摘要："Rear wheel hop" is a fundamental trials technique during which the athlete performs a series of hops with the bicycle that is balanced on the rear wheel. In trials, hands and feet are the only points of contact with the bicycle; therefore, the corresponding joints (in particular the ankle) are required to check (through a series of adjustments) the connection with the pedal to prevent losing contact with it because quick-release pedals are not used. The purpose of this study is to evaluate the activity of lower leg muscles to understand the control mechanisms that act on the ankle during the performance of this basic technique. This study involved one subject (i.e., an athlete practicing trials), who was able to properly perform the technique. The data were acquired for both legs using a 6-camera optoelectronic system, a force platform to define the events, and an 8-channel surface electromyograph. Ankle flexion–extension and the root mean square (RMS) of the surface electromyography (sEMG) signal of tibialis anterior, soleus, lateral and medial gastrocnemius muscles were calculated. The obtained results show that the muscles that control the ankle joint are similar to those that required in hopping, as it is possible to see from different electromyographic investigations carried out by various authors, therefore, in specific sports training, similar exercises can be used to train this muscle group. This case study provides insights into the sport of trials (which is still under-studied) as well as useful information so that coaches could implement more specific training programs.
关键词：mountain bike trials;electromyography;biomechanics;ankle
