Quantifying Coordination between Agonist and Antagonist Elbow Muscles during Backhand Crosscourt Shots in Adult Female Squash Players

• Main Authors: Abdel-Rahman Akl, Amr Hassan, Helal Elgizawy, Markus Tilp
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: racket sport; injury; elbow; electromyography; co-activation
• Online Access: https://www.mdpi.com/1660-4601/18/18/9825

The purpose of this study was to quantify the coordination between agonist and antagonist elbow muscles during squash backhand crosscourt shots in adult female players. Ten right-handed, international-level, female squash players participated in the study. The electrical muscle activity of two right elbow agonist/antagonist muscles, the biceps brachii and triceps brachii, were recorded using a surface EMG system, and processed using the integrated EMG to calculate a co-activation index (CoI) for the preparation phase, the execution phase, and the follow-through phase. A significant effect of the phases on the CoI was observed. Co-activation was significantly different between the follow-through and the execution phase (45.93 ± 6.00% and 30.14 ± 4.11%, <i>p</i> < 0.001), and also between the preparation and the execution phase (44.74 ± 9.88% and 30.14 ± 4.11%, <i>p</i> < 0.01). No significant difference was found between the preparation and the follow-through phase (<i>p</i> = 0.953). In conclusion, the co-activation of the elbow muscles varies within the squash backhand crosscourt shots. The highest level of co-activation was observed in the preparation phase and the lowest level of co-activation was observed during the execution. The co-activation index could be a useful method for the interpretation of elbow muscle co-activity during a squash backhand crosscourt shot.