Sunday, April 25, 2021

Should Youths Run Long Distances?

Picture by Richseow from Flickr

I had a friend ask me on Thursday if his friend's kids should come in to our clinic for physiotherapy or sports massage as they were complaining of feeing 'tight' in their muscles. This year, some of the National School Games are allowed to proceed (after being called off because of Covid-19 last year), so many school athletes are competing again.

I do not recall having such privileges during my time. Perhaps we were hardier or maybe ignorant about recovery and whatever help you can get from sports medicine/ physiotherapy. Besides, I was never into running high mileage during my school days. There were other teenage runners who mentioned that they clocked 100 km a week, while I seldom got above 30 km. We did a lot of quality intervals rather than quantity. Definitely no junk miles. Preparing for the GCE 'A' levels did not leave us much time to run that much either.

There have been studies of youth athletes (not specific to runners) that show sport specialization makes them more prone to injury. Especially those who played their primary sports for more than eight months in a year. These youth athletes had more overuse injuries in the upper and lower limbs compared to those who spent less time in their primary sport.

Youth athletes who participated in their primary sport more hours each week than their age in years had more injuries of any type. They were also more likely to have a history of overuse injuries if time spent training exceeded recommendations for their age. Hence it is important to do different sports for youths. And not to push them.

A running specific study on track and cross country events (989 girls and 1022 boys between 12-18 years) found that youth athletes who specialized had more overuse and previous injuries of any kind compared to those who did not specialize (Post et al, 2017)

Another study (of 126 female cross country and distance track and field athletes) found an increased risk in those runners who specialized compared to those who did not (Rauh et al, 2018).

In order to reduce the risk of running related injuries in the youth runner, we must take into account the complex interaction of various factors, including growth related changes unique to this population. A summary of the risk factors are in the table below taken from Krabak et al (2021).

In addition, the following recommendations are based on expert opinions in the study by Krabak et al (2021). A musculoskeletal screening on your youth athletes for previous injuries, menstrual dysfunction (girls) biomechanical concerns and training errors.

Youth runners should take part in high impact and multidirectional activities focusing on control of the backhip and lower extremities through puberty to reduce injury and promote bone health.

Make sure your youth runners have at least one rest day a week, 1-2 weeks off every 3 months and limit participation to less than 9 months each year. Single sport specialization should be discouraged until they pass puberty.

Self motivated youths can be allowed to take part in long distance events if they follow an acceptable supervised training program, maintain normal growth in height and weight and are healthy with good nutritional intake.  

So all physical education teachers, coaches and parents, if your youth athlete has BMI < 17.5kg/m2 or body weight below 85 percent of normal for their age, bone density scores of Z > 1.0, untreated eating disorders, high risk stress fractures (in femoral neck, proximal tibial or navicular bone) and female runners without menarche by 16 years old or less than 6 menstrual cycles in the past 12 months then they will require further medical evaluation.


Krabak BJ, Roberts WO, Tenforde AS et al (2021).Youth Running Consensus Statement: Minimising Risk Of Injury And Illness In Youth. BJSM. 55: 305-318. DOI: 10.1136/bjsports-2020-102518.

Post EG, Trigsted SM, Riekena JW et al (2017). The Association Of Sport Specialization And Training Volume With Injury History In Youth Athletes. AJSM. 45: 1405-1412. DOI: 10.1177/0363546517690848.

Rauh MJ, Tenforde AS, Barrack MT et al (2018). Associations Between Sport Specialization, Running-Related Injury, And Menstrual Dysfunction Among High School Distance Runners. Athl Trg Sp Health care. 10: 260-269. DOI: 10.3928/19425864-20180918.

Sunday, April 18, 2021

Does Your Growing Child Have Knee Pain?

Recently, we have seen some young athletes in our clinics, complaining about pain after playing sport. I've written about growing pain in young children/ athletes before. When these children/ athletes are having a growth spurt during adolescence, the long bones grow faster than muscles. The muscles take a while to lengthen so the muscles tend to pull on the attachments on the bone.

This is especially so when a child is active, the muscles will pull on the bony attachments where the muscles attach causing pain (also known as apophysitis).

An area of pain at the knee which is common in children is known as Osgood Schlatters disease (OSD). The pain is located where the patella tendon finishes at the tibia, known as the tibial tuberosity.

Researchers from Denmark studied 51 youth athletes (51 percent female) between the ages to 10 to 14 with OSD. The youths already had pain for an average of 21 months.  Intervention consisted of four visits with a physiotherapist with both child and parent. The first block of treatment focused on decreasing load through decreased activity, education and static hold exercises.

The next block the subjects progressed to exercises which led to a return to their sport. Follow up was done at 4,8,12, 26 and 52 weeks. 

All subjects showed improvement at 12 weeks (study endpoint) with less kids complaining of pain and increased function and quality of life. 31 percent of subjects still suffered from discomfort at 12 weeks, discomfort that they would be not happy to live with, while 80 percent were very satisfied with their treatment results.

Only 16 percent of the subjects managed to return to their sport (RTS) at 12 weeks, compared to 69 percent at 52 weeks follow up. Thigh and hip abduction strength which was the focus of the exercise interventions improved significantly by 12 weeks as did vertical and horizontal single leg jumps.

At one year follow up, only 5 percent of subjects were very unsatisfied with their progress and unable to return to sport.

The study called for significant restrictions (guided by pain/ symptoms response) at the start of sporting activity to decrease load on the tibial tuberosity. Data from the tracking device the subjects wore prior to start of the study to the first block of treatment showed a decrease of 15 minutes per day of moderate to vigorous activity. This may suggest that getting active kids to slow down is difficult. 

Parents may need to explain to the child that activity modification is key to reducing symptoms. Reining in the kids in the short term will help return to sport sooner.

Surprisingly, the tracking devices showed that activity levels decreased by 37 minutes per day by week 12, suggesting that although many reported feeling better and can do more, they were actually less active.

We usually do not encourage stretching the affected muscle as static stretching can place more traction forces on the tendon insertion on the bone. Correct strength training that is pain free often helps to take the load off the tendon attachment. Meaning the weight does not have to be heavy. Elastic bands are very useful too when the young patients cannot handle the weight.

Please come and see us in our clinics if your young and teenage athletes need help.


Rathleff MS, Winiarski L, Krommes K et al 92020). Activity Modification And Knee Strengthening For Osgood-Schlatter Disease: A Prospective Cohort Study. Ortho J Sp Med.6(4): 2325967120911106. DOI: 10.1177/2325967120911106

*note that OSD or Osgood Schlatter's disease is not a disease. It is named after Robert Osgood (1873-1956) and Carl Schlatter (1864-1934), an American and Swiss surgeon respectively that described the condition concurrently.

Picture from ESSR
An x-ray of fragmentation of the tibial apophysis n a child with OSD. It is NORMAL in pain free adolescents. 

Wednesday, April 14, 2021

Where The Streets Have Allyson Felix

I've written about Allyson Felix before previously and I hope she will still be a force to reckon with at the Tokyo Olympics. Being Nike's poster girl previously, I admired how she spoke up when Nike were unfair to their sponsored pregnant athletes.

As you can see from the article above, she still found a way to train when stadiums were closed during the lockdown after getting her coach to use a measuring wheel to mark out distances "on literally the street in front of her door". 

What a sight it must have been for her neighbors to behold when a six-time Olympic Olympic gold medalist, 13 times World Champion comes sprinting down the road at full speed. Along with her coach yelling encouragement at the top of his voice. 

Instead of complaining about what she can't do, I love the way she and other athletes resorted to unorthodox ways to train so they can be ready to compete when they can. 

I know too, that our Team Singapore athletes have resorted to ingenious ways to train too, chapeau to them. 

Let's see how she fares if the Olympics does go on.

Sunday, April 11, 2021

Can Your Menstrual Cycle Make You More Prone To Injury?

Photo by Jeffrey F Lin from Unsplash

Ladies, it's true that sometimes men don't get it, but not the way you think. Not when it comes to injury risk anyway. 

I've written way back in 2009 that women are more prone to ACL injuries compared to men during the time of the month because changing hormone levels affect ligament strength. The bad news is it's not just ligaments. Researchers found evidence that muscles, tendons, joint and ligaments were more affected across the menstrual cycle.

The English women's national football team (from under-15's to the senior squad) were studied over a four-year period for this study. Injuries during training camps and competitions were tracked. Only players with regular menstrual cycles and not on hormonal contraceptives were included in the analysis. 156 injuries from 113 players were recorded.

The key finding seems to be that estrogen has broad effects on decreasing stiffness of ligaments and tendons. While this is may be helpful during childbirth, it also make your knees, ankles and other joints less stable when estrogen levels are higher.

My wife explains that at the start of menstruation (which is the follicular phase), estrogen is lowest.  Estrogen levels begin to rise to a peak shortly before ovulation (luteal phase). It then drops sharply, before rising again to a gentler peak during the luteal phase.

Bearing the above in mind, ACL injuries tends to be more likely during the late follicular phase where estrogen levels tend to be highest and ligaments tend to be loosest. During this phase, knee joints get one to five millimeters looser (Chidi-Ogbolu and Baar, 2018). 

It can be that tendons that have became looser or more lax may actually decrease injuries to the muscles since they may be able to absorb some of the impact from forces that may strain or tear a muscle (Chidi-Ogbolu and Baar, 2018). 

The analysis showed that muscle and tendon injuries were about twice as likely during the late follicular phase (higher estrogen levels leading to lax muscles and tendons) compared to other phases.

Joint and ligament injuries were significantly less during the late follicular phase (24 in total). Quite the opposite of the study's hypothesis (lax ligaments bad, lax tendons good).

An interesting note was that 20 percent of the injuries happened when a player's menstrual cycle was late or overdue (based on when the players expected their next period to start). This may be due to the "female athlete triad", which involves persistent calorie deficits and can lead to missed or irregular periods, lower bone density and increased overall injury risk.

Some of you reading this may be planning to avoid contraceptives during training and then using them during during the competition season since hormonal contraceptives can be protective of ligaments (since they suppress the higher peaks in estrogen). Beware of the trade-offs though, higher estrogen levels help promote muscle building and repair muscles and tendons in response to training.

It is clear that hormonal fluctuations matter although clearer guidelines on the menstrual cycle may be needed since knowing estrogen can affect injury risk may not pan out totally in the real world. 

My suggestion would be to track and record your periods so you are aware of what factors can and may be at training/ competition. Knowledge is certainly power in this case.

More research is definitely needed and you'll be the first to know the latest information when you read it in our blogs.


Chidi-Ogbolu N and Barr K (2019). Effect Of Estrogen On Musculoskeletal Performance And Injury Risk. Frontiers Physiol. 9: 1834. DOI: 10.3390/fphys.2018.01834.

Martin D, Timmins K, Cowie C et al (2021). Injury Incidence Across The Menstrual Cycle In International Footballers. Frontiers in Sp Active Living. DOI: 10.3389/fspo.2021.616999.

Sunday, April 4, 2021

Scoff Not At Elastic Resistance Bands

Tan Howe Liang(pictured below) is still the strongest man I know. Yes, the same Tan Howe Liang that won Singapore's first ever medal at the 1960 Rome Olympics. He was a senior gym instructor at the gym at the old National Stadium and we often bumped into each other when I was still working there. I was always amazed when he told stories about his training days. Mind you, he could still squat with very heavy weights whenever I saw him train then. 

Silver at the Rome Olympics, SNOC picture

But don't fret if you don't have easy access to a gym or other fancy, expensive gym equipment. Other than your bodyweight, elastic resistance bands can be great for strengthening muscles too.

Not many of you may believe me if I said that training with elastic bands can be just as effective as training with weights for strengthening muscles.

The following systematic review and meta-analysis is possibly the first to compare the effects of strength training for strength gains with elastic tubes and bands versus conventional devices (dumbbells and weight machines).

The search identified 365 articles, of which eight studies were within the inclusion criteria comprising of 224 individuals between 15 to 88 years old. All subjects were performing regular strength training. In these groups were physically active individuals, athletes, individuals with coronary heart disease and moderate chronic obstructive pulmonary diseases.

Results of the meta-analysis showed that there is no superiority for both upper and lower limbs between training performed with elastic bands and training with free weights on strength gains. This was consistent across groups mentioned above and also when compared with a control group in the elderly, individuals with osteoarthritis and even fibromyalgia. 

The authors conclude that training with elastic bands is just as good as conventional resistance for promoting strength gains in different populations using diverse protocols. 

Having elastic bands at home to train with eliminates the need to travel to the gym and this may be more practical and a lot cheaper for certain people who may find it difficult to go to a gym. patients will have greater adherence to strengthening programs too. 

Personally I feel elastic bands are great for strengthening and correcting muscular imbalances. I still use them on a very regular basis. Especially after my accident.

Exercising with bands in my back brace in 2013

Do not let anyone tell you that you are wasting time if you are not using heavy weights and expensive equipment. Effective strength training can be achieved with body weight, free weights and especially elastic bands too.

We have managed to rehabilitate many national athletes back from injury and even avoid surgery in many cases using elastic bands to strengthen the injured areas. Especially in cases when a weight plate/ bar is initially too heavy and risk further injury and load to the person's joints.


Lopes JSS, Machado AF, Micheletti JK et al (2019). Effects Of Training With Elastic Resistance Versus Conventional Resistance On Muscular Strength: A Systematic Review and Meta-analysis. Sage Open Med. DOI: 10.1177/2050312119831116.

Don't neglect the legs