, Kroll J and Schwameder H (2019). Does Enhanced Footwear Comfort Affect Oxygen And Running Biomechanics? Eur J Sport Sci. 20(4): 468-476. DOI : 10.1080/17461391.2019.164028

Luo, G, Stergiou P et al (2009). Improved Footwear Comfort Reduces Oxygen Consumption During Running. Footwear Sci. 1(1): 25-29. DOI: 10.1080/194242809002993001

Mundermann A, Stefanyshyn DJ and Nigg BM et al (2001). Relationship Between Footwear Comfort of Shoe Inserts and Anthropometric And Sensory Factors. Med Sci Sport Ex. 33(11): 1939-1945. DOI: 10.1097/00005768-200111000-00021.

Notes on the shoes in this study provided by Adidas

Five different shoes based on criteria previously reported in another study (Luo et al, 2009) were provided for this study. The shoe conditions showed variations in total mass (80 grams), heel lift (3.7mm), forefoot cushioning, rearfoot cushioning forefoot bending and rearfoot bending. The shoes in this study includes a standard neutral running shoe, shoes equipped with non standardized features like carbon fiber plates for increased longitudinal bending stiffness, exaggerated arch support and a cross training shoe.

One interesting point was that the researchers glued lead to the heel counters of the shoes that were lighter (since shoe mass influences oxygen consumption by about 1% per 100 grams of additional mass).

Another Way To Improve Your Running Economy

Small, quick steps

I wrote a few days ago about how to improve your running (or cycling) economy by inhaling carbon monoxide. Despite it being easier than training at altitude (and legal) compared to injecting yourself with illegal drugs, it can go terribly wrong if it's not done in a laboratory.

Well, I just read another article about improving your running economy, and it's a much easier way compared to the last article.

The researchers investigated whether a short training program of running 15 minutes for 10 days to increase cadence (or step frequency) to 180 steps per minute (90 strides / minute) will improve running economy.

The subjects were divided into two groups and they did training at the laboratory for 12 consecutive days. Running economy tests were done on day 1 and 12, followed by a maximal oxygen uptake test (day 1 only).

One group of runners completed a 10-day training program to increase cadence (or step frequency) on days 2-11. This consisted of running 180 steps per minute for 15 minutes at a self selected pace.

The control group completed the same runs without the step frequency training.

Oxygen consumption was significantly lower  for the group that did the cadence training but not the control group. The cadence training runners also had a faster cadence (7%) subsequently as well as a shorter step length (3.7%). Hear rates were 5.1% lower as well.

Seems like a much safer way to improve running economy to me than trying to inhale carbon monoxide from your car if you can't do it in a laboratory.

In the same way, cyclists can similarly improve by using a smaller gear to achieve a high pedaling rate.

As with all things pertaining with new training, do allow for time for your body to adapt to the new technique.


Reference

Quin TJ, Dempsey S et al (2019). Step Frequency Training Improves Running Economy In Well-Trained Female Runners. J Strength Cond. DOI: 10.1519/JSC.0000000000003206.

Achilles Tendon Length And Running Performance

My patient's L Achilles

Two years ago, after my marathon running patient tore his left Achilles tendon (AT) and had it repaired. About six weeks after the surgery, his surgical site got infected. The surgeon had to remove the repaired tendon. After the infection was cleared, the surgeon grafted the lateral gastrocnemius (calf) muscle to repair the tendon. 

Needless to say, he couldn't really run let alone think of finishing another marathon. After trying traditional Chinese medicine (TCM) and seeing another physiotherapist for over two years with not much improvement, a fellow runner I've treated before suggested he come and see me.

For runners, the hips, knee and ankle joints generate large amounts of forces during running. The ankle joint (via the Achilles tendon ) contributes remarkably to supply the power required while running.  

R calcaneus bone, where the Achilles inserts

The AT plays an important role in storing and returning elastic potential energy during the stance (foot flat on the ground) phase in walking and running. 

L Achilles inserting on calcaneus

I was wondering how else to help my patient when I came across a research paper investigating AT length and running performance on male Japanese 5000 meter runners (between 20-23 years of age). Their personal best times range from 13:54 minutes to just under 16 mins.

Their running economy was tested by calculating energy costs with three 4 minute runs at running speeds of 14, 16 and 18 km/h on a treadmill with a 4 minute active rest at 6 km/h.

Ready for the results? The researchers found that absolute length of the medial (inner) gastrocnemius (or calf), but not lateral gastrocnemius and soleus muscle correlated with a faster 5000 meter race time and lower energy cost during the submaximal treadmill tests at all 3 speeds tested.

This is after normalizing medial gastrocnemius muscle length with the subject's leg length. That is, the longer the medial gastrocnemius muscle, the better the running performance in endurance runners.

For the medically inclined, note that each AT length was calculated as the distance from the calcaneal tuberosity to the muscle tendon junction of the soleus, medial and lateral gastrocnemius respectively.

Possible reasons to achieving superior running performance may be that the longer medial gastrocnemius and AT store and return more elastic energy (and potentially reduces energy cost) from the ground reaction force compared to a shorter AT.

Have to treat both R and L leg

Reading that paper definitely gave me more clues to treat my patient (and other patients with Achilles tendon and plantar fascia problems). I am happy to say that my patient has since progressed to running up to 12 km.

He is now definitely looking forward to running his next marathon.

Reference

Ueno H, Suga T et al (2017). Relationship Between Achilles Tendon Length And Running Performance In Well-trained Male Endurance Runners. Scand J Med Sci in Sp. 28(2): 446-451. DOI: 10.1111/sms.12940.

Don't Start Too Fast In Your Race

Picture by richseow from Flickr

I've written about why why you shouldn't start too fast in your race before. Well. here's the science behind it.

Researchers studied a group of world class orienteers and skiers whose average VO2 max read 80.7ml/kg/min. Now that is truly world class.

The subjects were first made to run hard to tire them out. They were allowed to recover for a few minutes until their lactate levels reach either 3 or 5 mol/L. Thereafter, their running economy was measure while they ran at their threshold pace (or before they start to accumulate lactic acid, usually at 4 mol/L).

The results showed that when they were less recovered (5mmol/L of lactate, their running economy (or how much oxygen and energy required to cover a certain distance) was 5.5 percent worse. This is a huge difference. The authors suggest this would translate to 30 seconds for a 10 minute run, three minutes in an one hour run or 8:25 minutes in a full marathon.

The authors suggest that this should caution anyone starting too fast in a race as too fast a start causes an accumulation of lactate and you'll not be running as efficiently for the latter stages of the race.

Bear in mind that the subjects in the study were tested in laboratory conditions (i.e ideal).

In hot, super humid and sunny Singapore, your running economy definitely worsens after an hour of running. Two hours or more of running? You betcha. If you didn't read how I started too fast (and lost) in my first serious 800m race, read this.

Reference

Hoff J. Storen O et al (2016). Increased Blood Lactate Level Deteriorates Running Economy In World Class Endurance Athletes. J Strength Cond Res. DOI: 10.1519/JSC.0000000000001349.

A Hard Warm Up Helps You Run Faster

Weight vest from Flickr by Dennis S Hurd

Wanna run faster in your next race? Turns out a hard warm up can help you run faster before your race.

If you've ever been to a track meet and seen the runners warm up, you'll probably see them jog/run a fair bit, do some running drills, short sprints or strides (depending on their event) and other fairly vigorous activities as part of their warm up. You'll probably see the same prior to hard track/ interval sessions of some runners if you run at your local track. Usually the shorter the race, the more intensive the warm up.

Now there's research backing this up. Researchers studied a group of runners who went through their warm up and a race simulation thereafter on 2 occasions.  Before each race simulation, the runners (as part of their warm up) did 10 mins of easy jogging, 5 mins at a brisk (but not all out pace), six 10-seconds of striding (or accelerations at their mile race pace or faster). The runners rested 10 mins and did a series of jumps, another submaximal 5 min run and then a treadmill test at peak running speed.

That's some weight vest! (Picture by Ving Henson from The Pit)

The only difference was the runners wore a weighted vest while doing their 10-second striding. The runners after warming up with the weight vest had results significantly better. Their running economy was 6% better on the post striding 5 min run, peak running speed was 2.9% faster! (Running economy measures your running efficiency. You can run faster at the same effort if your running economy improves as that pace will feel easier, hence elite runners often use intervals to improve their running economy).

The researchers think that increased "leg stiffness" noted in the post striding jumps primed the legs and improved running economy in the runners, leading to faster times. I suppose an exercise scientist would say that running with the weight vest causes neuromuscular training adaptations (which means your brain is also being trained)  which makes the runners' legs stiffer so their running economy improves.

If you said "Jump", I'd say "How high?" Picture from The Pit 

A similar scenario may be felt for those of you who run intervals. You will probably notice that during your first 2-3 reps (of say a 10 x 1 km interval session) will feel more difficult than the next few reps as your body acclimatizes.

Now before you go and order that weight vest, do keep in mind that this work best for track middle and long distances and for road races up to 10 km. You should also try this in your interval training sessions and before low key races to see how it works for you before trying it prior to an important race.

Reference

Barnes KR, Hopkins WG et al (2013). Warm-up With A Weighted Vest Improves Running Performance Via Leg Stiffness And Running Economy. J Sci and Med in Sport. DOI: 10.1016/j.jsams.2013.12.005.

Don't Set Off Too Fast

Here's a personal experience from one of our patients at a race recently. Standing at the start line, training all gone to plan. Well rested and taper went well. When the horn sounded for the start, the runners at the front burst off and my patient follows. Legs feel fresh, the first few kilometres past quickly, a check of the watch says a PB (personal best) on the cards.

Upon reaching the halfway mark about 8 minutes ahead of schedule, doubt crept in slowly "Have I started too fast". By the finish line, target time was missed by 5mins (let alone a PB) and my patient was left swearing at the unintentional over ambitious start.

How many of you actually heard about the runner (or any runner) who started their race too slowly and finished wishing they'd started off faster? Probably not huh? It doesn't happen very often. But starting too fast is a mistake that even the most experienced runners make. Getting the pace right for a training run is hard, doing it in a race even more so.

Yours truly made the mistake before as well. In my first serious 800m race, I bolted into the lead at the start and led the race til the last 100 metres when I begin to struggle big time. Two of my competitors came around me and I ended up 3rd. I could have placed better or even won had I paced myself better (I proved that point when I won the same event the following two years in a row against the same runners).

That's why you see rabbits (pace makers) in all the big races - Boston, Berlin, London marathon etc. These runners are paid to run at a certain pace for the big guns racing. Those who run track and watch the Golden League Grand Prix meets can testify to that as well. Most of the world records are set this way, with their (pace makers) help. Like most things in running and racing, there is no short cut, you'll have to practice running a certain distance at 3,4, 5 minutes per kilometer to learn how to pace yourself.

You have to be aware of your stride rate, length, breathing pattern, arm swing etc and then observe how they change as you get tired whilst running. As you get stronger, probably all these will get easier and you can step your training up a notch. Using a GPS or heart rate monitor can help, but as you know, all electronic devices are fallible. If you can learn how to pace yourself you won't make be left at the mercy of a flat battery or failing signal. Plus, except for very long races, it is always better to leave the gadgets at home during the races (my personal opinion).

Before your race you would have know from your training what sort of time you can expect to maintain over the distance raced. Find out about the course, know which part of the course has terrain or slopes/ hills that may slow you down. Allow time to get across the start line in races which has large fields and accept that your pacing and finishing time may be affected.
Don't try to make up for lost time in the first few kilometers, try to claw it back a few seconds at a time . And when you can see the finishing or at least hear the race announcer at the end and a race marshal tells you last few hundred metres then you can muster up a decent sprint for the line.

The scientific rationale for this is simply that slower, steadier pace at the earlier stages (of any endurance race) will spare some of your carbohydrate stores since at slower speeds the body is more inclined to burn fat. This means that there will be some carbohydrate available at the later stages of the race so that fatigue and "hitting the wall" can be avoided.

Sometimes wearing a "pace band" around your wrist to clearly show your optimum split times will be most useful. I've seen runners write it on the back of the hands with permanent markers as well.