Sunday, March 31, 2024

Even Olympic Athletes Do Not Sleep Well

Thinking of winning even while sleeping
I managed to have an extra bike ride this week due to the Good Friday Public Holiday. If you include my regular Saturday bike ride, I rode 88 km a day on both days. Partly due to the heat, I felt extra tired, and did not sleep as well as I would have liked.

Whether you are an athlete or not you need to sleep. In theory, athletes need to sleep a lot, since sleep can boost performance, protect against injury and even help recovery. I have written before that a lack of sleep can lead to negative consequences. It can affect your mood, cognitive function and physical performance.

Ever wonder if champion athletes are also champion sleepers? Or they sleep just as badly as average athletes?

A recently published paper studied the sleep habits of more than 1600 Olympic and Paralympic USA athletes in the lead up to the 2021 Tokyo Olympics. The athletes filled up a Pittsburg Sleep Quality Index (PSQI) for that study.

The study compared the typical sleep pattern for male versus female athletes, summer versus winter Olympians and team versus individual sports.     

You may be surprised to know that almost 40 percent of athletes were rated as having poor sleep based on their PSQI scores. The scores accounted for how long they typically sleep, how often their sleep is disturbed, how long before they fall asleep and whether sleep medications were taken.

The results were similar to that of Dutch Olympic athletes (41 percent poor sleepers) and Australian Olympic athletes (52 percent poor sleepers).

A goal of the study was to provide what was normal values for athletes training hard compared to the general population on whom the PSQI was first tested. The PSQI has a maximum score of 21, the higher the number indicating a greater number or greater severity of sleep problems. A score of 5 and above classifies you as a poor sleeper. The average among the USA Olympians was 4.3. 

25 percent scored above 6 while 10 percent scored above 8 and 5 percent scored above 10. The top scorer was 16 while the lowest got zero (I am definitely envious)!

Reasons for the poor sleep? An early training session at 6 am will definitely affect sleep. Those athletes traveling across time zones to get to training camps/ races/ competitions will also be affected. If your legs or arms are aching from hard training ( I can testify to that), or if your heart/ mind is racing before a competition , you will not sleep well. That's my personal experience too.

The results do not specify what is happening exactly, but they do suggest that a serious athlete typically scores 5 or 6 on the PSQI, so they are classified as a 'poor sleeper'.

This study by Anderson et al (2024) has more subjects compared to previous similar studies which allows the data to be cetegorized into sub categories. Here is what else was reported. Female athletes had poorer sleep quality (4.7 versus 3.9) than men even though they went to bed earlier.

The female athletes were also less likely to report falling asleep straight away after going to bed. They were also more likely to report using sleep medication. A possibility is the variation in sex hormones across the menstrual cycle which may interfere with sleep, although no mechanism was found in this study. 

Team sports athletes got up earlier and had poorer sleep than individual sport athletes although this was not what previous studies found.. Perhaps a team mate who got up earlier caused the rest of the team to get up earlier as well?

May I boldly suggest that all the sub patterns were confounded by a huge variety of sports in this study. A runner is not equal to a tennis player or swimmer. Competition timings will play a part as well since most marathons are held in the early mornings compared to the later starts in some other sports. Especially those held in the late evenings. 

Defintely sleep is a great untapped frontier. Since 40 percent of Olympic athletes are poor sleepers, imagine one's advantage if you can improve or even master sleep.

Is good sleep "nice to have" rather than "need to have" for achieving sporting excellence? Or you may even argue that sleep may not be that important if all these Olympians are not sleeping well and are good enough still to compete at those lofty levels. 

Personally I do think sleep is important for sporting performance as well as keeping you sane during the day. 

On a side note, I will add that the cost to mental health is significant too, especially for the general population. Sleep problems may increase risk for developing certain mental illnesses like depression and anxiety disorders, as well as result from them. In this age of poor mental health among the young, are they getting enough sleep to begin with?

If you're an athlete, take your sleep habits seriously, but remember that if you still have problems, you are in Olympic level company.


Anderson T, Galan-Lopez N, Taylor L et al (2024).Sleep Quality In Team USA Olympic And Paralympic Athletes. Int J Sp Physiol Perform. 19(4): 383-392. DOI: 10.1123/ijspp.2023-0317

Sunday, March 24, 2024

Just One Set Of Exercises Can Make You Stronger

Leg extension exercise
Doing just one set of exercises can make you stronger even if you are a "non-responder". But you will need to do more sets to get bigger muscles. At least that is what a recent study showed (Lixandrao et a, 2024).

This concept of non-responders were first described in studies done in the 1980s and 1990s. These studies explored the role of genetics in exercise response. 

When a bunch of people were given the same training program, their genes can explain about half the variance in how their fitness improves. Some people did not get fitter at all even after months of training. Note that later studies took the non-responders from a study and had them train harder or a higher volumes, they did get fitter. The studies above focused on aerobic exercise, but this study (Lixandrao et al, 2024) was on strength training. 

The authors had a total of 85 subjects (41 men, 44 women) above the age of 60 and not currently doing any strength training (Lixandrao et al, 2024). The study was designed to see if adding extra sets would turn the non-responder into responders. The subjects were assigned to different strengthening routines with each leg. That eliminates variations that can cloud results of strength training studies.

Note that older adults are usually less responsive to size and strength stimulus of strength training, making non-response more likely.

The exercse program consisted of 2 workouts a week for 10 weeks, Each set consisted between 10-15 reps of single leg knee extension with the weight selected to reach failure in each set. Each subject did 1 set per workout with one leg and 4 sets per workout with the other leg.

Muscle size of the subjects was measured by MRI. As expected, there were many non-responders who did the 1 set routine. 60 percent of the subjects did not gain more than 3.3 percent in the cross section of their quadriceps (this is the minimum threshold for a statisically significant improvement). 

The proportion of non-responders for those who did 4 sets decreased to 19 percent. Yes, you read this correctly, those who responded to only 1 set of training had bigger responses than those who did 4 sets!

Conclusion: Doing more sets lead to greater muscle gain, even among those who do not seem to repond initially.

Note that doing 4 sets of exercises did not produce bigger strength gains than 1 set, which was both surprising and unfair. Previous studies have also shown this in experienced lifters. Doing 5 sets was better than 3 sets, which in turn was better than 1 set for muscle size. However all 3 options were basically the same for muscle strength. 

Stength is a function of muscle size and the (complex) signaling process between brain and muscle. Both do not always go hand in hand.

Among those who responded to 1 set of exercise, only 51 percent got significantly bigger muscle size results from 4 sets. 15 percent actually did worse doing 4 sets. Note that the 1 set and 4 set parts of this study were taking place simultaneously in the same person but different legs. This may suggest that while 4 sets are better than 1 for some people, they really are worse for others.

Take away from this study (Lixandrao et al, 2024)? You can get away with a minimum of 1 set of strength training if your main goal is to get stronger. However, if your main goal is to gain or maintain muscle mass, you will benefit from more sets.

Note that the more interesting take away is this rule is not always true for everyone. Definitely a little annoying if you ask me. My suggestion? If what you have been doing is not working, even if it is suggested by the latest research, you need to try changing it.


Lixandrao ME, Bamman M, Vechin FC et al (2024). Higher Resistance Training Volume Offsets Muscle Hypertropjy Nonresponsiveness In Older Individuals. L Appl Physiol. 136(2): 421-429. DOI: 10.1152/japplphysiol.00670.2023

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.


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.


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


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 . 


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