Saturday, June 26, 2021

How Much Exercise Is Good For Your Brain?

I rode 105 km before work this morning. No prizes for guessing I was thirsty, hungry (despite eating before I started work) and needless to say, tired. 

There are days when after a run or ride I feel alive, my mind is laser clear, and all my synapses are firing. Today's ride was definitely not a ride where I felt clarity afterwards. 

There's plenty of evidence that short bouts of moderate exercise improves your performance in the ability to perceive, react, process and understand, store and retrieve information, or do cognitive tasks afterwards. You may not feel it, but the finding is highly repeatable.

However, we do not know how much exercise is enough to trigger this effect. Or whether how fit you are or what type of cognitive task you're doing matters.

I found an article where researchers in Australia tested 21 trained cyclists and triathletes (11 male, 10 female). These athletes did 15 minutes of moderate cycling followed by a pair of cognitive tests lasting 4 minutes. They rode another 30 minutes moderately before repeating the same cognitive tests. This was followed by an incremental ride to exhaustion (taking about 11 to 12 minutes on average) before doing a final round of cognitive tests (McCartney et al, 2021). Three different timepoints were measured, after 15 minutes, 45 minutes and exhaustion.

Moderate cycling was done at 50 to 55 percent of peak power from a previous test and this got them to average 75 percent of max heart rate (HR) after 15 minutes and 80 percent of max HR after 45 minutes.

Results showed that 45 minutes of exercise trumped 15 minutes. For these trained endurance subjects, their cognitive performance decline definitely did not happen after 45 minutes of moderate exercise.

Contrary to what the researchers expected, the decline did not happen after complete exhaustion as well, being better than after 15 minutes. Note that there was a 2 minute delay from the moment of exhaustion until the start of the cognitive tests so this delay may just be enough to recover.

Bear in mind that exercising for longer does not always mean better since there will be a point for everyone where if you exercise long enough your cognitive performance will start to drop. 

These subjects were also not allowed to drink during the testing. Male subjects lost 2.3 percent of their starting weight while the females lost 1.7 percent. This is well above the threshold suggested to cause cognitive impairment. 

The subjects repeated the testing twice. In one testing, they were given 2 capsules and told that the capsules were "designed to enhance cognitive function" during exercise. 

The capsules were just placebos, as the researchers wanted to test whether the subjects were influenced by this. The placebos did not have any significant effect which supports the case that this is a physiological effect - a result of enhanced blood flow to the brain or elevated levels of neurotransmitters.

There was another study done in 2015 where researchers from Taiwan found that 20 minutes of moderate exercise produced the biggest cognitive boost, compared to 45 minutes. The biggest difference between the two studies is that this Taiwanese study used healthy but non athletic university students (Chang et al, 2015).

Since the 2021 study used trained endurance athletes, it makes sense that they will probably benefit from a longer exercise duration compared to the university students.

There you have it, exercise does makes you improve your brain function. However, we cannot always go out for a run or ride before an important meeting, deadline or decision. It can also be shooting hoops or lifting some weights or any other exercise if running or cycling ain't your thing. Just do it when you have the opportunity.


Chang YK, Chu CH, Wang CC et al (2015). Dose-Response Relation Between Exercise Duration And Cognition. Med Sci Sp Ex. 47(1): 159-165. DOI: 10.1249/MSS.0000000000000383

McCartney D, Desbrow B and Irwin C (2021). Cognitive Effects Of Acute Aerobic Exercise: Exploring The Influence Of Exercise Duration, Exhaustion, Task Complexity And Expectancies In Endurance-Trained Individuals. J Sp Sci. 29(2): 183-191. DOI: 10.1080/02640414.2020.1809976.

Our Sat ride before Covid-19

Sunday, June 20, 2021

Are S&C Coaches Or Physiotherapists The Real Exercise Professionals?

This week's post is on an article I read in the blog from the British Journal of Sports Medicine where the author asked whether physiotherapists or strength and conditioning (S&C) coaches are the real pros when it comes to prescribing rehabilitation exercises and getting patients/ athletes to return to sport (RTS).

The author compared physiotherapists and strength and conditioning (S&C) coaches working with athletic populations (in the UK). His view was that the physiotherapist has always been the decision maker or 'top dog' when it comes to managing the injured athlete or any patient that needed exercise to rehabilitate or improve physical function. 

He feels that the physiotherapy profession has not kept up to date with professional developments in exercise science and S&C, even falling behind and out of step in some aspects. This is despite the fact that there has been an increase in demand by physiotherapists in the UK for weekend courses in S&C training to fill in gaps in expertise and knowledge. 

The author thinks these short 2 day courses is "really an insult to those S&C professionals that have devoted time, effort and financial resources to their expertise" as they have studied exercise science, S&C at undergraduate level and gone on to postgraduate study and even advanced professional accreditation to work.

He also feels that the undergraduate training program for physiotherapists in the UK does not provide enough basic grounding in exercise prescription and training science despite claims by the physiotherapy profession that they have a firm grounding in basic clinical sciences so they can circumvent the need for extensive training in S&C.

This has then led to a deficit in rehabilitating athletic populations such that it even slows an athlete's full RTS. The athlete is usually handed to the S&C team or left to their own devices. He concludes that rehabilitation of recreational and professional athletes must be recognized as an advanced practiced skill requiring specialist training. If these gaps/ deficits in both under and post graduate training are not addressed, then physiotherapists will be relegated to technicians in the restoration of the patient/ athlete.

My thoughts? I used to work at the *Singapore Sports Council in the Sports Medicine department (the current Singapore Institute of Sport). The doctors, physiotherapists, S&C coaches and other sports science staff (nutrition, biomechanics, psychology) all have degrees and/ or postgraduate qualifications and definitely had a good working relationship. We had a weekly case discussion where the athletes who were not progressing well after injury were brought up and analyzed.

Other than that sort of setting and perhaps in the Singapore Sports School and Football Association of Singapore, I think that physiotherapists in  hospitals and private practices that treat sporting populations may differ in their ability to enable these patients to RTS. It boils down to the interest and exposure of each physiotherapist. Whether they had any previous sports/ athletic background, how interested they are in sports, and most importantly, their tenacity to want to better themselves. 

There will be S&C coaches, sports and functional trainers, CrossFit coaches and personal trainers who, with their interests and commitment to improve themselves, will be superior to some physiotherapists with regard to rehabilitation and returning patients to sport. Likewise, there will be physiotherapists who can more than hold their own. 

It is, ultimately, up to each individual in their respective line of work to keep themselves up to date, to keep improving to help athletes recover better and faster. And also to recognize when they aren't the best person to return an athlete to sport and refer them out to someone who is.

Here's another sugggestion for physiotherapists not working in those sort of sports settings. If, most if not all undergraduate physiotherapy courses does not provide enough basic grounding in exercise prescription (like the author writes), then perhaps we, as physiotherapists should be doing what we are trained best at. To use our hands! All the manual assessing, mobilizations, manipulations etc, that other heatlhcare professionals can't do. Why are we not doing more of what we are best trained for?

Instead of giving patients exercises to do during treatment sessions, physiotherapists should be doing things that the patients cannot do themselves. Now, the robots or other healthcare professionals cannot replace that type of physiotherapist.


Blog article from British Journal of Sports Medicine, published on May 2, 2021.

* Thanks to my former colleagues and former S&C coaches Todd Vladich and James Wong (also multiple SEA Games gold medalist and discus throw record holder), whom guided my S&C program when I was still competing. James, a few other colleagues and I used to train at the old KATC gym at the old National Stadium 3 mornings a week at 7:30 am before we started work when we were not traveling or competing. We did this year round, especially in the off season. Those sessions and attending a Level 1 Australian Weightlifting Federation course while working there definitely made me competent at getting patients to return to sport quickly and most importantly, safely.

Sunday, June 13, 2021

Evidence For Using Floss Bands

showing how Flossing is done
Remember the floss band courses we used to teach? We often had participants asking what is the evidence behind increasing joint range of motion (ROM), sporting performances, helping with recovery and decreasing pain. In short, they all wanted to know how it works

I wrote previously that you've got to try it to believe it, well there is now a published *scoping review article for floss bands (Konrad et al, 2021), referenced below.

The review paper summarizes the existing evidence for the effect of floss band treatment on range of motion (ROM), sporting performance (strength or jump performance), recovery (due to DOMS) and pain (due to disease or injuries).

In all, 24 studies met the inclusion criteria with a total of 513 subjects. 15 of the 24 studies investigated the effects of a single floss band application on the ROM of several joints. On the ankle joint, flossing was found to have a significant change of 11.17% in the dorsiflexion ROM.  

4 studies investigated the effects of calf flossing on the ankle, showing a very large increase of 19.95% in dorsiflexion of the ankle.

Similarly 4 studies measured thigh flossing and found a significant increase in knee bending (3.61%), and knee straightening (7.38%). However, another study showed no improvement in hip ROM after flossing the thigh. None of studies showed any decrease in range after flossing.

Of the two studies that investigated the effects of flossing on DOMS, one study reported significantly reduced DOMS 24 and 48 hours post exercise in the study group (in the upper arms) compared to the control group. The other study (on leg muscles) found no difference in the intervention versus control group following 12, 24, 36, 48 60 and 72 hours post exercise.

When comparing flossing to other treatment like dynamic stretching, flossing had a more noticeable effect in increasing hip range of motion and maximal eccentric knee extension (Kaneda et al, 2020b). With regards to static stretching and flossing, rate of force development was more pronounced in the flossing group compared to the static stretching group (Kaneda et al 2020a). Kaneda and colleagues concluded in both studies that flossing should be applied as a warm up rather than as a stretching exercise. This is exactly what my patients who do CrossFit tell me. They normally use a floss band for warm up before they start their easier routines, before the heavy lifting.

I know all athletes are after improved performances. Results from the individual studies showed that 11 of of the 44 performance measures showed a significant improvement (comparing pre and post floss band application, Table 3 in article). There is some evidence that joint flossing (ankle and knee) can increase jump height, although sprint performance (5 to 20 m sprints) seems to be unaffected after ankle flossing. (Personally, I would floss the quads and hamstrings and calf muscles if I wanted to improve sprint times rather than the ankle). 

One study showed improvement in maximal voluntary contraction (strength) in the quadriceps muscle and hamstrings after thigh flossing.

The researchers suggest this is possibly due to hormonal responses related to the flossing. Similar to other occlusion (or blood flow restriction methods), enhanced growth hormone and norepinephrine levels increase may be responsible for increase in performance reported. More importantly, the review concluded that from the involved studies there was no detrimental effects on performance from a single floss band treatment.

Evidence also show that a single floss band treatment is able to increase ROM of the related joint and can positively affect jumping and strength performance. Possible mechanism is suggested to be changed neuromuscular function rather than changed mechanical properties.

after surgery in 2016
After Ronald Susilo (above) ruptured his patella tendon and tore his anterior cruciate ligament at the same time, he came to see me after the surgeon reattached his patella tendon. He did not have the range to even pedal one round on the stationary bike. I definitely increased his knee ROM with a single floss band treatment. He could pedal immediately after a single floss band application. 

Yes, back then it was only one subject (or n=1), however it was a definite improvement. Those of you reading then may be critical and probably not even believe it, but I have since replicated it many times in our clinic. Hence I feel that clinical evidence (what we see in the clinic) is just as good as published evidence (like this scoping review).

There will probably be long term studies about the effects of flossing treatment on joint ROM, sporting performance, whether it helps with recovery and decreasing pain. I am sure there also will be studies that say there are no benefits to it. The question is does it work for you?


Konrad A, Mocnik R and Nakamura M (2021). Effects Of Tissue Flossing On The Healthy And Impaired Musculoskeletal System: A Scoping Review. Front. Physiol. 21 May 2021. DOI: 10.3389/fphys.2021.666129

*A scoping review has a broader scope compared to traditional systematic reviews with correspondingly more expansive inclusion criteria.

Let's do the twist

Sunday, June 6, 2021

My Patient Was Told She Has Freiberg's Disease

Dr Domenico Nicoletti rID: 44376 Radiopaedia

A patient came in last week asking for a second opinion for her toe pain. She had seen a doctor at her local polyclinic, gone for an x-ray and was told she might have early signs of Freiberg's disease.

She was subsequently asked to see a foot surgeon by the doctor. Her friends also suggested she see a podiatrist.

Freiberg's infarction or Freiberg's disease as it is commonly known is actually not a disease but microtrauma causing pain in usually the second toe of the foot at the metatarsal head. It can occur in other toes too. 

It is most common among teenage girls during puberty and more common in the second toe. This is especially if the second toe is longer than the big toe as this increases stress on the 2nd metatarsal head while walking, running and during sports. 

The physical stress causes multiple tiny small fractures where the metatarsal meets the growth plate. Pain is commonly felt in the forefoot while pushing off. The affected joint may sometimes be swollen and range of motion is limited there. Due to avascular necrosis (bone tissue dying due to lack of blood supply), the metatarsal head flattens (see picture below). This is usually confirmed by x-ray. 

There is no definitive treatment for Freiberg's, as it is also thought to be related to a stress fracture. Doctors will often get the patient to be non weight bearing to immobilize the foot. Corticosteroid injections may sometimes be given. In less severe cases, a rocker boot may be prescribed. Podiatrists may also prescribe orthotics with metatarsal pads and/ or low heel footwear. Severe cases may require surgery.

As you can see from the x-ray report above, my patient is clearly not an adolescent (although people of all ages can be affected by it). Even the reporting radiologist said it could be a normal variant. She also had been inactive for the past 3 years. 

What did I do? I treated her foot and plantar fascia along her Superficial Back Line and taught her to modify her gait for the time being. She was happy to be pain free after that and even asked if she could run. If she really had Freiberg's disease/ infarction, I would not, in my humble opinion, be able to change her symptoms that much in just one session.


Carter KR, Chambers AR and Dryer MA. Freiberg Infarction. (updated Mar 17, 2021). In: StatPearls (Interbet). Treasure Island (FL): StatPearls Publishing; 2021 Jan-.

Lin H and Liu AL (2013). Freiberg's Infarction. BMJ. Case Reports: 2013010121. DOI: 10.1136/bcr-2013-010121.