The effect of leg length asymmetry on leg stiffness and dynamic postural stability in vertical landing

Background: Assessment of asymmetries in dynamic postural stability and lower extremities kinetics during landing technique are considered factors for injury prevention and achieve optimal athletic performance. Nevertheless, the relationship between these factors has not been established. This study aimed to investigate the effects of leg length asymmetry on dynamic stability and leg stiffness upon initial contact with the ground after vertical landing. Methods: Twenty healthy adult men landed on the ground from a height of 30 cm; we measured leg length, leg stiffness, lateral pelvic tilt angle, peak vertical force (PVF), the loading rate, dynamic postural stability index (DPSI), and the correlations among these variables. Results: At initial contact, the right leg was significantly longer and showed greater lateral pelvic tilt than the left leg. These characteristics increased the loading rate at the time of PVF on the right leg, which in turn affected leg stiffness and pelvic tilt. The DPSI was also decreased for the right leg compared with the left leg. In the correlation analysis, we observed strong, positive correlations and high explanatory power for PVF, the loading rate, vertical stability index, and DPSI, with r ≥0.822 and R2${}^2$ ≥57%. Conclusions: The identified associations support the validity of the result, showing that the right leg failed in its rapid stabilization strategy. The leg length asymmetry is suspected to affect asymmetrical impact patterns, DPSI, and leg stiffness. Given the number of individuals with leg-length inequalities who play sports relying on jumping and landing patterns, reducing the rate of injury possibly incurred.

vertical landing; leg stiffness; dynamic postural stability; asymmetry

[1] Niu W, Wang Y, He Y, Fan Y, Zhao Q. Kinematics, kinetics, and electromyogram of ankle during drop landing: a comparison between dominant and non-dominant limb. Human Movement Science. 2011; 30: 614–623.

[2] Schot PK, Bates BT, Dufek JS. Bilateral performance symmetry during drop landing: a kinetic analysis. Medicine and Science in Sports and Exercise. 1994; 26: 1153-1159.

[3] Carpes FP, Mota CB, Faria IE. On the bilateral asymmetry dur-ing running and cycling–a review considering leg preference. Physical Therapy in Sport. 2010;11:136–142.

[4] Serrien DJ, Ivry RB, Swinnen SP. Dynamics of hemispheric spe-cialization and integration in the context of motor control. Na-ture Reviews Neuroscience. 2006; 7: 160–166.

[5] Čuk, T., Leben-Seljak, P., & Štefančič, M. Lateral asymmetry of human long bones. Variability and Evolution. 2001; 9:19–32.

[6] Kapreli E, Athanasopoulos S, Papathanasiou M, Van Hecke P, Keleki D, Peeters R, et al. Lower limb sensorimotor network: issues of somatotopy and overlap. Cortex. 2007; 43: 219–232.

[7] Luft AR, Smith GV, Forrester L, Whitall J, Macko RF, Hauser T, et al. Comparing brain activation associated with isolated upper and lower limb movement across corresponding joints. Human Brain Mapping. 2002; 17: 131–140.

[8] Murray-Leslie CF, Lintott DJ, Wright V. The knees and ankles in sport and veteran military parachutists. Annals of the Rheumatic Diseases. 1977; 36: 327–331.

[9] Cummings G, Scholz JP, Barnes K. The effect of imposed leg length difference on pelvic bone symmetry. Spine. 1993; 18: 368–373.

[10] Fann AV. The prevalence of postural asymmetry in people with and without chronic low back pain. Archives of Physical Medicine and Rehabilitation. 2002; 83: 1736–1738.

[11] Boden BP, Dean GS, Feagin JA, Garrett WE. Mechanisms of anterior cruciate ligament injury. Orthopedics. 2000; 23: 573–578.

[12] Wikstrom EA, Powers ME, Tillman MD. Dynamic stabilization time after isokinetic and functional fatigue. Journal of Athletic Training. 2004; 39: 247.

[13] Chijimatsu M, Ishida T, Yamanaka M, Taniguchi S, Ueno R, Ikuta R, et al. Landing instructions focused on pelvic and trunk lateral tilt decrease the knee abduction moment during a single-leg drop vertical jump. Physical Therapy in Sport. 2020; 46: 226–233.

[14] Critchley ML, Davis DJ, Keener MM, Layer JS, Wilson MA, Zhu Q, et al. The effects of mid-flight whole-body and trunk rotation on landing mechanics: implications for anterior cruciate ligament injuries. Sports Biomechanics. 2020; 19: 421–437.

[15] James C. Considerations of movement variability in biomechan-ics research. Innovative Analyses of Human Movement. 2004: 29–62.

[16] Farley CT, Houdijk HH, Van Strien C, Louie M. Mechanism of leg stiffness adjustment for hopping on surfaces of different stiff-nesses. Journal of Applied Physiology. 1998; 85: 1044–1055.

[17] Silder A, Besier T, Delp SL. Running with a load increases leg stiffness. Journal of Biomechanics. 2015; 48: 1003–1008.

[18] Wikstrom EA, Tillman MD, Smith AN, Borsa PA. A new force-plate technology measure of dynamic postural stability: the dynamic postural stability index. Journal of Athletic Training. 2005; 40: 305.

[19] Hoffman M, Payne VG. The effects of proprioceptive ankle disk training on healthy subjects. The Journal of Orthopaedic and Sports Physical Therapy. 1995; 21: 90–93.

[20] Verhagen E, Bobbert M, Inklaar M, van Kalken M, van der Beek A, Bouter L, et al. The effect of a balance training programme on centre of pressure excursion in one-leg stance. Clinical Biome-chanics. 2005; 20: 1094–1100.

[21] Bullimore SR, Burn JF. Consequences of forward translation of the point of force application for the mechanics of running. Jour-nal of Theoretical Biology. 2006; 238: 211–219.

[22] Plagenhoef S, Evans FG, Abdelnour T. Anatomical data for analyzing human motion. Research Quarterly for Exercise and Sport. 1983; 54: 169–178.

[23] Konradsen L. Sensori-motor control of the uninjured and injured human ankle. Journal of Electromyography and Kinesiology. 2002; 12: 199–203.

[24] Konradsen L, Voigt M. Inversion injury biomechanics in func-tional ankle instability: a cadaver study of simulated gait. Scan-dinavian Journal of Medicine and Science in Sports. 2002; 12: 329–336.

[25] Dufek JS, Bates BT. Biomechanical factors associated with in-jury during landing in jump sports. Sports Medicine. 1991; 12: 326–337.

[26] Pappas E, Carpes FP. Lower extremity kinematic asymmetry in male and female athletes performing jump-landing tasks. Jour-nal of Science and Medicine in Sport. 2012; 15: 87–92.

[27] Vagenas G, Hoshizaki B. A Multivariable Analysis of lower ex-tremity kinematic asymmetry in running. International Journal of Sport Biomechanics. 1992; 8: 11–29.

[28] Irmischer BS, Harris C, Pfeiffer RP, Debeliso MA, Adams KJ, Shea KG. Effects of a knee ligament injury prevention exercise program on impact forces in women. Journal of Strength and Conditioning Research. 2004; 18: 703–707.

[29] Crossley K, Bennell KL, Wrigley T, Oakes BW. Ground reac-tion forces, bone characteristics, and tibial stress fracture in male runners. Medicine and Science in Sports and Exercise. 1993; 31: 1088–1093.

[30] Mizrahi J, Susak Z. Analysis of parameters affecting impact force attenuation during landing in human vertical free fall. En-gineering in Medicine. 1982; 11: 141–147.

[31] Hennig EM, Lafortune MA. Relationships between ground reac-tion force and tibial bone acceleration oarameters. International Journal of Sport Biomechanics. 1991; 7: 303–309.

[32] Hewett TE, Lindenfeld TN, Riccobene JV, Noyes FR. The ef-fect of neuromuscular training on the incidence of knee injury in female athletes. The American Journal of Sports Medicine. 1999; 27: 699–706.

[33] McMahon TA, Valiant G, Frederick EC. Groucho running. Jour-nal of Applied Physiology. 1987; 62: 2326–2337.

[34] Farley CT, Blickhan R, Saito J, Taylor CR. Hopping frequency in humans: a test of how springs set stride frequency in bouncing gaits. Journal of Applied Physiology. 1991; 71: 2127–2132.

[35] Farley CT, González O. Leg stiffness and stride frequency in human running. Journal of Biomechanics. 1996; 29: 181–186.

[36] Ross SE, Guskiewicz KM. Examination of static and dynamic postural stability in individuals with functionally stable and un-stable ankles. Clinical Journal of Sport Medicine. 2004; 14: 332–338.

[37] Baker J, Côté J, Abernethy B. Learning from the experts: prac-tice activities of expert decision makers in sport. Research Quar-terly for Exercise and Sport. 2003; 74: 342–347.

[38] Besier TF, Lloyd DG, Ackland TR. Muscle activation strategies at the knee during running and cutting maneuvers. Medicine and Science in Sports and Exercise. 2003; 35: 119–127.

[39] Borotikar BS, Newcomer R, Koppes R, McLean SG. Combined effects of fatigue and decision making on female lower limb landing postures: central and peripheral contributions to ACL injury risk. Clinical Biomechanics. 2008; 23: 81–92.

[40] McLean SG, Samorezov JE. Fatigue-induced ACL injury risk stems from a degradation in central control. Medicine and Sci-ence in Sports and Exercise. 2009; 41: 1661–1672.

[41] Proske U. Kinesthesia: the role of muscle receptors. Muscle and Nerve. 2006; 34: 545–558.