Table 2.

Potential risk factors for stress fractures.

Intrinsic Factors
Demographic characteristics	Female sex
	Age, with athletes over 40 and under 18 most at risk
	Race (other than white)
Anatomic factors	High foot arches
	Uneven leg and/or foot alignment
	Flat feet (pes planus)
	Knock-knees
	High quadriceps angles
	Leg length discrepancies
Bonce characteristics	Geometry
	Low density
	Uneven leg and/or foot alignment
Physical fitness	Lower aerobic fitness
	Lower muscle strength
	Lower muscle endurance
	Lower flexibility
	Body composition
	Body stature
Health risk behaviors	Sedentary lifestyle
	Tobacco use
	History of injury, stress fracture
	Low calcium intake
	Low protein intake
	High caffeine intake
	Prolonged intake of certain medicaments or drugs
Extrinsic Factors
Type of activity/sport	Track and field
	Dance
	Soccer
	Basketball
	Military basic training
Physical training	High amount of training
	High duration of training
	High frequency of training
	High intensity of training
Equipment	Shoes
	Boots
	Insoles
	Orthotic inserts
Environment	Road
	Trail
	Track