Sunday, November 26, 2023

How Long Does Your Running Shoe Last?

Picture from Run Repeat
Ever wondered how long before you need to change your running shoes? A bit of history on midsole technology. Previously, the midsoles in running shoes were all made with ethylene-vinyl acetate (or EVA). Then Adidas managed to secure (Adidas bought the technology from BASF) their Boost midsole out of thermoplastic polyurethane (TPU) in 2013 which led to many marathon world records falling. In 2017, Nike's super shoe, the Vaporfly, was made of polyether block amide (PEBA) and it is still the current dominant midsole.

Previous anecdotal evidence and hearsay suggest EVA midsole running soles tend to last between 300 to 500 miles (480 to 800 km). There was an older study supporting this information (Cook et al, 1985). The researchers measured shoes shock absorption at frequent intervals between 0 to 500 miles. 

A machine was used to simulate running impact as well as 2 vounteers who actually ran 500 miles (pictured above). The 2 human volunteers show similar patterns compared to the machine (see diagram). Human testing showed that EVA midsole shoes retained 80 percent of shock absorption after 150 miles (240 km) and 70 percent after 500 miles (800 km). The curve then flattens out between 300 to 500 miles which is probably where we get shoe lifespan information from.

More recently, a bunch of researchers teamed up with the brand On and manufactured prototype running shoes that were almost identical (Rodrigo-Carranza et al, 2023). One had the new PEBA super foam while the other had the traditional EVA midsole. 
Shoe testing from Rodrigo-Carranza et al (2023)
Both versions also had a curved carbon fiber plate. They tested the shoes before and after 280 miles (448 km). 22 runners performed a running economy test to measure how much energy they used at a given pace, once in fresh shoes, once with pre-worn shoes. The researchers themselves actually ran 280 miles (448 km) in each pair of shoes to pre-wear them for the research!

The researchers found that the new super foam did lose their powers quicker. In fact they were no better than the traditional EVA midsole when they did. A key finding was that energy consumption while running with the new PEBA midsole shoe was 1.8 percent less than using the new EVA shoe. This strengthens the case that the super foam itself is more important ingredient since both versions of the prototypes had carbon plates in them.

Another key finding was that after 280 miles (448 km), there was no significant difference between the 2 shoes. The EVA did not lose anything while the PEBA super foam shoe got 2.2 percent worse. Please note that not all PEBA foams are created equal. On's super foam may not be totally similar to Nike's and other brands.

I have not converted to super shoes yet as I do not like them stacked too high. Moreover, I currently only run 2-3 times a week and I rotate between 2 to 3 pairs of shoes with EVA and TPU midsoles. I run in them until they start to feel "flat". It is relatively easy to feel especially if one of my other newer pairs still feels supportive by comparison. I usually retire that "flat pair" from running but will still use them for walking. If you're using the PEBA foam super shoes, you may have to change them earlier.

If you are interested, have a look at Run Repeat, where infomation on a huge range of high performance super foams are available. The author, Carlos Sanchez runs 100 km a week and has run three sub 3 hours marathons. Sanchez suggests that shoe foams take more than 24 hours to 'recover' and some foams recover faster than others so you may want to rotate your running shoes to maximise comfort and shoe life.


Cook SD, Kester MA and Brunet ME (1985). Shock Absorption Characteristics Of Running Shoes. AJSM. 13(4): 248-253. DOI: 10.1177/036354658501300406

Rodrigo-Carranza V, Hoogkamer W, Gonzalez-Rave JM et al (2023). Influence Of Different Midsole Foam In Advanced Footwear Technology Use In Running Economy And Biomechanics In Trained Runners. Scan J Med Sci Sp. DOI: 10.1111/sms.14526

Sunday, November 19, 2023

Is There An Ideal Running Cadence Rate?

Picture from Tracksmith
180 steps per minute seems to be the accepted magic number for cadence (or the number of steps) in long distance running. If you read the old Runners World magazine, you will know that legendary running coach Jack Daniels got that magic number by counting the number of steps the elite runners took at the 1984 Los Angeles Olympics.

This is also part of the 'ideal running form' criteria. It is also a relatively simple quantity to measure and change since it's much easier to tell a runner to increase their cadence than altering than heel strike.When you take smaller, quicker steps, it optimizes your efficiency and minimizes your injury risk by reducing impact on your knees and hips with each step. 

What if you can turn over your legs even faster? Watch the elite female Japanese marathoners when they race, they get close to 200 steps per minute. Does more mean better? What does current research say?

Burns and colleagues (2019) found that running cadence varies greatly. It actually depends on your running speed. Your cadence will differ when doing a track interval session versus an easy recovery run.

They studied 20 males and females who placed in the top 25 male and female finishers at the 2016 Ultra Running100 km world championships. The race was held in Spain and consisted of 10 laps of 10 km each lap along an almost completely flat course. This is ideal to determine if there were any specific characteristics that had an effect on cadence. Data was collected from the smart watches of the runners.

A survey was done after the race via email asking about their age, weight, height, training, racing experience and their racing speed.

Only speed and height of the runners have an effect on each individual runners' cadences. The study showed that when the runners run faster, their step frequency increased. Taller runners also had lower step counts compared to shorter runners. This study found that every extra inch in height was associated with a decrease of just over 3 steps per minute in cadence. A 6 foot tall runner in the race took about 18 steps per minute less than another runner who is 5 foot 6 inches.

Makes sense that longer legs will take fewer steps each minute to cover the same distance. 

The lead author, Burns, finished 5th in the race and included himself in the study. The runners' cadences differed greatly, ranging from 155 to 203 steps per minute. The highest and lowest averages actually finished within a couple of minutes of each other. 

Guess what number came up when Burns took an average of all the runners' cadences? 182 steps a minute. Now, that is really close to the optimal 180.

The study also showed that fatigue had no effect on cadence, possibly due to the very flat course. Even when the ultra runners were in the later stages of the race, they held the same pace from the start. In fact they had even faster step counts near the finish when they ran faster despite being tired.

According to the article, there are only 2 ways to increase your cadence, become shorter (like the elite female Japanese marathoners) or go faster. Bear in mind that everyone has a different optimal cadence. Having a higher cadence (than 180) does not necessarily make you a better runner. 

Burns finds that when he is fitter, his cadence is lower at a certain pace since his steps are longer. When his cadence is faster than normal at the same pace, he uses that as a sign that he needs hill work or speed work to get stronger. 

That is a much better way to use cadence to improve your running rather than aiming for a specific number. Especially when everyone's mechanics are different. It is also a good and simple aspirational goal for runners since many runners overstride and land on their heels, putting excessive forces on their knees. 


Burns, GT, Zendler JM and Zernicke RF (019). Step Frequency Patterns Of Elite Ultramarathon Runners During A 100-km Road Race. J Appl Physiol. 126(2): 462-468. DOI: 10.1152/japplphysiol.00374.2018

Sunday, November 12, 2023

How To Be A Better Trail Runner

Picture by Melvin Lee
Many of my patients are now running on trails, making the switch from running on the road which they say is boring. There are also many more organized trail races world wide, and many of our patients participate in these trail races.

What does it take to become a better trail runner? A recent published study compared elite and recreational trail runners in a series of lab tests and found that the elite runners were more efficient over both hilly and level terrain (Besson et al 2023). As a result, they required less energy to maintain a given pace. They were found to have greater leg strength compared to recreational runners. 

The same researchers found similar results when they compared elite trail and elite road runners. The trail runners had stronger leg muscles and were more efficient on hilly terrain (Sabater et al, 2023)

So, do leg strengthening exercises if you want to run better on the trails. Other than visiting the weights room, you can carry a heavier backpack while climbing stairs or walking/ running up and down stadium steps. I used to wear a weight vest while training for the Oxfam Hong Kong Trailwalker event at the old National Stadium steps. It definitely made the uphill sections easier during the event.

Another pattern that has turned up in studies of hilly running trail races is to keep your effort and not your pace constant. The faster finishers showed greater variability in their pacing. They ran slower (or walked) on the steeper sections and ran faster on the downslopes to make up time (Corbi-Santamariaet al, 2023). 

Most trail runners tend to have a fixed pace and try maintain that regardless of terrain. A more efficient strategy is slow down on the uphills and speed up on the downhill sections relative to your average pace. So don't push harder on the up slopes to keep pace, slow down instead to keep your effort constant. You can run faster on the downslopes to get back the time you lost for those who are racing.

Please bear in mind that there's a skill to running fast downhill, particulary on technical terrain. More so during ultras as more than10 hours of racing makes one very fatigued. Not worth having a catastrophic fall while running downhill.

Are trekking poles useful? Usage of trekking poles can be contentious among trail runners.  Giovanelli and colleagues (2023) tested runners on the steepest treadmill in the world, in their lab. Their treadmill can be set to 45  degrees, at a grade of 100 percent! They found that using trekking poles does not save energy, but they do save your legs. On a hill climb of 20 degrees incline, runners applied 5 percent less force on their legs but reached the top 2.5 percent faster.

Picture from
Even Killian Jornet uses trekking poles (pictured above). Why shouldn't you?

There you go, three ways to become a better trail runner. Strength training, varying your pace and trekking poles. Watch out for tree roots on the trails while running!


Besson, T, Sabater PF, Varesco G et al (2023). Elite Vs Experienced Male And Female Trail Runners: Comparing Running Economy, Biomechanics, Strength, And Power. J Strength Cond Res 1: 37(7): 1470-1478. DOI: 10.1519/ JSC.0000000000004412

Sabater PF, Besson T, Berthet M et al (2023). Elite Road Vs Train Runners: Comparing Economy, Biomechanics, Strength, And Power. J Strength Cond Res 1: 37(1): 181-186. DOI: 10.1519/ JSC.0000000000004226

Corbi-Santamaria P, Herrero-Molleda A, Garcia-Lopez J et al (2023). Variable Pacing Is Associated With Performance During The OCC Ultra-Trail Du Mont-Blanc (2017-2021_. Int J Environ Res Pub Health. 13: 20(4): 3297. DOI: 10.3390/ijerph20043297

Giovanelli N, Pellegrini B, Bortolan L et al (2023). Do Poles Really "Save The Legs" During Uphill Pole Walking At Different Intensities? Eur J Appl Physiol. DOI: 10.1007/s00421-023--05254

Sunday, November 5, 2023

Strength Matters More Than Size

Pawel Poljanski's legs at the Tour De France
My colleague was wondering why I was not 'big' (or muscular) despite exercising regularly. I explained to her I was more Type I muscle dominant (or slow twitch muscle) as most endurance athletes are. Those who have predominantly Type I muscle fibers are lean, not big and muscular.

Her obesrvation is accurate. I actually lift weights twice a week and even though I can squat 90 kg, my thighs are still skinny.

I also explained to her that it is better to be strong than have big muscles. Weight training can make you stronger and your muscles bigger. They are both related since bigger muscles are usually stronger. However, they are not identical. You can get stronger without adding muscle bulk. 

This happens when the signaling from your brain to your muscles become more efficient and how effectively your muscle fibers are recruited. You can add muscle without getting stronger, this typically happens when you gain weight.

Strength is also a much better predictor of cognitive performance than muscle mass. Storoschuk and colleagues (2023) studied 1424 adults above 60 years of age between 1999 and 2002 in a health and nutrition examination study (NHANES). These subjects had DEXA scans to assess body composition, leg strength tests, a digit symbol substitution test (cognitive test) and questionnaires that assessed physical activity habits. The DEXA scan is used to determine how much muscle one has in their arms and legs and fat-free mass index (FFMI), which shows total muscle to height.

The figure above presents the benefits of different variables on cognitive performance. The farther on the right each square is, the greater the cognitive benefits. You can see that low FFMI (low muscle mass) has no significant effect on cognitive scores, while peak leg force (a measure of strength) definitely have a significant benefit. Those who did resistance training (or weight training) for at least once a week has an even stronger effect.

Strength explained about 5 percent of the variance in cognitive scores, while muscle mass explained only 0.5 percent. Low strength levels raised the risk of premature death, but low muscle mass did not. In contrast, another study by Tessier et al (2022) found that low muscle mass predicted more rapid cognitive decline over a 3 year follow up period, after accounting for differences in strength. Perhaps it would be premature to conclude that muscle mass (being big) does not matter.

Confused? Storoschuk et al (2023) explained that there is a difference between the muscle you get from physical activity and muscle you get in the process of gaining weight. Greater muscle mass may just be a larger body size rather than greater strength, which does not seem to translate into protection from cognitive decline and other health benefits.

Moreover the conflicting results from the 2 studies are possible due to different popolulations, different cognitive tests and different sample sizes. 

My take on this? It is good if you have big muscles and I will still lift weights twice a week to at least maintain and avoid losing what I have. Getting stronger is much better, and that is the main reason why I do weight training. Even though I do not seem to gain muscle I am able to increase the reps and quality of the exercises I perform. 

So, to ward off cognitive decline, strength training is just as important as aerobic exercises.


Tessier A, Wing SS, Rahme E et al (2022). Association Of Low Muscle Mass With Cognitive Function During A 3-Year Follow-up Among Adults Aged 65 To 86 Years In The Canadian Longitudinal Study On Aging. JAMA Netw Open. 5(7): e2218826. DOI: 10.1001/jamanetworkopen.2022.19926

Storoschok KL, Gharios R, Potter GDM et al (2023). Strength And Multiple Types Of Physical Activity Predict Cognitive Function Independent Of Low Muscle Mass In NHANES 1999-2002. Lifestyle Med. 4: e90. DOI: 10.1002/lim2.90

Sunday, October 29, 2023

Rob It To Get It Free

What if you could go to a running store, pick something you like and run away with it free? No, I am definitely not suggesting that you shoplift from a running store. 

This promotion is exactly what a running store in Paris came up with last month to steal whatever you want. The catch is you will have to outrun the store's security guard, who happens to be Meba Mickael Zeze. 

Zeze happens to be a two time Olympian, who can run the 100m in 9.99 seconds and the 200m in 19.97 seconds!

Zeze had as much fun as the participants, looking at the video. He said the job reminded him of playing tag as a child, adding that he needed only a third of his top speed to catch most of the 'thieves'.

Only 2 managed to evade him, most probably as a result of Zeze having to run all day.

Distance Paris was super happy with the result despite losing 2 out of 76 attempts to 'thieves', so much so that it was turned into an video (see below).

This is a super clever idea by Distance Paris and it definitely gave them a lot of eyeballs. Any running store in Singapore willing to try this? 

Perhaps Shanti Pereira can be the security guard.

Thursday, October 26, 2023

Embroidery For Our Team Building Event

You read correctly, we had Isabel Lim from Isabel Lim Designs teach us this morning. It was great fun and we had a great time together.

Isabel was really patient when it came to explaining and teaching us what to do. Here are some of the designs.


Kaylee did this

Pretty cool huh? We definitely have some hidden talents in our midst.

We then proceeded to have lunch at Bumbu. Also a farewell lunch for Byron who is leaving us to move to Adelaide, South Australia. All the best to you Byron.

Saturday, October 21, 2023

Sports Solutions is 14!

Yes, Sports Solutions is 14! Has it really been that long? Yes, it has. We started at Amoy Street and moved to Chip Bee Gardens in Holland Village in 2014.

A big thank you to all our families, staff, friends and patients for all your support all this while. We wouldn't have done it without all of you.

Our goal is the same all this while. To make our patients better quicker. "As long as we're happy and enjoy treating our patients, it's not really work."

Here's to many more years to come!

Friday, October 20, 2023

Accepting Payment For Online Reviews

I read with interest in a Straits Times article as restaurant owner Charlene Yan posted online on Oct 4th that food website asked for $2300 to be featured on their food blog. In addition, the email she received from one of Seth Lui's employee's offering her a spot on that list to be placed 1st, 2nd or 3rd position for an additional $400 to $600. No research, no actual food tasting done, just asking for money straight up to be featured on that list.

No prices for guessing when ST reported in the newspapers on 20th October, 2023 that paid restaurant reviews are "standard practice". Singapore chef Benny Se Teo said paid food reviews are definitely on the rise and raise concerns about objectivity since financial interests are entangled with the restaurants they are reviewing. 

The Advertising Standards Authority Of Singapore states on its website that it should be clear that "anyone who looks at the advertisement is able to see, without reading it closely, that it is an advertisement and not editorial matter".

That means any compensation like a free drink or dessert that a food blogger receives, should be clearly disclosed to the reader or viewer. If payment by the establishment is made, to be on such lists, it is then no longer an editorial decision but an advertisment and that must be clearly stated otherwise that list has no credibility.

Will you be surprised that this happens in the healthcare industry too. I received a total of 3 emails (pictured above and below) dated 14th, 16th and 20th October, asking if we want our clinics to be featured in the "25 Best Physiotherapy Clinics in Singapore (2023)". Their fees range from $500 to $2000.

You would think that the employee sending me the emails would have kept in touch with the brouhaha regarding paid restaurant reviews after it went viral on RedditFacebookand of course the newspapers.

At least I know the employee is persistent since I received 3 emails asking if our clinic wanted to be on that 'best' physiotherapy clinic list.

Aized tells me that we have been approached multiple times as well to be on such lists on print copies of magazines targeted at the expatriate coummunities too. 

The authenticity of such reviews for physiotherapy clinics are definitely questionable. Our clinics probably will not be on such lists since we do not pay to be on them.The main criteria for compiling a list like this is monetary and without full disclosure to the readers. Now you know.

Thankfully, majority of patients who see us and get better refer us to their family members and friends so we do not have to be on such lists.

Sunday, October 15, 2023

Regarding Prepaid Packages

A patient told me she was 'convinced' to buy a 100 session prepaid chiropractic package that she had to use within 6 months to 'maintain' her neck and back health after she went for a free trial. 

A chiropractic clinic offered a free trial session at a roadshow in a mall and she went to try. She had appointments to go 3 times a week, which is terrible for a working adult's schedule. To add salt to injury, each appointment lasted less than 5 minutes. 

You may have heard similar horror stories or even experienced them personally. Not just chiropractors, it can also be the beauty therapist pointing out all you flaws while offering you a limited time promotion to treat them while you were in a vulnerable position. 

Actually, the beauty industry received 1454 complaints last year, accounting for about 10 percent of all complaints that the Consumers Association Of Singapore (CASE) received.

My wife was in a similar position too previously. She had gone for a massage and while lying face down was asked to add essential oils and buy a package. She felt trapped in the room until she agreed to buy more sessions.

Prepaid packages often happen in pressure sales tactics where you are told that your crooked back, posture, freckles etc can lead to paralysis or something worse if left untreated. Often they prey on your fears to ensure that they can hang on to you, hoping that they will not lose you to another competitor. You are then locked in as all the money is paid upfront.

There are physiotherapy clinics that sell packages too, despite the Ministry of Health saying physiotherapists cannot do so. Perhaps these clinics pay kickbacks to rouge agents and doctors to refer them patients so they practice such tactics. MOH investigated physiotherapists, doctors, insurance agents and others after a physiotherapy clinic in Camden Medical Centre went bust for inflating insurance claims by selling packages.

As a business owner, I can understand that this helps to protect the businesses that sell them. Running a physiotherapy clinic (or beauty salon) requires significant capital, which includes staff, rent and equipment as part of overhead costs. When patients/ clients buy a package, it helps to allay these costs quickly, especially for a new clinic.

Selling a package does not work in our clinic. For instance, if I treated 5 new patients a day and each of them buys a package of say, 10 sessions. I would owe them 9 sessions after their first session, but I would soon run out of appointment slots to see them if all new patients buy a package. 

It will only work if the patient sees another colleague or each session is less than 5 minutes. In our clinics, initial sessions are 60 minutes long and follow up sessions 30 minutes if needed.

Actually we try to make our patients well as soon as possible instead of hanging on to them. We prefer that they get pain free and be happy patients so that they refer their families and friends to us. 

As patients (or customers), please do not be afraid to say no if you are asked to buy a package. If a promotion sounds too good to be true, it probably is. These salespeople/ healthcare professionals will try hard selling tactics, often by preying on your fears. However, you have the right to decline any offer that does not align with your needs or if you are not ready to make a decision. Stick to your decision firmly and politely.

Remember under the Allied Health Professions Council which registers physiotherapists in Singapore, does not allow physiotherapists to sell packages. You can definitely visit a clinic that does not offer any packages so you do not have to worry about committing to any large upfront payment.

Sunday, October 8, 2023

Front Knee Pain After ACL Surgery?

ACL marked 20mm from each end by Dr Nuelle
While looking for a topic to write this week, I came across a research paper by Rahardja et al (2023) comparing knee pain and difficulty with kneeling between the bone-patella tendon bone (BTB) and hamstring graft after anterior cruciate ligament (ACL) reconstruction. 

I subsequently found a Twitter thread concerning the article where an orthopaedic surgeon says he "don't believe" what the paper says (see picture below).

Compared to now, there were more patients whose surgeons used the BTB graft when they tore their ACL's when I started work as a physiotherapist in the late 1990's. The hamstring autograft (not cadaver graft) is most commonly used now. 

One of the main reasons patients are told not to use a BTB graft  is because it (supposedly) causes anterior (or front) knee pain. 

A total of 10,999 patients who had ACL reconstructions were analyzed at 2-year follow-up. 9.3 percent (420 cases out of 4492 reported consequential knee pain (CKP) while 12 percent (537/4471) reported severe kneeling difficulty (SKP). For those into research, the Knee and Osteosrthritis Outcome Score (KOOS) was used to identify patients reporting CKP, defined as a KOOS Pain subscore of ≤ 72 points. 

The authors wrote that the most important predictor of CKP at 2-year follow-up was having significant pain before surgery while the most important predictor of SKP was the use of a BTB versus hamstring graft.

I do not agree with the authors' observation. I have treated many patients who had ACL reconstructions in the past 24 years. In the first few weeks after the ACL reconstruction, patients who choose either graft do have a little anterior knee pain presumably from the operation itself. After 6 weeks, anterior knee pain is very rare especially for those with the BTB graft. Very occasionally if they kneel onto the BTB graft site, they may have some kneeling pain which goes away quickly once they change position.

In fact, an orthopaedic surgeon commented that his few "non BTB" (i.e. hamstring graft) patients tend to have more anterior knee pain than his BTB graft patients (see picture below).

Moreover if you have read my earlier post, Spindler et al (2020) suggests that the HS graft is 2.1 times more likely to tear aagain compared to the BTB graft. Surely this is supporting evidence that the BTB graft is the 'better' and 'stronger' graft? 

There should be no reason to use "anterior knee pain" as an 'excuse' to use other graft choices rather than the BTB graft. 

Choosing your graft after tearing your ACL will definitely be influenced by discussions with your doctor, surgeon and physiotherapist. If you do not want to use your own BTB and hamstring graft, you can also use an allograft (cadaver) now. 

Please keep this information in mind if you were to tear your ACL. Come talk to us if you have any questions.


Rahardja R, Love H, Clatworthy MG et al (2023). Comparison Of Knee Pain And Difficulty With Kneeling Between Patella Tendon And Hamstring Tendon Autografts After Anterior Cruciate Ligament Reconstruction: A Study From the New Zealand ACL Registry. AJSM. DOI: 10.1177/03635465231198063

Spindler KP, Huston LJ, Zajichek A et al (2020). Anterior Cruciate Ligament Reconstruction In High School And College-age Athletes: Does Autograft Choice Influence Anterior Cruciate Ligament Revision Rates? 48(2): 298-309. DOI: 10.1177/0363546519892991.

Sunday, October 1, 2023

Optimal Exercise Form Is Not Always Right

Aized and I had an interview with a physiotherapist last week. She found out physiotherapists in our clinic worked 4 days a week and she was keen to join our team. The interview had a practical component where she had to ask questions, assess and treat my "mid and low back pain" (for my twice broken back). 

After some questions and assessments, she decided that my weight lifting form was causing my discomfort. She then proceeded to "correct my form" for my weight training.

I understand the need to be very strict with textbook form for lifting and making sure technique is efficient to complete the task at hand whether it is during a rehab exercise or just moving a barbell in a strength movement from A to B.

Just so we can be on the same page, I am writing about what most personal trainersstrength coaches and physiotherapists consider textbook form. Feet shoulder width apart, back straight during a squat/ deadlift for instance.

That being said, there are definitely situations where less than "ideal" or "optimal" form is indicated and this is what I will be writing about.

Patients who have anatomical or even mobility limitations cannot do an exercise with textbook form or through full range correctly. Consider the following pictures above and below. Our bones and joints are shaped and angled differently and this will mean that there will be a large variability in individual ranges of motion and variations in exercise form and technique. You may have to squat wider with toes out while others may squat in a narrower stance with toes facing inwards.

Different femoral head angles
The squat technique is usually advised when lifting heavy objects over the stoop technique since this technique is thought to result in lowering intervertebral disc (IVD) compression and shear forces compared to the stoop technique.

Squat (a) versus stoop (b) lifting
However, when we compare squat versus stoop lifting, the squat lifting is not favored over stoop lifting (this is in contrast to current recommendations). 

The following study actually showed that lifting with a flexed spine produced LOWER spinal compression forces than lifting with a neutral spine (Van Arx et al, 2021).

Then there are patients who have widespread chronic pain but no tissue pathology. There is often lots of fear and avoidance of activity in these patients that if you focus too much on form it will be counter productive.These patients may be in a deconditioned state and I will be happy just to get them moving compared to someone who wants to deadlift a 100 kg.

Similarly with patients who are not active and had never play sport their whole lives. They often struggle with what we think are really simple movements and exercises. So long as there is no pain and they are not aggravating anything in low level exercises (example a half squat), I am fine with form that is not ideal for the time being and may work at improving it later.

Older patients often have other multiple health conditions and they may be other things to work on instead of spending too much time trying to teach a single exercise.

Physiotherapists who treat patients with neurological conditions like Parkinson's disease and stroke, will tell you that these patients definitely cannot do exercises with textbook form.

This post is not meant to ridicule anyone who insists on teaching textbook form while teaching exercises. Nor am I suggesting you let your patients have freedom to do whatever they want when exercising. I am simply suggesting that there are situations where insisting on textbook form is not ideal nor practical.


Von Arx M, Liechti M, Connolly L et al (2021). From Stoop To Squat: A Compressive Analysis Of Lumbar Loading Among Different Lifting Styles. Front Bioend Biotech 4: 9: 769117. DOI: 10.3389/fbioe.2021.769117

Please read this for more on squat versus stoop lifting.

Different shaped pelvis

Sunday, September 24, 2023

Steroid Injections Accelerate Damage To Joint Surfaces

Picture from Ortho Arizona
Many patients with knee osteoarthritis (OA) who come to see us in our clinics often tell us that they were given intra articular (inside the joint) corticosteroid injections (IACS). ICAS is a common treatment choice that is considered minimally invasive to delay knee replacements for patients with severe OA

Other than providing brief pain relief, the pain often comes back. I wrote earlier this year that steroid/ cortisone injections significantly increases the risk of tendon tears.

Perhaps it's time to think more than twice before you allow anyone to inject into you knee joint. Make it any other joint for that matter as latest published research shows that individuals who got IACS were twice as likely to have harmful effects on knee articular cartilage structure than those who received no or placebo treatment.

Different stages of articular cartilage damage
A group of researchers investigated the effect of IACS on articular cartilage structure in patients with knee OA using joint space width on x-ray and articular cartilage thickness with MRI.

They found 6 studies consisting of a total pf 1437 participants. The estimated effect of IACS on articular cartilage structure showed significant odds of it worsening as measured by joint space narrowing and articular cartilage thickness. The authors concluded that their meta- analysis showed that IACS increases the likelihood of knee joint deterioration.

Other than increasing the risk of tendon tears, steroid/ cortisone  injections into knee joints may be doing more harm than good by accelerating joint surfaces degeneration. The short lasting pain relief is definitely not worth the long term consequences of your articular cartilage degenerating. 


Ibad HA, Kasaeian A, Ghotbi G et al (2023). Longitudinal MRI-defined Cartilage Loss And Radiographic Joint Space Narrowing Following Intra-articular Corticosteroid Injection For Knee Osteoarthritis: A Systematic Review And Meta-analysis. Osteo Imaging. DOI: 10.1016/j.ostima.2023.100157

Thursday, September 21, 2023

PS Sim Summits K2

Summit of K2
Yes, it was last month that many of you would have read about PS Sim reaching the top of K2 - the second highest mountain in the world after Everest.

Straits Times article on 240823
Well, she came by our clinic today and both MJ and Kaylee were both ecstatic to meet her. In fact, they have been asking about her ever since they have seen her pictures in our clinic. The 2 fan girls got to ask her whatever questions they wanted. And of course they wanted pictures with her (below).

Kaylee asked her to compare Everest to K2. In her words, "Everest is a walk in the park compared to K2". To which I replied that it's not a walk in the park definitely.

We are all inspired by you PS!! Please put up an exihibition/ show and tell of all your pictures/ videos from Everest, K2 and the rest of 7 summits, we will definitely come.

Sunday, September 17, 2023

Hip Adductor Related Groin Pain

If you follow Aussie Rules Football (or AFL), yesterday was the 2nd second semi final with GWS Giants defeating Port Adelaide 93-70. Aized and I had to help Aussie Rules football players back when we were  doing our post graduate physiotherapy studies in 2003. I still follow the AFL league from time to time. AFL footballers often suffer from groin pain.

Other than AFL footballers, soccer (also known as football), rugby players and those who play badminton and squash etc are involved in rapid acceleration, deceleration and sudden changes in direction are all more prone to groin injuries.

Athletes with a previous groin injury are at a greater risk than those with no previous injury. This can be up to 2.4 times greater over consecutive seasons with football players (Haglund et al, 2006).

The hip adductors
Football players have a yearly incidence of adductor related groin pain of 10-18 percent. 53 percent of theses cases are from overuse. Groin injuries in male club footballers accounted for 4-19 percent of all injuries and 2-14 percent in women club footballers.

Different types or groin pain
It can be difficult to diagnose groin injuries since there can be many different complex causes. Hip adductor related groin pain is defined as hip adductor tenderness and pain with resisted hip adduction testing. It is also the more common causes of groin pain. Other than hip adductor groin pain, the iliopsoas, inguinal and pubic symphysis are other causes of groin pain (pictured above).

Exercise therapy is commonly prescribed for groin pain although there is no specific exercise protocol. Exercises, particularly adductor eccentric strengthening seems to be beneficial for pain reduction and return to sports at 16 week follow up in comparison to stretching, electrotherapy (ultrasound, interferential currents) and transverse friction massage.

We do see many patients with groin pain in our clinics. However, our approach to treatment is different. We do not get our patients to do the strengthening exercises when they are in the clinic. We prefer to treat them using mostly our hands instead. For example, for a patient with groin pain, they may also have a higher hip on one side (pictured below).

R hip lower
We can treat the hip with respect to the shorter side. Short in terms of length. It also depends on what our assessments show. The patients can do the strengthening exercises they need on their own. We treat what they cannot do themselves in the time they have with us. Come see us in our clinics if you have hip pain.


Haglund M, Walden M and Ekstrand J (2006). Previous Injury As A Risk Factor For Injury In Elite Football: A Prospective Study Over Two Consecutive Seasons. BJSM. 40: 767-772. DOI: 10.1136/bjsm.2006.026609

Weir A, Brukner P, Delahunt E et al (2015). Doha Agreement Meeting On Terminology And Definitions in Groin Pain In Athletes. BJSM. 49: 768-774. DOI: 10.1136/bjsports-2015-09486

Yosefzadeh A, Shadmehr A, Olyaei GR et al (2018). Effect Of Holmich Protocol Exercise Therapy On Long-standing Adductor-related Groin Pain In Athletes. BMJ Open Sp Ex Med. 4: e000343. DOI: 10.1136/bmjsem-2018-000343

Sunday, September 10, 2023

Avascular Necrosis

Picture by Frank Gillard from Radiopaedia
Seeing this x-ray reminds me of what I was suspected of having when I started having persistent knee pain back in early 2002, which then led me to having 3 knee surgeries. A doctor I consulted suspected I had early avascular necrosis in my lateral femoral condyle. 

Avascular necrosis (also know as osteonecrosis) is the dying of bone tissue due to lack of blood supply. Depending on where it is, it can lead to tiny breaks in the bone and cause the bone to collapse. This process can take years to occur.

A dislocated joint or a fracture in parts of the bone can also hinder or stop blood flow to a section of the remaining bone. This commonly occurs at the epiphysis (end part) of long bones at weight bearing joints. Some common sites include the femoral head, talus, humeral head, knee and the scaphoid bone (in the wrist).

Avascular necrosis is associated with long term use of steroid medications and injections and too much alcohol. Anyone can be affected. It tends to be most common in people between the ages of 30 and 50.

Repetitive trauma can also cause avascular necrosis. This is not as commonly discussed in the medical journals. This form of avascular necrosis is most common in athletes. Rafael Nadal has a chronic left foot ailment, Mueller-Weiss syndrome where there is avasular necrosis in his navicular bone. Young gymnasts that I have previously treated are also prone to this in the wrist, knee and hips.

The doctor I consulted for my persistent knee pain back then felt that my super high mileage  (I was training for the 100 km Trailwalker event in Hong kong and the full Ironman) caused my knee pain.

The cause of avascular necrosis brought on by trauma (or repetitive stress like running and jumping) is not fully understood. Genetics combined with certain medication (like corticisteroids), excessive alcohol intake and other diseases like sickle cell anemia and Gaucher's disease can play a role as well.

Fatty deposits (or lipids) in blood vessels can block blood vessels and reduce blood flow to bone as well. There are suggestions that long term and high doses of corticisteroids (like prednisone) can increase lipid levels in blood, reducing blood flow to the bones.

Some people have no pain or symptoms at all in the early stages of avascular necrosis. As it worsens, the affected joints may hurt when weight bearing. Eventually there may be pain even at rest. Pain can be mild or severe and develops gradually. 

Having too many alcoholic drinks over several years can also cause fatty deposits to form in blood vessels.

Certain medical treatments like radiation therapy for cancer can also weaken bone. Kidney transplant patients have also been known to be associated with avascular necrosis.

To reduce the risk of avascular necrosis, please limit your alcohol intake since heavy drinking is one of the top risk factors for developing avascular necrosis. 

Keep your cholesterol levels low as tiny bits of fats (lipids) are the most common substance blocking blood supply to bones. Stop smoking as smoking narrows blood vessels which will reduce blood flow.

For those doing repetitive sports, I always suggest running on softer surfaces like grass or sand. Do not be in a hurry to increase your mileage, your bones and joints need time to get used to the load.

Lessen the junk miles or better still ride the stationary bike or use the elliptical trainer to target different areas. Strength training is very important for your bone health.


Shah KN, Racine J, Jones LC et al (2015). Pathophysiology And Risk Factors For Osteonecrosis. Curr Rev Muscu Med. 8(3): 201-209. DOI: 10.1007/s12178-015-9277-8

Sunday, September 3, 2023

Best Vehicle Seat Position For Driving

Picture from the European Spine Journal
The laundry (towels, bed covers, pillowcases) in our clinics get picked up twice a week for the past 16 years by a husband and wife team - Ray and Elaine. Elaine does the driving while Ray does the pickup and delivery of the huge laundry bags. I spoke to them and Elaine was complaining about her back pain after all that driving and I told her it's probably linked to her lumbar (lower back) load from all the driving and sitting in their van.

Picture from the European Spine Journal
A recently published study used a Christophy spine model (inclusive of head, neck and limbs, pictured above) and compared calculated lower back loads and muscle forces while driving to experimental data from previous studies. 

Using data from previous radiology studies, this Christophy spine model was tested in different driving positions with different back supports. The load on the lower back was then calculated with the various back supports and backrest inclination angles.

0 cm, 2 cm and 4 cm lumbar supports were used along with inclinations of the backrest from 23 degrees to 33 degrees (by 2 degrees intervals).  

Ready for the results? Especially for those of you who drive a lot.

The overall lower back spinal loads and muscular forces at the L3-L4, L4-L5 and L5-S1 decreased very obviously with the 4 cm back support, with the seat inclination angle set to 10 degrees. With the 4 cm back support, the overall lower back spinal load decreased by 11.3 percent while  muscular forces were reduced by 26.24 percent.

The recommended backrest inclination angles are between 29 to 33 degrees with a 10 degrees seat cushion to the horizontal. 

This is a useful study to explain the association of drivers' sitting postion and the change in lower back load. It helps provide a reference for the prevention of low back pain.

Now if someone can send these recommendations to car manufacturers to improve the design of vehicle seats, that would be great.


Christophy M,  Faruk Senan NA, Lotz JC et al (2012). A Musculoskeletal Model For the Lumbar Spine. Biomech Model Mechanobiol. 11: 19-34. DOI: 10.1007/s10237-011-0290-6

Gao K, Du J, Ding R et al (2023). Lumbar Spinal Loads And Lumbar Muscle Forces Evaluation With Various Lumbar Supports And Backrest Inclination Angles In Driving Posture. Eur Spine J. 32: 408-419. DOI: 10.1007/s00586-022-07446-x.