Sunday, January 29, 2023

Taking Nitric Oxide Supplements?

Picture from NTUC Fairprice 
A patient who does triathlons just asked if he should start taking nitric oxide supplements as his personal trainer said it can help boost his sporting performance. 

What is nitric oxide anyway? Nitric oxide is actually a gas that our body produces on its own. It is a vasodilator as it causes the blood vessels to relax and expand, allowing for greater transmission of blood flow. This helps deliver more oxygen and nutrients to your muscles when you exercise, which can help you perform better and work out longer. 

Since vasodilators help to widen our blood vessels, nitric oxide supplements are also taken to treat heart conditions and erectile dysfunction. As nitric oxide helps improve blood pressure, it may help reduce your risk for heart disease, especially for people who do not exercise regularly. For these people, an increase in L-arginine may promote vasodilation that may not occur without exercise

Nitric oxide production is hindered in people with Type II diabetes, which diminishes the health of their blood vessels. This increases the risk of heart disease and high blood pressure. This may the reason why people with Type II diabetes are told to supplement with nitric oxide supplements.

Here's the catch when you take nitric oxide supplements Nitric oxide supplementation involves the precursor molecules L-arginine and L-citrulline. Precursors are compounds involved in the creation of another compound - nitric oxide in this case.  Nitric oxide supplements provide the body with the building blocks for nitric oxide production.

Nitric oxide supplements cannot contain nitric oxide because it is only available in gas form. Nitric oxide is chemically made in our bodies from L-arginine (an essential amino acid) and this is why all nitric oxide supplements contain L-arginine and L-citrulline. These supplements do not actually contain nitrous oxide, they are hoping that the extra L-arginine and L-citrulline consumed can be converted to nitrous oxide chemically in our tissues.

Note that our bodies usually makes enough L-arginine on its own. L-arginine is found in fish, meat, beans and dairy. Vegetables like beetroot and leafy greens (spinach and arugula) are rich in nitrates and can contribute to higher nitric oxide levels in the body. This is why many studies have studied whether drinking beetroot juice leads to increased performance enhancement in sports.

What exactly can nitric oxide supplements do? Since the supplements are supposed to increase nitric oxide in your body, it can potentially  help heart health, exercise performance and even treating erectile dysfunction. 

While nitric oxide is essential for vasodilation, not all research support claims that L-arginine supplements produce more nitric oxide than normal dietary intake and exercise

Side effects of taking nitric oxide supplements are mostly gastrointestinal issues like vomiting, diarrhoea, dizziness and headaches. More serious side effects are allergic reactions and difficulty breathing.

What does the evidence says? Some research shows improved fitness performance for runnerscyclists and swimmers although other research shows little to no effect. 

Another published systematic review and meta-analysis related to the effects of taking nitric oxide supplements regarding exercise performance concluded that nitric oxide supplements may "improve tolerance" to aerobic and anaerobic exercise in people who are not in shape or who are moderately trained. However there seems to be no benefit in highly trained people. More research is needed to show whether these supplements help improve sporting performance.

If you're still game to try, note that doses of 6 to 13 grams are usually the doses taken in studies and this seems to be well tolerated by most people.Those who are diabetic, have high blood pressure, heart problems or any other health conditions, may want to consult their doctor before starting.


Bescos R,  Sureda A, Tur JA et al (2012). The Effect Of Nitric-oxide-related Supplements On Human Performance. Sp Med. 42(2): 99-117. DOI: 10.2165/11596860-000000000-00000.

Gallo L, Percoraro S, Sarnacchiaro P et al (2020). The Daily Therapy With L-arginine 2,500 Mg And Tadalafil 5 Mg In Combination And In Monotherapy For The Treatment Of Erectile Dysfunction: A Prospective, Randomized Mutixenter Study. Sex Med. 8(2): 178-185. DOI: 10.1016/j.esm.2020.02.003.

MaMahon NF, Leveritt MD and Pavey TG. (2017). The Effect Of Dietary Nitrate Supplementation On Endurance Exercise Performance In Healthy Adults: A Systematic Review And Meta-analysis. Sports Med. 47(4): 735-756. DOI: 10.1007/s40279-016-7.

Saturday, January 21, 2023

Chinese New Year Spring Cleaning

How to clear this befor CNY?
We had quite a few patients who came in this week complaining of neck, shoulder and low back pain. All from spring cleaning their homes to prepare for Chinese New Year. 

For Chinese families, it is tradition and superstition for them to clean their houses and surrounding areas before the start of the Chinese new year. 

The word 'dust' in Chinese is a homophone for 'old' , hence cleaning the house is symbolic for driving away the bad luck from the previous year to allow for a new start. Besides getting rid the of bad luck and misfortune from the past, it also opens up spaces for all the new, good luck to enter your house and infuse your life. 

Many of us have clutter in our homes, offices and cars. Sometimes cleaning it out seems like a huge task. This messy environment can affect our minds, making us anxious and can hurt our ability to relax, focus or sleep. We take longer to do things, we may lose or break things. It just makes life harder.

It can also cause emotional distress since we are constantly faced with reminders of the clutter and messiness which does not conform to our identity as someone whs has their act together. This was shown in a recent study that tested the effect of mess on behavior by placing subjects in a normal versus chaotic kitchen (Vartanian et al, 2017). Those in the messy kitchens tended to over indulge in less healthy snacks more than those in normal kitchens.

So other than Chinese tradition and superstition, you now have another good reason to clear out the clutter and clean up the mess.

Happy Chinese New Year to all our patients and readers.


Vatanian LR, Kernan KM and Wansink B (2017). Clutter, Chaos, And Overconsumption: The Role Of Mind-set In Stressful And Chaotic Food Environments. Env and Behav. 49(2): 215-233. DOI: 10.1177/0013916516628178.

Sunday, January 15, 2023

Does Your Kneecap Position Matter?

Recently we saw quite a few patients after they had knee replacement surgery in our clinics. Having treated many patients' knees over the years, I have seen lots of variations of how the kneecap (or patella) is positioned.  Some patients have kneecaps that are 'aligned' nicely, yet they regularly complain of knee pain. Others have kneecaps that seem to sit terribly yet they have no knee pain nor need a knee replacement. 

There is definitely still a lack of knowledge regarding the variability of patellofemoral (kneecap) alignment in both healthy and osteoarthritic knees. Yet, while training to be physiotherapists, we were taught about the importance of kneecap alignment. They said it should sit nicely in the middle of the knee, and the sulcus and patella tilt should be a certain "normal" angle.

When patients come into our clinics complaining of knee cap (patella) pain, it is not always due to knee cap alignment. Hochreiter and colleagues (2020, 2021) published 2 systematic reviews demonstrating that both healthy and osteoarthritic knees have highly variable patellofemoral (knee cap) alignment.

15 studies met the inclusion criteria for healthy knees while 8 studies were used for osteoarthritic knees.

The authors concluded that both healthy and osteoarthritic knees have extremely variable patellofemoral alignment. This may be due to variables when doing x-rays/ MRI scans, measuring techniques and the people studied. 

R Kneecap position
In order to treat patients with healthy knees with knee pain, a more precise knowledge of the complex relationship between the trochlea and patella (pictured above) is needed since the exact role of knee joint alignment in development of knee pain/ symptoms remains unclear. I have written previously that the hip, especially in females, and not so much knee alignment causes knee pain.

The authors also suggest that surgeons operating on osteoarthritic knees need to consider individual pre-operative patellofemoral alignment if they want to reduce anterior knee pain for patients after total knee replacement surgery. Note that running will not wear out your knees (or your joints). So what does? There is now evidence that osteoarthritis is not due to a mechanical aging process. Even if you already have osteoarthritis, exercise will not wear out your joints quicker.

So healthcare professionals should not be telling patients that their knee joint alignment is abnormal, especially since we do not even know what normal alignment is.


Hochreiter B, Hess S, Moser LB et al (2020). Healthy Knees Have A Highly Variable Patellofemoral Alignment: A Systematic Review. Knee Surg Sports Trau Arthrro. 28: 398-406. DOI: 10.1007/s00167-019-05587-z.

Hochreiter B, Moser LB, Hess S et al (2021). Osteoarthritic Knees Have A Highly Variable Patellofemoral Alignment: A Systematic Review. Knee Surg Sports Trau Arthrro. 29: 483-490. DOI: 10.1007/s00167-020-05928-3.

Sunday, January 8, 2023

Update On Hamstring Injuries

Previous published research defined 2 main types of hamstring injuries. Sprint type (which usually occurs while sprinting hard) and slow-stretch type which occur during movements leading to excessive lengthening of the hamstrings. For example during high kicking, doing a split during taekwondo training or sliding tackles during football. You can read more here.

These 2 different mechanisms of injury affects functional deficits, injury location and return to sport time. 

Sprint related hamstring injuries typically occurs during late swing phase. The bicep femoris is usually the muscle injured and tends to present more severely at first, but allows a quicker return to sport (RTS). 

Stretch-type injuries which often involved semimembranosus muscle typically have a less severe initial presentation, but take longer to RTS. They normally occur in a position of excessive hip flexion with a hyperextended knee (pictured below).

Picture from Zentrum Sports
2 studies using systematic video analyses published in 2022 provided new insight into hamstring injuries as they examined the role of the trunk (or torso) during agility and evasion movements in field sports where hamstring injuries abound.  

Kerin et al (2022) described professional rugby injuries occurring in 5 distinct patterns - kicking, running, decelerating, while tackling and in the ruck.The authors also observed that trunk flexion and ipsilateral (same side) rotation along with knee extension at the point of injury.

Gronwald et al (2022) studied hamstring injuries in elite German soccer players and showed that stretch type injuries occurred during kicking and braking (while running) and were frequently caused by indirect contact from an opponent (contact to the body not the hamstring). 

It is also interesting to note that unlike previous studies, Gronwald et al (2022) found that most stretch type hamstring injuries involved the bicep femoris instead of semimembranosus. The authors also found that T-junction hamstring injuries (where the long and short head biceps femoris merges) have the highest re-injury rate. They usually occur in late swing (or early stance) phase, with ipsilateral trunk rotation (while catching a pass, tackling, reaching for a ball or looking behind). 

Knowledge of hamstrings injuries have definitely evolved with recent publications describing multiple scenarios and types of hamstrings injuries.  Previous prevention strategies to train the hamstrings muscles in late swing phase may be insufficient. We should now also give some consideration to the trunk (torso) in different planes to reduce injury incidence. This involves training hamstring strength when the muscle is in a lengthened position while the trunk and knee are in flexion. 


Kerin F, Farrell G, Tierney P et al (2022)> It's Not All About Sprinting: Mechanisms Of Acute Hamstring Injuries In Professional Male Rugby Union- A Systematic Visual Video Analysis. BJSM. 56(11): 608-615. DOI: 10.1136/bjsports-2021-104171.

Gronwald T, Klein C, Hoenig T et al (2022). Hamstring Injury Patterns In Professional Male Football (Soccer): A Systematic Video Analysis Of 52 Cases. BJSM. 56(3): 165-171. DOI: 10.1136/bjsports-2021-104769.

Sunday, January 1, 2023

Small Acts Of Kindness

It's often easy and even real quick to do something small to help someone even though we don't do it often enough. 

I brought my son to get a haircut and held the glass door open for an elderly lady walking in after us. She was pleasantly surprised and said "A thousand blessings to you!"

Research shows that acts of kindness, no matter how small have a positive impact on the recipient. The researchers (Kumar and Epley, 2022) conducted a series of experiments with different acts of kindness, such as offering someone a ride home or covering the cost of someone's cup of coffee. 

In one such experiment, study participants at an ice skating rink on a cold winter day gave other skaters a cup of free hot chocolate. Then both parties were asked to rate how much the gesture was worth. The givers consistently undervalued how much the hot chocolate meant to the recipients.

Another recent paper published in the Journal of Personality and Social Psychology by Liu et al (2022), came to a similar conclusion about human behavior. The paper showed that we underestimate the power of reaching out to friends, family and colleagues. A quick call or text makes a big difference.

When it comes to doing nice things for others, a little goes a long way. Even though they may be small and simple, these kind gestures have immense underestimated power. That should encourage all of us to put in extra effort to make someone smile.

Now that you know this you can make someone's day a lot better. When in doubt, make that phone call, whatsapp message or offer the last cookie you have. It means a lot more than you think.

Here's wishing a very Happy New Year to all our patients and readers. 


Kumar A and Epley N (2022). A little Good Goes An Unpectedly Long Way: Underestimating The Positive Impact Of Kindness On Recipients. J Expt Psych. DOI: 10.1037/xe0001271.

Liu PS, Rim SY, Min L et al (2022). The Surprise Of Reaching Out: Appreciated More Than We Think. J Pers Soc Psych. DOI: 10.1037/pspi000402