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The preferred balance leg absorbs more energy than the preferred striking leg in single leg landings

The preferred balance leg absorbs more energy than the preferred striking leg in single leg landings. Steve McCaw, Mitch Waller, Kevin Laudner & Pete Smith. Landing. Landing = moving body to rest Integral to many sport activities and Activities of Daily Living

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The preferred balance leg absorbs more energy than the preferred striking leg in single leg landings

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  1. The preferred balance leg absorbs more energy than the preferred striking leg in single leg landings Steve McCaw, Mitch Waller, Kevin Laudner & Pete Smith

  2. Landing • Landing = moving body to rest • Integral to many sport activities and Activities of Daily Living • Implicated in a variety of lower extremity injury • Ankle sprain • Osteoarthritis • ACL damage • A good model to investigate • Mechanism(s) of injury • Mechanism of energy absorption • Interesting phenomenon on its’ own.

  3. Landing Research Perform two leg landing, only one leg analyzed • “Dominant Leg” • Madigan & Pitcoe, J EMG & Kinesiology, 2003 • Effects of fatigue on landing biomechanics • Pollard et al, Clin J Sport Med, 2006 • Pre and post season evaluation of injury training • “Preferred Limb” (lead leg when drop jumping) • Kulas et al, J App Biomech, 2006 • A, K & H energy absorption and LE impedance Bilateral comparisons of Lower Extremities • “Right” vs “Left” • Schot et al, MSSE, 1994 • Quantify bilateral asymmetry • “Dominant” vs “non-dominant” • Hewett et al, J Bone Joint Surg, 2004 • Investigate MS changes with maturation

  4. Hewett, Meyer & Ford

  5. Hewett, Meyer & Ford Increased maximum valgus angle reflects decreased neuromuscular control

  6. General Concept of Lateral Preference • Guiard, Y. (1987). Asymmetric Division of Labor in Human Skilled Bimanual Action: The Kinematic Chain as a Model. J Motor Behavior, 19:4:486-517. • Unimanual tasks* • Dart throwing, brushing teeth • Bimanually symmetric • In phase: Rope skipping, weightlifting • Out of phase: rope climbing • Bimanually asymmetric • Dealing cards, cursive writing • Individuals exhibit a preference for one of the two possible ways of assigning two roles to two hands

  7. Dynamic Dominance Hypothesis • Sainburg, RL. (2005). Handedness: differential specialization for control of trajectory and position. Exerc Sport Sci Rev,33:4:206-213. • Hemispheres /limb systems specialized for complementary functions • Dominant side: controlling limb trajectory dynamics • Non-dominant side: controlling limb position • Non-dominant arm slightly more accurate • Dominant arm used less elbow muscle torque

  8. Applicable to Lower Extremity? • Nunome et al, 2006. Segmental dynamics of soccer instep kicking with the preferred and non-preferred leg. J Sports Science, 24:5:529-541 • Highly skilled players achieved a well-coordinated inter-segmental motion for both the preferred and non-preferred leg • Faster leg swing observed for the preferred leg • result of larger muscle moment

  9. Purpose Compare LE kinetics and energetics between single-leg drop landings onto preferred striking & balance legs Hypothesis Preferred balance limb will absorb more energy than the preferred striking limb

  10. 21 college-age female volunteers 21.5±2.2 y 1.64 ± 0.08 m 65.2 ± 8.2 kg Regular lander Free of LE traumas 10 trials R & L leg Random order “Land comfortably” 32cm bench Force Platform (1000 Hz ) 3 cameras (200 Hz) Sagittal plane kinematics Inverse dynamics for JMF JMP = JMF •ω Paired t-tests (α = .05) Methods

  11. Modified Waterloo Handedness Questionnaire • Identify preferred “action” leg in bilaterally asymmetric tasks • Strong agreement with ball “striking” leg

  12. Joint Position Preferred Striking Leg Preferred Balance Leg Joint Angle (degrees) Time to Max Knee Flexion (%)

  13. Joint Torque Preferred Striking Leg Preferred Balance Leg Joint Torque (N·m•kg-1 ) Time to Upright Stance(%)

  14. JointPower Preferred Striking Leg Preferred Balance Leg Joint Mechanical Power (W/kg) Time to Upright Stance(%)

  15. Percent Energy Absorption Hip ± SD% Hip±SD% Relative joint contributions will be significantly different. Knee±SD% Knee ± SD% Ankle±SD% Ankle ± SD% Preferred Striking Preferred Balance

  16. Conclusions • Bilateral Preference Concept [Guiard, 1987] & Dynamic Dominance Hypothesis [Sainburg, 2005] may apply to lower extremity • PBL better energy absorber than PSL • LE comparisons should identify analyzed limb according to preference rather than dominance • Appropriate limb terminology should be utilized

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