1. Introduction

Rock Climbing is a fast-growing sport and has recently been included in the Tokyo Olympic Games ^[1]. This imposed high demands on the level of sports professionalism ^[2][3]. This will lead to an increase in the volume and intensity of stress and the number of injuries ^[4][5][6]. Climbers get the most injuries during exercises aimed at strengthening the grip. The main element is One-Arm Hang ^[3][4][7].

The upper extremity is heavily loaded in rock climbing ^[8][9]. This leads to such injuries and diseases: damage to the ring ligaments of the fingers, chronic pain in the elbows associated with epicondelitis, and damage to the muscles of the rotator cuff of the shoulder ^[10].

But why do some athletes get injured, and in some cases quite often, and some athletes almost never face this problem? One of the main factors that ensures safe movement is the right technique ^[11].

Proper technique is the basis of efficient and safe movement ^[3][4][11]. However, in climbing so far there is no data on the correct or incorrect climbing technique. Therefore, the scientific substantiation of the technique of the element "One-Arm Hang" will allow to give a methodical basis for the formation of technology of this sport, on the basis of which it will be possible to develop means of injury prevention ^[3][11].

2. Material and Methods

The first stage: definition the basic kinematic characteristics of the one-arm hang in climbing for beginners and qualified athletes ^[3][4][11]. There were analyzed the technique of one-arm hang in climbing among 20 leading climbers of the World and Ukraine and 20 beginner male amateur climbers. A qualified athlete participated in the demonstration of various models of one-arm hang performance. By means of Kinovea software 0.8.15, the kinematic characteristics of two models of technique were analyzed (model 1 for beginner athletes, model 2 for qualified athletes). All subjects were male; age: 22.4 ± 3.2 years, body length: 178.5 ± 12.5 cm, body weight: 72.2 ± 8.5 kg.

The second stage: development and definition of the influence of neuromuscular training on the injury risk to rock climbers.

The intervention group: 40 athletes  at an amateur level; the body length: 173.4 ± 8.7 cm, the  body weight: 66.1 ± 6.6 kg, the climbing experience: 2.2 ± 1.4 years, ages: 18-19 years.

The control group:  44 athletes  at an amateur level; the body length: 172.5 ± 8.5 cm, the body weight: 65.2 ± 6.5 kg, the climbing experience: 2.4 ± 1.2 years; ages: 18-19 years.

Based on our findings, we included in the  Neuro-muscular training program ^{[12][13][14][15]} of injury prevention exercises performed in a closed kinematic chain with eccentric and strength exercises. This is because a closed kinematic chain ^[12] involves all the muscles that make up this kinematic chain. We used exercises in closed kinematic chain, with an emphasis on shoulder retraction to improve muscle coordination.

Exercises performed in eccentric mode promote smooth activation of the antagonist muscles [16]. This contributes to their strengthening during movements aimed at maintaining the position of the body when performing interceptions while climbing. Therefore, we can conclude that the combination of these exercises with each other and with strength exercises has a theoretical basis, and in our study it was experimentally confirmed.

3. Results

The main kinematic parameters of the one-arm hang in climbing for various models of the technique which is typical for athletes of different qualifications were identified. Unskilled athletes are characterized by a type of technique with minimal tension in the muscles of the shoulder, back, a large angle between the shoulder and shoulder girdle, and the almost vertical position of the lower spine with curvature in the upper section. Qualified athletes are characterized by a type of technique with tension in the muscles of the shoulder, back, a large angle between the shoulder and shoulder girdle, and a large angle between the spine and the vertical axis.

The presence of significant differences (p<0.001) in the angles between the shoulder and shoulder girdle, between the spine and the vertical axis in the phase of fixation of the hang is provided. So, the angle between the shoulder and shoulder girdle in the first model of the technique was 146⁰, in the second model of technique this angle is 97⁰. The angle between the lower spine and the vertical axis in the first model was 11⁰, in the second model this angle was 28⁰.

The dynamics of the angle between the shoulder and shoulder girdle from the moment of capture of the climbing hold to the phase of fixation of the one-arm hang is presented. At the moment of capture of the climbing hold, the angle between the shoulder and shoulder girdle is almost the same for both models of the technique. In the second model of the one-arm hang technique, the angle between the shoulder and shoulder girdle gradually decreases from the moment of the capture of the climbing hold to the fixation phase of , while in the first model this value is kept the same.

It is shown that in the first model, the one-arm hang in climbing is carried out mainly due to the ligamentous apparatus of the joints of the shoulder girdle with minimal inclusion of muscles, which is dangerous by trauma to the ligaments of the shoulder joint ^[3][4][11]. In the second model, the one-arm hang in climbing ensures the inclusion of muscles, which reduces the strain from the ligamentous apparatus and lowers the possibility of injury to the ligaments of the shoulder joint. The theoretical substantiation of the correct technique of the one-arm hang in climbing is provided in terms of the laws of mechanics and the laws of the interaction of forces in the kinematic chain.

The total number of all recorded shoulder injuries during 1 year of the experiment was 21 in the control group and 3 in the experimental group. Injury rate per 1000 AEs of all recorded shoulder injuries in the control group during 1 year of the experiment was 3.182 (95% Ci, 1.061; 5.367), in the experimental group - 0.5 (95% Ci, 0.068; 1.375), P <0.001.

Injury rate of mild shoulder injuries per 1000 AEs during 1 year of the experiment in the control group was 3.182 (95% Ci, 1.061; 5.303), in the experimental group - 0.5 (95% Ci, 0.068; 0.968). Injury rate of moderate shoulder injuries per 1000 AEs during 1 year of the experiment in the control group was 1.06 (95% Ci, 0.347; 1.773), in the experimental group - 0.17 (95% Ci, 0.098; 1.172. Injury rate of severe shoulder injuries per 1000 AEs during 1 year of the experiment in control in the first group it was 0.91 (95% CI, 0.124; 1.695), in the experimental group - 0 (no severe injuries were detected in the experimental group).

Incidence rate ratio for cohort (injuries = no) for mild shoulder injuries during 1 year of the experiment was 0.861 (0.737; 1.007). The incidence rate ratio for cohort (injuries = no) for moderate shoulder injuries during 1 year of the experiment was 0.862 (0.751; 0.990; P = 0.039). Incidence rate ratio for cohort (injuries = no) for severe shoulder injuries during 1 year of the experiment was 0.864 (0.768; 0.971; P = 0.017).

The use of exercises in a closed kinematic chain and exercises in an eccentric mode reduces the Incidence rate ratio of shoulders among students - amateur climbers. The incidence rate ratio decreases for mild, moderate, and severe shoulder injuries, but a significant decrease was found for moderate and severe injuries. Application of the developed program reduces the risk of mild shoulder injuries by 3,636 times, and the risk of moderate shoulder injuries - by 6,364 times. This value for severe shoulder injuries was not determined as no severe shoulder injuries were recorded in the intervention group.

4. Conclusions

The use of the neuromuscular training program on the base of exercises in a closed kinematic chain and exercises in an eccentric mode reduces the Incidence rate ratio of shoulders among amateur climbers. The incidence rate ratio decreases in the intervention group for mild, moderate, and severe shoulder injuries.

We recommend the neuromuscular training program using closed-chain exercises with eccentric and strength exercises to prevent shoulder injuries in amateur climbers.