Biomechanics of Sport Shoes (Lecture 4) Flashcards
Lecture 4 of 5
Describe the anatomy of a sport shoe
How are running and basketball shoes adapted for their sport?
Running shoes - more cushioned midsole and heel to shock absorb heel strikes
Basketball shoes - High top design and harder heel counter provide more lateral stability
What is the difference between running and walking?
The airborne period of time between toe off and foot strike of opposite feet is the difference
What does FS, MS and TO stand for in this schematic?
- Foot strike
- Mid strike
- Toe Off
How do animals and humans absorb shock when running differently
- Animal shave a knee-ankle damper system that absorbs the ground reaction force time
- Humans land on their heels with straight legs while running so the shoes absorb the shock
How do barefoot runners biomechanics differ from a regular runner?
- Barefoot runners don’t have heel shock absorbers so change the landing mechanics
- Barefoot runners run with a flexed knee and ankle joint to absorb the shock of impact
What is a downside to barefoot running?
- Most of us are not used to running like this, so earlier fatigue and potential risk of injuries due to the additional contact if suddenly changed to this style of running
What did Benno Nigg determine about the plantar region? and what is the purpose of the main receptor?
- The plantar region senses for external stimuli and there are 3 types of receptors
- The dominant receptor SA 2 Mechana, is sensitive to pain, forcing the runner to change their posture/biomechanics to adjust
- He theorises that this receptor is not stimulated in running shoes because of the thick midsole cushioning and so runners do not adjust to damage leading to repetitive impact injuries
What is this graph showing?
- When rearfoot striking (conventional running) there is a primary vertical component called the impact peak which tells us the loading rate and initial ground contact force
- Then following this is another peak which is the active peak where we absorb additional force to the peak, then begin pushing back off the ground
- In forefoot striking (barefoot running) the energy is absorbed by the knee and ankle and so there is no initial impact peak
What factors may worsen or reduce the initial impact peak?
- The distance/height or force that is being absorbed by the heel strike
- The thickness of the shoe midsole (thicker cushioning will absorb more)
How can worn shoes lead to injury?
- The cushionability drops
- leading to greater repetitive stress on heel and plantar region
- Chronic injury and pain
What are some common injuries caused by repetitive stress?
- Plantar fasciitis, heel spur pain, shin splints
What is the foot bed concept?
- A bed is comfortable if it conforms to the human body contour
- ie. the areas of high pressure deform more to spread the pressure
- the sole is the ‘foot bed’ and if it can distribute body weight over a larger surface area to avoid peaks, it will be more comfortable
Why is it that hard insoles are beneficial for the sprinting performance?
- All the lower limb joints flex to lose energy and then extend generating energy upon push off
- The metatarsal-phalangeal joint soes not do this, it only bends losing energy
- Hard soles and carbon plates have been put in shoes to avoid this bending and by extension reduce the energy loss
- This has been recorded to a 2% saving of energy
What is special about these shoes?
- They are said to have the same level of compliance and energy return after 1 million compressions as the first