Elford/Johnston and all others that are concerned about metatarsal Stress Fractures:
A stress fracture is a break in a bone cause by repetitive stress. It may occur in any bone, but is quite common in the metatarsal bones of the foot. There is often no recollection of injury. The patient may simply develop a painful forefoot after some activity, such a walking, sports, or stooping down onto the ball of the foot. A small crack develops in the cortex (outer shell) of the bone. Without proper treatment, this may progress to a "through and through" (overt) fracture of the bone. The second and third metatarsals are the most commonly affected. Metatarsal stress fracture may not become apparent on x-rays until a few weeks after the injury.
Symptoms
Sharp pain in the forefoot, aggravated by walking
Tenderness to pressure on the top surface of a metatarsal bone.
Diffuse swelling of the skin over the forefoot.
Causes
Decreased density of the bones (eg. osteoporosis)
Unusual stress on a metatarsal due to malposition or another forefoot deformity (eg. bunion)
Abnormal foot structure or mechanics (eg. flatfoot)
Increased levels of activity, especially without proper conditioning
Obesity
What you can do
Seek professional help as soon as possible
Keep weight off the foot
Ice the top surface of the forefoot for about 20 minuets every hour.
To reduce swelling, wrap the foot in a tensor bandage with moderate compression.
Wear a shoe with a very stiff sole.
What the doctor may do
Take x-rays to look for fracture
Order special diagnostic bone scans to establish a questionable diagnosis
Apply orthopedic taping and padding to relieve stress from the metatarsals.
Dispense a surgical/ trauma shoe to splint the foot.
Prescribe medication for pain and inflammation.
Use physical therapy in the later stages of healing.
Occasionally a plaster cast is necessary.
Other causes of forefoot pain
Morton's neuroma (benign tumor of a nerve running between the metatarsals)
Metatarsalgia (painful and inflammation of the metatarsal bones and their soft tissue sheath)
Capsulitis (painful and inflammation of the joints between the metatarsal bones and toes)
Tendonitis (inflammation of the tendons which course along the top of the foot)
Dislocation of a joint between a metatarsal and a toe (metatarsal-phalangeal joint)
Severe plantar callus(callus on bottom of the foot) or bursitis(an inflamed fluid-filled sac often between a bone and an area of pressure)
The only references to adding padding to the foot are after one has a diagnoses of a stress fracture and this is obviously useful to aid in healing. So the point I am trying to make is that one can not expect to prevent a stress fracture by simply wearing a little more padding in their shoes. Like I have suggested before the whole idea that one needs the padding of today's regular training shoes is just speculation/observation by some people which I clearly disagree with because of my own personal observation and other conflicting research that has already been verified.