Sport injuries fall into two categories: Intrinsic and Extrinsic risk factors. Running injuries are all classified as Intrinsic.
Intrinsic risk factors:
Often attributed directly to the Martini-sippers' past experiences with running.
Stanford University determined that disabling problems in the legs were five times as likely to occur in sedentary individuals, compared to athletes who engaged in running.
The lesson? If you want your legs to fall apart, your best strategy is to do nothing. If you become sedentary, your leg muscles and bones will decline in function at a rather brisk and predictable rate.
Heel impact – amplitude of the impact peak is 2-4 times body weight.
Active peak – center of mass of the body over the weightbearing foot.
“Active” – duration of curve is long enough to allow the neuromuscular system to act in a feedback mode while the foot is on the ground. (Nigg, B.M. Biomechanics of running shoes).
Internal Active Forces
The maximal active internal force (body weight) for various joints of the lower extremity during walking and running.
Walking |
Running |
|
---|---|---|
Hip |
5.0 – 5.8 |
10-14 |
Knee |
3.2 – 7.0 |
7-18 |
Ankle |
5.2 |
10.5-12 |
Subtalar joint |
4.0 |
8-10 |
(Nigg, 1986)
Ground-reaction forces at the foot and the shock transmitted through the body all the way up to the head when running on different surfaces varies very little as one transfers from very soft to very hard surfaces.
All runners coordinate the actions of the muscles, tendons, and ligaments in their legs so that the overall leg behaves like a single, mechanical spring during ground contact.
The basic idea is that today's athletic shoes tend to treat human feet as fragile objects which need lots of cushioning.
This cushioning creates a feeling of comfort which 'knocks out' an athlete's intrinsic musculoskeletal defense mechanisms against impact forces and perhaps increases the risk of injury.
Faulty equipment- running shoes start to deform after 250 miles.
Equipment changes- switching from training shoes to spikes changes the running mechanics.
Changes in training surface - running on the beach or side of the road.
Changes in training-frequency, intensity, and duration.
Runners pick up the tab for high mileage for reasons other than function.
Being a Mercedes runner is not without certain advantages. For example, when you become a high-mileage runner you are more likely to become acquainted with members of the sports-medicine community in your city or town, and they are usually not bad folks.
Grade 1 – Pain after exercise, usually felt hours after exercise.
Grade 2 – Discomfort with exercise, not pain and does not reduce performance.
Grade 3 – Pain interferes with performance.
Grade 4 – Pain prevents any type of running.
The exceptions
Severe Biomechanical abnormalities
Severe degeneration of tissue (Achilles tendinosis)
Abnormal joints – A joint is never the same after major surgery
Need to understand the fears and psyche of the runner.
Most Injuries are diagnosed with the hands not an X-ray.
All running injuries have a cause.
First treat the Biomechanical abnormality then the injury.
Rest will cure the acute symptoms but will not correct the cause of the injury.
Only injuries that make running impossible (stress fx.)