Single Leg Versus Double Leg Training

L leg bigger

We see many cases where patients have one limb bigger than the other in our clinics. There is an imbalance or deficit between limbs e.g. healthy versus injured, left versus right or dominant versus non dominant. This is also known as interlimb asymmetry in research. 

Strength, power, reactive strength have been shown to be affected when there were interlimb asymetries, especially in sporting performances. I have seen differences of 10-15 percent in deficits for patients even 5 years after they had surgery. Hence, I often suggest that patients work on single limb exercises to reduce this deficit/ asymmetry.

Single leg and double leg strength exercises, plyometrics, balance and even core training have been investigated in a wide variety of athletic populations to understand the effects of interlimb asymmetry. The following systematic analysis was to examine if training interventions are effective in reducing interlimb asymmetries and which types of interventions were more effective in the athletic population.

The single leg counter movement jump (SLCMJ), single leg broad jump (SLBJ), single leg lateral jump (SLLJ) and change of direction (COD) speed were the most commonly used test to check for sprint performance, jump height and COD speed.

Ready for the results? The review suggested that all training interventions have a small to moderate effects on the reduction of asymetry in SLBJ, SLCMJ and COD speed from pre to post training, although no statistically significant differences were reported. This was found in the intervention groups versus the control groups.      

The researchers suggested both unilateral and bilateral training should be considered to decrease interlimb asymmetries. If you're an athlete and have any limb asymmetries and no pain, then definitely do both single and double leg exercises to reduce the asymmetry. 

Please note that the above study was done on athletic populations. I will definitely avoid single leg exercises in the recently injured/ immediate post surgery patients and get them to do bilateral leg exercises first.

What about patients who are not loading equally a year (or longer) after a knee replacement or ACL reconstruction? I always see patients who tend to compensate too much with the non injured/ painful leg. By doing single leg exercises (pictured above), I can make their weaker side work harder.

Reference

Bettariga F,Turner A, Maloney S et al (2021). The Effects Of Training Interventions On Interlimb Asymmetries: A Systematic Review With Meta-Analysis. Strength Cond J. DOI: 10.1519/SSC.0000000000000701

Your Workout Today May Trigger A bright Idea Next Week

Picture from Triana et al (2024)

What if I told you your exercise session today can trigger a bright idea next week? That's exactly what a recent study by Finnish researchers found. They tracked a person's brain and behavioural activity for 5 months using brain scans and data from smart phones and wearable devices. 

This research (Trinan et al, 2024) was unusual since few brain scan studies involve such detailed monitoring over months. Using wearable technology in this study was crucial, especially since brain scans (while being useful) only shows the subject lying still for 30 minutes. 

2 distinct patterns were identified by the researchers. A short term wave that lasted under 7 days and a long term wave by up to 15 days. The short term wave reflects rapid adaptations like how focus is affected by poor sleep although it recovers quickly. The long term wave suggests more gradual, lasting effects, especially in areas tied to our attention and memory.

The study found that our brains do not respond to our activities of daily living in immediate, isolated bursts. Our brain activity evolves in response to our sleep patterns, physical activity, mood, and respiration rate over many days. This means that your exercise session or a restless night from the previous week can still affect your brain. Hence your memory, cognition and attention can be affected well into the next week.

It is a great study linking brain activity with environmental and physiological data as tracking our brain changes in real time can help detect mental health and neurological disorders early. This allows for earlier interventions and better outcomes.

Even though this study was not focused exclusively on exercise, the results showed that we definitely need a consistent exercise routine and maintain good sleep habits for our overall well being. I find myself particularly sensitive to these as I age. 

Reference

Triana AM, Salmi J, Hayward NME et al (2024). Longitudinal Single-subject Neuroimaging Study Reveals Effects Of Daily Environmental, Physiological, And Lifestyle Factors On Functional Brain Connectivity. Plos Bio. DOI: 10.1371/journal.pbio.3002797

Something You Do Not Know About Muscles

Picture from Burke et al, 2024

This is a very interesting finding about muscles. The muscles we use while exercising can actually communicate with our adipose (fat) stores in our body.

This study was done with 32 human subjects. A single bout of resistance exercise (or strength training) releases muscle specific microRNA-1 (miR-1) from muscles that are then transported to abdominal fat tissue via extracellular vesicles or EVs to stimulate lipolysis. Lipolysis is the breakdown of fats and other lipids to release fatty acids. This means you can use fats for energy, sparing your carbohydrate and protein.

I know what some of you reading must be thinking. Is spot reduction possible? Spot reduction means selective loss of body fat in regions involved in the exercise. Meaning can we isolate the fat in the abdomen (for men) by doing cruches or sit-ups?  Or doing lunges for the buttock and thighs (for women) and get rid of the fat there first? 

Well, sorry to disappoint you. In this study, the exercises were mainly done in the lower body- squats, leg press, leg extension and also lat pulldown (for the upper body). 3 sets of 8 reps at 80 percent of 1 rep max on the aboved mentioned exercises were performed. A fourth set to failure was performed straight after.

The lipolysis or fat breakdown in the adipose tissue was in a non specific area - the abdominal region. This was confirmed by the EV's found there.

Perhaps this is an interesting consideration suggesting that our muscles can function like a secretory organ. Like a giant endocrine organ in the body, more than we realize anyway. (Note : thoughts are my own, not from the study).

We are definitely only scratching the surface of understanding how exercise has so many other unknown benefits.

The women in the study did not have as strong an effect compared to the men in the study. Also note that is is a relatively small study with only 32 subjects.

If you are not already doing any strength training, you should. Not only it can increase your bone density, helps with insulin sensitivity, promote better sleep etc, it can also break down your stored fat.

Reference

Burke BI, Ismaeel A, Long DE et al (2024). Extracellular Vesicle Transfer Of miR-1 To Adipose Tissue Modifys Lipolythic Pathways Following Resistance Exercise. JCI Insight. DOI: 10.1172/jci.insight.182589

Best Grip For Strength Training

Pronated (overhand) grip

My son and I were discussing what grips work best while performing strength training exercises that require us to hold weights when we push, pull or carry. Especially also when doing pull-ups. He was really surprised that such a small detail like the orientation of his grip can have dramatic increase in weight lifted or reps done.

The pronated (or overhand grip) is probably the most commonly used when you do a pull-up or do a strict deadlift. While a supinated (or underhand) grip is used when you do a dumbbell curl or a chin-up. 

Alternate (mixed) grip

There is also the mixed (alternated) grip (pictured above) in which one hand is pronated and the other is supinated. A neutral grip is when both palms (or fists) face each other like when doing a hammer curl. A hook grip (pictured below)is often preferred by advanced lifters when using very heavy weights. The thumb is 'hooked' between the bar and wrapping your index and middle fingers around the thumb for a more secure hold.

Hooked grip

I explained to my son when it comes to grip positions, it is all about all about anatomy. Even slight variations in hand positions during a lift will change which muscles you are using. 

Let's look at the dumbbell curl. When you use the supinated grip, your biceps are the prime movers. When you rotate your hands 90 degrees to a neutral grip, the emphasis changes to a different elbow flexor, your brachialis. If you rotate your hands 90 degrres again to a pronated grip, you will target brachioradialis, yet another elbow flexor.

Supinated (underhand) grip

How do you choose between the supinated versus the pronated grip? It usually depends on the exercise. It will be difficult to do the standard deadlift with a supinated grip since it would be more difficult to hold the bar. Other than that, the main difference between the 2 grips will be the slight difference in muscle recuitment.

Similarly doing pull-ups with the pronated grip will target your latissimus dorsi and trapezius more while the supinated grip for chin-ups will involve your biceps more.

From previous experience,  a grip change is often useful for any exercise that you have not had a significant improvement in the last 4-6 weeks. Say you have not been able to increase weight in your bicep curl, try the hammer curl as it will target your brachialis, which is the strongest of the elbow flexors.

A word of caution, do not try to change your grip for the Olympic lifts (if you do them) since they already work best within the rules of the sport.

With other lifts, a small change can get bigger gains.

Still Doing Those Pendulum Exercises For Shoulder Pain?

Quite a few patients who came to our clinic this week had frozen shoulder. Almost all of these patients had been prescribed pendulum exercises (also know as Codman pendulum exercises) by their previous healthcare provider. The intention is to move/ rehabilitate the glenohumeral (or shoulder) joint while not worsening recently injured or operated tissue.

This is done with the patient standing with a slightly bent torso with the affected arm hanging downwards, using the momentum of the torso/ trunk to move the arm without activating the muscles in the shoulder girdle. The arm can be moved side to side, forwards and backwards, or in a circular motion. Codman pendulum exercises are also always  prescribed after shoulder surgery . In fact, they are the mainstay of many shoulder rehabilitation protocols.

However, Cunningham et al (2020) demonstrated that Codman pendulum exercises involved minmial glenohumeral and scapular-thoracic movement. Movement is mainly from the trunk. They may be a safe way to start early movement/ stretching of the upper limb but may be of limited further use in restoring passive shoulder range of motion.

In fact Gurney et al (2016) found that Codman pendulum exercises induced the least muscle contraction in rotator cuff activity when they investigated several tasks, common rehabilitation exercises and ambulation. Wearing and taking off a shirt induced the highest. Even walking produced substantially higher muscle activity than the Codman exercises. 

Of course if the movement is directly generated from the shoulder rather than the trunk as well as performing larger pendulum circles, there will be increased rotator cuff muscles activity.

Personally, in our clinic, I find that teaching patients 3 basic exercises with elastic resistance bands work much better for the shoulder. Intensity, dosage and exercise position will have to be modified dependent on the surgery and condition the patient has. 

I show them the one arm shoulder frontal raise (pictured above), the lateral raise and a simple basic rowing exercise where the shoulder blade is retracted (or pulled back). In fact, the same few exercises and the single arm reverse fly (pictured below) were found to be effective for office workers to perform daily for 10 minutes to reduce neck and shoulder pain (Saterbakken et al, 2020). 

From Saterbakken et al (2020)

You can definitely stop doing those Codman pendulum exercises.

References

Cunningham G, Charbonnier C, Ladermann A et al (2020). Shoulder Motion Analysis During Codman Pendulum Exercises. Arthrosc Sp Med Rehab. 2(4): e339. DOI: 10.1016/j.asmr.2020.04.013

Gurney AB, Mermier C, LaPlante M et al (2016). Shoulder Electromyography Measurements During Activities Of Daily Living And Routine Rehabilitation. Ex J Orthop Sp Phy Ther. 46(5): 375-383. DOI: 10.2519/jospt.2016.6090.

Saterbakken AH, Makrygiannia P, Stien N et al (2020). Dose-response Of Resistance Training For Neck-and Shoulder Pain Relief: A Workplace Intervention Study. BMC Sp Sci Med Rehab. 12:8. DOI: 10.1186/s13102-020-0158-0

When Does Your Body Age The Fastest?

Picture by Steven Gregor from The Guardian

I always thought that age was just a number. How you feel is more important. Definitely being young at heart helps too. Mentioned this to my friend who's in his 60's while cycling this morning and he said that's the problem when you are young at heart. He said that he feels young at heart but the problem is that his heart is not that young.

Newly published research from Stanford University suggest that humans age very quickly in 2 periods, once around age 44 and the other around 60 (Shen et al, 2024).

Researchers in this study collected and analyzed more than 135,000 biological samples from 108 subjects ranging from 25 to 75 years. Cytokines, skin, oral, nasal microbiome, proteins, lipids, bacteria, ribonucleic acid etc were studied. They found that at around 44 years, those studied had a dramatically different mix of molecules than others just a few years younger. This indicates a spike in the risk of a heart attack, faster skin and muscle aging and slower alcohol and caffeine metabolism.

The next period of acclerated aging happened around age 60. More signs of aging for the heart, skin and muscles. Once into the 7th decade, our immune systems are weakened, kidney function reduces and decreased carbohydrate metabolism that can lead to Type II diabetes.

This shows that biological aging is not linear. It depends on our lifestyles primarily and genetics secondarily and how they interact. For many people, the early 40's and 60's tend to align with major life changes. Your children leaving for university, stopping work, downsizing your home etc.These changes may influence your diet, exercise, social exposure and other factors that affect how your bodies work.

Can we slow the biological aging? The researchers suggest adopting healthy lifestyle habits and ditching the bad ones to delay the aging in the 40's and 60's. If you are not yet 40, start paying attention to heart healthy habits, monitoring especially your cholesterol and triglycerides levels. Have a healthy diet, get enough exercise, minimise smoking and sugar.

Research suggests calorie restriction may protect health and longevity by protecting DNA from age related changes. Subjects who ate less calories by an average of 12 percent slow down their rate of aging by 2-3 percent (Waziry et al, 2023).

Bad sleep does not only make you tired, but makes you look old and haggard. Sleeping less than 6 hours each night can add about 15 months to your biological age and speed up the pace of aging (Kusters et al, 2024). Make sure you get enough shut eye.

Steven Gregor from The Guardian

Those who are yet to hit their 60's definitely need to strength train since muscle loss accelerates. Losing 1 to 2 percent of your muscle mass every year causes you to lose your ability to move freely and easily. Your health plummets as a result. A recent study by Da Silva et al (2024) showed that middle aged and older adults who did 12 weeks of progressive strength training delayed or even reversed sarcopenia (age related muscle loss). 

Now you know.

References

Da Silva AC, Mapa V, Ferreira-Junior JB et al (2024). Progressive Strength Training Can Reverse Sarcopenia Stage In Middle-aged And Older Adults Regardless Of Their Genetic Profile. Arch Geron Geriatrics. Vol 117. DOI: 10.1016/j.archger.2023.105182

Kusters CDJ, Klopack ET, Crimmins EM et al (2024). Short Sleep And Insomnia Are Associated With Accelerated Epigenetic Age. Pysch Med. 86(5): p453-462. DOI: 10.1097/PSY.0000000000001243

Shen X, Wang C, Zhou X et al 92024). Nonlinear Dynamics Of Multi-omics Profiles During Human Aging. Nat Aging. DOI: 10.1038/s43587-024-00692-2

Waziry R, Ryan CP, Corcoran DL et al (2023). Effect Of Long-term Caloric Restriction On DNA Methylation Measures Of Biological Aging In Healthy Adults From The CALERIE Trial. Nat Aging. 3(6): p249-257. DOI: 10.1038/s4357-022-00357-y

Can You Prevent Running Injuries?

We have been seeing some runners in our clinic recently. Some seasoned runners, but quite a few new, novice runners. My definition is unless the runners have been training, running and/ or racing for at least 5 years, they are still considered novice runners.

As a runner I would love to run long and hard daily, alas if we do that injury definitely beckons. How do we prevent that from happening? Can we actually prevent running injuries?

I came across an article investigating if it was possible to prevent running injuries. In this particular study (Leppanen et al, 2024), there were 325 participants who were fairly new runners (less than 2 years of running experience) and aged between 18-55 years. Interventions were completed before the actual runs. The runners attended group training twice a week with a physiotherapist for 6 months.

They were divided into 3 training groups, 2 intervention and 1 control group. All 3 groups followed a similar training program and all runners were taught about the basics of running technique. The first intervention group (108 runners) did strength and conditioning exercises for the hip and core. The 2nd group (111 runners) did exercises to strengthen the ankle and foot, while a third control group (106 runners) did static stretching.

Each training session lasted about 30 minutes twice a week with the exercises and difficulty level progressing over the course of 6 months. Each exercise had 4 different versions with different levels of difficulty and intensity. After the training session, the participants ran outdoors for 30-75 minutes. The participants reported all running related injuries each study week using a mobile application.

Results show that the group that focused  on hip and core training sustained the least injuries among the 3 groups. They had 39 percent lower prevalence of all overuse injuries and 52 percent lower prevalence of overuse injuries compared to the control group. 

I was surprised that the  ankle and foot exercise group did not prevent running related injuries compared to the stretching group. The incidence of acute injuries was lower in the control group than ankle and foot exercise group perhaps suggesting that stretching may help prevent acute running injuries. However, do take note that there were a low number of acute running injuries in this study so this observation should be approached with caution.

This study shows that beginner or novice runners injury rates can be significantly reduced by training the hip and core muscles. Overuse injuries can be cut by about half by strengthening this area compared to stretching which has always been traditionally thought to prevent injuries. And it's really easy to do with just body weight and/ or resistance bands.

Come see our physiotherapists at Physio Solutions and Sports Solutions to learn about what stregthening exercises would help prevent running injuries for you.

Reference

Leppanen M, Viiala J, Kaikkonen P et al (2024). Hip And Core Exercise Program Prevents Running-related Overuse Injuries In Adult Novice Recreational Runners: A Three-arm Randomised Controlled Trial (Run RCT). BJSM. 58: 722-732. DOI: 10.1136/bjsports-2023-107926.

Are Good Athletes Born Or Made?

Unleash the ROAR

I brought my son to football practice earlier today and noticed that some kids were really athletic, a lot quicker and stronger than most of the children of the same age. Of course some were not so. 

Which begets the question of whether good athletes are born with physical gifts or can hard work trump talent?

Here is what a recently published study (Silventoinen et al , 2024) says. This really interesting study involving 198 twins (6-18 years old) used 15 tests to assess for genetic contribution or environmental contributions. In short, the twins completed a battery of tests to analyze whether it is just talent or training that made them good or not so good athletes. Genes versus environment. 

40 percent (78) of the twins were monozygotic (or identical twins), sharing the same DNA. The rest were fraternal, meaning they share about half their DNA. This would mean that if the results of a certain test are more similar within identical twins than fraternal twins then that suggests a larger genetic influence.

The results (below) show that genes played a big role in the results. Between 52-79 percent of your flexibility, power and strength is determined by your genes. Thank your mum and dad for those of you blessed in those areas. I will definitely thank mine for what they gave me.

Picture from Silventoinen et al, 2024

See the figure above, 52 percent in the standing long jump, and a whopping 79 percent for sit and reach showing that the girls performing better than boys in flexibility. The boys performed better than girls in cardiorespiratory endurance and muscular strength. Most of the tests actually showed modest to moderate genetic correlations. 

The 3 tests that were most correlated with the rest of the tests were push-ups, standing long jump (standing broad jump for us Singaporeans) and the Beep Test. Need a simple and quick way of assessing someone's overall fitness, these 3 are the easiest. Perhaps our schools' DSA, Singapore Armed Forces and sports talent ID department should take note when assessing talent.

What about the role of the environment? We need to consider 2 components here. Shared environmental factors, like the area you grew up in, socioeconomic status, opportunities to play sports etc. There are also unique environmental factors, which reflect your own path through life. Whether you joined a sports team, broke your leg /arm or had a great physical education teacher that believed in/ motivated you.

The effects of shared environmental factors appear to be negligible in this study. This is in contrast to earlier published data. So this study's analyses focused on genetic and unique environmental factors.

From my previous readings, work and experience, I would have thought running fast (sprinting) and explosive power (jumps) were 'gifts' from your parents more so than endurance. You may have heard the saying that sprinters are born while endurance runners are made. You may also know a runner that trained loads before becoming a great marathon runner. 

The results in this study do not totally back those assumptions since standing long (or broad) jump (the best measure of explosive power in the tests) had the lowest genetic contribution. But that may be the difference between 2 facets of talent : untrained performance levels and trainability. 

The standing long jump performance may show the explosive properties in their muscles, but it does not reflect a determined and serious effort to train.

Similarly, the 12 min run results do not tell what happens when you clock 100 km of training a week. They are all estimates of 'starting points' but will not tell us how much, with sufficient hard (and smart) work, where we might end up. 

In 2001while representing Singapore

A physiotherapist that treated me after I had stress fractures in both my shins (when I was 20) told me that I would not become a good triathlete. Happy to prove that person wrong later (pictured above with Dimitry Gagg, 1999 World Triathlon Champion And Daniel Lee, 2006 Asian Games Silver medalist) and doubly so when I overheard that same physiotherapist telling another colleague that our physiotherapy department had athletes too after I joined them.

You may be blessed with the best genes, but if you do not train smart and hard enough, there will be others with less talent who will be able to be better than you because they trained smarter and harder.

Some of those ideas are not solely my own. They are discussed in detail by David Epstein in his 2013 book The Sports Gene. 

Whatever genes you have, remember to thank your parents.

Reference

Silventoinen K, Maia J, Sillanpaa E et al (2024). Genetic Regulation Of Physical Fitness In Children: A Twin Study Of 15 Tests From Eurofit And Fitness gram Test Betteries. Med Sci Sp Ex. DOI: 10.1249/MSS.0000000000003496

Is Hyrox Just A Fad?

ST 240824

Hyrox is the newest brand of fitness trend currently sweeping Singapore and the world, it seems.

I do not have an Instagram account, but my wife and colleagues tell me that their IG feed had been flooded with friends dripping with sweat as they did lunges with 24kg sandbags, pushed 152kg sleds (pictured below), did burpee broad jumps etc interspersed with 1 km runs after Singapore hosted a race on 29/6/24. Our local paper, The Straits Times, also featured an article in today's (240824) paper on page A16 (pictured above).

Picture by Kenneth Lee from CNA

Hyrox cofounder and CEO Christian Toetzke wanted to create a sport with broader appeal that could bring mass participation to the gym and running space. He partnered Moritz Furste, previous Olympic gold medalist in field hockey to start their version of exercise. The special 'ingredient' is its mix of 8 movements requiring strength, power and endurance which requires you to push, pull, run, carry and throw. Exercises that could be assessed quickly by officials on the course were chosen since the idea was to hold events with large waves of competitors.

The exercises need to be relatively safe to do under fatigue and mustn't be more difficult for women than men. Hence, box jumps were taken out (for safety) and monkey bars too (more difficult for women). And so, Hyrox was 'born' in 2017 with 8 exercises and a total of 8 km of running.

The first ever Hyrox event was held in Germany with 650 participants in November 2017. Nearly 7 years later, Hyrox is on course to host 45 events for 425,000 participants in 5 continents this year (according to the company's statistics). Singapore's event on June 29th this year drew 6,500 participants, up from 3,500 last October. Singapore will be hosting another event next week on 1/9/24. More than 70 percent of the 6,500 participants in Singapore were millennials.

My wife who goes to UBX at Holland Village tells me that it helps that participants are doing the same exercises together. That strong community element definitely helps when the chips are down and helps with training adherence. The friendships made provide a sense of belonging especially for some people who have never participated in team sports before so this gives them a chance to experience camaraderie and accountability. For Hyrox, this sense of community is global since the race follows an identical format anywhere it is organized.

Gym owners and others in the fitness industry may feel all too familar with the hype around Hyrox after previous flavors of the month have come and gone. Perhaps some gym owners are wary after a recent spate of gym closures although the Hyrox Singapore organizer said that its standardized and accessible nature sets it apart.

I have not taken part in any Hyrox event, but I have done all the different exercises before, albeit not all at once. I will say that Hyrox will definitely help strength and endurance. Unlike the higher intensity CrossFit programmes which can be technically difficult for beginners and thus sets a higher bar for entry, Hyrox fits well in the group exercise spectrum. It also allows one to gauge your own progress.

Critics (not me) have mocked such fitness events/ trends and wondered why anyone would pay to do exercises that could be performed elsewhere for free. One of my patients said with humour that he paid almost $200 to 'torture' himself with friends. Some patients that I asked also said they started because of a 'mid-life' crisis.

One can call Hyrox a fad especially if they do not see the appeal. I am just happy people are getting off their couches and desks to start any form of physical activity to improve their health. Especially when Singapore's young adults' diets and physical activities in Singapore did not comply with international health guidelines (Leu et al, 2023).

81.8 percent of the surveyed participants did not meet World Health Organization requirements of at least 150 minutes of moderate intensity aerobic exercise or 75 minutes of vigorous intensity exercise and muscle strengthening exercises at least twice a week. 

Most of those surveyed said their exercises were walking to public transport stations and while looking for food. One subject even said that the weekend is the only time to like just "collapse".

Hyrox is definitely trendy and seems glamorous now that people love to post about it on social media, which is also contributing to its popularity. I am just glad Singaporeans are more active in whatever form of exercise they choose. Plus, if they overdo it and get injured they can come see us in our clinics.

Reference

Leu J, Rebello SA, Sargent GM et al (2023). Hard Work, Long Hours, And Singaporean Young Adults' Health - A Qualitative Study. Frontiers Pub Health. Vol 11, 12th June. DOI: 10.3389/fpubh.2023.1082581.

May The (Knee) Forces be With You

Picture from Hart et al, 2022

We were discussing the knee joint in our clinic this past week. Meaning ALL the conditions that can cause pain in the knee. Patellofemoral joint pain, patella tendinopathy, MCL, ACL injuries, fat pad irritation, torn meniscus etc. 

In order to understand knee joint injuries, we need to know what can increase load or amplify forces in the knee joint. An increase in joint forces can increase symptoms when one has patellofemoral pain (PFP) so it will be most helpful to know what activities may influence patellofemoral joint reaction forces (PFJRF).

Picture from Dr JT Andrish

So happened that I came across an article explaining how PFJRF compares across different activities and interventions.

intercondylar notch

PFJRF is created by tension (or forces) in the quadriceps and patella tendon which moves the patella into the intercondylar (pictured above) surface (of the femur). It can increase due to greater quadriceps muscle force or when there is an increase in knee flexion (or knee bending).

The article (systematic review) examined PFJFR in daily activities, exercises, interventions (treatment). It also compares healthy individuals to those with PFP or osteoarthritis (OA).

A total of 71 articles were included in the systematic review. Approximate PFJRF for healthy individuals during various activities are pictured below where BW = body weight. 

Knee joint forces in healthy individuals

As you can see, activities that involve greater knee flexion or greater external load resulted in higher PFJRF. For example a deep squat with a heavy weight.

An increase in knee flexion can increase the contact area (in the intercondylar area) and may therefore reduce patellofemoral contact pressure. The authors felt this would be the case in a knee that is "normally aligned". However, certain movements during loading such as increased hip adduction (pictured below) and/ or internal rotation may reduce contact area and increase contact pressure.

Increase in hip adduction in picture A

The authors reported that there were no discernible differences in peak PFJRF during daily activities between healthy individuals and those with PFP/ OA.

There are 3 options if you have knee pain and we need to reduce PFJRF. Reduce knee flexion/ bending during loading. Reduce external load. Reduce hip adduction/ internal rotation during loading.

So if you are weight training by doing a squat and your knee hurts. You can squat less (70-80 degrees) and / or using a lighter weight. Preferably with less hip adduction too. 

In running we can apply this by increasing step rate/ cadence to reduce patellofemoral load. Smaller, quicker steps reduces knee flexion and hip adduction during the stance phase of running. Or better still make your gluteus medius, hamstrings and calf muscle a lot stronger.

Note that the goal is to reduce load only when symptoms are present and the knee is irritated. You can gradually increase load again when able. For other clinicians and physiotherapists reading this, a progressive approach is needed and utimately it will be your patient symptoms and goals that will guide you.

Do note that the exact link between PFJRF and knee pain is complex and the lack of difference between those healthy inviduals without knee pain and those with PFP/ OA draws attention to this. 

The authors also mentioned that when articular cartilage is underloaded (not enough load), it may be an issue too. 

Reference

Hart HF, Patterson BE, Crossley KM et al (2022). May The Force Be With You: Understanding How Patellofemoral Joint Reaction Force Compares Across Different Activities And Physical Interventions- A Systematic Review And Meta-Analysis. BJSM. 56: 521-530. DOI: 10.1136/bjsports-2021-104686

Bioelectrical Impedance To Measure Body Fat?

BIA from Weightology

Last week, my helper's cousin asked me for suggestions with regards to measuring her body fat levels. Her cousin was about to sign up with a personal trainer  and he wanted to measure her body fat levels before they started. Of course that came with a cost before the training even started.

Picture from Bodybuilding Wizard 

I told my helper the most accurate method would be hydrostatic underwater weighing (or underwater weighing) which was very dificult to do (pictured above). I only did it as a physiotherapy student while doing the exercise physiology module in year 1. Next best was using callipers to measure the sum of 7 skinfolds (pictured below).

However, my helper said the trainer suggested using bioelectrical impedance analysis (BIA) to measure her cousin's body fat levels.

Bioelectrical impedance is a popular way to measure body fat levels. It is also practical  as it takes a relatively short analysis time. It is not invasive at all and it is available commercially at an affordable cost.

BIA measures body composition based on the rate at which an electric currrent travels through your body. Body fat (adipose tissue) causes greater resistance (impedance) than lean mass (muscle) and slows the rate of electric current traveling through the body. Based on that rate and your height, gender and weight, your body fat levels, fat free mass etc are calculated.

However, BIA is not accurate at all for determining body fat levels. A recently (Aug 2024) published study showed that all 3 BIA devices tested significantly underestimated body fat levels.

28 firefighters were evaluated using 3 BIA devices. A multifrequency BIA hand-to-foot device, a single frequency BIA foot scale and a single frequency handheld BIA device. These were measured against dual x-ray absorptiometry (DEXA) for comparison (Jagim et al, 2024).

All 3 BIA devices significantly under measured body fat levels. Errors ranged between 4 to 5.5 percent when compared to the DEXA scans. Despite it's ease of use and practicability, BIA should not be used to assess body fat levels.

If you do or if your trainer insists on using BIA, bear in mind that they are not accurate, but you can still use them to track changes over time. 

Picture from Topendsports

I would suggest using the sum of 7 skinfolds if you want to track your body fat levels rather than BIA as it would be more accurate. The callipers are also not expensive. The following locations are commonly used. The abdomen, pectoral area, mid axilla, subscapular area, quadriceps, suprailiac area and the triceps.

There is more to health than your body fat percentage or weight. These measurements are not a reflection of your general well being. 

Reference

Jagim AR, Luedke J, Erickson JL et al (2024). Validation Of Bioelectrical Impedance Devices For The Determination Of Body Fat Percentage In Firefighters. J Strength Cond Resc. 38(8): e448-453. DOI: JSC.0000000000004809. PMID: 39072665

Rock Climbing Injuries

Zi Yun competing

This is the second time rock climbing is contested at the Olympics since its debut at the 2021 Tokyo Olympics. For those who are not familiar, the three climbing disciplines include lead climbing, speed climbing, and bouldering. They are designed to challenge endurance, speed, and power, respectively.

Climbing gyms in Singapore has more than doubled since 2018, with nearly 40 climbing facilities now available. Contrary to popular belief, climbing is not only a physical sport that emphasizes on strength and technique, but also a test of mental tenacity. It demands problem solving skills, focus, composure, and resilience, whether you are a serious climber or just climbing recreationally. 

In a study on 436 climbers, 77.1% of the injuries affected the upper extremities, 17.7% lower extremities and 5.2% other body regions (Lutter et al, 2020). The most frequent injuries were finger pully injuries and finger tenosynovitis.

Bouldering has caused more acute injuries than rope-protected climbing. There are more knee injuries and shoulder dislocations. Young climbers were found to have more finger growth plate injuries.

There were also higher incidences of upper extremity injuries in bouldering (Kovářová et al, 2024). especially to the hands, fingers, wrists, and elbows.

Lead climbers had a broader range of injuries, including head, shoulder, and foot related injuries.

Traditional climbing (done outdoors in the natural environment) often results in more severe injuries involving long falls. Interestingly it's not personal characteristics (gender, age, weight or height) but human factors like concentration and fatigue that had significant impact on the number and severity of injuries  (Kovářová et al, 2024).

Just like other sports, if you increase your climbing intensity too quickly, have large muscle strength imbalances and rest insufficiently, you have a much higher chance of sustaining an injury. Many climbers do not rest or stop due to a fear of losing strength, leading to a decline in performance.

According to published studies, only 36% of injured climbers seek medical help. While some injuries were unavoidable, many were caused by the climbing culture of training with injuries and disregarding the need for recovery. This issue is compounded by insufficient knowledge on training and recovery, and ignorance. Many climbers also take injuries lightly and try to return to climbing too quickly.

However, you do not always have to completely stay off the wall or away from climbing related activities to recover. Modifications and other compensatory mechanisms can be done to your climbing session to achieve the same results. 

In order to attain climbing longevity, climbers need to be aware of the risks they are taking  and maintain appropriate recovery measures. If you are injured and unsure on how to go about your training, do come and see us for a thorough assessment, we will plan your treatment according to your concerns and goals. We promise to do our best to get you back strong on the wall as soon as possible.

*This week's post is written by Zi Yun (paper cloud), one of our new physiotherapists. She is a super rock climber. She wins most if not all the local rock climbing competitions and more. Having started climbing seven years ago, she has encountered many climbing related injuries and can defintely treat you if you are injured. Above pictures by Zi Yun.

References

Kovářová M, Pyszko P, and Kikalová K. (2024). Analyzing Injury Patterns in Climbing: A Comprehensive Study Of Risk factors. Sports, 12(2), 61. DOI: 10.3390/sports12020061

Lutter C, Tischer T, Hotfield T et al (2020). Current Trends In Sport Climbing Injuries After The Inclusion Into The Olympic Program. Analysis of 633 Injuries within the years 2017/18. Mus, Ligs Tendons J. 10(2), 201. DOI: 10.32098/mltj.02.2020.06

Science, Pseudoscience And Superstition At The Olympics

Picture by Greg Martin

If you stayed up to watch the opening ceremony of the XXXIII Olympic Games in Paris, you would have witnessed the historic boat parade down the River Seine. This display was the first time the Olympic opening ceremony was staged outside the main stadium, making it the biggest ever launch for the greatest sports show on earth.

Alas, that gamble made 300,000 people who lined the river banks very wet from the torrential rain as the athletes went past the Effiel Towel, the Lourve and the Notre Dame Cathedral.

Other than watching the games, I will be watching the athletes who continue to blend proven, unproven and even disproven strategies at the games. 

It may have all started in Beijing, 2008 when Kinesio Taping donated more than 50,000 rolls of kinesio tape to athletes and sports teams at that Olympic games. You would see kinesio tape on body parts of athletes in many televised sports especially beach volleyball (pictured below) and track and field (pictured above). That exposure catapulted Kinesio Taping to the big time. 

Many subsequent studies showed no evidence of 'improved lymphatic drainage', no decreased risk of injuries etc. But most if not all of the reviews and meta-analyses were done by researchers not trained in the correct taping techniques. Some researchers outright rejected offers to show them the proper taping techniques. 

Of course there were many research papers showing Kinesio taping works if done correctly. These were conducted by researchers who have learnt the correct taping techniques.

In 2016, Michael Phelps 'poisoned' the pseudoscience well with large purple bruises across his back and shoulders while adding 5 gold medals to his haul. Cupping therapy was the next big thing for recovery as demonstrated by Phelps, who later launched his own cupping device in 2023. 

Also popular are cold (ice) water immersions for recovery. Mo Farah, the British Olympic gold medalist who famously won 4 gold medals at the 2012 and 2016 Olympics in the 5,000 and 10,000 metres made cold water immersions a regular part of his recovery as he was convinced that it would reduce inflammation. The opposite was true since cold water immersions after hard exercise suppressed signaling pathways associated with recovery for several days. At best, it is just perceived benefits on muscle soreness, although it does help reduce pain.

Other than pseudoscience (termed by Novella, 2016), there are are undertones of superstition too. If you watch Rafa Nadal's  rituals (above) like how he places his bottles with labels facing the sides he plays and always letting his opponent cross the net first during changovers etc.

Sha'carri Richardson, who won the 100m at last year's world track and field championships always prays and acknowledges with her fingers before the start (pictured above).

We know that rituals and superstitions do not work to make one run faster, jump higher or throw further. They may however, give athletes a form of control and subsequently confer a performance advantage. 

Having worked with athletes and going to 2 Olympics in the past, I can say that elite athletes are a stubborn lot. They have immense determination and will not quit even when sick or injured. I will not mention some of Team Singapore athlete's rituals and superstitions.

Definitely true that science, pseudoscience and superstitution are connected at the highest sporting levels. Pseudoscience is lucrative and thriving as it extends into society with tik tok health experts/ gurus, fitness influencers and snake oil salesmen. They will not have a nuanced understanding of the science nor their audiences' best interests at heart. 

Of course there are also athletes who are also driven by data, power output stroke rate, stride length and other metrics that can be recorded with modern technology. 

Our clinics will try, through our practice, readings and treating our patients, to sort out the science from the pseudoscience and we'll let you know.

Let's watch the Olympic Games!

Reference

Novella S. (2016). Cupping- Olympic Pseudoscience. Science-Based Medicine (August 10). Online at https://sciencebasedmedicine.org/cupping-olympic-pseudoscience/

Sural Nerve Pain

I recently saw a patient who had pain resulting from her sural nerve. Let me go through a little about the anatomy and location of the sural nerve.

The sural nerve sits superficially below the skin's surface at the back of the calf. It is formed from the medial sural cutaneous nerve and the lateral sural cutaneous nerve.

It is usually between the medial and lateral gastrocnemius (calf) muscles, running parallel to the saphaenous vein. At the ankle, the sural nerve 'wraps' around the outer ankle near the peroneal tendons before it splits into 2 branches at the level of the 5th metatarsal.

The sural nerve is a sensory nerve, it provides sensation to the lower one third of the outer leg, outer heel and foot. It's main function is to let you feel sensation on your skin. It can also detect your foot position, temperature, pain, vibration and touch.

Since the sural nerve is positioned so superficially, it can be irritated from any muscular of fascial entrapment and sometimes from a simple outer ankle sprain. It can also be 'over stretched' from sitting too long with the foot pointed down and out or after a long driving trip. When the nerve is irritated, it can result in burning pain in the lateral shin or foot (known as sural neuritis).

A common cause of sural nerve pain is after a sprained ankle when the foot is rolled outwards quickly. This can over stretch the sural nerve causing pain over the area it covers. 

I also remember a previous patient who had very tight fitting ballet shoes with a strap over the outside ankle which compressed her sural nerve.

A lot of metal work

Another patient had irritation from her metal implants (pictured above) after orthopaedic surgery from fracturing both tibia and fibular. 

Patients may describe their pain being constantly present, made worse with activity but present even at rest. This constant pain at rest is what differentiates the symptoms of sural nerve pain from other conditions, where pain normally eases with rest.

I usually do a modified Straight Leg Raise tension test to compare both sides. The patient will tell you the affected side will worsen their symptoms. It may also be tender to touch along the path of the nerve.

Appropriate manual therapy will easily relieve and treat sural nerve pain. Mobilizing the ankle, stretching the nerve and of course treating the fascia that is putting tension on the sural nerve.