Interaction between pre-landing activities and stiffness regulation of the knee joint musculoskeletal system in the drop jump: implications to performance

Abstract

The purpose of the present study was to investigate the interaction between the pre-landing activities and the stiffness regulation of the knee joint musculoskeletal system and the takeoff speed during a drop jump (DJ). Nine healthy male subjects performed a DJ test from the height of 50 cm. The surface electromyographic (EMG) activity of the vastus lateralis (VL) muscle was recorded to evaluate both the pre-landing and post-landing muscle activation levels. Simultaneous recording of the jumping motion and ground reaction force was performed by a high-speed video camera (100 frames x s(-1)), and a force platform was employed to allow joint moment analysis. Joint stiffness was calculated by a linear regression of the knee joint moment/angle relationship. Elasticity of the knee extensor muscle during DJ was estimated by means of a four-element muscle model consisting of a parallel elastic component, a series elastic component (SEC), a viscous damper, and a contractile element. DJ performance correlated positively with the positive peak power of the knee joint (P < 0.01) and with the moment of the knee joint at the end of stretch (P < 0.01). However, there was no significant relationship between DJ performance and the positive peak power of the ankle joint. The knee joint moment at the end of stretch correlated with the SEC stiffness during the transmission phase from the end of the initial impact to the onset of the concentric action (P < 0.01) and with the maximum rate of isometric force development of the knee extensors (P < 0.01). Multiple regression analysis showed that the SEC stiffness during the transmission phase of the knee joint can be explained by a combination of the pre-activity of the VL muscle and the knee joint angular velocity at touchdown (F = 5.76, P < 0.05). These results seem to emphasize the functional significance of the pre-programmed activity for controlling the subsequent stiffness regulation and then contributing to the performance in DJ. Thus, it can be suggested that the centrally pre-programmed activity and the associated elastic behavior of the SEC in the knee extensor muscle in conjunction with the muscle contractile property play a major role in regulating the performance in DJ.

Anticipatory motor patterns limit muscle stretch during landing in toads

“…Studies have shown that muscles become active prior to impact and that the nature of this pre-activation changes based on the height of the drop [10,11]. The pre-activation of muscles, specifically the co-contraction of antagonists, prior to impact is thought to function to stiffen the joints and may prevent limb collapse at impact [15]. The pre-activation of muscles may also function to increase the sensitivity of stretch receptors and prime the sensory feedback response of the limb after impact [9].…”

“…Such tuning of muscle activity in anticipation of impact is not limited to humans and has been documented in non-human primates [12], cats [13] and most recently in toads [14]. The anticipatory recruitment of landing muscles has thus far been considered a critical mechanism for stiffening joints and preventing the collapse of limbs at impact [15]. However, a complementary function of anticipatory muscle recruitment may be to alter the operating length of the muscle prior to an active stretch.…”

The Effect of 8 Weeks of Core Stability Muscles Training on Kinetics of Single-Leg Landing

“…Co-Contraction of flexor and trunk extensor muscles and lower extremity muscle increases rigidity and protection of lower extremity joint structures in a way that magnitude of many contact forces during landing increase trunk stiffness [41]. Iida et al (2011) reported that contact force has positive relationship with maximum voluntary contraction of rectus abdominis.…”

“…Previous studies showed preactivation of the lower extremity [42][43][44] and trunk muscles [37,44] before contacting with the ground during landing. Okubo et al (2013) investigated abdominal muscles activities during the jump landing.…”

Hip and Knee Extensor Moments Predict Vertical Jump Height in Adolescent Girls

“…Previous authors have found that joint moments and kinematic variables can be used to predict, through linear regression analyses, the vertical height in which males jump (1,15). For example, men have exhibited that increased knee and hip extensor moments are correlated with an increased vertical jump height (1,15,18). This indicates that hip and knee extensor musculature strength may be critical components that could be targeted in a strength and conditioning program that aims to improve jumping performance.…”