Zone 2 or HIIT? Or Neither?

My 58 year old patient walked in yesterday to the treatment room and the first question she asked was if she should start HIIT training. Woah! Hang on, I said to her do you really know what HIIT is? (*See end of article for what HIIT is please).

She said her friends, children and all the fitness influencers she sees extols the benefits of HIIT. Then without batting an eyelid, she said, "What about Zone 2 training?"

That is basically what is happening online. One group says train at Zone 2 while the other says go hard or go home, HIIT is the way to go.  

What do the best in the world actually do? A new study by Sandbakk et al (published in April 2025) investigated elite endurance coaches and their training were not what you expected. These coaches had athletes winning more than 380 international medals in long distance running, biathlon, rowing, cross country skiing, road cycling, swimming, triathlon and speed skating.

All the coaches stick to a traditional periodization model, including a gradual shift towards overall lower training volume and more competition-specific (race pace) training as the competitive period approaches.

Another common emerging feature was an emphasis on high volume low intensity training. Look at the picture above, MOST (80-90 percent) of the weekly training was easy. Here is the key insight, majority of the easy work was not in Zone 2. It was in Zone 1. Slower than what the internet experts are obsessed with. Slower means more sustainable and more adaptation over time. That's how you get stronger. 

True aerobic development is only possible from accumulating volume. It also allows one to recover and handle key sessions. 

This Zone 1 low intensity sessions along with combined with 2-3 weekly "key workout" days consisting of 3-5 intensive training sessions. The sessions are purposeful and focused, with recovery all planned. 

Finally, coaches across all sports focused on getting high training quality by optimizing training sessions by controlling the load-recovery balance to ensure optimal preparations for major competitions.

The athletes go through all the zones (see the above picture), not just high intensity (Zone 5), but also in between. Short, fast intervals and controlled thresholds. The exact proportion is dependent on their competition demands. There were not a lot of really hard anaerobic sessions. 

Why the big difference between these elite coaches and what we see online with all the fitness influencers? Firstly the fitness influencers usually do not compete in races or competitions. They won't be posting so many videos if they do. Train easy, adapt, get stronger does not sell as well as "unlocking this magic Zone of HIIT". High performance is not about shortcuts. It's about accumulating consistency over time. Not as attention catching, but it definitely works.

To sum up, it's mostly sessions of low intensity, with occasionally high sessions adjusted to the individual. Balance stress and recovery and consistency over all else. Now you know.

* Many gyms, fitness influencers and trainers get patients to do what is traditionally circuit training but call it HIIT. Circuit training is like 30 seconds doing push ups, rest a minute, go to another station and perform 30 seconds of high knee lifts, rest a min, 30 seconds of lifting dumbbells etc

HIIT stands for high intensity interval training. Or interval training for short.  Example, you run 15 intervals or repetitions of 400m with a one minute rest in between or the coach will say run 6 x 1km going every 5 minutes (meaning if you run your kilometer in 3:50 min, you get 1:10 min rest before starting again). You can also cycle intervals outdoors or on a trainer with your bicycle attached.

Circuit training does not sound sexy, but HIIT certainly does!

Reference

Sandbakk O, Tonnessen E, Sandbakk SB et al (2025). Best-practice Training Characteristics Within Olympic Endurance SpoRts As Described By Norwegian World-Class Coaches. Sports Med 11:45. DOI: 10.1186/s40978-025000848-3

Are Treadmill Calorie Counters Accurate?

My patient said he ran 20 km on a treadmill recently. He also told me stats like his average pace and treadmill incline of the run and calories burned. Since he mentioned about the calories he burned, I told him that they were not very accurate.

Different treadmill manufacturers will have their own formulas that they use for their treadmills, elliptical, X-trainer, stepper etc. Speed, treadmill incline, and distance are typically used to calculate how many calories you burned.

However, for a more accurate reading, your gender, height, weight, muscle, fat mass, heart rate and fitness levels are typically needed as well. Note that a higher heart rate may be associated with greater energy expenditure, hence a lower heart rate running at a certain pace means you are fitter and will burn less calories.

Heart rate is affected by temperature (of the gym), medication, food you ate, what muscles are being used and whether your run is continuous or in spurts/ bursts.

You may also notice that your run becomes much easier when you hold onto the hand rails while running. By taking some weight off by holding on to the rails, actual effort is reduced but the calorie counter does not account for that and will overestimate calories expended.

Treadmills and elliptical machines need to be calibrated regularly (especially in busy commercial gyms) otherwise the speed you may be running at may not be accurate. That discrepancy alone can influence the accuracy of the calorie count.

I could not find much research specifically on how accurate the calorie counts on treadmills. There was a 2018 study by Glave et al (referenced below) involving elliptical machines. Their study found that the calories burned were significantly overestimated. More than 100 calories were added for a 30 minute workout.

So take your exercise machine calorie counts with many grains of salt since they are definitely not accurate and may be way off in some cases.

You can certainly use a smart watch to track your calorie estimates too but even these tend to overestimate energy expenditure. My previous post covered that, but do note that fitness and smart watch technology is consistently improving so they may be more accurate now.

One can also use an online calorie counter to provide an estimate of how many calories you've used. Again it's just an estimate.

Remember not to totally rely on treadmill calorie counts or your smart watch to rule your workout. Sticking to your exercise plan consistently is what really counts, not just the numbers you see on the treadmill or elliptical machine.

Reference

Glave P, Didier JJ, Oden GL et al (2018). Caloric Expenditure Estimation Differences Between An Elliptical Machine And Indirect Calorimetry. Ex Med. 2:8. DOI: 10.26644/em.2018.008

Past Versus Present

Adizero PR (top) versus Adizero X Parley

I've always preferrred running in racing flats so I ordered the OG Adizero PR a few weeks ago when I saw them online. I'd worn quite a few pairs of those in the early 2000's when they were really popular. Actually, Adidas made a custom pair for me when I represented Singapore at the SEA Games triathlon event in 2005 (pictured below).

I did my first run in them on Friday 2 days ago. It was a terrible run! Compared to my previous Adidas racing flats, the Adizero X Parley (which I bought in 2023), I felt the hard ground with every single step.

Adizero PR

My calfs were sore and tired after less than a kilometer of running. Later, I went back to the Adidas website and realized that the Adizero PR's foam was EVA foam compared to the Parley's more advanced Lightstrike foam (pictured below).

Adizero X Parley

Meanwhile, have a look at the humble, really minimalist 1970 Onitsuka Tiger (now known as Asics) compared to the 2025 Asics carbon plated supershoe pictured below. One used for marathons back in the 1970's and the one used currently. The latest version is packed with space age technology. 

Those who raced marathons back in the 1970's used shoes with almost no cushioning, no support and definitely no energy return. The classic Onitsuka Tiger model has an almost zero drop profile and super thin outsole (to save weight). Runners back then needed super efficient running form/ technique, lots of grit and mental toughness since there was no technology back then. There will not be many runners who heel strike with these shoes. They will feel it straight away. Heel strikers back then were definitely 'handicapped'.

And guess what, these shoes are now still making the rounds as a casual sneaker and making Onitsuka Tiger / Asics lots of money.

Now in 2025, we have super highly stacked midsoles, super responsive PEBA foam, uppers that are  optimized biomechanically and carbon plates of course. These can offer runners with energy return on every stride, propulsion and fit designed to minimize fatigue over the whole marathon distance. Just like wearing a springboard when you run.

Today's footwear gives an undeniable edge to help you train and race and definitely run faster. Especially for weaker runners who cannot rely on their muscles as much and efficient running form to run injury free. Good to be able to run and not feel 'damaged' post run. 

I still prefer to be lower to the ground and more stable compared to feeling more 'wobbly' when the midsole is stacked higher. Definitely does not help when you have to turn around on a run or avoid a child on the pavement. I've treated many runners who have sprained their ankles as a result.

I probably will not run in super shoes yet. Call me old school (or OG- original gangster), but I still prefer to be lower to the ground. I prefer the newer versions of the racing flats using PEBA instead of EVA foam. But no highly stacked midsoles and no carbon plates. Not yet anyway.

Majority Of Patients Prescribed Rocker Boots Do Not Need Them

Picture from Orthomed.ca

My patient came in to our clinic with a rocker boot recently. My opinion was that she should never have been prescribed one. She just had a very mild ankle sprain. Actually, the majority of patients that I have seen coming in to our clinics in a rocker boot do not actually need them. When patients are immobilized, there are side effects from wearing the boot. 

Have a look at how quickly another patient's leg had lost its size and, of course, strength after wearing a rocker boot pictured below.

See the size difference?

Rocker boots are often over prescribed. And patients who do not know better use them for way too long. I have a cupboard in our clinic with a collection of expensive boots, donated by patients so we can loan them to patients who actually need them.

These rocker boots are also known as controlled ankle motion (CAM) boots in published studies. They are below knee devices prescribed for managing foot and ankle injuries when there is a need to reduce ankle range of motion (ROM) and to take load off the foot and ankle while allowing ambulation during recovery. 

What's good with the CAM boots are that they can be prescribed as an alternative to plaster cast bacause they cabn be removed to allowed the fracture/ wound site to be cleaned and regularly checked. When used correctly, CAM boots improved mobility, decreased hospital stays and allows for earlier return to work.

There is still a lack of clarity within the current literature over biomechanics and the effectiveness of CAM boots.

A systematic review (Stolycia et al, 2024) published last year found that compensatory mechanisms occur at the hip and knee joint during CAM usage. This is a result of the incurred leg length discrepancy (LLD) caused by the thickness of the CAM boot sole when used with standard footwear on the non injured side.

This has been found to cause secondary site pain specifically at the ipsilateral (same side of ankle injury) knee and contralateral (opposite) hip and lower back with 1 out of 3 patients reporting new or worsened pain 3 months post CAM boot wear.

There was actually a study (Harvey et al, 2010) that suggested that the incurred LLD can also cause development of knee and hip osteoarthritis later in life. This may be true for older patients who may have an early onset or worsening of osteoarthritis at the knee and hip due to overuse caused by the increased load.

Of course there are occasions where they are needed. The findings of this systematic review (Stolycia et al, 2024) show that CAM boots are useful when needed to decrease pressure from the forefoot. but not the hindfoot. This can be useful for diabetic patients for treating plantar ulcerations or in patients with a toe fracture(s) in the forefoot.

The review (Stolycia et al, 2024) also found that tall (compared to short) CAM boots (pictured above) are more effective at restricting ankle ROM. So unless you have a fracture there, wearing the boot will severly reduce your ankle ROM. For those who do, as as soon as the fracture heals, you need to stop wearing it.

So, if you have been prescribed to wear a rocker boot, please understand the rationale for it, the plan, and the timeline that you need to be in it. For many patients, they stay in their rocker boot way too long for their condition. 

To sum up, question your healthcare professional if you are asked to use one. Very often they are not necessary.

Reference

Stolycia ML, Lunn DE, Stanier W et al (2024). Biomechanical Effectiveness Of Controlled Ankle Motion Boots: A Systematic Review And Narative Synthesis. J Foot Ankle Res. 17(3): e12044. DOI: 10.1002/jfa2.12044

Can Neurodynamic Mobilization help DOMs?

Picture from The Sensitive Nervous System

We invited our neighbours over for dinner on Friday night. She had just done circuit training at Virgin Fitness a few days ago (for the 1st time in a few years) and was sore and aching all over. She definitely had delayed onset of muscle soreness (DOMs).

There's not much we can do to recover quickly from DOMs. So I was very surprised to read that neurodynamic mobilization (NM) helped with DOMs.

NM (or neural mobilization) is a physiotherapy technique (made popular by David Butler, who first wrote about this in 1991) that can treat nerve dysfunction by mobilizing the nerves. Manual techniques involve stretching, moving and even 'pulling' on nerves to improve/ restore balance between neural tissue (nerves) and surrounding structures. It helps the nerves glide (or slide) better, decreases adhesions around nerves and surrounding structures to enhance nerve function.

Our brain and the spinal cord are packed in fluid in the skull and the spinal canal. Similarly, our nerves are covered with fluid too, in a sheath like structure. It's sort of like a fluid-fluid tube (nerve) inside another fluid filled tube. 

Neurodynamic mobilization helping DOMs? Now that is news to me.

Researchers had 34 untrained males randomized into the neurodynamic mobilization (NM) or random group. Femoral nerve NM and a placebo technique were performed for 3 weeks in both groups. 

Each session consisted of 3 sets of 10 repetitions with a 2 minute break between sets. Nine sessions were conducted within 3 weeks. The participants were lying sideways on their non-dominant leg side. The physiotherapist stood behind, supporting their upper leg to have the hip in a neutral (no adduction or abduction) position. The upper dominant leg was flexed and the hip extended until soreness/ pain was felt by the patient. This was held for 3 seconds before being released. See picture A below.

Picture from article Sozlu et al, 2025

For the placebo group. the participants were also lying sideways on their non-dominant leg side. The physiotherapist was behind with the upper leg held in full extension and the hip abducted for 3 seconds while the pelvis was stabilized. Each session also consisted of 3 sets of 10 repetitions with a 2 minute break between sets. Nine sessions were also conducted within 3 weeks. See picture B above.

Subsequently, all participants did 300 maximal isokinetic contractions of their dominant leg knee extensors (thigh muscles). 

Creatine kinase, lactate dehydrogenase (both markers of muscle damage), inflammation (IL-6, TNF-α), muscle soreness, pressure pain threshold (PPT) were compared. These were measured at baseline, immediately before exercise (pre) and after (0 hours) the exercise induced muscle damage (EIMD) protocol. Measurements were also taken at 24, 48 and 72 hours after exercise.

Muscle soreness peaked at 24 hours after EIMD, while PPT was at its lowest. The NM group had significantly lower muscle soreness and higher PPT values compared to the placebo group at 0, 24, 48 and 72 hours. Muscle function scores was at its lowest at 0 hours, withe the NM group demonstrating significantly higher function scores than the placebo group both before EIMD protocol and at 0 hours. 

The researchers concluded that 3 weeks of femoral nerve NM applied to healthy untrained individuals had positive effects on DOMs. NM may help sooth inflammation and muscle damage symptoms and shorten recovery time following DOMs.

Now that will be music to my neighbour's ears!

Reference

Sozlu U, Basar S, Semsi R et al (2025). Preventative Effect Of The Neurodynamic Mobilization Technique On Delayed Onset Of Muscle Soreness: A Randomized, Single-Blinded, Placebo-Controlled Study. BMC Muscskel Diso. 26: 464. 

Is The Adductor Magnus Muscle Really An Adductor?

Picture from Getbodysmart

Our adductor magnus muscle is a very large muscle in the medial (inner) part of the thigh. It has long been thought to be a hip adductor. If you are standing with your feet wide apart and you bring your left leg in towards the midline, you will be adducting your left leg. 

Think about that movement, we do not always actively adduct a lot do we? Even while walking or running, we do not need to adduct much. Why is the adductor magnus muscle so big if we do not adduct a lot? Unless you ride horses, donkeys or ponys, what do we need such large hip adductors for?

Adductor magnus also helps with flexion and medial rotation of the hip. And if were to read about group of Japanses researchers work, it is actually a very strong hip extensor. 

A group of Japanese researchers (Takahashi et al, 2025) tested the hypothesis that the adductor magnus is actually a hip extensor more than a hip adductor.

Picture from Takahashi et al, 2025

The researchers utilized advanced diffusion tensor imaging and reconstructed the entire muscle in 15 young adults pictured above. Adductor magnus is divided into 3 portions based on fascicle insertion. The posterior (back) and anterior-distal portions comprised over 80 percent of the whole muscle volume and cross-sectional area. These 2 portions demonstrated that hip extension was more commonly being activated rather than hip adduction.

Because of this, the maximal force generating capacity of the whole muscle was over 2 fold greater for hip extension than adduction. These results support the authors' hypothesis that adductor magnus is actually a major hip extensor rather than hip adductor, challenging the traditional view of this muscle as a hip adductor.

Those of you who have read this far (thank you) must be wondering what is the big deal? Or how does this help? Consider the following pictures that show a more 3D view of the adductor magnus.

Picture by John Hull Grundy

Look at the right leg in the picture on the left. The top part is actually adductor longus. See the twist below rarely seen in 2 dimensional anatomy books? This twist allows adductor magnus to be a major stabilizer of the pelvis (hip). If you bend down to pick something off the ground, the large muscles on the front, side and back of your pelvis are doing most of the work while adductor magnus prevents them working together to throw you off balance. It is uniquely positioned to resist too much hip flexion, extension, lateral rotation of the hip, swaying side to side and hip abduction. 

Many therapists may not know that adductor magnus' squarish shape and twisted nature makes it a very important pelvic stabilizer. One that we cannot ignore when patients come in with hip or back pain.

Yes back pain included. The longest part of adductor magnus is at the back (pictured above from Anatomy Trains). It almost looks like a separate muscle with its fibers going straight down from the ischial tuberosity (just like the hamstrings) and finishing at the medial epicondyle of the femur (inner part of the knee).

 

This part of adductor magnus keeps the pelvis and your upper body from falling forward. This is done much more efficiently by this part of adductor magnus compared to the hamstrings. So when patients or other therapists tell you that you have "tight" or "short" hamstrings, it is because your hamstrings are working too hard to stabilize your pelvis and upper body from falling forward.

The next time you have low back pain or hamstring pain, consider getting your adductor magnus checked!

Reference

Takahashi K, Tozawa H, Kawama R et al 92025). Redefining Muscular Action: Human "Adductor" Magnus Is Designed To Act Primarily For Hip "Extension" Rather Than Adduction In Young Living Individuals. J App Physiol. DOI: 10.1152/japplphysiol.00600.2024

Can Faith Kipyegon Run A Sub 4 Minute Mile?

Picture from Nike

Remember Nike's Breaking 2 project where Eliud Kipchoge went under 2 hours for the marathon? Nike is at it again, this time with Kenya's Faith Kipyegon, who will attempt to make history by becoming the first woman to go under 4 minutes for the mile.

Kipyegon already holds the mile and 1500 m world records and has worn 3 Olympic gold medals in the 1500 m. Her current world record for the mile is 4:07.61 min. Can she take more than 7 seconds off the world record? It is definitely an audacious attempt, but she wants to push boundaries and "dream outside the box".

The Breaking 4 project was announced by Nike in partnership with Kipyegon last week with Nike pledging to create a "holistic system of support that optimizes every aspect of her attempt".

This is good news as Nike had fallen behind their competitors during the Covid-19 years. Then Nike CEO John Donahoe who was appointed in January 2020 for his digital chops so he could help Nike cut out retailers (like Foot Locker and Macy's) by improving their e-commerce operations. As Nike cut off their wholesale partners, it paved the way for other upstart competitors like On Running and Hoka to take over crucial shelf space and grab market share.

Personally, I felt that Donahoe (former eBay and ServiceNow CEO), lacked the deep understanding required for the sneaker culture and industry that Nike required. Donahoe went too much into releasing different editions of Nike's classic sneaker lines (Dunks, Air Force 1's and Air Jordans). He  neglected the innovation section which led to Nike developing the Alphafly's that help Kipchoge break 2 hours  for the marathon.

Am glad he was replaced by Elliot Hill as CEO in October, 2024. Hill had retired from Nike in 2020, prior to Donahue being appointed. Hill was previously with Nike for more than 32 years. He will be better at getting back to the fundamentals that made Nike the market leader in sneakers and athletic apparel previously.

Kipyegon currently trains in Kenya with Kipchoge (who else) while Nike has a team at its headquarters in Oregon crafting her spikes and apparel while analyzing her scans to help her. 

She will only make 1 attempt on June 26, 2025 at the Stade Charlety in Paris, where she previously set world records for the 5,000 metres in 2023 and the 1,500 metres in 2024.

Can she break the world record? Da Silva and colleagues (2025) recently published an article suggesting that with "greatly improved" yet "reasonable" aerodynamic drafting off pacesetters, Kipygeon can break the barrier. 

Let's see if she can do it.

Reference

Da Silva ES, Hoogkamer W, Kipp S et al (2025). Could A Female Athlete Run A 4-Minute Mile With Improved Aerodynamic Drafting? Royal Soc Open Sci. DOI: 10.1098/rsos.241564

Male And Female Hearts Respond Differently To Exercise

Picture from Intermountain Health

Our hearts respond differently when we lift weights or perform endurance workouts. Our heart muscles get stronger, more efficient and they also get physically larger in some cases.

However, both men and women respond differently to weight training and endurance training. How different? A randomized crossover study examined how the heart's structure and function change after 12 weeks of endurance versus weight training in males and females (Naylor et al, 2025).

64 untrained but healthy individuals (38 females, 26 males) were randomized to either 12 weeks of endurance training (running or cyling 3 times a week) or 12 weeks of weight training (progressive weights, 3 times a week).

The 2 groups swap training routines after a 12 week cooling off rest period. This allowed researchers to compare how the same participants responded to both types of training.

The results showed that overall, endurance training led to healthier heart adaptations than weight training. weight training in men led to thicker heart walls but this led to worse diastolic function (relaxation), potientially increasing stiffness in walls of the heart.

Endurance training improved the size of the left ventricle and its ability to pump blood (systolic function) and to fill with blood (diastolic function) efficiently.

Men's hearts responded more to weight training, the left ventricle size increase significantly. However, men showed signs of worsened diastolic function after weight training. Their hearts became stiffer.

The women in the study showed no major heart changes after weight training. Their hearts also adapted more to endurance training. Left ventricle size increased in both men and women in the study , but the women showed better diastolic function improvement. 

The womens' hearts also adapted more to endurance training. Left ventricle size increased in both men and women, but the women showed better diastolic function improvement. 

Both men and women had no major changes in systolic function after endurance training.

So what does this mean for runners or endurance athletes and those who favour gym exercises/ weight training? 

Those who favour weight training need to include aerobic training so that their heart walls do not get too stiff to impede diastolic function.

If you are looking at heart health, endurance training improves heart structure without adding stiffness to the walls, this is true especially for women. Since endurance athletes will do more aerobic training they should still include weight training for better heart health and performance.

Even though endurance training improves heart function, weight training definitely benefits health (especially strong bones) and performance too. This is why we do both.

Reference

Naylor LH, Marsh CE, Thomas HJ et al (2025). Impact Of Sex On Cardiac Functional Adaptation To Different Modes Of Exercise Training: A Randomized Cross-Over Study. Med Sci in Sp Ex. DOI:10.1249/ MSS.0000000000003654

Should You Try Fasted Exercise?

Picure from Boycemode

I rode to Kukup, a small fishing village in Johor, Malaysia on Good Friday. My bicycle speedometer showed (pictured below) that I rode 160 km when I got home. I had to lie down on the floor after setting my bike aside. I was super tired and was cramping everywhere. Took me quite a while before I could shower.

160 km

There must have been about 40 riders in that group. We stopped for a drink at a small coffee shop in Kukup and I overhead another rider saying he fasted for the ride. I don't know how he did that.

Fasted training means one abstains from consumption of food for 8-12 hours in advance of a training session. Most people do an overnight fast so training is done in the morning before breakfast. It has become popular among people interested in fat loss, metabolic health and for performance or adaptation reasons (especially endurance athletes).

Why would anyone do fasted training? There are lots of videos and reels online suggesting that when you train in a fasted state, your insulin levels are lower, so your body is more likely to use your fat stores for fuel (lipolysis) and better fat utilization.

There are endurance athletes who use fasted training to encourage adaptations like increased mitochondrial density. This is to allow their cells to make more new mitochondria and increase existing mitchondria.  Our cells often increase mitchondria biogenesis in response to increased energy demands triggered by physical activity. With more mitochondria in our cells we become stronger.

With fasted training, endurance athletes are training for better fat utilization to spare their glycogen stores so they can have better endurance. This may work if you're exercising at lower intensities, not when you are going fast at higher intensities since carbohydrate/ glycogen is still very much needed. With fasted training, there will be a severe restriction on the ability to do anaerobic work.

Moreover, over the course of a day, the net fat loss may not be that much different from fed training.

Fasted training may improve insulin sensitivity and glucose tolerance especially in sedentary or overweight individuals.

I also know people who feel better when  they exercise or train on an empty stomach and most find it logistically easier to exercise right after waking up.

Although fasted training can help metabolic adaptations described above, it can also potentially lead to a deficit in total daily calorie intake and this has been shown in active males.

If this reduction in daily calorie intake is not the intended outcome of fasted training it can potentially lead to a state of low energy availability, which when repeated frequently may lead to stress fractures and poor bone health (Raleigh et al, 2024). 

The incidence of bone injury was 1.61 times higher in those who currently use fasted training compared to those who never used it.

Fasted training is not ideal for everyone since you may feel sluggish, lift less (if you're weight training) and perform worse in high intensity workouts. In prolonged fasted states, there is a higher chance that your muscles will be broken down to be used for fuel with intense workouts.

In summary, weigh the pros and cons of fasted training, be aware of how your body responds to it and ensure that it works for your body in the long run.

References

Raleigh C, Madigan S, Sinnott-O'Connor C et al (2024).Prevalence Of Reducing Carbohydrate Intake And Fasted Training In Elite Endurance Athletes And association With Bone Injury. Eur J Sp Sci. 24(9): 1341-1349. DOI: 10.1002/ejsc.12170

Zouhal H, Saedi A, Salhi A et al (2020). Exercise Training And Fasting: Current Insights. Open Access J Sp Med. 21(11): 1-28. DOI: 10.2147/OAJSM.S224919

X-ray Based Diagnosis Leads To Potientially Unnecessary Surgery

Picture by Balint Botz from Radiopaedia

I've written previously that many patients had back surgery when a doctor sends them for an MRI within the first 6 weeks of an initial visit.

Well, guess what? Taking an X-ray to diagnose knee arthritis may make you more likely to consider potentially unnecessary surgery (Lawford et al, 2025) as well.

Many of my patients who go to a doctor or surgeon for their knee pain end up being sent for an X-ray or even an knee MRI. Many of these patients have osteoarthritis (OA) in their knees. Actually, routine X-rays may not be necessary to diagnose the condition. A skilled and thorough assessment based on symptoms and medical history is good enough to make the diagnosis. 

A huge and common misconception is that OA is caused by 'wear and tear'. Research clearly shows that the structural changes seen in a joint X-ray does NOT correspond with the level of pain or disability a person feels. Nor can X-rays predict how symptoms will change.

In fact, X-rays are NOT recommended in Australia to diagnose knee OA. Nearly half of new patients there with knee OA get sent for a knee X-ray and cost their health system A$104.7 million each year.

Researchers in Australia showed that using X-rays to diagnose knee OA can affect how a person thinks about their knee pain and prompt them to consider potentially unnecessary knee replacement surgery.

Many patients with 'terrible' X-rays have no pain while patients with no damage on X-ray have a lot of knee pain. Hence, X-rays are not recommended for diagnosing knee OA or guiding treatment decisions.

The Australian study had 617 subjects across Australia who were randomly assigned to watch one of three videos. Each video showed a hypothetical consultation with a general practitioner (GP) about knee pain. 

The first group received a clinical diagnosis of knee OA based on their age and symptoms and were not sent for an X-ray. The other 2 groups had X-rays done to determine their diagnoses (the doctor showed one group thier X-ray images but not the other group). After watching their assigned video, the subjects completed a survey of their beliefs about OA management.

The results showed that the group who received an X-ray based on their diagnosis and were shown their images had a 36 percent higher perceived need for knee replacement surgery compared to those who received a clinical diagnosis without X-ray.

What was worse was, they even believed that exercise and physical activity could be harmful to their joint. They were also worried about their condition worsening and were more fearful of movement.

The subjects were slightly more satisfied with a X-ray based diagnosis than a clinical diagnosis. This may reflect the common misconception that OA is caused by 'wear and tear' and the joint needs to be replaced.

The study's finding shows that it may be important to avoid unnecessary X-rays when diagnosing knee osteoarthritis. Changing this can be challenging, since many people still expect or want  X-ray imaging. If we can change this mindset, it will minimize unnecessary concern about joint damage, reduce demand for expensive and potentially unnecessary joint replacement surgery.

In my opinion, we as health professionals should not focus on joint 'wear and tear' since it can make patients more anxious about their conditions and concerned about damaging their joints. There are a range of non surgical, non invasive options that can reduce pain and improve your mobility. Exercise is one of many if you read this Cochrane review.

Our health minister says healthcare spending in Singapore could hit 30 billion a year by 2030 in a Straits Times article just 2 days ago. Perhaps this is an area where we need to be more mindful of unnecessary X-ray imaging and joint replacements to bring healthcare spending lower.

You can read about what actually causes your joints to wear out here if you are keen.

Reference

Lawford BJ, Bennell KL, Ewald D et al (2025). Effects Of X-ray-Based Diagnosis And explanation Of Knee Osteoarthritis On Patient Beliefs About Osteoarthritis management: A Randomised Clinical Trial. Plos One. DOI: 10.1371/journal.pmed.1004537 

Brain Myelin Levels Takes 2 Months To Recover After A Marathon

Picture from MSIF

I ran my first marathon when I was 16 years old, just after finishing my GCE 'O' levels. Despite not training as much as I would have liked, I finished in 4:00:16 hrs. If  I had ran just 17 seconds faster, I would have gone under 4 hours. 

I can still remember the exhaustion and agony I felt after the finishing line. I had willed myself to keep going despite hitting the proverbial wall and that led me to wonder about the brain's response to endurance exercise.

So I am not surprised that a recently published study shows that marathon running can cause a temporary reduction in brain myelin content. Full recovery only takes place after 2 months. Myelin is a fatty substance that covers and protects nerve fibers in the brain and spinal cord. It makes up 40 percent of the brain's white matter. The white matter is in charge of nerve signaling to enable learning, memory, sensory perception, motor control and cognition.

Other than allowing faster transmission of nerve impluses (which helps you move more quickly or learn with better focus), myelin helps convert glucose into energy for the brain. This is very important since so much energy is needed for all those nerve signals, especially when running a marathon.

Researchers used advanced MRI with multicomponent relaxometry to assess the myelin water fraction (MWF) to measure the amount of myelin in the brain. This was done on 10 runners ages 45 to 73,  both before and 48 hours after completing a marathon. 

They found substantial reduction in MWF in 12 areas of white matter after the race. The most significant reductions were observed in the pontine crossing (28%) and corticospinal tracts (26%). The affected areas are crucial for motor function and integrating sensory and emotional inputs, suggesting impact on movement and emotional regulation.

Since this was a small study, they did follow up scans 2 weeks after the marathon and 2 months after to track recovery.

MWF levels begin to rebound within 2 weeks and recovered fully to pre-race levels by 2 months. These findings suggest that brain myelin content is temporarily and reversibly diminished by severe exercise. Analyses of brain volume and hydration status showed that dehydration was not responsible for the changes in MWF. 

Since the brain and your legs are both competing for glucose while running a marathon, the brain turns to myelin lipids for energy. Previous studies have shown that lower brain myelin content is linked to cognitive decline - in areas related to verbal fluency and excutive function.

Should those of us who participate in endurance sports be concerned about myelin depletion in our brains? The authors say the breakdown of myelin from endurance exercise is actually beneficial, especially since it generates between 2 weeks to 2 months as it 'exercises' the brain's metabolic machinery.

Reduction in myelin levels can be similar to how muscles react to strength training. Your muscles break down as glycogen levels get depleted during weight training and endurance exercise before building back stronger with adequate rest. 

Better fueling with carbohydrates help sustain effort during training and races and may possibly reduce the amount of myelin used. Some runners in the research took carbohydrates during the marathon while others none, but there were no differences in this research. 

The authors did not investigate running speed. Perhaps running faster if underfueled may exacerbate brain myelin reduction.

So I was drawing on my myelin lipids to support my brain function in my maiden marathon and many times subsequently while exercising and competing for all those years. 

Can repeated depletion and restoration of myelin have long term consequences for people who frequently engage in prolonged, strenuous exercises and competitions?

The reversible nature of MWF is definitely reassuring (to me at least) and as I am still able to write an article for you readers weekly, I think all those hammer sessions and races definitely helped improve my brain function. 

I don't do those long, intense sessions much compared to before, but  I will make sure to have enough rest after. Make sure you do too.

Reference

Ramos-Cabrer P, Cabrera-Zubizarreta A, Padro D et al (2025).Reversible Reduction In Brain Myelin Content UponMarathon Running. Nat Metab. DOI: 10.1038/s42255-025-01244-7

Kinesio Foundations Course

I will be teaching the Kinesio Foundations course at Sports Solutions on the 21st and 22nd of June this year. This replaces the Kinesio Taping Assessments, Fundamental Concepts and Techniques (or Kinesio Taping Level 1-2) course previously.

The course is now a two day (16 hours) in person course with a 4 hour online pre course. Most if not all other taping courses takes place over just 2-4 hours. Compared to the 2 previous versions of the course, there is now a much bigger emphasis on the Kinesio Medical Taping section instead of just the Kinesio Taping Methods where muscles, joint and tendons were the main focus. 

Unlike other tapes, Kinesio Medical Taping utilizes much lower tensions (no pulling/ stretching of the tape) and thinly cut applications. There is a much bigger focus on skin and fascia stimulation to improve superficial, lymph and interstitial circulation. Hospitals in Singapore only use Kinesio tapes (and not other brands) when they have to treat patients with lymphedema.

Personally, I have great results using the EDF (epidermis, dermis and fascia), jellyfish and the Space Correction webcut applications with bruising and swelling. A patient with a partially torn calf muscle yesterday immediately felt better and could walk with less limping after the jellyfish application (pictured below.

Attendees will learn multiple taping techniques and be able to treat clinical cases using Kinesio tape alone or in conjunction with other strategies. There will be ample time to practice assessments, screenings and taping techniques to a variety of upper and lower body conditions.

Past participants have said that they were able to "immediately use the taping on the patients with good results" when they resumed work the day after attending the course.

Interested to attend the course? I have attached the link to sign up here. You can also email us if you need more details.

Muscle Damage Affects Your Running Gait

Picture from Aspetar

I was away for my Kinesio Taping recertification for Instructors last week and had to exercise in a new environment. As the gym was much bigger and had equipment that I do not normally have access to, I chose to use mostly those. 

As a result I ended with muscle soreness almost all over. I went for a run a day after I came home and my running stride felt 'off.' Turns out I was not imagining it. That is how our bodies try to protect itself. So is that good or is that a problem?

Turns out it may be both (Markus et al, 2025). The muscle soreness indicate that adaptations are beginning. However, that soreness can also change our running form, increasing injury risk.

To assess how exercise induced muscle damage (EIMD in this study) or delayed onset of muscle soreness (DOMS) affects running biomechanics and recovery, researchers got their subjects to run downhill for 60 minutes. This was done on a treadmill at -10 percent gradient. The runners ran at 65 percent of their max heart rate.

The researchers tracked running gait changes, muscle soreness, blood markers for muscle damage and also did MRI scans of thigh muscles immediately post run, 24, and 48 hours after.

The runners took shorter steps 24 and up to 48 hours after that run, likely as a compensating mechanism since taking a smaller stride is the body's way of reducing impact when muscles are fatigued or damaged. Damaged muscles were verified (significantly elevated) using blood markers (creatine kinase and lactate dehydrogenase) and MRI scans showed thigh muscles damage. 

Take home message? If you just had a hard training session or especially a race, you have to expect some biomechanical changes for at least 48 hours after that if you still want to run. Since you have a reduced stride length, your pace will be slower and you will be running less eficiently. 

Anything else that will help? My personal experience suggests that performing reduced intensity and low volume exercise will increase blood flow to the affected muscles and often reduce pain. Pedaling at low resistance on a stationary bike is ideal as you don't have to worry about traffic (if you ride on the roads). An easy swim or just walking in waist or chest height water works well too.

 Wearing compression garments will help reduce it as well. These above mentioned strategies do have some support in the research.

Or better still, give yourself a few days of well earned rest (especially after a race) before going hard again. 

Reference

Markus I, Arutiunian A, Ohayon E et al (2025). Kinetics Of Recovery And Normalization Of Running Biomechanics Following Aerobic-Based Induced Muscle Damage In Recreational Male Runners. J Sci Med Sport. DOI: 10.1016/j.sams.2025.01.002

Kinesio Taping Instructor Recertification (CKTI) In Bangkok

I have not taught any Kinesio taping courses since 2019 in Malaysia, just before Covid-19 struck. In fact, the last course I taught in Singapore was in August 2018.

Kinesio Taping Association International needs our licence as a CKTI (certified Kinesio Taping Instructor) to be renewed  every 3 years to be able to teach again. There was an online recertification during the Covid years in 2021 which I attended, but due to the many rules in place I did not teach since then.

So I chose to come to the recertification in Bangkok since Alburqurque (held in October 2024) and Barcelona (January 2025) were much further away.

There was a memorial for Dr Kenso Kase (who passed away in August 2024) and Jim Wallis (December 2024) (a very senior instructor) at the event to honour them.

The course has definitely evolved. It is now called the Kinesio Foundations course (over 2 days) and we spent a lot of time (pictured below) over the last 2 days learning how to teach the new syllabus.

Sports Solutions will definitely be teaching the new Kinesio Foundations course. They will be held on 21st to 22nd June. Here's the link to sign up.

With Elisa Kase

Race Pace Versus Heart Rate Variability Guided Training

Picture taken from Flowly

A patient came in this week after he raced the Tokyo marathon last weekend. He was not happy as he started cramping in his hamstrings after 'only' 5 km.

I asked about how his training went. He told me he did 4 runs a week, all on a treadmill, mostly easy runs. His longest run was by time, 2:55 hrs (which he thought was equivalent to about 20 km).

He did all his runs with a heart rate monitor, training at "Zone 2" mostly and followed recovery metrics like heart rate variability *(HRV). Zone 2 training is low intensity exercise that involves training at 60-70 percent of maximum heart rate. He did not do any interval training nor any race pace training.

I discussed with him how he can do better since he will be running the Chicago marathon on October 12th this year. He really wants a improvement after his self described disastrous Tokyo race. I shared with him a study that tested 3 different approaches of training (Ranieri et al, 2025).The researchers split the runners into 3 different groups for 6 weeks. 

First, a heart rate based training group where training is prescribed by heart rate zones. Next a race pace training group in which training is prescribed running at percentages of race pace. Lastly a HRV guided training group. The HRV training group did training prescribed by heart rate zones but this was adjusted daily based on HRV readings. Hence their intensity was based on how well they recovered. 

All the runners did lab tests before and after the study. V02 max, running economy, ventilatory thresholds and other key endurance metrics. Participants were assessed by a 7 km time trial after the training period.

Results? Race pace training was the most reliable for improving race performance. Every single runner in that group went faster in the 7 km time trial with an average improvement of 3.8 percent. The runners also had gains in fat loss and maximal aerobic speed. The heart rate training group improved their ventilatory threshold readings but this did not lead to V02 max or time trial improvement. It did not deliver clear performance advantages over race pace training.

The HRV training group led to bigger physiological improvements. They had significant increases in ventilatory thresholds and V02 max, but this did not translate as well to race performance. Some participants also put on weight (fat mass) perhaps due to more frequent easy training days.

The authors concluded that race pace training had the least variablilty in response, meaning it worked reliably across runners. HRV based training showed individual differences, some saw gains, others did not. This is not surprising since HRV itself is highly variable.

I suggested to my patient that he needed to do some race pace training if he wanted to achieve his target timing. He can take his target finishing time and calculate how fast he needs to do his 1 km, 5 km or even 400m repeats. This teaches his body to gauge the pace he needs to run and not go too fast especially at the start. It will also prepare his body for the demands of race day.

I also suggested running more outdoors rather than solely indoors on a treadmill since the treadmill is softer and will not mimic the road conditions that he races on. Specificity is key. The gym environment is temperature controlled unlike outdoors. So if the race location is hotter and more humid then he will be less able to handle it.

Takeaway message? The best approach is not to train solely on a single approach. It is best to know when to use each approach. For example, you cannot train exclusively by race pace. The body will not be able to handle the load, one would likely get injured. 

Heart rate based training can definitely be used but should not be relied on exclusively too. It will improve physiological markers and your lab based testing (V02 max, lactate threshold), but may not result in faster race timings. 

HRV is a useful tool for monitoring stress and how well your body is recovering. Many professional athletes use it. However this study raises an important question of whether better physiological markers lead to better performance.

If you're looking for a fool proof way to inprove your race times, this study suggest that training at your race pace sould be a part of your training routine.

Reference

Ranieri LE, Casada A, Martin D et al (2025). Performance And Physiological Effects Of Race Paced-Based Versus Heart Rate Variability-Guided Training Prescription In Runners. Med Sci Sp Ex. DOI: 10.1249/MSS.0000000000003671

*Heart rate variability (HRV) is a measure of how much time passes between each heart beat. It is better to have a higher than lower number. It is physiological measurement that is used to understand how your body is coping with life and environmental changes. A low HRV may suggest that your body is not rested, less resilient  and may not handle changing situations. You can measure HRV with a smart watch, fitness tracker etc.