1. Are we born to run? A biomechanical analysis of barefoot/minimalist running and its correlation to prevention of common running injuries Jason W. Harnett

2. Topics discussed Running in todays society Evolution of running in humans Invention of the modern day running shoe Biomechanics of shod vs. barefoot/minimalist running with analysis Common running injuries and causes Exercise prescriptions Case Study Culminating Activity 3. Running: todays society Today there are over 20 million runners in america that run more than 100 times each year(SGMA, 2012) $2.46 billion spent on running shoes (SGMA, 2012) Over $1 billion dollars in charity raised (SGMA, 2012) 4. Why Run? 5. Running and Injury Rates 79% of runners running over 12 miles a week will get injured at some point within a 12 month span (Van Gent et al. 2007) 6. Evolution of Running Are we born to run? 7. Environmental Shift Geologic evidence suggests a climate change over 2 million years ago. Woodlands disappeared, savannahs resulted (Hazarika, 2007) 8. Diet Change Austrailopithecus were frugivorous (mainly ate fruit) and were anatomically designed to walk and climb trees. Extinction due to environmental shift spawned the evolvement of home erectus about 2 million years ago (Hazarika, 2007). Homo erectus first hominid anatomically designed to run. Primarily a meat eater First throwing weapon was the spear dating back 500,000 years ago (Wilkens et al, 2012) Persistence hunter chasing prey to the point of exhaustion (Carrier, 1984) 9. Anatomical evidence we evolved to run 10. Why are we getting injured? If we evolved to run, it is counterintuitive that we get injured doing it. 11. Its gotta be the shoes! SpikeLee 12. Evolution of the Running Shoe First shoe discovered similar to the huarache 13. Evolution of the Running Shoe 1890s Reebok 14. Evolution of the Running Shoe 1925 Adidas 15. Evolution of Running Shoe 1963 Asics 16. Evolution of running shoe 1972 Nike 17. Evolution of the running shoe Modern day running shoe 18. Do shoes prevent injury? Van Gent study confirmed that injury rates have not seen any significant improvement since the 1970s How running shoes are commonly prescribed Motion control Stability Cushioned Marine Corps Study (Knapik, 2010) No study has ever verified running shoes reduce injuries! 19. Kenyan Runner 20. Modern Shod Runner 21. Minimalist Runner 22. Barefoot vs. Shod landing Forefoot striking Heel Striking 23. Shod Running Running in Shoes 75% of shod runners are heel strikers (Hasegawa, 2007) Why? 24. Kenyan running in Shoes 25. High Heeled Shoes? Shoes alters biomechanics, almost forces you to land heel first (Leiberman, 2010) 26. Barefoot/Minimalist Running 75-91%Landed with a mid foot/fore-foot strike pattern (leiberman, 2010) Why? Could this be the connection for injury prevention? 27. Biomechanics of Running What is Biomechanics? Analysis of Shod running vs. barefoot or minimalist running F = ma T = fd 28. Newtons 3rd Law For every action, there is an equal and opposite reaction Ground Reaction Forces 29. Forces of Heel Striking (barefoot) 30. Forces of forefoot striking (barefoot) 31. Forces of heel striking (shod) 32. Minimalist 33. Forefoot striking in shoes 34. Where We land.. Heel strikers had Longer stride length than forefoot runners (Squadronne, 2010) 35. What is Torque? Moment Arms! 36. Torques on the Joints Forefoot runners knee torques are reduced in flexion, internal rotation and varus (Kerrigan 2009, Standifird 2012) Decreased stride length = decreased hip adduction and extension moment of knee (Heiderscheit 2011) Morley et al (2010) showed a decrease of >5 degrees in calcaneal eversion range and velocity when forefoot striking = decrease pronation. 37. Why the increased Pronation? Heel strikers pronate more because there is no musculature to attenuate the forces. Forefoot strikers can control their pronation with the eccentric contraction of the tibialis posterior along with the transfering of forces to rotational motion of the talocrural joint. In other words, heel striking may cause excessive pronation because impact forces cannot be transmitted through a mobile ankle to the gastroc-soleus complex. Forces are transmitted by the subtalar joint, leading to rapid pronation forces. (Morley, 2010) 38. Lateral Heel Counter 39. Kinetic Chain Increased pronation= Internal tibial rotation = Increased valgus = Increased hip adduction 40. Torques 41. How to tell is you are over striding? Cadence = Amount of steps per minute Ideal number is 180 per minute Count number of steps in 6 seconds x 10 42. Video Analysis (istherea properformtorunning?) Can you find 2 biomechanical deficiencies that may be contributing to this runners injuries? 43. Results Heel striker = increased transient force (more force in short amount of time) Over strides = cadence of 160 steps per minute = increased torque on joints 44. Common Running Injuries Plantar Fasciitis IT Band Syndrome Patellofemoral Pain Shin splints Stress Fractures 45. Plantar Fasciitis Plantar Fasciitis is caused from weak intrinsic foot musculature, placing more stress on the fascia, and flexibility deficits in the posterior calf. (Kibler, 1991) Minimal/Barefoot strengthens intrinsic foot musculature and lengthens the posterior calf muscles (Robbins, 1987) 46. IT Band Syndrome The development of iliotibial band syndrome appears to be related to increased peak hip adduction and knee internal rotation. (Noehren, 2006) According to Heiderscheit (2011), increased stride length commonly seen in shod runners increases both hip adduction and internal torque of the knee. 47. Patella Femoral Pain Excessive impact shock during heel strike and at the propulsion phase of running may contribute to an increased risk of developing PFP (Thiis, 2008). Foot pronation causes a compensatory internal rotation of the tibia and femur which upsets the patellofemoral mechanism (Zappala, 1992). 48. Shin Splints According to Moen (2011), excessive pronation is linked with medial tibial stress syndrome. Shod and heel striking increases pronation motion and velocity (Morley et al. 2010) 49. Stress Fractures Studies suggest that runners with higher than normal tibial acceleration and vertical-force loading rates are at increased risk for tibial stress fractures (Crowell, 2010) Barefoot/minimal running reduces the rate of loading (Lieberman, 2011) 50. Summary 51. barefoot/minimalist is not for everyone Surgeries that have fusion impair proper mechanics of foot Other major orthopedic issues Overweight Impaired sensation (ie diabetics) 52. When to recommend change in form or footwear? When runners have tried everything and are still suffering from injuries and other symptoms When runner are serious about making a changeit requires time and dedication If patients are healthy and compliant, its easy to get injured. What about people with flat feet and orthotics?....Robbins study proves feet can be strengthened and arch heights increased. 53. Negative Effects There have been several studies that suggest running barefoot or in minimalist can increase injury rate Jenkins 2011 meta-analysis study: Flawed studies, no formal transitional training ever took place Runners were given minimalist shoes without assuring they knew how to properly use them. 54. Transitioning Running Form Shoes have essentially weakened our feet by shortening the Achilles and weakening the intrinsic and extrinsic foot muscles and which possibly increases injury. (Robbins, 1987) 4x more likely to develop flat feet wearing shoes (Rao, 1992) Strengthening and stretching program must be implemented before attempting to run with a new gait = 55. How to transition Shod to minimal/barefootStart Slow! 4-6 month process Most people have been shod or heel strike runners their entire life. 56. Transition Phase - Flexibility Assess motion at the ankle and forefoot 57. Transition Phase - Flexibility Increase Flexibility 58. Muscle coordination 85% of weight needs to be controlled with big toe during single leg stance during running Yoga Toes 59. Foot and Ankle Strengthening 60. Foot and Ankle Strengthening Plantar Flexors 61. Foot and Ankle Strengthening Flexor Hallucis Longus Flexor Digitorum Longus 62. Foot and Ankle Strengthening Dorsal Interossei & Plantar Interossei & Abductor Hallucis Adductor Hallucis 63. Foot and Ankle Strengthening Flexor Hallicus Brevis and Flexor Digitorum Brevis 64. Foot and Ankle Strengthening Intrinsic Foot Musculature 65. Proprioception Single Leg Balance Perform with Intrinsic Foot Muscular Exercises Rotate Ball Toss Eyes Closed Foam Mat 66. Dynamic Preparation 67. Group Case Study 34 year old male recreational runner whom recently began training for Flying Pigs Marathon. He comes to you complaining of anterior knee pain. Questions? Formulate groups and discuss questions you would ask, tests and measures you would conduct, and exercise prescription and education you would advise this particular patient. 68. Patient Running 69. Culminating Activity Lets experience the difference!! Audience will run shod for 30 seconds on treadmill Then run barefoot for 30 seconds Note the differences you personally feel 70. Conclusion Scientists agree that we have evolved to run Shoes alter biomechanics of running Injury rates have not changed in over 30 years and no study confirms shoes prevent injuries Heel striking increases rates of loading and over-striding, which increases torques on joints Both shoes and heel striking encourage excessive pronation Shoes are proven to weaken intrinsic foot musculature and shorten Achilles tendons There is enough anecdotal evidence to suggest these facts may contribute to common overuse running injuries Could less be more????? 71. The Foot 26 bones 33 articulations Arch that 4 muscle layers thick Several tendons and ligaments The human foot is a masterpiece of engineering and a work of art. - Leonardo di Vinci 72. references Kibler WB, Goldberg C, Chandler TJ. Functional biomechanical deficits in running athletes with plantar fasciitis. The American Journal of Sports Medicine. 1991;19(1):66-71. Hazarika, Manji (1630 June 2007). 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