Rock climbing is a trending sport and there are more and more young people practicing it. Currently, the International Federation of Sport Climbing estimates that there are 35 million climbers worldwide with an average age of 23 years, and more than 140 countries have climbing walls.

The climbing grade of a rock climber is measured by the difficulty of the route overcome without any falls. Several studies reviewed the relationship between the years of experience, the maximum climbing grade and the type of climbing with the risk of injury [1], [2], [3], [4], although without specifying the injuries that affect the forefoot. Usually, the level of the climber is related to the time of experience, which implies more time of use of the climbing shoe, and this factor has been related to a higher prevalence of foot injuries and deformations [5], [6], [7], [8].

There are three different types of climbing shoes depending on the curvature of the sole and the adduction of the shoe last. The little elastic properties of the climbing shoe material combined with its narrow, the asymmetrical last, the unphysiological shape and the general habit of wearing smaller sizes tailored to the foot, alter the biomechanics of the foot during climbing [5], [8]. Previous studies found that between 81–91% of climbers reported enduring pain derived from the generalized use of climbing shoes smaller than common footwear [5], [6], [8], used to obtain a better performance, even when there is no scientific evidence to show that forcing the foot in these positions improves performance in any of the types of climbing [7], [9], [10].

Few studies have clinically evaluated the alterations that experienced climbers may present in the forefoot and more specifically in the first metatarsophalangeal articulation (1MTP), which is one of the structures that suffer a greater functional demand when performing the different technical gestures typical of climbing. Schöffl et al. carried out an evaluation of the chronic deformations of the foot in 30 climbers with more than 5 years of experience, observing that 100% of the climbers analyzed presented pressure marks and skin conditions on the dorsal part of the toes; 53% had hallux valgus and 20% had it bilaterally [10].

The lack of evidence justified to investigate about the factors related with foot injuries in rock climbing, and to do so for the first time with a quantitative scale to assess the degree of dysfunction of the hallux joints.

Perform a quantitative evaluation of the 1MTP function in rock climbers;

Analyze the possible relationship between hallux dysfunction in climbers and their physical characteristics and performance.