The military has a lot of slang and initialisms, a string of letters made from the first letter of a string of words, but they can’t be pronounced as words. e.g. USN, USMC.
Acronyms on the other hand are made from the first letter of a string of words but are pronounced as if they were words themselves. e.g NASA. Any shortened form of a word is an abbreviation.
Now that that is cleared up, in the USMC when we weren't moving from one place to another by helicopters (choppers) we traveled by SLT...Shoe Leather Transport. The feet inside the SLTs are remarkable bio-mechanical structures.
Nearly a quarter of all bones in our bodies are in our feet. Most people, but not all, have 26 bones in each foot. Some people have have accessory or extra bones; they're very rare though. Usually they don't cause a problem and people that have them may not even be aware of it.
Fourteen of the 26 bones are found in the toes. Each toe has three bones, except the big toe, which has two. But, it is not uncommon for the little toe to have only two bones as well.
A foot has 33 joints, 19 muscles, 10 tendons and 107 ligaments and the soles of our feet contain more sweat glands and nerve endings per square inch than any other body part. Together the two feet have 250,000 sweat glands that are capable of producing half a pint of sweat in a single day. The skin on the soles of your feet is thicker than anywhere else on your body. The Achilles tendon is the strongest tendon in the body.
Babies are born with more cartilage than bone in their feet. Their arches are filled with fat and does not become fully developed until the age of two or three.
Gait patterns: gait is a person’s pattern of walking. It's really not so simple...it is a complex and coordinated series of movements that involve both the arms and legs.
Gaits is divided into heel strike, flat foot, mid-stance, push-off, acceleration, mid-swing and deceleration. The gait pattern of the right foot usually does not match that of the left foot. This is usually not a problem, but it can be if there is a significant mal-alignment which can can lead to knee, hip and back pain.
When a person is walking normally, the whole foot is never flat on the ground. A normal gait starts with heel strike with weight to the outside of the foot. As we move forward the weight shifts to mid-line and then to the inside, ending with a push-off with the big toe.
Each foot takes 1.5 times your body weight when you are walking; more if you are traveling by SLTs and carrying 50-100 pounds of combat gear. Normal running puts five times your weight on your feet.
The average shoe size for men and women has increased over the 30 years. 30 years ago the average size for women was 7.5 and 9.5 for men. These days it's 9.5 and 10.5.
20-30 percent of the world's population have Morton’s toe, a condition where the second toe is longer than the big toe. The average person walks 110,000 miles in their lifetime. They say ankle sprains are the most common foot ailment, but in the days I traveled by SLTs it was blisters. Lose a toenail and it'll take a year to a year-and-a-half to regrow!