plan for this week (8/31/04) and next (9/7/04) n tuesday 8/31/04: -website homework due -complete...

Plan for This week (8/31/04) and next (9/7/04)

Tuesday 8/31/04:- Website homework due- Complete perspectives and Ex Equip Evaluation Article- Begin Biomech considerations for ground-foot interfaces

Thursday 9/02/04:- Complete Biomech ground-foot interfaces- Read Ch 2 for next class and submit 2 questions

Tuesday 9/07/04- Review Ch 2 and PowerPoint on Running and Court Shoes

Thursday 9/09/04- Guest speaker on pedorthics: Eddie Olson and Johanna, Olson Shoe

Shop in Aggieville

Biomechanical Considerations for Foot-Ground Interfaces

Mechanical Aspects of foot-ground interfaces Anatomical aspects of foot-ground interfaces Question for next class:

- What masters should a foot-ground interface serve, or what is (are) the functions of a foot-ground interface?

Mechanical Aspects

Friction ( Fig 1.1, p. 5)- depends on normal force and nature of surfaces

Ground reaction forces (GRF)- magnitude and rate of increase of vertical GRF

are most important (round off the peaks) Pressure (round off the peaks) Weight of shoe – MOI Stability

Coefficient of Sliding Friction

Force Plates – Measurement of ground reaction forces

Force Vectors on different parts of the

foot:

GRF While Walking

GRF while Running

Foot pressures while walking:

Foot pressures while running

Other Mechanical Factors Moment of Inertia (MOI)

- With a shoe, MOI about knee or hip axis increases directly with weight Stability is directional and can be increased by increasing shoe

sole in direction of desired stability Stability decreases with height of foot &Increases with distance from COMto edge of base of support

Anatomical Aspects

Foot structure Foot misalignments Leg and thigh misalignments (Fig 1.6, p.10)

- Lateral deviations• Valgus - segment goes outward from prox to distal• Varus - segment goes inward from prox to distal• Genu varus at knee - bowlegged

- Torsional deviations - Tibial torsion - tibia rotated outward (toe out)

• femoral torsion - femur rotated in relative to tibia

Foot Bones

Foot misalignments

Subtalar Axis:

Types of foot arches – the “Wet test”

Foot Pronation and Tibial Torsion:

Tibial torsion

Rearfoot Movement During Running:

Plantar Fascium

What is the plantar fascium? - attaches to calcaneus posteriorly and to the first row of phalanges anteriorly

What is its function?- passive intertarsal stabilization

Arches of the Foot:

Plantar Fascium:Plantar fascitis is 4th most common cause of pain among runners(1st – knee pain, 2nd – shin splints, 3rd- achilles tendonitis)

Plantar Fascitis – 4th leading cause of pain in runners

What causes plantar fascitis(inflamation of plantar fascium)?- anatomic anomalies

• microtears in fascium and bone spurs• inadequate flexibility of plantar flexors• inadequate strength of plantar flexors• functional pronation (eversion and abduction)

- overuse• overweight• poorly designed and poorly fitted shoes• running and jumping on hard surfaces• sudden increase in stress

Treatment- remove the cause(s)- Therapeutic treatment to promote body’s natural healing

• NSAIDS• Intermittent ice and heat• Ultrasound, diathermy, massage

Applications to shoe design First, ask the question: What functional

masters must the shoe/boot/skate serve- Friction?- Spread pressure over large area?- Force management?- Stability – which direction?- Protection from elements (e.g., cold, wet, rocks)- Other?

Assignment for next class

- Read Chapter 2 of Kreighbaum book on running and court shoes

- Submit 2 questions from your reading on running and court shoes that could be used as exam questions, or about concepts you don’t understand or want to know more about.

Plan for This week (8/31/04) and next (9/7/04) (revised)

Tuesday 8/31/04:- Website homework due- Complete perspectives and Ex Equip Evaluation Article- Begin Biomech considerations for ground-foot interfaces

Thursday 9/02/04:- Complete Biomech ground-foot interfaces- Begin unit on running and court shoes- Read Ch 2 for next class and submit 2 questions

Tuesday 9/07/04- Complete Unit on Running and Court Shoes- Begin Unit on Hiking Boots and Shoes- Read Ch 3 and submit 2 questions for discussion

Thursday 9/09/04- Guest speaker on pedorthics: Eddie Olson and Johanna, Olson Shoe Shop in Aggieville