Types of injuries tend to differ between the groups. Heel strikers tend to have more knee and hip injuries, and forefoot strikers tend to have more achilles and calf strains and metatarsal injuries. Midfoot strikers will have characteristics in common with the both, often moving between the heel and forefoot strike patterns. Many things can influence Foot Strike Type—speed, footwear, and terrain being the most common. Insole X can assess the impact of footwear to improve footwear selection and form & variance while running in natural environments.