Comparison of Isometric Knee Extension Torque-Angle Relationship between Taekwondo Athletes and Normal Adults

Title & Authors
Comparison of Isometric Knee Extension Torque-Angle Relationship between Taekwondo Athletes and Normal Adults
Jo, Gye-Hun; Oh, Jeong-Hoon; Lee, Hae-Dong;

Abstract
Objective : In order for Taekwondo athletes to perform destructive kicking performance, they are expected to have Taekwondo-specific muscle properties such as high muscle strength and power. The purpose of this study was to investigate the joint angle-dependent force-producing property of Taekwondo athletes' knee extensor muscles, which is one of the primary muscle groups involved in kicking performance. Method : Ten Taekwondo male athletes (age: $\small{19.9{\pm}0.7yrs}$, height: $\small{180.6{\pm}6.2cm}$, body mass: $\small{75.9{\pm}8.9kg}$, career: $\small{9.2{\pm}2.9yrs}$.) and 10 healthy male non-athletes (age: $\small{26.3{\pm}2.6yrs}$, height: $\small{174.2{\pm}4.8cm}$, body mass: $\small{72.8{\pm}7.7kg}$) participated in this study. Subjects performed maximum isometric knee extension at knee joint angles of $\small{40^{\circ}}$, $\small{60^{\circ}}$, $\small{80^{\circ}}$, and $\small{100^{\circ}}$ (the full knee extension was set to $\small{0^{\circ}}$) with the hip joint angles of $\small{0^{\circ}}$ and $\small{80^{\circ}}$ (the full extension was set to $\small{0^{\circ}}$). During the contractions, knee extension torque using an isokinetic dynamometer simultaneously with muscle activities of the rectus femoris (RF), and the vastus lateralis (VL) and vastus medialis (VM) using surface electromyography were recorded. Based on the torque values at systematically different knee-hip joint angles, the joint torque-angle relationships were established and then the optimal joint angle for the knee extensor was estimated. Results : The results of this study showed that the isometric knee extension torque values were greater for the Taekwondo athletes compared with the non-athlete group at all hip-knee joint angle combinations (p<.05). When the hip joint was set at $\small{80^{\circ}}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($\small{313.61{\pm}36.79Nm}$ and $\small{221.43{\pm}35.92Nm}$, respectively; p<.05) but the estimated optimum knee joint angles were similar ($\small{62.33{\pm}5.71^{\circ}}$ and $\small{62.30{\pm}4.67^{\circ}}$ for the Taekwondo athletes and non-athlete group, respectively). When the hip joint was set at $\small{0^{\circ}}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($\small{296.29{\pm}45.13Nm}$ and $\small{199.58{\pm}25.23Nm}$, respectively; p<.05) and the estimated optimum knee joint angle was larger for the Taekwondo athletes compared with the non-athlete group ($\small{78.47{\pm}5.14^{\circ}}$ and $\small{67.54{\pm}5.77^{\circ}}$, respectively; p<.05). Conclusion : The results of this study suggests that, compared with non-athletes, Taekwondo athletes have stronger knee extensor strength at all hip-knee joint angle combinations as well as longer optimum muscle length, which might be optimized for the event-specific required performance through prolonged training period.
Keywords
Taekwondo;Knee Extensor Muscles;Torque-Angle Relationship;Optimal Joint Angle;Muscle Activity;
Language
Korean
Cited by
References
1.
Brughelli, M., Cronin, J., & Nosaka, K. (2010). Muscle architecture and optimum angle of the knee flexors and extensors: a comparison between cyclists and australian rules football players. Journal of Strength and Conditioning Research, 24(3), 717-721.

2.
Chen, T. C., Nosaka, K., & Sacco, P. (2007). Intensity of eccentric exercise, shift of optimum angle and the magnitude of repeated bout effect. Journal of Applied Physiology, 102(3), 992-999.

3.
Gordon, A. M., Huxley, A. F., & Julian, F. J. (1966). The variation in isometric tension with sarcomere length in vertebrate muscle fibres. The Journal of Physiology, 184(1), 170-192.

4.
Herzog, W., Guimaraes, A. C., Anton, M. G., & Garter-Erdman, K. A. (1991). Moment-length relations of rectus femoris muscles of speed skaters/cyclists and runner. Medicine & Science in Sports & Exercise, 23(11), 1289-1296.

5.
Herzog, W. (2009). The biomechanics of muscle contraction: optimizing sport performance. Sport Ortho Trauma, 25(4), 286-293.

6.
Hill, A. V. (1938). The heat of shortening and the dynamic constants of muscle. Proceedings of the Royal Society of London, 126(843), 136-195.

7.
Katz, B. K. (1939). The relationship between force and speed in muscular contraction. The Journal of Physiology, 96(1), 45-64.

8.
Kulig, K., Andrews, J. G., & Hay, J. G. (1984). Human strength curves. Exercise and Sport Sciences Reviews, 12(1), 417-466.

9.
Lee, H. D., Kim, S. J., Lee, D. Y., Kurihara, T., Lee, Y. S., & Kawakami, Y. (2010). Shift in optimal joint angle of the ankle dorsiflexors following eccentric exercise. Experimental Mechanics, 50(5), 661-666.

10.
Marginson, V., & Eston, R. (2001). The relationship between torque and joint angle during knee extension in boys and men. Journal of Sports Sciences, 19(11), 875-880.

11.
Morgan, D. L., & Allen, D. G. (1999). Early events in stretch-induced muscle damage. Journal of Applied Physiology, 87(6), 2007-2015.

12.
Savelberg, H. H., & Meijer, K. (2003). Contribution of mono and biarticular muscles to extending knee joint moments in runners and cyclists. Journal of Applied Physiology, 94(6), 2241-2248.

13.
Ullrich, B., & Brueggemann, G. P. (2008). Moment-knee angle relation in well trained athletes. International Journal of Sports Medicine, 29(8), 639-645.

14.
Ullrich, B., Kleinoder, H., & Bruggemann, G. P. (2009). Moment-angle relations after specific exercise. International Journal of Sports Medicine, 30(4), 293-301.