Human Locomotion Focus on Walking Taylor Murphy HSS 537

Objectives  Understand the relationship between center of gravity, stability, and mobility  Know the importance of force  Identify the importance of the transition from standing to walking  Understand the fundamentals of walking  Review the main points of locomotion

Important Terminology  Center of Gravity (COG): the balance point or point where all the weight of the body or object is concentrated  Stability: when an object is in equilibrium  Mobility: when an object is in motion

Center of Gravity  Two conditions must be met: All the linear forces acting on the body must be balanced All the rotary forces (torques) must be balanced  Location of COG of humans in normal standing position varies with body build, age, and sex

Stability and Equilibrium  All objects at rest are in equilibrium  All objects at rest are not equally stable Stable Equilibrium Unstable Equilibrium Neutral Equilibrium

Stable vs. Unstable vs. Neutral

Factors Affecting Stability  Size of base of support  Height of the COG  Relation of the line of gravity to the base of support

Law of Reaction  Newton’s Third Law: for every action there is an equal and opposite reaction

Gait Cycle  Gait Cycle: is the continuous repetitive pattern of walking or running  Gait Cycle is comprised of 2 phases Stance Phase:  Heel Strike  Foot Strike  Mid Stance  Toe Off Swing Phase:  Acceleration  Mid Swing  Deceleration

Gait Cycle (cont.)

Stance vs. Swing Phase

Additional Walking Terminology  Stride: is from heel strike on one leg to the next heel strike with the same leg  Stride Length: is the distance covered during a single stride  Step: begins with the heel strike of one leg and ends with the heel strike of the contralateral, or opposite, leg

Objectives of Gait  Maintain balance  Produce/Resist/dissipate forces  Move body in intended direction  Conserve energy  Shock Absorption

In Conclusion  Normal Locomotion is achieved with complex combinations of stability, mobility, motor control, and force  These factors will work congruently to provide the most shock- absorbing and energy efficient forward movement

References  BMC Musculoskeletal Disorders 17.6 (2005): 1-9. Print.  Kinesiology: Scientific Basis of Human Motion. 11th ed. New York: McGraw-Hill, Print.  Normal Human Locomotion, Part 1: Basic Concepts and Terminology 6 (2006): 1-8. Print.  Normal Human Locomotion, Part 2: Motion, Ground Reaction Force and Muscle Activity 6 (2006): Print.  Sports Injury Clinic. Sports Injury Clinic, 23 Apr Web. 20 Nov

Thank You  Human Locomotion with a focus on walking