A Study of Antagonist/Agonist Isokinetic Work Ratios of Shoulder Rotators in Men Who Play Badminton

Abstract

Study Design: Normative descriptive study. Objectives: Exploring the isokinetic work ratios of eccentric antagonist/concentric agonist shoulder rotators in the late cocking and deceleration phases of a forehand overhead smash in badminton players. Comparing the work ratios between dominant and nondominant shoulders. Background: The strength of shoulder muscles for badminton players has been studied but there is little information on the work output of these muscles for a specific range of movement. Methods and Measures: Twenty-five skilled men who play badminton at club level with a mean age of 29.4 years (SD = 6.1) were measured for concentric and eccentric isokinetic work (joules) of shoulder internal (IR) and external (ER) rotators on both upper extremities at 120°/s. Bilateral isokinetic work ratios for eccentric IR/concentric ER between 60°and 90°of shoulder external rotation were calculated to denote strength profile in the late cocking phase of the badminton smash. Work ratios for eccentric ER/concentric IR between 10°external rotation and 30°internal rotation were calculated to denote strength profile in the deceleration phase of the badminton smash. The respective work ratios were compared between both shoulders. Result: The eccentric IR/concentric ER work ratios in late cocking were 1.9:1 and 1.3:1 (P = 0.001) for the dominant and nondominant shoulders, respectively. The eccentric ER/concentric IR work ratios in the deceleration phase were 1.1:1 and 1.3:1 (P = 0.003) for the dominant and nondominant shoulders, respectively. Conclusion: The work ratios of eccentric antagonist/concentric agonist are different between dominant and nondominant shoulders of skilled badminton players. Rehabilitation for injuries of these athletes should aim at developing the optimal antagonist/agonist work ratios to return them to this sport.

Assessment of agonist–antagonist shoulder torque ratios in individuals with paraplegia: a new interpretative approach

“…For the U/Es, this method has been proposed, to better evaluate the relationship between shoulder rotators. [16][17][18] Ng et al 19 and more recently Yildiz et al 18 used this eccentricconcentric approach to report torque ratios over an angular section (terminal range) where the antagonist muscles played a decelerator role (eccentric contractions). For these authors, this method is well adapted for investigating shoulder dynamic stability, especially among athletes performing overhead tasks (that is, throwing).…”

Angle Specific Analysis of Side-to-Side Asymmetry in the Shoulder Rotators

“…Greater repetitive use of the preferred arm in throwing actions in recreational and sporting activities may explain our asymmetry results [2,21]. However, previous studies have used a variety of different speeds in order to provide sport specific information about strength imbalance and injury risk in the shoulder rotators [3,4,9]. The use of a single velocity to describe angle specific strength is a limitation of our study.…”

“…In addition, a few studies have opted to use 5°, 10°, 15° or end of ROM angle specific torque (AST) intervals for a more accurate estimation of unilateral dynamic muscle balance of the knee or shoulder joints [1,3,4,[6][7][8][9]. Dehail et al [7] demonstrated there was a significant progressive decline of flexion/extension and abduction/adduction AST strength ratios as the shoulder progressed to flexion and abduction, respectively.…”

“…The shoulder rotator muscles are important for coordinated performance of overhead activities, such as pitching in baseball, swinging a racket in tennis or pushing against the water in swimming [1][2][3]. Forceful and repetitive actions in overhead sports have been associated with an increased susceptibility of shoulder rotator injuries [3,4], strength differences between external (antagonists) and internal rotator (agonists) muscles [1,[3][4][5], and side-to-side differences between upper-limbs [2,5].…”

“…Forceful and repetitive actions in overhead sports have been associated with an increased susceptibility of shoulder rotator injuries [3,4], strength differences between external (antagonists) and internal rotator (agonists) muscles [1,[3][4][5], and side-to-side differences between upper-limbs [2,5]. Typical shoulder strength asymmetry has been reported as an upper-limb dominance of 5%-10% measured by independent peak torque (IPT) in nonathletic and recreational-level athletes [5].…”