Trunk Motion and Muscular Strength Affect Knee Valgus Moment During Single-Leg Landing After Overhead Stroke in Badminton

Abstract

Background Anterior cruciate ligament (ACL) injury in knees opposite to the racket-hand side frequent occurs during single-leg landing after overhead stroke in badminton. Although large lateral inclination of trunk during single-leg landing seems to generate knee valgus moment which causes ACL injury, it has not been examined. Objective To evaluate if there was a correlation between trunk kinematics and knee valgus moment during single-leg landing after overhead stroke, in addition, to evaluate an association with muscular strength of trunk. Design Controlled laboratory study. Setting Female college badminton players with no history of knee injury. Participants 8 right-handed players. Risk factor assessment Subjects performed single-left-legged landing after an overhead stroke following back-stepping. The kinematic and kinetic data of the trunk and left lower extremity during landing were measured using 3-dimensional motion analysis system. Isometric trunk flexion and extension strength was measured using a dynamometer. Main outcome measurement Change in lateral trunk bending angle and maximum knee valgus moment during landing were measured. The correlation between these and trunk strength were analyzed. Results The average of maximum knee valgus moment was 0.34±0.24 Nm/kg/m, and the change in lateral trunk bending angle was 22.9±13.3 degrees, respectively. The mean trunk flexion strength was 2.2±0.9 Nm/kg. The knee valgus moment was significantly correlated with the change in lateral trunk bending angle (r=0.87, P<.05) and the trunk flexion strength (r=−0.94, P<.01). The change in lateral trunk bending angle was also significantly correlated with the trunk flexion strength (r=−0.94, P<.01). Conclusions Larger lateral trunk bending associated with weak flexion strength increased knee valgus moment during single-leg landing. The core muscle training focused on trunk flexion strength may improve neuromuscular control of trunk and avoid excessive knee valgus moment in playing badminton, and this may play an important role of ACL injury prevention.

The Effect of Core Stability Training on Dynamic Balance and Smash Stroke Performance in Badminton Players

“…In this regard, trunk rotation and core muscles endurance are integral parts of the improvement power and transfer the energy up to the kinetic chain from lower body to upper body extremity transferred [14], this mechanism confirmed by previous studies which reported significant improvements in trunk strength after core stability training [6,9,12].…”

“…Previously, core stability exercises were widely used for reducing the injuries of the low back and lower extremities [9,11,12]. Recently, core stability training has been purported to improve player performance [7,[13][14][15], but the previous studies have not supported these claims in badminton sport.…”

“…Although, overhead smash stroke performance is a complex motion, which depends on several components such as lower body strength, leg power, technique and the proper kinetic chain [12,23,40], the core stability training varied movements in current study allows players to perform the exercises at high rhythmus speed compared with traditional strength training which depend on free weights or machines, but with greater force compared to those performed during sport competition [8,10,14]. Moreover, it can be explained that the positive smashing velocity and accuracy results by the high coordinative closeness of core stability exercises which were selected based on the nature of badminton sport which characterized by many repetitive striking.…”

“…In badminton, the non-contact technique when player landing from the jump after smash overhead stroke, sometimes caused injuries for the knee which probably occurs as a result of strength loose or stability weakness and balance. In this context, [12] observed that poor trunk flexion strength increase the knee valgus moment during the landing with single leg following an overhead stroke skill in badminton players.…”

The Effect of Core Stability Training on Dynamic Balance and Smash Stroke Performance in Badminton Players - An Evidence Based Study

“…In badminton, the non-contact technique when player landing from the jump after smash overhead stroke, sometimes get injured at knee which probably occurs as a result of reduced strength or instability and balance issues. [7] Balance defined as an ability to maintain a base support with minimal movement actions and dynamically to perform a motor task while maintaining a stable position. Badminton is a dynamic equilibrium process which involves loss of balance in the air to restore balance after landing.…”