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

Abstract

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%, p < 0.001), and also between the preparation and the execution phase (44.74 ± 9.88% and 30.14 ± 4.11%, p < 0.01). No significant difference was found between the preparation and the follow-through phase (p = 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.

Changes in Electromyographic Activity of the Dominant Arm Muscles during Forehand Stroke Phases in Wheelchair Tennis

“…In contrast to the triceps brachii muscle, the highest values of muscle activity were shown during the followthrough phase (16.96% MAX), and low values of muscle activity were observed during the execution phase (4.53% MAX). This result reflects the role of muscle synergies during elbow movements, specifically during flexion [34,45,46]. Thus, the primary muscular activations of the biceps brachii and triceps brachii were identified throughout the three phases in which the elbow muscles control the position and movement of the elbow joint and stabilize the integrity of the impact-induced vibration during ball contact [47].…”

“…Regardless of the importance of the performance, the risk of injury, and the examination of wheelchair tennis, there has been no research into the electrical activity of the muscles during the forehand stroke in wheelchair tennis, despite many studies investigating the muscle activity of other racket games such as table tennis [27], tennis [28][29][30][31][32][33], and squash [34], and the fact that several studies have investigated temporal and biomechanical variables such as velocity, force, power, and moments, and recommended further investigations evaluating the physiological and biomechanical characteristics of wheelchair tennis [5,[35][36][37][38]. According to our understanding, only velocity, push and cycle time, power output, and sprint time were measured in the literature [2,5,35].…”