Friday, August 26, 2016

Can Watermelon Juice Make You A Better Athlete?

You've read from our blogs about drinking coconut water, green juices, lemon water etc. I am sure that  when it comes to our health or getting a competitive edge, we are always eager to try something new but evidence-based.

Guess what I read in a recent article? L-citrulline supplementation appears to help VO2 max levels and high intensity exercise performances. In real food form, watermelons are the best natural sources of L-citrulline.

In the published study, ten cyclists were given either L-citrulline, L-arginine or placebo tablets over a period of three seven-day cycles. On day six and seven, the subjects completed a moderate and intense cycling test.

Only the subjects taking the L-citrulline tablets had improved their VO2 max, time to exhaustion and maximum power during a 60 second all out sprint. There were no changes in performance in the L-arginine or placebo group.

Now, before you run out and eat/ drink all the watermelons you can, here are some of my personal thoughts.

The sample size (10 athletes) in the study was relatively small. Recreational cyclists were used in the study so the results may be different in elite athletes. So great news if you're a recreational athlete.

For elite athletes however, probably you may want to wait for more studies to be replicated to make sure the results are valid.

The subjects in the study were given L-citrulline tablets. You'll need to drink about 2.5 litres of watermelon juice to get the same dose of L-citrulline used in this study. And probably have to go the the toilet pretty soon after.


Bailey SJ, Blackwell JR et al (2015). L-citrulline Supplementation Improves O2 Uptake Kinetics And High -intensity Exercise Performance In Humans. J App Physiol. 119(4): 385-395. DOI: 10.1152/japplphysiol.00192.2014.

Sunday, August 21, 2016

Do Compression Garments Help While Exercising? Or Only With Recovery?

Picture I retook with my iPhone 6 from Alex Hassentein/ Getty Images
Allyson Felix just missed another gold medal in Rio earlier in the week, finishing second in the 400 meters after losing to a dive by Shaunae Miller of the Bahamas.

Last night, she just won her 6th gold medal at the Olympics in the Women's 4 x 400 m relay, the most ever by a woman in track and field.

Five of her gold medals have come in relays. Her individual gold came in the 200 meters in 2012.

Why am I writing about Allyson Felix? Other than being one of my favorite runners, she is also one of many athletes in the Rio Olympics wearing compression sleeves (see picture above) while competing.

You too would have seen many athletes wearing them while training or racing. I've written about compression garments before way back in 2009.

Newly published studies suggest they definitely do help muscles recover significantly after exhausting exercise. The compression garments can aid the the movement of blood through muscles after exercising, when blood flow would otherwise be slow.  This increase in circulation may help reduce inflammation and muscle aches.

To provide such benefits, the compression garments must be quite tight, which some people may find uncomfortable. They must be also be worn for several hours after exercising/ racing, even if they become unpleasantly damp and stinky.

However, they do have certain downsides that may cause some of us not to wear them. Most recent studies indicate that compression garments do not boost blood flow through muscles during exercise, most probably because the movement of blood when we are exercising is already at its peak.

Even though many athletes report that exercise feels easier when they wear compression garments, these athletes performed similarly whether they wear the compression garments or not.

The authors concluded that compression garments has small effects on short duration sprints, running at VO2 max, as well as time trial performances (Born et al, 2013).

Like I wrote before  I've never raced with compression garments, I've only worn them after hard training so I can recover and train again the next day.

Maybe Allyson Felix didn't have to wear her calf compression sleeves after all ......


Born DP, Sperlich B et al (2013). Bringing Light Into The Dark: Effects Of Compression Clothing On Performance And Recovery. Int J Sp Physiol Perf. 8(1): 4-18. DOI: 10.1123/jisppp.8.4

Engel FA, Holmberg H and Sperlich B (2016). Is There Evidence That Runners Can Benefit From wearing Compression Clothing? DOI: 10.1007/s40279-016-0546-5.

*Here's another look at Allyson Felix's compression sleeves - took the picture with my iPhone 6 from the original by Cameron Spencer/ Getty Images.

Saturday, August 13, 2016

Too Much Recovery May Slow You Down

*You did great Jo!!!
You've read that it's best to do a recovery ice bath after your training session, eat within 30 minutes of your exercise to replenish your glycogen stores, get a massage etc.

Well, you'd better stop that. Are you kidding me? Isn't that what Michael Phelps, Joseph Schooling and all the other top athletes do after training? And you're asking me not to do that?

Well, don't be recovery-obsessed, not while you're in training anyway.

Exercise and training are all about adapting to stress. However, the more time you spend "forcing" recovery, the less chance your muscles have to build up strength and endurance.

Researchers are discovering that when you try to recover quickly (from training) by removing the signals of stress (from your exercise/ training), you may be helping only short term recovery. This will also reduce the signals needed for your muscles to adapt.

While the researchers are suggesting that you still need to recover from training, but you just need to plan and periodize recovery the same way you would plan and periodize your training.

Meaning, you don't have to achieve optimal recovery after every training session. Some fatigue and soreness is acceptable and even necessary at certain times in your training program.

However, during high quality training sessions and especially during competition, an increased focus on recovery (and not adaptation) is needed.

So here are some general guidelines. Most often your recovery strategies should be targeted towards the longer term.

During base training/ pre season or easy workouts, adaptation to training stress is fine. You want some fatigue and soreness (or "inflammation") because this is part of the muscular adaptation process. Using ice immersion post training will often interfere with the adaptation process leading to less than optimal adaptations.

Ice immersion can and should be used during competitions especially if you're racing in a few events a few hours later (like Phelps and Schooling during the Olympics) or over a few days. It is also time to eat real god food to recover, get your massage sessions in etc.

You'll probably have to figure what works best for you as different recovery strategies work differently for everyone. Some prefer a massage while others prefer ice baths.


Halson SL, Bartram J et al (2014). Does Hydrotherapy Help Or Hinder Adaptation To Training In Competitive Cyclists? Med Sci Sports Ex. 46(2):1631-1639. DOI: 10.1249/MSS.0000000000000268.

Roberts LA, Raastad T et al (2015). Post-exercise Cold Water Immersion Attenuates Acute Anabolic Signaling And Long-term Adaptations In Muscle To Strength Training. J Physiol 593(18) : 4285-4301. DOI: 10.1113/JP270570.

*I used to swim with and treat Jo Schooling way back in 2004-2008 when we were both swimming at the Centre of Excellence under coach John Dempsey. He used to kick my butt in the pool even when he was ten years old. Great job on winning Singapore's first ever gold medal at the Olympics. So very happy and proud of you!

Sunday, August 7, 2016

Race Faster With Racing Flats

Used to race in the Nike Duellist PR when I was a kid
I've had a few patients ask me this past week what shoes to wear for their upcoming races especially since they want to achieve a personal best timing. Other than definitely no new gear on race day, I am happy to share what I know regarding racing flats.

Why racing flats? You can definitely turn your feet over much faster if your footwear is lighter. Think about this or try it out if you want. If you had to, would you prefer to run 5 km wearing a 10 kg weight vest or run with a 5 kg dumbbell in each hand (or 5 kg ankle weights strapped to each ankle)?

Hence, I would definitely suggest investing in a good pair of racing flats, as light as possible without sacrificing support of course.

Racing flats aren't minimalist shoes like the Vibram Five Fingers, they are ultralight running shoes designed to give runners an additional edge in competition. No fancy cushioning or support, just the bare basics.

I also recall the most famous published article on the topic. Subjects ran in the exact same pair of shoes in that research with lead weights inserted into a sleeve sewed onto the sides of the shoe so both toe and heel drop remained the same. So only weight adjustment was tested in the study, with no variables like midsole height difference.

The researchers found that the "effect of carrying extra weight on the foot during running has been measured at 1 percent (increased aerobic demand) per 100 grams per foot".

100 grams is about 3.5274 ounces. Each extra ounce will cost 0.2835% more (1 divided by 3.5724). So if you're running a t 5:40 min per mile pace, every mile will save you 0.83 seconds per ounce less weight.

Although that Nike funded study was done a long time ago that message has always stayed with me. Ever since I started racing track and cross country in my teenage years I would warm up in my normal training (usually a lot heavier) shoes and then switch to race in the lightest racing flats.

Before you run out and get the lightest racing flat you can find, please bear in mind that cutting down shoe weight usually means sacrificing on cushioning. That's the reason why you never see elite marathoners competing in Vibrams. They may train with it, but never race with it.

Here's the reason. "As shoe weight went lighter, the cost (energy of the runner) also dropped some, but when the weight went too light, then the cost went up because there was getting to be less midsole cushioning and the runner's muscles had to start absorbing more landing shock and that costs more energy."

The surface you run on is also important. A nice soft artificial track will absorb some landing shock (so you can get away with minimalist spikes) but on the road, you'll definitely need some cushioning and that adds a little weight to the shoe.

So, your ideal racing flat will differ from another runner and vary according to speed and race distance. More time spent on your feet generally requires more support. You can probably get away with a lighter shoe for a 5 or 10 km race.

The lighter your footwear, the faster you can turn over your feet ......  Now you know.


Frederick EC (1984). Physiological And Ergonomics Factors In Running Shoe Design. Applied Ergonomics. 15(4): 281-287/ DOI: 10.1016/003-6870(84)90199-6.

Another racing flat, my Air Streak from 1997