Influence of hand hold rotation and pulling velocity on force and muscular activity during a therapeutic climbing exercise
Creators: name: Mally, Franziska
Publisher: name: RMIT University
Year: 2024
Subjects: classificationCode: 400607
subject: Signal processing
classificationCode: 420199
subject: Allied health and rehabilitation science not elsewhere classified
classificationCode: 420701
subject: Biomechanics

description: Within the last century, climbing has evolved from an extreme sport to a competitive sport and even to a therapeutic discipline within such fields as orthopaedics, neurology, psychotherapy and geriatrics. Especially the long-lasting trend of indoor climbing facilities in urban areas promotes this rather young therapeutic discipline. Physicians, physiotherapists and sports scientists, who themselves are passionate climbers realized the positive effects of climbing and the possible usage as a highly controllable treatment for different kinds of indications. For example, climbing can improve the sensibility and motor sensory control of patients with multiple sclerosis, can help people overcome anxiety and addictions and has been proven to have positive effects on adolescents with attentional deficits. In the treatment of orthopaedic indications, such as lower back pain or shoulder instability, the strengthening of core and trunk muscles is crucial for a positive therapy outcome. The high demands of climbing in this matter in order to create a stable equilibrium provide the perfect basis for the use as a therapeutic treatment. While the patient has to keep up a certain overall tension throughout the exercises, it is still possible to set the focus on specific structures by adding rather simple movement tasks, releasing single anchor points or by just increasing the difficulty for example through altering wall inclinations.<br><br>Although these promising effects of therapeutic climbing have extensively been reported within relevant literature by presenting case studies of successful treatments, the scientific approach in order to investigate the fundamental effects on the musculoskeletal system still leaves a lot of questions unanswered. Most studies so far have either presented the therapeutic outcome of rather unspecified climbing tasks or have investigated the effects of static exercises.<br>In this study a simple, pull-up like therapeutic climbing exercise has been investigated regarding the influence of pulling velocity and handhold rotation on the force applied at the climbing holds and the muscle activation of relevant trunk muscles. It was hypothesized that different muscles react differently to the changing of those factors and that the activation increases with increasing force, which can in turn be influenced by a higher pulling velocity.<br><br>For that 15 healthy subjects (7 male, 8 female; age: 28.13 ± 4.78 yrs.; weight: 72 ± 18.58 kg; height: 172.73 ± 12.45 cm) took part in this study and performed the specified exercise multiple times at three different pulling velocities (slow, medium, fast) and at six different handhold rotations (0°, 45°, 90°, 135°, 180°, -90°). Ten subjects had previous experience in climbing, but none of them was a professional climber. Three-dimensional forces were measured at both handholds using two ME K3D120 force sensors (ME-Meßsysteme GmbH, Hennigsdorf, GER), whereas muscle activation of eight muscles was recorded bilaterally with a myon 320 16-channel wireless wireless surface electromyography system (myon AG, Schwarzenberg, CH). The muscles investigated were the m. trapezius descendes (TD), m. trapezius transversus (TT), m. trapezius ascendens (TA), m. latissimus dorsi (LD), m. erector spinae (ES), m. multifidus pars lumbalis (MF), m. rectus abdominus (RA) and m. obliquus externus abdominis (OE). The exercise that had to be performed was a symmetric pulling exercise with the hand and feet both placed shoulder-wide apart on a self-built therapeutic climbing wall. In the initial position the elbows were fully stretched and then flexed in the different velocities to reach the final position. During the exercise the subjects had to keep a stable core position. Maximum resulting force normalized to the initial position at 0° handhold rotation and maximum muscle activation in percent of the intra-subjective maximum at 0° rotation and medium pulling speed were evaluated. Statistical significance was tested with a Wilcoxon signed rank test and Spearman’s correlations were calculated between maximum resulting force and muscle activation.<br><br>Results suggest that a higher pulling velocity leads to a significantly higher resulting force at the climbing holds. Furthermore, the maximum muscle activity of the upper back muscles (TD, TT) and the core muscles (ES, MF, RA, OE) is significantly higher during fast pulling compared to slow and medium pulling. The difference between slow and medium pulling velocity does only appear to be significant for single comparisons. Regarding the influence of handhold rotation, low, but significant differences were found for the maximum resulting force. Maximum activation of the TD and TT was significantly highest at -90° handhold rotation and lowest at this rotation for the LD. Handhold rotation did not seem to have a high effect on the maximum activation of the TA, ES, MF, RA and OE. Correlations between the maximum activation of muscles and the maximum resulting force could only sufficiently be found at 0° handhold rotation.<br><br>These results can assist therapists to plan their exercises more precisely, depending on which structure the focus should lie on. For example if tension of the neck muscles is a problem, high activation especially of the TD should be avoided and the pulling should therefore not be performed at -90° handhold rotation and with fast velocity. However, if the abdominal muscles need to be strengthened, fast pulling under 0° handhold rotation leads to the most promising output regarding the activation.<br>