Running Twice A Day?

Remember earlier in the year I wrote about how it wasn't really increasing total weekly mileage that caused running injuries. Instead, huge single session mileage increases known as "single-session paradigm" more likely caused injuries. That study (Frandsen et al, 2025) found that large jumps in a single-session distance predicted injuries much better than large jumps in weekly mileage.

The 5,205 runners were followed over 18 months and accumulated 588,071 run sessions. The authors found that instead of keeping your longest run to within 10 percent of your previous longer run, a 10-30 percent increase increased your injury risk by 64 percent. A 30-100 percent increase increased risk by 52 percent while more than 100 percent increase increased risk by almost 128 percent.

To increase mileage safely, instead of running say 10 km at a go, you can run 5 km in the morning and a second 5 km in the evening. Each 5 km run stays well within what your body can tolerate. Instead of doing one run further than what your body can normally handle, you can log more volume by running 5 km in 2 manageable sessions separated by many hours of recovery.

Moreover, a 5 km run definitely feels easier than the last 5 km if you are running the last 5km in a 20 km run. Your running form stays better, you have less fatigue and that second run may feel better after a stressful day at work.

When I used to race triathlons, I can run up to 15 km in the morning and then do another easy 5 km in the late afternoon. It allows me to log 20 km without needing to do all 20 km in the morning.

While it's not mandatory to run twice a day, it's probably one of the simplest and safest way to increase mileage compared to running as many days as you already can. Especially if that is your goal without getting injured.

Reference

Schuster Brant Frandsen J, Hlme A, Parner ET et al (2025). How Much Running Is Too Much? Identifying High-Risk Running Sessions In A 5200-Person Cohort Study? BJSM. 59 (17): 1203-1210. DOI: 10.1136/bjsports-2024-109380

Lots Of Volume Needed

A nice place to log some serious mileage

Previously I wrote that high mileage alone may not enough for you to run fast. Just because Sebastian Sawe clocked over 240 km a week leading to his sub-2 hour marathon does not mean you too have to clock huge distances to run fast. 

So this post is for serious runners. For runners who want and can log long distances. Runners who want to run fast and are prepared to spend lots of time running. The recommendations will not help weekend warriors who just want to complete a race or fitness influencers to quote this to their followers.

Here is what a comprehensive analysis of the training intensity distribution (TID) across runners from different performance levels looks like. Researchers looked at different training sessions from 16 weeks before 151,813 marathons (yes you read correctly), done by 119,452 runners.

TID was measured using a 3 zone approach (Z1, Z2 and Z3) where critical speed is defined the boundary between Z2 and Z3. Note that this IS different from the Zone 1-5 runners talk about. The Zone 2 most runners talk about is Z1 here and Z3 here is Zone 5 on that scale.

The transition between Z1 and Z2 was assumed to occur at 82.3 percent of critical speed. Critical speed is the maximum running speed you can maintain for 30 to 60 minutes without fatiguing rapidly. It is strongly correlated to your lactate threshold.The training characteristics and TID were reported based on the runners' marathon finish time.

Results show that training mileage was 45.1 ± 26.4 km each week. The fastest runners in the study group (marathon finishing time between 120-150 mins) ran greater than 3 times more volume than slower runners.They did not run fast often.

The amount of time spent training in Z2 and Z3 remained relatively stable across all performance levels, but the proportion of training time spent in  was progressively higher in faster runners.

More than 80 percent of the runners with faster marathon times had a pyramidal approach where the volume of training (mileage) decreases as intensity increases. Visually it forms a pyramid pictured below. A big base of easy Z1 running, a smaller middle section of moderate effort and a tiny peak of high intensity work. 

With regards to total mileage that the faster runners covered, the more time they spent in Z1 (really easy pace), the faster their marathon finish time (p < 0.01 - highly siginificant statistical finding, less than 1 percent chance this happened by coincidence). Moreover, R² ≥ 0.9, meaning over 90 percent of the variance in marathon finish times can be explained by looking at how much total volume the runner did and how much of it was in Z1.

The study also found that the more time a runner spent training at Z2 or Z3 intensities, the slower their marathon finish time. p < 0.01 and R² ≥ 0.85, at least 85 percent of the variance in slower finish times can be predicted by an over reliance on Z2 and Z3 training.

Focusing too much on hard and moderate efforts usually backfires. Why? Running too 'fast' on easy days and not hard enough on hard days means you are in the "grey zone". Not easy enough to get the aerobic adaptations needed and not hard enough to get the benefits of the high quality intervals.

Spending too much time in Z2 (moderately hard) causes higher fatigue levels without the beneficial effects of Z1 nor the high end fitness gains of Z3. 

The fastest runners in this study achieved their better times by increasing training volume mainly in Z1. They also ran less when they incorporated high intensity runs to allow for recovery. 

Is that true for all distances? What about a 5km or 10 km race? Will you still need to run lots of easy Z1 miles. If you want to simply finish the race, no. But if you consider that even a mile race of 5 km race is predominantly aerobic (pictured above) then you will understand why a large volume is needed to build a large base. 

Slower means more sustainable over time, you will not get injured so easily and hence more adaptation over time. That's how you will get stronger. 

Find more ways to increase your training volume with long easy runs. True aerobic developmnent is only possible from accumulating volume.  It allows you to recover and handle the key sessions. You cannot HIIT your way to the top. If you cannot get your hours in then it would be a lot more difficult to run faster.

Reference

Muniz-Pumares D, Hunter B, Meyler S et al (2025). The Training Insity Distribution Of Marathon Runners Across Performance Levels. Sports Med 55: 1023-1035. DOI: 10.1007/s40279-024-02137-7

Run Faster With Zero Drop Shoes

And we thought zero drop shoes were 'dead'. Zero drop shoes were all the rage after Christopher McDougall wrote about the Tarahumara Mexican Natives in his book, 'Born To Run', in 2009. Remember those Vibram shoes? Now, Vibrams I will classify as barefoot type and then there were minimalist type running shoes (or racing flats). Maximalist shoes have since replaced minimalist zero drop running shoes.

The research article I read was to determine if shoe heel-toe drop affects running economy. The researchers studied how shoe heel drop affects metabolic energy (total energy usage) in runners during running. 

20 runners were recruited for the study. Running speed was 3.5m/ sec (or 12.6km/ hr) in custom footwear that only differed in heel-toe drop of 0, 10, 20 and 30 mm. Running shoe and weight of the shoe were fixed with a US size 10, Air Pegasus. The heaviest shoe mass was the 30 mm shoe at 260 grams. Small weights were attached to the exterior heel of the shoes with the lower heel drops (pictured below).

During the research, the runners first did a standing 5 minute test and then ran for 5 minutes in their own running shoes at 3.5m/ sec (or 12.6km/ hr) on a force measuring treadmill (Treadmetrix). Each runner then completed a 5 min running trial at 3.5m/ sec in each of the 4 heel-toe drop shoe conditons in a randomized order. Participants rested at least 5 minutes between the runs.

To measure metabolic energy (or total energy usage), open circuit expired gas analysis was done to record oxygen and carbon dioxide uptake. Normalized net metabolic power (W/kg) was derived by subtracting the participants's corresponding standing metabolic power from each running trial and divided by their masses.

The results show that higher heel drop shoes increased plantar flexion in the ankles and knee flexion during ground contact. This we know from past research since runners who previously had knee pain had decreased knee forces and knee pain when they switched to zero drop running shoes.

Higher shoe heel-toe drop also increased metabolic power by 0.08W/kg per 10mm of heel-toe shoe drop.

One limitation in the study was that they only had one relatively large shoe size (US 10) which resulted in only one female participant in their study. Future studies may be warranted to test for potential effects between male and female runners.

Based on the researchers findings, they concluded that decreasing shoe heel-toe drop from 20mm to 0mm elicits a 1.6 percent more economical running which is predicted to improve total marathon performance by 1-3 minutes. 

Perhaps we will see the carbon plated maximalist running shoes come with zero heel-toe drop next?

Reference

Renninger K, Beck ON (2026). Shoe Heel-Toe Drop Affects Running Economy. J Appl Physiol. 141(1): 280-290. DOI: 10.1152/japplphysiol.00886.2025

27 Year Old Mile World Record Broken

I wasn't a fan of Josh Kerr before I read up on him while researching for this post. He always seemed too confident which many others (and I) interpreted as cocky. I realized what it really is, is a deep conviction that's founded in the work he and his coach Danny Mackey have done.

In front of 60,000 fans in the London Diamond League meet, Kerr ran 3:42.66 min to beat Hichan El Guerrouj's record set 27 years ago in 1999. 

Earlier in March this year, Kerr announced Project 222, an attempt to beat one of track's hardest and most hallowed record, El Guerrouj's 3:43.13 min mile world record. In typical Kerr fashion, he said: "It's time for that record to have a real go at it, and I'm going to be the guy to do it."

And he did it on 18th July! He etched his name into track and field history, joining previous UK legends like Bannister, Ibottsen, Coe, Ovett and Cram.

Both Kerr and his coach Danny Mackey are always methodical in their preparation, one of the reasons why Kerr always performs in the big meets where the lights are the brightest. Kerr won the 1500m world athletics championship gold medal in 2023, and was 3rd at the 2021 Tokyo Olympics and 2nd at the Paris 2024 Olympics in the 1500m. 

So difficult to do, but both Kerr and Mackey almost always get it right. A big part of that comes from how they approach training and performance. They know that consistency is what matters most.

They know that being consistent compounds. It is not having one super workout now and then. It is putting in the necessary work that prepares Kerr. 

While preparing for this, Kerr ran 2:42 min for a 1200m time trial at altitude, 5,355 feet in Albuquerque, New Mexico while being paced by Brannon Kidder, who also paced him in London. The last 400m done in 51.88 seconds. During El Guerrouj's world record run, he reached the bell lap in 2:47.9 with a lap to go (1209m).

Kerr says he "don't do crazy workouts or crazy mlileage. I just don't miss days. Consistency is my biggest weapon. I'll break any athlete down with how consistent I'm going to be training and just getting the work done." 

"The way that I get fast is stacking. I'm stacking years, I'm stacking days, I'm stacking months." "If you show up and put in the same level of effort regardless of how you feel, you're winning every day."

Sure he had 2 rabbits pacing him til 1000m. But he had to run the last 600m on his own. In those last 600m his 100m splits only varied between 13.7 and 13.9 seconds! Super consistent. One of the most impressive performances I've seen. 

Have a look at his official splits.

400m: 55.3 seconds

800m: 1:51.1 (56.8)

1200m: 2:46.5 (54.9)

1600m: 3:41.4 (54.9)

Finish (mile): 3:42.66 min. WR!!

It's even more amazing if you look at his splits by 100m.

100m: 13.8 seconds

200m: 27.5 (13.7)

300m: 41.0 (13.5)

400m: 55.3 (14.3)

500m: 1:09.3 (14.0)

600m: 1:23.2 (13.9)

700m: 1:37.0 (13.8)

800m: 1:51.1 (14.1)

900m: 2:05.1 (14.0)

1000m: 2:18.8 (13.7)

1100m: 2:32.6 (13.8)

1200m: 2: 46.5 (13.9)

1300m: 3:00.3 (13.8)

1400m: 3:14.0 (13.7)

1500m: 3:27.7 (13.7)

1600m: 3:41.4 (13.7)

Mile (1609.34m) : 3:42.66 min (1.2 sec for final 9.34m)

https://x.com/_OwenM_/status/2078491974399574210 - watch the video

Picture from Letsrun.com

Day 2 Of Kinesio Foundations Course

Most of the participants left some of the Kinesio taping done on Day 1 on them throughout the weekend. We went through how that felt so they can better understand how patients feel with tapes on after they leave to go home. Everyone felt that the taping had good results.

We then started Day 2 with the Kinesio Corrective Techniques. The occupational therapists in the class requested for a few scenarios for the upper arm and shoulder after a patient has a stroke and we covered that too, even though that was not in the syllabus.

We left more time at the end to do the Jelly fish and the epidermis, dermis and fascia (or EDF) techniques. The participants took their time as those techniques needed lots of focus and handling skills.

Doing the jellyfish taping

A big thank you to all the participants, my family and colleagues for helping out. Could not have done it without all of you. Stay tuned for the next course most likely in mid 2027.

Kinesio Foundations Course Day 1

Sports Solutions hosted Day 1 of the Kinesio Foundations Course today. We have occupational therapists, physiotherapists, a medical doctor, a yoga instructor in our class this time.

With Dr Sangita and Sarah

Stay tuned for Day 2 tomorrow where there is a bigger emphasis on the Kinesio Medical Taping section instead of just the Kinesio Taping Methods where muscles, joint and tendons were the main focus. 

Some of the techniques include the Space Correction and webcut applications for bruising and swelling. We will also do the EDF (epidermis, dermis and fascia) and jellyfish taping. 

None of the other brands of tape have any of those techniques mentioned above.

Tarsal Tunnel Syndrome

Picture from Orthopaedia.com

A patient came in to our clinic declaring she has plantar fascia pain in her right foot. She had seen another physiotherapist a few years ago for plantar fascia pain in her left foot and had gotten better. This time she tried orthotics, lots of stretching and even shockwave (or ESWT) with the same physiotherapist, but there was no improvement.

This is how she described her foot pain. She said there was a burning, aching pain at the bottom of her foot and on the inner heel. She said it almost feels like an electric shock. Her pain gets a lot worse after prolonged standing and sometimes wakes her up at night. She also gets numbness in her toes. 

None of those symptoms sound like plantar fascia pain to me. Patients with plantar fasciitis usually have pain during the first few steps when they get out of bed in the morning. There is rarely numbness, burning or electric shock sensations in the toes.

Upon assessment, there was no pain on the posterior calcaneal tubercle (where the PF inserts) nor along the plantar fascia itself. 

I elicited her pain when I did a modified Straight Leg Raise test by holding her foot in full dorsiflexion and eversion. However, there was no tingling or zinging in the foot when I tap on the medial malleolus (over the tarsal tunnel) - also known as Tinel's test. Online articles often describe a positive Tinel's test.

I explained my findings to her. My patient actually has Tarsal Tunnel Syndrome. This is when the posterior tibial nerve gets 'trapped' and irritated in the tarsal tunnel at the inner part of the foot (pictured below). 

Picture from Teachmeanatomy

The tarsal tunnel is a space just behind and below the medial malleolus and serves as a passageway for the posterior tibial artery, nerve and what we call Tom Dick and Harry muscles (tibialis posterior, flexor digitorum longus and flexor hallucis longus). The 'roof' of this tunnel is covered by the flexor retinaculum. It is a thick and strong fibrous band that holds Tom, Dick and Harry in place.

Tom, Dick and Harry- back of R leg

Entrapment of the posterior tibial nerve in the tarsal tunnel caused my patient's foot pain, not plantar fasciitis.

Online or AI* searches always say that flat feet or severe overpronation can cause tarsal tunnel pain as it can stretch the nerve although my patient does NOT have flat feet.

My patient did have a severe right ankle sprain a few months ago that caused swelling and perhaps thickening in the connective tissue in the tunnel that eventually caused this. It was also not treated properly, causing her to compensate and stand and walk differently possibly 'tractioning' her posterior tibial nerve.

A ganglion cyst in the canal may also cause this since it reduces the space in the tunnel. I have never come across this though in the 27 years of being a physiotherapist.

When a patient complains of bottom of foot pain, plantar fasciitis is usually the diagnosis one thinks of. The symptoms of tarsal tunnel syndrome pain can be similar to lumbar radiculopathy, diabetic and peripheral neuropathy or plantar fasciitis. Hopefully this article will correct that. 

 (*All the articles in this blog are written by me not by AI).

Reference

Boers N, Haverkamp M, Eligh AM et al (2026). Differences in Diagnosing Tarsal Tunnel Syndrome Across The Literature: A Systematic Review And A Call For Standardization. JBJS Rev. 14(2): e25.00222. DOI: 10.2106/JBJS.RVW.25.00222

L flexor retinaculum

Picture from https://drjustindean.com/retinaculaofthefoot/