Grit your teeth when you want to go faster. It might not bring a smile to your face but experiments show that clenching your jaw will boost your pedal power.
It may be an old saying but a new study gives it more than mere lip service. The tighter you close your mouth, the quicker your legs will turn those cranks.
Exercise scientists have known for a while that clamping the jaw, gripping tightly with the hands and trying to breathe out through a closed mouth, all at once, increases knee power by 14.8% (Reference: The effect of remote voluntary contractions on knee extensor torque). That’s one reason a weightlifter pulls such ugly faces as he or she tries to hoist the bar off the mat.
Now, for the first time, it’s been shown that cyclists, too, can get a similar surge but using only their jaws. It’s not known how much more pedal power you can get by pressing together your pearly whites but there is definitely some benefit.
Researchers in Taiwan have confirmed the discovery almost by mistake (Reference: Frowning and Jaw Clenching Muscle Activity Reflects the Perception of Effort During Incremental Workload Cycling). They wanted to see if facial expressions are a reliable indicator of the degree of difficulty a cyclist is feeling. Nobody smiles when they’re suffering but how accurate a give-away is a grimace?
So they put 18 men and 15 women on laboratory exercise bikes (ergometers) and wired them up to measure the electrical signals from their brains to the muscles in their foreheads and jaws.
The experiment confirmed what everybody knows from experience – the harder the cycling gets, the more you tighten your jaw and the more you furrow your brow. Not a pretty sight.
In the lab, the electrical signals proved to the scientists that these ugly faces are an accurate indicator of how hard the leg muscles are working and how difficult the cyclist is finding the ride.
The scientists also say that cyclists could use this connection between the face and leg muscles in reverse. If you clench your jaw voluntarily, when you’re not suffering at all, you’ll activate leg muscles and be able to pedal harder.
It seems from the electrical activity that the soleus muscle, in the calf area, and the pretibial muscles, which help to work the ankle, are boosted by a deliberate grimace. To paraphrase Sir Dave Brailsford, it’s another example of marginal gurns.
Why is there this mysterious connection between your face and leg muscles?
Nobody knows for sure but the theory is that one part of the brain contains an area that’s subdivided to control the muscle force of the face and limbs.
These divisions overlap and are interconnected so, when one body part is calling for a lot of work to be done, the electrical control signals can overflow to the other.
It’s a strange phenomenon but only a slack-jawed loser would look such a gift horse in the mouth. It’s a trick that might be the difference between winning and coming second.
And maybe that’s why so many top cyclists earned nicknames connected to biting – the Badger (Bernard Hinault) is an animal renowned for its super-strong jaw muscles and where would the Cannibal (Eddy Merckx) be without a decent set of gnashers?
Try it for yourself – go for a spin and close your jaw tightly for up to a minute. Did you go faster? Let us know in the Comments box below.