Sunday, March 17, 2024

Knees Out Or Knees In When You Squat?

Out (left) versus in (right)
Here is a post that will perhaps change the way you squat. It depends on what area you want to work on. Previously, some physiotherapists and personal trainers hated me for saying that you can let your knees move forward when you squat. Most, if not all, personal trainers teach their clients that it is taboo to let your knees move forward while squatting, They get their patients or clients to stick their bums out instead.

Those same physiotherapists and trainers may be aghast if I suggest squatting with your knees pointing in (gasp!) or pointing out. 

The author recruited 14 males and 18 females for the squatting study (Chiu et al, 2024). Using 3D motion cameras and force platform meausures, normal squats required hip extensor, adductor and lateral rotator net joint movements (NJM). The gluteus maximus muscle exerts hip extensor and lateral rotator moments. The adductor magnus (pictured below) exerts hip extensor and adductor moments. Both muscles combine meet hip demands contributing to hip extensor NJM.
When squatting with hip in lateral rotation (feet pointing outwards), there was smaller hip extensor, lateral rotator and larger hip adductor NJM than normal squats. This loads the adductor magnus.
Medial rotation squats (feet pointing inwards) had smaller hip extensor and adductor NJM and larger hip lateral rotator NJM than normal squats. This loads the gluteus maximus.

Likewise if you stick your bum out when you squat, you are engaging more of your bum (Gluteus Maximus) muscles. If your let your knees move forward when you squat, you are definitely using your thigh (quadricep) muscles. If you want to increase hip adductor (adductor magnus) work, squat with your knees out. It just depends on what muscles you want to engage or work harder. Try it yourself.

There is definitely no real need to restrict forward knee movement when you squat. It's one of the biggest training myths ever. You can add squatting with your knees pointing inwards and outwards to the list of myths as well. 

This information should 'challenge' some old school "perfect squat" gurus.

Reference

Chiu LZF. "Knees Out" Or "Knees In"? Volitional Lateral Versus Medial Hip Rotation During Barbell Squats. J Str Cond Res. 38(3): 435-443. DOI: 10.1519/JSC.0000000000004655.

Sunday, March 10, 2024

The Most Efficient Way to Run (According To Science)

I came across a recently published (6/3/24) systematic review on what is the most efficient way to run, according to science (Van Hooren et al, 2024). 51 studies were reviewed in this systematic review.

It's a long review paper, key findings in the pictures attached. Let me highlight some of the important points. The paper does lend some support for increasing your cadence or step rate to improve running economy as this increases leg stiffness and reduces vertical oscillation. When you watch some runners run, you can see that they tend to 'bounce' up and down while running, that is vertical oscillation. 

Initial Contact
At Initial Contact (or foot flat) phase, higher cadence (step rate) may be associated with a lower energy cost of running. Decreased trunk flexion and knee flexion during swing phase may also be associated with better running economy.

Mid stance 

During Mid Stance phase, decreased trunk flexion and reduced vertical oscillation may be associated with improved running economy. Increased vertical and leg stiffness may also be associated with lower energy cost.

Toe off

At the Toe Off phase, if trunk flexion and ankle plantarflexion are reduced, running economy may be improved.

Those metioned above are just he key findings which I have summarised. However, there are many more details and applications in the paper itself. You can read the free paper here.

I have previously written before on running cadence and running form if you wish to read further.

Reference

Van Hooren B, Jukic I, Cox M et al (2024). The Relationship Betwen Running Biomechanics And Runnng Economy : A Systematic Review And Meta-Analysis Of Observational Studies. Sports Med. DOI: 10.1007/s40279-024-01997-3

Summary


Can Your Sports Bra Restrict Your Breathing?

Excellent post by Aized on whether your sports bra can restrict your breathing when you exercise in our Physio Solutions blog. Have a read here.

Sunday, March 3, 2024

What Time Do You Eat Dinner?

Picture from Yahoo
My patients are usually shocked when I tell them that I normally have dinner by 6 pm. My family usually has dinner at around 6 pm (plus minus 10 minutes). 

I do not know for sure what time most Singaporeans have dinner, but 3 in 5 Americans normally have dinner after 9 pm (Farsijani et al, 2023).

Our bodies are much better at digesting and processing nutrients during the day and powering down and resting at night. So eating close to bedtime can cause a whole range of issues. There are studies linking late night eating to heartburn while others demonstrate how it can affect your sleep quality. As you know, Singaporeans already do not have enough sleep

There are also recent studies that link late night eating with increases in body weight and the risk of diabetes. When you limit your calorie intake 3 to 4 hours before bedtime, it can help with blood sugar control and weight management (Vujovic et al, 2022). This is likely linked to the circadian clock which reduces the energy we use after a meal in the evening.

Again in America, early dinners seem to gaining popularity among Americans of all ages. 5 pm is the fastest growing time slot for dinner reservations while bookings for 8 and 9 pm are falling.

Surprisingly, many Gen z-ers are embracing this early bird lifestyle. Americans between the ages of 15 to 34 are getting more sleep each night (9 hrs 12 mins) over the last decade if you look at data from the U.S. Bureau of Labor Statistics. 

I am surprised to say that the youths (Americans at least) today are more well rested than I thought, possibly because these youths are ditching late night drinks in favor of . Less daily commuting in this era of remote work enables them to sleep in, while an increase in venture capital for sleep tech definitely helps too.

When you limit your calorie intake 3 to 4 hours before bedtime, it can help with blood sugar control and weight management (Vujovic et al, 2022). This is likely linked to the circadian clock which reduces the energy we use after a meal in the evening.

Eat early, sleep early that seems to be what the research is telling us to ensure good health . 


References

Farsijani S, Mao Z, Cauley JA et al (2023). Comprehensive Assessment Of Chrononutrition Behavirs Among Nationally Representative Adults: Insights From National Health And Nutrition Examination Survey (NHANES) Data. Clin Nutri. 42(10): 1910-19-21. DOI: 10.1016:/j.clnu.2023.08.007

Vujovic N, Piron MJ, Qian J et al, (2022). Late Isocaloric Eating Increases Hunger, Decreases Energy Expenditure, And Modifies Metabolic Pathways In Adults With Overweight And Obesity. J Clin and Transl Report. 34(10): 1486-1498. DOI: 10.1016/j.cmet.2022.09.007

Sunday, February 25, 2024

Ulnar Nerve Entrapment

Left ulnar nerve
My patient who is a Team Singapore cyclist came in with a case of ulnar nerve entrapment on Friday. Ulnar nerve entrapment* is the second most common nerve condition happening in the upper limb after carpal tunnel syndrome.

The ulnar nerve arises from the brachial plexus at C8-T1 and travels down the inner part of the upper arm through the arcade of struthers (pictured below).

At the elbow, the ulnar nerve travels just behind the bony part on the inner part of the elbow. This is also know as the "funny bone" when you can get sensations of pins and needles after bumping the area. 

Picture by Conor Jones
As the ulnar nerve crosses the elbow, it passes through a bony tunnel and up to 2 other potential points for blockage making it vulnerable to pressure or stretching. Prolonged periods of sleeping with the elbow bent can also cause over stretching of the nerve. My patient hurt her ulnar nerve after riding for a few hours in a new position after changing her handlebars. Riding for a few hours on bumpy roads did not help. She had also fractured both her clavicles (R followed by L in the last few months). This is also known as the cubital tunnel syndrome.

The ulnar nerve supplies the sensation and muscles to the 5th and half the ring finger. Symptoms are related to degree of irritation of the nerve. They start off intermittent in nature and may only come on at night after the nerve has been stretched for a longer time. 

Pins and needles, aching or tingling in the little and/ or ring finger will be the common symptoms. This is what my patient felt. If the irritation persists, the symptoms may become constant and progress to numbness in the 5th and/ or ring finger and ultimately weakness in the hand.

As the ulnar nerve exits the bony tunnel, it goes into the flexor carpi ulnaris muscle. Follwing that at the wrist, it travels superficially to the flexor retinaculum and passes into Guyon's canal.  

R wrist
Guyon's canal is formed by 4 borders (pictured above). The roof is the palmar carpal ligament, the floor being the transverse carpal ligament, the ulnar (inner) border is the pisiform and the radial (outer) border is hook of hamate.  If the nerve is irritated at the wrist it is known as Guyon's canal syndrome.

Picture from Medical Art Library
The flexor carpi ulnaris and inner half of flexor digitorum profundus muscles are innervated by the ulnar nerve and the hypothenar muscles (pictured above).

Knowing the exact site of nerve irritation during an accurate clinical examination will help decide what needs to be done for treatment. Some doctors send their patients to do a nerve conduction test, but I personally find that an upper limb tension test (with radial nerve bias) done correctly does a much better job. Others may do ultrasound imaging to help diagnosis. Do not confuse it with thoracic outlet syndrome.

Just remember not to have a steroid/ cortisone injection.

*Ulnar nerve entrapments are commonly seen in cyclists, golfers, weightlifters and construction workers.


References

Kong G, Brutus JP, Vo TT et al (2023). The Prevalence Of Double- And Multiple Crush Syndromes In Patients Surgically Treated For Peripheral Nerve Compression In The Upper Limb. Hand Surg Rehabil. 42(6): 475-481. DOI: 10.1016/j.hansur.2023.09.002

Raut P, Jones N, Raad M et al (2022). Common Peripheral Nerve Entrapments In The Upper Limb. Br J Hosp Med. 83(10): 1-11. DOI: 10.12968/hmed.2022.011

Sunday, February 18, 2024

Does Strength Training Help Runners Prevent Injuries?

Last week I wrote about how we have been told for years that the key to staying pain and injury free can be found somewhere close to your belly button. That got most people obsessed with strengthening their core or abdominal muscles. Which you know by now that it is not totally true.

Likewise many runners also believe that strength training like squats, deadlifts and other power lifting staples can make you faster, more powerful, more efficient and less injury prone.

Ever wonder what sort of strength training do top runners do? Blagrove et al (2020) did a survey of 667 distance runners (local to internationally competitive) about their strength and conditioning exercises. Most common was stretching (86.2 percent), core training (70.2 percent),  weight training (62.5 percent) and plyometric training (35.1 percent).

What was most interesting was the motivation these runners reported for the strength and conditioning routines. There were 2 main answers. Reducing injury risk (63.1 percent) and improving performance (53.8 percent). There was no relationship found between strength and conditioning training and injury history in runners. The key predictor of injury was training volume. The more you ran, the more likely you would get injured.

 In another systematic review published last month, Blagrove and colleagues (Wu et al, 2024) found that strength and conditioning does not appear to reduce the risk and rate of running related injuries (RRI). Please bear in mind that Richard Blagrove has authored a book Strength And Conditioning For Endurance Running and worked with many elite runners on their strength routines in case you think he is against strength training.

Their systematic review consist of 9 articles with 1,904 runners. Exercises done include lunges, squats, plyometric hops/ jumps, core routines, foot strengthening etc. Given the wide variety of of regimens, there was NO significant benefit for the exercise groups compared to the control group in injury risk (runners who got injured during the studies) or injury rate (how many injuries they suffered for a given amount of running).

For now that is the state and level of evidence we have with regards to strength and conditioning exercises preventing RRI. Strange that this approach (strength and conditioning) has robust evidence that it works in soocer, but not in running.

What was most interesting is that 3 of the studies that produced the lowest injury risk also happened to be the 3 studies where the exercise routines was supervised rather than assigned to be performed at home. Research shows that people tend to get bigger gains when they have a spotter or trainer looking on. Similarly, runners tend to run their intervals faster and more consistently when the coach is standing on the track with a stopwatch in hand. It could also be the only way to ensure people actually do the strength and conditioning exercises. 

I can remember many patients who come for a follow up visit claiming they have done their exercises diligently but cannot do it when asked to demonstrate it. A strengthening exercise can only work if you actually do it and have done it correctly.

Take home message? If the study (Wu et al, 2024) is true, strength training or other forms of exercise may not lower your risk of getting injured while running. Even though the logic is sound and evidence from other sports is positive. However, there is very good evidence that strength training improves running economy and boosts long term health. It would be nice to get injury prevention as an added bonus but it still sounds like a good deal to me. So I will still strength train.

Researchers need to have more robust studies that include supervised interventions to investigate further.


References

Blagrove RC, Brown N, Howatson G et al (2020). Strength And Conditioning Habits Of Competitive Distance Runners. J Stren Cond Res. 349(5): 1392-1399. DOI: 10.1519/JSC.0000000000002261.

Wu H, Brooke-Wavell K, Fong DTP et al (2024). Do Exercise-Based Prevention Programs Reduce Injury In Endurance Runners? A Systematic Review And Meta-Analysis. Sports Med. DOI: 10.1007/s40279-024-01993-7.

Monday, February 12, 2024

Weak Core, Tight Hamstrings And Weak Glutes?

Hope you have been enjoying your Chinese New Year break!

A patient came in this past week with low back pain and was told by another physiotherapist that she had a weak corehamstrings and weak glutes and that was why her back hurts.

Now, I do not agree with that. Actually studies show that back extensor strength is more important than  flexor (abdominal) strength when it comes to low back pain (Lee et al, 1999).

Like I wrote previously, the idea for the need of a strong core was first introduced by Paul Hodges (Hodges and Richardson, 1998) when he published his article on the Transverse Abdominis (TA) muscle. His research compared the timing of TA and Multifidus in people with low back pain (LBP) for 18 months or more against healthy subjects with no LBP.

Hodges suggested that the TA was likely to be the main cause of LBP as it is the most important and deepest muscle in the abdomen. It looks and works like a corset to stabilise the back.

This article made the allied healthcare/ fitness industry conclude that the TA was a trunk stabilising muscle that was very important to strengthen for those with LBP. Patients who had LBP had weaknesses in their TA which led to instability in the spine.

Similarly with 'tight' hamstrings (Halbertsma et al 2001) and weak glutes. This female patient of mine can deadlift 90 kg. Her glutes are not weak nor are her hamstrings tight. 

You can put all those myths to rest. Your low back pain is not caused by a weak core, tight hamstrings nor weak glutes. Stengthening your back extensors will be a much better option than the previously mentioned.


References

Halbertsma JP, Goeken LN, Hof AL et al (2001). Extensibility And Stiffness Of The Hamstrings in Patients With Nonspecific Low Back Pain. Arch Phys Med Reh. 82(2): 232-238. DOI: 10.1053/apmr.2001.19876

Hodges PA and Richardson CA (1998). Delayed Postural Contraction Of Transversus Abdominis In Low Back Pain Associated With Movement Of The Lower Limb. J Sp Disorders. 11(1): 46-56.

Lee JH, Hoshino Y, Nakamura K et al (1999). Trunk Muscle Weakness As A Risk Factor For Low Back Pain. A 5-year Prospective Study. Spine (Phila Pa 1976). 24(1): 54-57. DOI 10.1097/00007632-199901010-00013