Walking, Jumping, and Landing Eric A. Nauman, Ph.D. Director, HIRRT Laboratory School of Mechanical Engineering, Weldon School of Biomedical Engineering, Department of Basic Medical Sciences Purdue University Post-cranial anatomy
• Single-legged stance phase of gait • Want to calculate the force on the head of the femur • Draw a free body diagram
Post-cranial anatomy
• Knowing the weight of the individual, calculate the force exerted by the gluteus medius and the joint contact force during the single-legged stance phase of gait.
Angle between Skeletons Distance to Muscle moment muscle force and center of gravity, arm, c, (mm) vertical (degrees) b, (mm)
Australopithecus 66 36 15
Homo sapiens (Amerindians, 79±5.2 50.6±1.7 12.9±2.2 male)
Homo sapiens (Amerindians, 82.9±4.5 45.4±3.8 13.3±2.8 female) Leg Injuries in Basketball are Related to Head Injuries in Football?
• Kevin Ware • Kevin Ware - High Definition Weightlifting – Clean and Jerk
http://www.owresource.com/lifts/index.php Weightlifting – Clean and Jerk
http://www.owresource.com/lifts/index.php Weightlifting
Initiation and progression of a patellar tendon rupture by a weightlifter in Olympic competition. From Sports Biomechanics by Roger Bartlett (E&FN Spon, New York, 1999).
Weightlifting
A schematic of a weightlifter’s lower legs just before he attempts to press the weight above his head. Note that we have included the reactions at both knees and both patellar tendons. Realistically, this problem requires a dynamic analysis, but we can learn a lot by starting with a static representation. Geometry
• How does the angle between the patellar tendon change as a function of position? Experimental Results
Peak Peak Force (N) Stress (Mpa) • Human ACL1 (16-26) 1725 37.8 • Human ACL1 (48-86) 734 13.3 • Human ACL2 (22-35) 2160 • Human ACL2 (60-97) 658 • Human LCL3 309 • Human Patellar Tendon 8400 N* 1 Noyes, F.R. et al. J Bone Jt Surgery, 1074-1082, 1976. 2 Woo, S.L. et al. Am J Sports Medicine, 217-225, 1991. 3 Sugita, T. et al. Am J Sports Medicine, 466-472, 2001. * Estimated based on Noyes et al., 1984. (from young donors) Becoming Batman
§ Becoming Batman by E. Paul Zehr Becoming Batman
§ What is the highest point from which Batman could leap and not destroy his legs? What are the weak points? What are the weak points?
• Bones (130 MPa in tension, 190 MPa in compression) • Patellar Tendon (3660 ± 830 N) • Meniscus - ?? • Cartilage (14 – 59 MPa) • Lower back - what is the weak link in the spine? Bones of the Spinal Column
Figure 2. Superior and lateral view of a typical cervical, thoracic, and lumbar vertebrae [1] Ligaments of the Spinal Column • The 6 ligaments of the spinal column – Anterior longitudinal ligaments – Posterior longitudinal ligaments – Joint capsules
– Ligamentum flavum – Interspinous ligament – Supraspinous ligament
• Ligaments positioned vertically along the spinal column Motion Segments
Disc degeneration; Herniation; Osteoporosis; Burst fractures; Annular tears
From Mow and Hayes Text