Altered Squat Jumping Mechanics After Specific Exercise

Abstract

This study examined squat jumping (SJ) mechanics following length restricted strength training regimens of the knee extensors and flexors. SJ from a 110° knee joint angle starting position and isometric moment-knee angle relations of knee extensors and flexors were analysed in 16 athletes before and directly after 8 weeks of strength training regimens that were restricted to knee joint angles corresponding to long muscle-tendon unit (MTU) length for the knee extensors and flexors. SJ mechanics were studied using a two-dimensional kinematic model with three rigid bodies (upper leg, lower leg, foot) in combination with force plates measurements of ground reaction force in the right and left lower extremity. Centre of mass jumping height significantly (p<0.05) increased post training, but this was not explained by enhanced absolute power generation in the knee joint. However, post training small but significant (p<0.05) shifts to smaller knee joint angles occurred in the normalized [% Max.] knee joint angle dependent power generation in the right and left knee joint during SJ. The isometric moment-knee angle relation of the knee extensors was also significantly (p<0.05) shifted to longer MTU lengths of knee extensors. Length restricted strength training may alter the mechanical situation during both isometric contractions and dynamic athletic movements.

muscle-function - strength training - isometric force - dynamic athletic tasks - moment-knee angle relation

References

• 1 Arampatzis A, Schade F, Walsh M, Brüggemann GP. Influence of leg stiffness and its effect on myodynamic jumping performance.  J Electromyogr Kinesiol. 2001;  11 355-364
• 2 Blazevich AJ, Cannavan D, Coleman DR, Horne S. Influence of concentric and eccentric resistance training on architectural adaptation in human quadriceps muscles.  J Appl Physiol. 2007;  103 1565-1575
• 3 Blazevich AJ, Cannavan D, Horne S, Coleman DR, Aagaard P. Changes in muscle force-length properties affect the early rise of force in vivo.  Muscle Nerve. 2009;  39 512-520
• 4 Bobbert MF, van Soest AJ. Effects of muscle strengthening on vertical jump height A simulation study.  Med Sci Sports Exerc. 1994;  26 1012-1020
• 5 Bobbert MF, van Zandwijk JP. Dynamics of force and muscle stimulation in human vertical jumping.  Med Sci Sports Exerc. 1999;  31 303-310
• 6 Bowers EJ, Morgan DL, Proske U. Damage to the human quadriceps muscle from eccentric exercise and the training effect.  J Sports Sci. 2004;  22 1005-1014
• 7 Brockett CL, Morgan DL, Proske U. Human hamstring muscles adapt to eccentric exercise by changing optimum length.  Med Sci Sports Exerc. 2001;  33 783-790
• 8 Burkholder TJ, Lieber RL. Sarcomere number adaptation after retinaculum transection in adult mice.  J Exp Biol. 1998;  201 309-316
• 9 Butterfield TA, Leonard TR, Herzog W. Differential serial sarcomere number adaptations in knee extensors of rats is contraction type dependent.  J Appl Physiol. 2005;  99 1352-1358
• 10 Dempster WT. Space requirements of the seated operator.  WADC technical report. 1955;  55-159
• 11 Goldspink G. Malleability of the motor system: a comparative approach.  J Exp Biol. 1985;  115 375-391
• 12 Gregory JE, Morgan DL, Allen TJ, Proske U. The shift in muscle's length-tension relation after exercise attributed to increased series compliance.  Eur J Appl Physiol. 2007;  99 431-441
• 13 Gruber M, Gollhofer A. Impact of sensorimotor training on the rate of force development and neural activation.  Eur J Appl Physiol. 2004;  92 98-105
• 14 Haan A, Huijing PA, Vliet MR. Rat medial gastrocnemius muscles produce maximal power at a length lower than the isometric optimum length.  Eur J Physiol. 2003;  445 728-733
• 15 Hakkinen K, Komi PV. Alen M. Effect of explosive type strength training on isometric force-and relaxation-time, electromyographic and muscle fibre characteristics of leg extensor muscles.  Acta Physiol Scand. 1985;  125 587-600
• 16 Hasson CH, Dugan EL, Doyle TLA, Humphries B, Newton RU. Neuromechanical strategies employed to increase jump height during the initiation of the squat jump.  J Electromyogr Kinesiol. 2004;  14 515-521
• 17 Herzog W, Guimaraes AC, Anton MG, Carter-Erdman KA. Moment-length relations of rectus femoris muscles of speed skaters/cyclists and runners.  Med Sci Sports Exerc. 1991;  23 1289-1296
• 18 Impellizzeri FM, Rampinini E, Castagna C, Martino F, Fiorini S, Wisloff U. Effect of plyometric training on sand versus grass on muscle soreness and jumping and sprinting ability in soccer players.  Br J Sports Med. 2008;  article in press: doi 10.1136/ bjsm. 2007. 038497
• 19 Kilgallon M, Donnelly AE, Shafat A. Progressive resistance training temporarily alters hamstring torque-angle relationship.  Scand J Med Sci Sports. 2007;  17 18-24
• 20 Kubo K, Ohgo K, Takeishi R, Yoshinaga K, Tsunoda N, Kanehisa H, Fukunaga T. Effects of isometric training at different knee angles on the muscle-tendon complex in vivo.  Scand J Med Sci Sports. 2006;  16 159-167
• 21 Kubo K, Yata H, Kanehisa H, Fukunaga T. Effects of isometric squat training on the tendon stiffness and jump performance.  Eur J Appl Physiol. 2006;  96 305-314
• 22 Lees A, Vanrenterghem J, De Clercq D. The maximal and submaximal vertical jump. Implications for strength and conditioning.  J Strength Cond Res. 2004;  18 787-791
• 23 Lynn R, Talbot JA, Morgan DL. Differences in rat skeletal muscles after incline and decline running.  J Appl Physiol. 1998;  85 98-104
• 24 Markovic G, Jukic I, Milanovic D, Metikos D. Effects of sprint and plyometric training on muscle function and athletic performance.  J Strength Cond Res. 2007;  21 543-549
• 25 Nagano A, Gerritsen KGM. Effects of neuromuscular strength training on vertical jumping performance. A computer simulation study.  J Appl Biomech. 2001;  17 113-128
• 26 Pincivero DM, Green RC, Mark JD, Campy RM. Gender and muscle differences in EMG amplitude and median frequency, and variability during maximal voluntary contractions of the quadriceps femoris.  J Electromyogr Kinesiol. 2000;  10 189-196
• 27 Ratamess NA, Kraemer WJ, Volek JS, French DN, Rubin MR, Gómez AL, Newton RU, Maresh CM. The effects of ten weeks of resistance and combined plyometric/sprint training with the Meridian Elyte athletic shoe on muscular performance in women.  J Strength Cond Res. 2007;  21 882-887
• 28 Savelberg HHCM, Meijer K. Contribution of mono-and biarticular muscles to extending knee joint moments in runners and cyclists.  J Appl Physiol. 2003;  94 2241-2248
• 29 Thomas GA, Kraemer WJ, Spiering BA, Volek JS, Anderson JM, Maresh CM. Maximal power at different percentages of one repetition maximum: Influence of resistance and gender.  J Strength Cond Res. 2007;  21 336-342
• 30 Ullrich B, Brüggemann GP. Moment-knee angle relation in well trained athletes.  Int J Sports Med. 2008;  29 639-645
• 31 Ullrich B, Kleinöder H, Brüggemann GP. Moment-angle relations after specific exercise.  Int J Sports Med. 2009;  30 293-301
• 32 Wilson GJ, Newton RU, Murphy AJ, Humphries BJ. The optimal training load for the development of dynamic athletic performance.  Med Sci Sports Exerc. 1993;  25 1279-1286
• 33 Winter, DA. Biomechanics and Motor Control of Human Movement. Waterloo, John Wiley and Sons, 193. 3rd ed., Hoboken, John Wiley and Sons 2005
• 34 Zatsiorsky VM, Selujanov VN. The Mass and Inertia Characteristics of the Main Segments of the Human Body. In: Matsui H, Kabayashi K, eds. Biomechanics VIII-B. Champaign (IL): Human Kinetics; 1983: 1152-1159

Correspondence