What Helps Prevent Muscle Atrophy During Immobilization

Which leg was immobilized?

We see many patients with muscle atrophy on their affected limb. This definitely happens after surgery where whole body or single limb immobilization may be necessary. This leads to decreased muscle size and strength.

What strategies are there to mitigate this? You may be very surpised.

20 male participants (average age 33) took part in this study (Labidi et al, 2024). All were former competitive athletes, primarily in athletics, now working as fitness coaches. 

The participants were split into 2 groups. They had 2 weeks of single lower leg immobilization with a orthopaedic walking boot . They were taught to use crutches and instructed not to weight bear on that leg. This was followed by 2 weeks of supervised rehabilitation before return to sport (RTS). 

The participants underwent 4 weeks of a standardized training program to ensure a common training base before the immobilization procedure. There were 5 sessions (3 resistance, 2 endurance) of training each week. They also received 4 nutritional sessions inclusive of face-to-face consults with a nutritionist and educational videos to standardized daily energy and protein intake throughout training, immobilization and rehabilitation phases.

Picture from SIU Med

The participants then underwent 4 weeks of supervised training. The 1st group had whole body heat therapy (HEAT) while the 2nd group had sham treatment (SHAM) throughout the immobilization and rehabilitation periods.

During the immobilization period, the participants received 11 passive interventions of 60 minutes. The HEAT group sat in a heat chamber at 48 to 50 degree celcius at 50% relative humidity (at 0 m altitude). 

During the rehabilitation period, the participants received 5 active interventions (conditioning) of 60 minutes. The HEAT group performed the sessions in the heat chamber at 35 degrees Celcius and 60 degress relative humidity at 0 m altitude. 

The SHAM group sat in an altitude chamber, set at only 200 m (to create a placebo effect while avoiding any effect of altitude). The temperature was at 24 degree celcius and 40% relative humidity.

Ready for the results? All of the following were measured pre-immobilization, post-immobilization and at RTS. Muscle strength (isometric and isokinetic) were measured. Muscle volume was measured by MRI and ultrasound while muscle biopsies were also obtained. Maximal isometric strength for the calf muscles (plantarflexion) was lower at RTS compared to pre-immobilization in SHAM. 

Isokinetic strength during a fatigue test was higher at RTS compared with pre-immobilization in HEAT but not SHAM. 

Shape of muscle and muscle thickness were lower at post-immobilization compared with pre-immobilization only in SHAM. Cross sectional area of the soleus and the medial, lateral gastrocnemius were decreased in SHAM. Only the medial gastrocnemius was smaller in cross sectional area in HEAT.

The results indicate that using heat therapy during immobilization and rehabilitation reduces muscle atrophy and maintains calf strength in healthy humans. Repeated heat exposures should be considered to counteract muscle atrophy during immobilization.

I'm not sure that it's practical to get in a sauna with a cast on but maybe with a boot or back slab that can be removed temporarily? I would do it if I wanted to return to sport badly enough or maybe if I'm old and wanted to prevent muscle bulk and strength while awaiting healing to happen. For those with with an aversion to heat, definitely no go.

Reference

Labidi M, AlhammoudM, Mtibaa K et al (2024). The Effects Of Heat Therapy During Immobilization And Rehabilitation On Muscle Atrophy And Strength Loss At Return To Sports In Healthy Humans. Orth J Sp Med. 12(10). DOI: 10.1177/23259671241281727

Our Words Affect Pain

Picture from Coregymball

It may be just words you think. Perhaps not. Recently published fascinating research suggest that how healthcare providers describe an injury can have a direct impact on a patient's pain. 

Not only were the patients blinded (a technique used to minimise bias), the patients also did not know they were part of a study.

Picture from article

50 recreational runners with Achilles tedinopathy took part in the radomized trial (pictured above). They ran 3 times a week. Runners in the experimental group received diagnostic information of tendon pain that highlighted reversible changes in muscle function as their primary problem. They did not hear any reference to tendon pathology.

The control group received an explanation of tendon pain that prioritised irreversible structural tendon pathology as the cause of pain.

The primary outcome measure was how much pain the runners had during a standardised hopping task measured on a scale of 0-100. Secondary outcomes were how stiff the lower limbs were hopping and time in seconds for pain to ease after completing the hopping task.

The diagnostic information immediately affected pain intensity during the hopping task. The average pain score was 25.4 in the experimental group versus 36.7 in the control group.

Time to ease (no pain) after hopping was near identical in both groups. Lower limb stiffness was higher in the experimental group. Note that higher leg stiffness is better for leg hopping because increased leg stiffness allows for greater force production and more efficient energy transfer. This leads to higher jump heights and faster movement.

This is a really intriguing area of research. We now have data showing that information from healthcare providers during the first visit has an immediate effect on pain. The language we use during clinical interactions can be powerful, shaping our perceptions and pain responses. This knowledge should change how we interact with our patients. 

However, we need to also be able to do this in our clinics without compromising the accuracy and necessary medical information.

Reference

Travers NJ, Travers MJ, Gibson W et al (2025). The Content Of Diagnostic Information Has An Immediate Effect On Pain With Loading In People With Morportion Achilles Tendinopathy: A Randomized Clinical Experiment. Bra J PT. 29(5). DOI: 10.1016/j.bjbt.2025.101244

Quadrilateral Space Syndrome

R posterior arm picture by Mickeymed.com

I treated an 11year old girl recently with pain in her quadrilateral space. What space you may ask? The quadrilateral (or quadrangular) space is a tiny window or space that the axillary nerve and other blood vessels (posterior circumflex humeral artery) exit from the shoulder to the back of the arm. It's boundaries are teres minor on top, the humerus (arm bone) on the right, teres major below and the long head of triceps on the left. The axillary nerve supplies the deltoids and the teres minor muscles. 

Picture from Clinical Anatomy & Op Surgery

This young patient plays softball for her school and is her team's first choice pitcher. Softball pitching is different as the ball is thrown to the batter using an underhand motion. The goal while pitching is similar to baseball, to get the batters out by strikes or preventing them from reaching base. 

Injury or compression in the quadrilateral space often leads to pain, numbness in the posterior shoulder/ arm and/ or weakness in those areas.

This condition is much more common in young athletes participating in arm over head sports like swimming, throwing and volleyball in their dominant hand. But she did do many overhead throws prior to having this pain in her posterior shoulder and arm. In addition, her coach also started her on a weight training program in the upper body and arms.

Injury or compression in the quadrilateral space often leads to pain, numbness in the posterior shoulder/ arm and/ or weakness in those areas. There is often tenderness in the quadrilateral space on palpation. 

My patient also had some paresthesia (numbness, tingling sensations) on the outer shoulder and elbow when I checked her upper limb tension test. Her shoulder external rotation strength was also noticeably weaker on her thowing arm, which should not be the case.

Once we determined the cause, treatment was easy as we simply had to 'widen' the quadrilateral space while also addressing the overhead throwing overuse and the sudden increase in weight training. A simple phone call to her coach,who happened to be a previous national pitcher and patient of mine solved that.

Reference

Pocellini G, Brigo A, Novi M et al (2025). Different Patterns Of Neurogenic Quadrilateral Space Syndrome: A Case Series Of Undefinied Posterior Shoulder Pain. J Orthop Trauma. 26(1). DOI: 10.1186/s10195-024-00813-y.

3 Common Sites Of Musculotendinous Junction Injuries

I recently had a patient with a musculotendinous junction injury. Also known as the muscle-tendon junction (MTJ), it acts like a bridge to transfer forces from the muscle via the tendon to the connecting bone the muscle attaches to. This allows for movement to take place. 

It is a special area where the muscle's fascia connects and inersects with tendon tissue. Structurally, the MTJ is seamlessly integrated into the tendon, with finger-like folds increasing the surface area for a stronger connection and to distribute stress (pictured above).

It's a common site for injury as the MTJ undergoes some stress during daily activities and substanstial stress while playing sports. MTJ injury is often accompanied with both muscle and tendon injuries leading to restricted force trasmission.

Due to it's highly specialized structure, it does not often heal well after injury. Conservative treatment are mostly effective for minor MTJ sprains while partial tears and complete ruptures will require surgical intervention.

It can happen during a fall leading to trauma to the area. It often occurs due to repeated overload, usually from high intensity training in young athletes or overuse in middle age or older adults. My observations are MTJ injuries usually happen after a period of rest/ decreased muscle use followed by a period of intense muscle activity. 

An example who be my patient mentioned above. He went on holiday for 3 weeks with no exercise and resumed his weekly basketball game on returrn and promptly tore his hamstrings at the MTJ. These tears occur frequently during eccentric muscle loading. 

They are usually complete muscle tears. In hamstring injuries this account for 14.4% of all bicep femoris injuries. The supraspinatus muscle has the highest incidence of the tendon midsubstance injuries (11.4%). Complete tendon avulsions are more frequent in the triceps brachii and pectoralis major.

Conservative treatmant options like rest, ice and compression etc helps in the initial stages if the tear is small. Several studies have indicated that surgical treatment yields better results in terms of function, strength, patient ratings and recovery to pre-injury performance for the more serious tears.

Continous development of tissue engineering that focuses on regenerating new tissue from cells are now helpful to MTJ injuries by utilizing biological and synthetic scaffold-based tissue. This helps in the repair and healing of MTJ tears. However it is not easy to fully mimic the unique characteristics of our muscles, tendons and the MTJ itself.

Hopefully, newer polymers and scaffolds will help with healing of MTJ injuries in the future. For now, please be vigilant in your exercise after a period of rest. Avoid exercising at higher intensities initially while allowing for your muscles to adapt again. Note that the calf, pectoralis major (chest) and hamstrings are the most vulnearble areas.

Reference

Tong Sm Sun Y, Kuang B et al (2024). A Comprehensive Review Of Muscle-Tendon Junction: Structure, Function, Injury And Repair. Biomedicines 12, 243. DOI: 10.3390/biomedicines12020423

The Old Do Not Need Gentle Movement

Picture from NRI Nation

I was very surprised to read that older adults need more than gentle movement. They need strength. Yes, a lot of stength if you read the following review by Toien et al (2025). This is in contrast to current guidelines which recommend low to moderate intensity (60-70 percent of 1 RM) and slow to moderate concentric velocity.

The review showed convincing benefits of maximal strength training (MST) in healthy and 'diseased' older adults including frail and post stroke patients. Training performed with heavy (80-84 percent) of 1 RM and very heavy loads (>85% of 1 RM).

Key benefits were increased strength gains (2.5 percent per session). 4.5 percent increases in muscle power per session. Increase in Type II muscle fiber size, decrease in oxygen cost of walking and stair climbing. It also helps with balance.

MST uses loads of about 90% of 1 RM, which can only be performed a maximum of 3-5 reps, 3-5 sets and maximum intentional concentric velocity.

Here are the guidelines. Do 4 sets of 4 reps at about 90% of 1 RM or 4 RM. Do this 2 to 3 times a week. Single set options are also effective twice  a week. Prioritize lower body compound lifts e.g. leg press, squats, step ups since strength reduction is more effective in lower compared to upper limbs with increasing age. Moreover the lower limbs are crucial for walking during everyday activities. 

Picture from article

For this, a horizontal leg press (pictured above) may be ideal over a free weight squat since technique and safety will minimally limit the intensity of the load. The health care provider needs to consider the main challenges of the specific disease or individual. Those with osteopenia or osteoporosis will benefit from axial loading through the spine to stimulate bone density enhancement. The hack squat or horizontal leg press where the back can be reclined to ensure loading through the spine is recommended to attain this axial loading of the spine while also protecting the impact of the heavy load. 

Some diseases or injuries may require other exercises to target an affected or impaired muscle or muscle group. Examples may include the bench press for wheelchair users, dorsiflexion for foot drop patients or hip abduction following hip surgery. Also note that very heavy unilateral (or single leg) strength training induces adaptations in the untrained, opposite injured limb. This is useful during acute or chronic periods of immobilization to limit the loss of function in the immobilized limb.

Supervised training are encouraged since it improves safety and confidence.

It is a very interesting read since it is good to have evidence that it is safe to use the heavier strength training lifts compared to the current guidelines. I am wondering if the 4 sets of 4 repetitions at 90 percent of 1 RM for older patients is a recipe for injury. Is the volume and frequency of the MST sustainable for the long term?

Reference

Toein T, Berg OK, Modena R et al (2025). Heavy Strength Training In Older Adults: Implications For Health, Disease And Physical Performance. J Cachexia Sar Muscle. 16(2): e13804. DOI: 10.002/jcsm.13804

Day 2 Of Kinesio Foundations Course

Ligament correction with Dr Frank Liew (dentist)

Most of the participants already took the Kinesio tapes off after the the first day. For the few who still haves them on, we started with some questions on how tape left overnight felt. The participants discussed why there were good or adverse reactions.

What's up Dr Kong (on the right)?

Day 2 Of Kinesio Foundations Course started with corrective techniques. Mechanical correction, fascia correction, ligament/ tendon correction and spring assist etc

Surprisingly, the 2nd day of the course zipped by much quicker than usual as we went through more the corrective techniques. There were practical applications such the association of MCL (medial collateral ligament) and your pes anserinus, how a rotated pelvis would affect the shoulder. How the hip affects the knee and also strategies on how to treat a foot drop. We covered all that and more.

Cutting the tape for EDF, jelly fish - not easy

The coup de grace were the EDF and jelly fish taping affecting the epidermis, dermis and fascia. The participants realized it's much easier to have a good pair of scissors for the EDF techniques.

A big thank you to the participants, my family and colleagues for helping out. Would not have done it without all of you. Looking forward to the next course.

Day 1 Of Kinesio Foundations Course

Sports Solutions hosted Day 1 of the Kinesio Foundations Course today. It's been quite a few years since we have had this course. During that course, we had 2 participants from Saudi Arabia. 

This time it's all local with 15 participants. We have 4 medical doctors, 1 dentist, 1 occupational therapist with physiotherapists rounding out the rest.

The course is now a two day in person course with a 4 hour online pre course. 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. 

Here are some of the pictures from today.

Stay tuned for Day 2 tomorrow.

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 you were to read about group of Japanese 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