Okay, let’s talk some more about heads bobbing forwards and backwards. I expect to mention this when writing about Mo Farah, the winner, but in the whole Olympic Men’s 5000 field in Rio it was practically an epidemic.
When I wrote about this phenomenon in my post about the women’s 10,000, I said that one way to think about a head that appears to move forwards and backwards (instead of just steadily forwards) is:
The spine is a bit hyperextended, so each time the runner extends her leg and hip, her spine also extends further, pushing her chest forward and head backwards.
However watching Farah in the 10,000 and then watching this race has caused me to reconsider, or rather to return to an older idea of why people do it.
Yes, Farah retracts his head, but he has a nice lean these days. And actually he bobs his head fairly little in the earlier stages of the race. But the harder he runs, the more it moves, pushing backwards with each step as if he were using it to push his body forwards.
I think that for Farah and the others who do this when running hard, it’s a switch in how he pushes against the ground. A runner with good technique whose head moves steadily forwards while moving appropriately side-to-side is alternately lengthening one side of their body, then the other. That is, not just the leg lengthening (ie straightening) but the side of the pelvis moving down, the ribs fanning apart, the shoulder turning forward and moving up, and the head moving towards the other side. This expansion is a recoil from the compression of midstance.
Most of the runners in the race were doing this, and in the photo at the top of this post you can see their heads aren’t centered, they’re shifted sideways over their stance legs. That’s just good running.
However if the head is going forwards and back like the guys in this race (Farah, Chelimo, Butchart, and a few others whose bibs I didn’t see) then the runner is actually using their extensors to push against the ground. In other words, instead of lengthening one side of the body, they work the back, extending all the involved joints from foot to head. This causes the arch of the back that pulls the head backwards.
Because the head is accelerating and decelerating with every step, and because the step doesn’t push the whole body forward evenly, this takes a lot of energy. But if you have that energy, does it help you go faster?
It seems to work for Farah, whose gold in this race makes it a double gold in the 5 and 10k for two Olympics, a remarkable achievement. Either it was a coincidence that more runners were doing it in this race than I’ve seen in a single race since I started paying attention around 2003 or people are starting to copy him. It might be conscious but it’s more likely unconscious, a desire to get the same pumping kick he wields.
It’s worth noting that the sideways shift of the head isn’t optional if you want to run fast, and upper body rotation is highly recommended. The first runner I noticed doing the head pump other than Farah was his teammate Butchart, but if you compare the two as they run near each other you’ll see that Butchart’s head is bouncing significantly up as well as a bit backwards. This is because he isn’t turning his upper body much. You can sense his higher braking force when his whole body is in view, which is a consequence, and his shorter stride length. He had a good run as it was, but it would be great for him to learn Farah’s large upper body rotation and maybe ease off the head bob.
It’s easy to get the feeling that running with that head pump is a way to get crazy speed. But it’s worth remembering that quieter options are less costly and more likely to pan out. I’ll never forget watching Keninisa Bekele pull ahead of Farah to win the Great North Run in 2013. He didn’t work harder in any way that was visible. He just smiled slightly, leaned in subtly, and pulled ahead. Food for thought.
If you missed the race and don’t have access to an online replay in your country, keep an eye on the Olympic YouTube channel. They eventually post HD videos of all Olympic events, and it looks like this year’s will be posted soon.