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UDO NEUMANN'S ROUTE to primary school weaved through Cologne Zoo. He’d watch the orangutans swinging in their cages, and in 2011, a longing to see these great apes in their natural habitat took the German – by then a rock-climbing adult, sports scientist and coach – to the Sumatran rainforests, where orangutans and black and white gibbons moved effortlessly overhead.
“I marvelled at the gibbons’ speed and the jungle’s complexity compared to climbing walls,” Neumann says. “It was more three-dimensional, with variables including flexing branches.” By then, he was coaching the German national bouldering team, and he hypothesised that if gibbons have neural circuitry similar to ours, humans should be able to climb faster and more fluidly by aping them. Now, as climbing prepares for its Olympic debut, Neumann’s hunch is being tested by some of the world’s best athletes.
Historically, rock climbing movement was conservative; one misstep while using rudimentary equipment could end badly. Slow movements and keeping the hips close to the rock enabled optimum control. The dogma was ‘four points of contact’; don’t look down, don’t let go.
As bouldering – climbing close to the ground above crash pads – boomed in the 1970s, stakes were lowered. Climbers attempted dynamic, risky moves before adapting them to higher climbs, loosening up and occasionally jumping for holds.
Indoor climbing catalysed skill acquisition, and by the 1980s it became competitive. The resin holds resembled tiny rock edges, and movement remained two-dimensional. In the 2000s, holds ranged from angular cheese wedges to bulging blobs. Climbing walls became 3D – mimicking what Neumann had seen in the rainforest.
In the 2010s, competition organisers eyeballed parkour and incorporated run-and-jumps. Simply pushing and pulling with hands and feet wasn’t enough — the whole body engaged, starting from the hips, which pushed out to generate momentum for wild leaps. Climbers unconsciously unleashed their inner ape, limbs flew. These showstopper movements also increased climbing’s appeal as an Olympic spectator sport.
Instead of executing discrete movements, top climbers linked moves in a flow of momentum. They evolved from climbing like sloths to moving like gibbons, without realising that their eye-catching style was less modern-day pro and more ancestral ape.
While most mammals move on all fours, humans are bipedal, but we’ve retained useful anatomical quirks that suit climbing. “There's no question that climbing is in our heritage,” says John Fleagle, distinguished anatomical sciences professor at Stony Brook University. “We didn’t inherit our mobile, multi-directional shoulders, elbows, wrists and flexible hips from a quadrupedal animal; they're a leftover from the suspensory ancestor.”
Fossils suggest that early humans spent significant time in trees around 3 million years ago. Homo sapiens’ ancestral ties to gibbons diverged around 17 million years ago, when we followed the Great Ape path, eventually splitting from our closest cousins – chimpanzees and bonobos – between six and eight million years ago.
Today, we’re a weird halfway house, mostly wandering on two legs and not using our upper limbs. “Climbing is harking back to something that we've been hanging on to but haven’t put to good use,” Fleagle explains.
Compared to gibbons, we have stumpy fingers and large legs – a burden to swing about. Gibbons are built to climb quickly; they’re the fastest, most agile of all tree-dwelling, non-flying mammals, swinging at up to 55 km/h and leaping up to eight metres in a single bound.
They have the longest arms of all primates relative to their size. “Their limb proportions are outrageous,” Fleagle says. In climbing, a commonly-held belief is that having an arm span longer than your height - meaning greater reach - is beneficial. The aptly-named ape index is calculated by subtracting height from arm span, giving a positive, neutral or negative result.
Adam Ondra, arguably the world’s greatest all-round rock climber, is +1cm, free-soloist Alex Honnold +8cm, and Team GB’s Shauna Coxsey +8.5cm. But to Neumann, a positive ape index isn’t necessarily a plus. “If climbers - especially kids - have a huge span, they can neglect learning important motor skills through bypassing moves,” he says.
And despite the ubiquity of the term, climbers rarely reached past its etymology to grasp the mechanics of ape movement, until Neumann came along.
HIS SUMATRA VISIT was a eureka moment. Neumann began studying gibbon movement, poring over primatology papers and taking his theories from the jungle to the gym, imparting knowledge to elite climbers. Aside from physiological adaptations, the crux of gibbon’s climbing expertise, Neumann learned, lies in the manipulation of their centre of mass (hips), which they swing to generate momentum. Gibbons can accelerate up to 8.3 metres per second in a single movement.
The technical term for pendulum-like swinging through trees – or along monkey bars, or between climbing holds – is brachiation. In the fight against gravity, climbing involves considerable muscle contraction. As well as conserving momentum, swinging generally requires less muscle activity; one gibbon study showed that climbing and hoisting required more shoulder and forelimb muscle activity than brachiation. “Gibbons lose as little momentum and therefore energy as possible between grip points by rapidly shifting their centre of mass and consequently their direction of travel during brachiation,” says John Bertram, professor at the University of Calgary and expert in gibbon locomotion.
Likewise, Slovenian Olympic number one seed Garnbret excels in keeping the mechanical costs of her movements low. “Garnbret makes pendular movements, mixing and matching trajectories of her limbs to continually exchange potential and kinetic energy to conserve energy,” Neumann observes.
Some climbers naturally move like apes. One girl learned from the best. In the ‘90s, US youth sensation Tori Allen won senior competitions with an unusually dynamic climbing style. Growing up in Benin, West Africa, Allen would chase her pet Mona monkey Georgie up trees while picking bananas and guavas. “I realised I was different at my first competition aged 10,” says Allen, now 33. “If I couldn't reach a hold, I’d jump! It was my instinct.”
Allen’s unconventional childhood climbing shaped her physically and mentally, developing a +3cm ape index, strong, elongated fingers and a head for heights. “Georgie unknowingly taught me to be fearless,” Allen says. “I was just playing – I didn't realise these skills would lead to a professional climbing career at 12!”
Twenty years later, Japanese Olympic No.1 seed Tomoa Narasaki caught Neumann’s eye. “Narasaki moves more proximal-to-distal than most climbers, initiating from his hips and following through to his extremities,” Neumann says – meaning that he relies less on fatiguing use of his arms and fingers. “He also has an innate ability to generate momentum with the flick of a limb.”
It helps to understand different body segments as having distinct centres of mass. “Gibbons use each segment to transfer angular momentum to different body parts in different axes and planes of movement and rotation,” Neumann explains – a study co-led by Bertram observed ‘trailing arm flexion’ and ‘leg-lifting', where gibbons flex their forelimbs to shift their centre of mass, or bend their lower limbs to shorten their pendular length and boost their upswing.
What goes up, must come down. If momentum is generated, it must be controlled. When a climber leaps and grabs a hold, their body will swing below, following the trajectory of their hips. If uncontrolled, the climber will slam into or fly off the wall. “Contact points only tolerate a certain amount of peak force, so damping is necessary,” Neumann explains.
Climbers focus on hand and foot positions, but often neglect to think about the position of the body between moves and how it counteracts force, something known as collision fraction.
“The body is a three-dimensional fractal damping system, meaning force is distributed through all joints,” Neumann says. “They’re arranged in opposing directions of motion, allowing the body to fold and unfold.” This allows climbers to exploit elastic energy, like a coiled spring. Owing to their long arms - and branch flexibility - gibbons can more easily absorb collision force. “Gibbons engage their strong forelimbs and rotate around their grip point,” Fleagle explains.
In climbing, multiple world champion Janja Garnbret exploits her signature 'scorpion' move, where she dramatically arches her spine and free-hanging limbs backwards to dampen a swing, or performs gibbon-like rotations around contact points — the so-called ‘Janja flick.’ “Garnbret typically has minimal collisional energy loss,” Neumann says. “The passage between two movements happens smoothly without abrupt changes in the path of her body's centre of mass.”
Alongside dynamic skills, climbers can also learn from gibbons’ slower, less spectacular movements. Gibbons are thought to be the best primate model for human bipedal evolution, since they walk on two legs along branches due to their ungainly arms.
Neumann recalls footage of a gibbon walking along a rope, using its outstretched arms to counterbalance like a tightrope walker’s pole. Its arms wobble up and down, decisively correcting every off-balance step. On inclined, off-vertical walls, climbers challenge themselves to teeter without holding on and sway their arms to stay in balance.
Neumann also observed climbers crouching on one foot and dangling their opposite leg, as Old World monkeys hang their non-prehensile tails beneath a branch to counterbalance. The best climbers, Neumann noticed, rapidly correct their balance, just like the wiggling gibbon.
AS A CLIMBER, I’m less monkey, more sloth. I’ve won multiple British titles and competed in international competitions from a young age, alongside achieving difficult ascents on rock. “Please don’t take this, well, personally,” Neumann comments after watching me climb, “but you look like you learned climbing before modern bouldering was invented.” He’s correct.
Twenty years ago, slow, balletic poise was considered the optimum style – especially for women. Moving quickly and dynamically was not my forte. Bouldering was considered too intense for kids at the time, so I focused on endurance climbs to the detriment of my technique and power. I relied mostly on static strength.
When I rejoined the GB team as a senior, I re-learned how to climb in the modern style. I started following Neumann’s ideas, watching his slow-motion analyses of the best climbers and experimenting with hip and limb positioning while swinging along monkey bars. I’m still no gibbon or Garnbret, but learning how to generate and absorb energy undoubtedly improved my skills. Monkey see, monkey do.
Neumann’s focus is on what he calls physical literacy, rather than physical strength. “Many climbers train slow muscle contractions, but rarely work on optimising elastic energy,” he explains. He also believes this approach has psychological benefits; committing to dynamic moves is scary, carrying injury risks. “The “play” aspect helps climbers relax,” he says. “This is the biggest difference between Garnbret and Narasaki and your typical “strong” climber.”
When comparing ourselves to other primates, however, we must remember that these wild animals have evolved to be relaxed in their environment, Neumann explains. He believes that personality and gender can influence willingness to experiment. “Girls can be socialised to take fewer risks and can shy away from trying moves,” he says. “Confidence is even more important than technique,” says Tori Allen. “You can drill someone with technique, but if they won’t commit, they’ll never stick the move.”
Counterintuitively, climbers are learning to let go in order to hold on as they swing back to the roots of our evolutionary tree. In the pursuit of defying gravity, mass can be a benefit and not a burden if used efficiently. Going ape over primates’ movement is worthwhile, and to be compared to them is the highest compliment.
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This article was originally published by WIRED UK
