TOKYO, Aug 3 ― Athletes scampered up giant walls and clambered over plastic boulders as climbing made its Olympic debut today, taking the sinew-straining, muscle-bulging sport to dizzying new heights.

Twenty climbers competed in the men’s qualifying round, testing their mettle over the three disciplines of speed, lead and bouldering.

South Africa’s Christopher Cosser and South Korea’s Chon Jong-won kicked off the opening speed round, where climbers race up a 15-metre vertical wall using a series of plastic holds.

Under a setting sun on the outside wall, Cosser zipped to the top in 6.48 seconds, while Chon slipped near the start and spun back down on his safety rope.

The combined score of the three events determines the final positions, with eight climbers going through to the final round.

The women’s qualifying event, featuring hot favourite Janja Garnbret of Slovenia, takes place tomorrow.

France’s Bassa Mawem took first place in the speed event with a best time of 5.45sec from his two attempts.

Japan’s Tomoa Narasaki ― one of the favourites for the title ― was second in 5.94, despite not even bothering to use his second run.

Bouldering sees climbers clamber over rocks and faces without a rope, trying to "solve” the course with dramatic leaps and impressive feats of strength.

Lead climbing involves athletes clipping hooks along the face of a 15-metre wall and trying to climb as high as they can. ― AFP