question: Why do soft things break falls, or standing on a soft mat prevent foot pain, when your weight is the same?
comment: Soft things squish, so they stop your movement more slowly and gently than hard rigid things. Standing on a soft mat will also soften any impact from moving, like shifting your weight or taking steps.
passages: BULLET::::- Soft supports might use materials like foam rubber of varying intensity, memory foam, EVA, carbon fiber, silicone gel or filled leather. Because they are soft, their contour is less relevant. Instead, these tend to flatten, serving as shock absorbers. These give the proprioception of support, causing muscles to trigger in response, without true articulated support of the firmer models. Many shoe manufacturers, including athletic shoes, include similar pads with their shoes. Some products might be rubber pads shaped for a specific problem spot. Some of those could include a wrapping apparatus to hold them in place.
   BULLET::::2. Shear (usually twisting forces between the skin and footwear)
  
  BULLET::::3. Repetitive stresses (for example, from walking)
  
  BULLET::::4. Peripheral neuropathy (damage to the nerves in the feet).
  
  These factors rarely cause problems in healthy people but the accompanying neuropathy means that the “pain feedback loop” that induces humans to limp or keep their weight off an injury no longer functions properly in diabetic patients. The result is that pressure and abrasion injuries, such as bruising and blisters caused by poor footwear, are not noticed and often ignored, and the continual use of the limb disrupts and damages the healing process.
   An advantage to weighted footwear is that they can be inconspicuous, depending upon the weight and the form of the footwear in question. This mainly applies to those with a fixed weight, adjustable weighted footwear is more obvious, and may not even be used as normal footwear at all inherent to their design, an example being weighted boots with a pole for the weight stack extending directly from the sole of the foot. For footwear which can be worn normally, an advantage to wearing them beyond additional training stimulus, is their additional mass, which creates far more downward force than one would otherwise have, with foot-dropping attacks such as axe kicks and stomps. To gain this energy, more initial energy must be expended in hip flexion (and possibly knee extension) to raise the foot from the ground.
   A support grip typically involves holding something, such as the handle of a bucket, for a long time. This type of strength is epitomized by the Farmer's walk competitive event, where the bucket is filled with sand or water, and carried over a long distance. A great deal of muscular endurance is necessary to have a good carrying grip.
  
  Section::::Types of grip.:Normative data.
   The firm or flexible models might require a period of adjustment. Depending on the severity of the arch collapse and the body's previous conditioning in response to that collapse, sudden readjustment can seem painful. Many attribute the feeling to walking on a walnut. It is recommended new users build up to wearing firm arch supports, starting with only a couple of hours the first day and adding an hour each successive day until the foot is adjusted to full-time usage. To mitigate this adjustment period, many manufacturers sell covering pads or have different gradations to build up to solid support. Some manufacturers cover their products in leather, which somewhat moderates the intensity of the correction while also adding to the stylistic look.
   Thigh weights are not ideal for movements involving quadriceps use, as they require tightness which may limit the use of the muscle and blood flow to the legs. For such movements, weights worn higher on the body or free weights are more ideal.
  
  Section::::Lower body.:Ankles.
  
  Ankle weights are a commonly found weight used in many activities. Further from the core, fixated above the ankle around the lower shin and Achilles tendon, due to leverage much less weight is needed to increase the forces on the body.
   In Imperial units, stiffness is typically measured in pounds(lbs) per inch.
   Rehabilitation is important. A significant percentage of these sprains also involve medial and/or lateral ankle ligament injury and slow recovery and continuing symptoms are common. However, limiting external rotation to protect healing ligaments is a primary concern and can usually be achieved by short leg casts, walking boots, and custom orthoses. The degree of permitted weight bearing can be individualized dependent on tolerance and those with less injury are able to ambulate with full weight-bearing. Nevertheless, most use crutches to reduce the burden to some extent and those with more discomfort may be limited to "toe touch" on the affected side for one to two weeks. Some advocate the ability to climb and descend stairs with minimal discomfort as an indication to permit full, or at least progressive, weight-bearing.
   The terminology "weight function" arises from mechanics: if one has a collection of "formula_19" objects on a lever, with weights formula_20 (where weight is now interpreted in the physical sense) and locations :formula_21, then the lever will be in balance if the fulcrum of the lever is at the center of mass 
  
  which is also the weighted average of the positions formula_23.
  
  Section::::Continuous weights.
   Impact resistance decreases with an increase in the modulus of elasticity, which means that stiffer materials will have less impact resistance. Resilient materials will have better impact resistance.
   Supination is the opposite, and occurs when the foot impacts the ground and there is not enough of an “inward roll” in the foot’s motion. The weight of the body isn’t transferred at all to the big toe, forcing the outside of the foot and the smaller toes which can't handle the stress as well to take the majority of the overweight instead.
   Ankle weights are useful in adding weight to pull-ups and dips, especially when incorporating leg raises into the movements. They are also useful in slow kicking katas, and static-active stretching of the legs when balancing on one leg, or suspended in the air.
  
  Light ankle weights have a history of use resistance for kicking in swimming, and of forward flexion in kicking, walking, jogging, and sprinting exercises. Concern has been expressed regarding this type of training. It may put too much stress on the joints, similar to the shearing forces found in leg extension and leg curl exercises.
   These basic requirements are covered in more detail in the standards listed below.
  
  BULLET::::- It should have just the right amount of give; it should not be too hard, which causes repetitive strain injuries, or too soft, which is tiring.
  
  BULLET::::- It should be even and flat with only small variation in characteristics across the surface.
  
  BULLET::::- It should be springy and return energy to lift the feet when moving, but not too springy like a trampoline.
  
  BULLET::::- It should absorb the energy of falls and reduce injuries.
   BULLET::::- Drop foot TC: Terminal contact that is observed in patients that have drop foot is quite different. Since patients tend to have weakness in the affected foot, they may not have the ability to support their body weight. Often, a walker or cane will be used to assist in this aspect.
   Physical fitness is related integrally to the development of knee problems. The same activity such as climbing stairs may cause pain from patellofemoral compression for someone who is physically unfit, but not for someone else (or even for that person at a different time). Obesity is another major contributor to knee pain. For instance, a 30-year-old woman who weighed 120lb at age 18 years, before her three pregnancies, and now weighs 285lb, had added 660lb of force across her patellofemoral joint with each step.
  
  Section::::Clinical significance.:Common injuries due to physical activity.
   Grip strength
  
  Grip strength is the force applied by the hand to pull on or suspend from objects and is a specific part of hand strength. Optimum-sized objects permit the hand to wrap around a cylindrical shape with a diameter from one to three inches. Stair rails are an example of where shape and diameter are critical for proper grip in case of a fall. Other grip strengths that have been studied are the hammer and other hand tools. In applications of grip strength, the wrist must be in a neutral position to avoid developing cumulative trauma disorders (CTDs).
   Increasing the size of the contact area on the ground (the "footprint") in relation to the weight decreases the ground pressure. Ground pressure of 14 kPa (2 psi) or less is recommended for fragile ecosystems like marshes. Decreasing the ground pressure increases the flotation, allowing easier passage of the body over soft terrain. This is often observed in activities like snowshoeing.
  
  Section::::Examples.
  
  "All examples are approximate, and will vary based on conditions"
  
  Note:
   Often, when an object is rigged with a skeleton, weights are applied to the vertices near the joints. The vertices closer to the joint will usually have a lower weight assigned; the reason is so that during deformation, the geometry of the skin does not fold in on itself. Weighting in this situation will most of the time be done automatically using skinning techniques but is often done by hand fine tune the skeleton's deformation effects.
   Another function of bones is the storage of certain minerals. Calcium and phosphorus are among the main minerals being stored. The importance of this storage "device" helps to regulate mineral balance in the bloodstream. When the fluctuation of minerals is high, these minerals are stored in bone; when it is low it will be withdrawn from the bone.
  
  Section::::The different muscles.:Muscular.
   Nearly half of all vertebral fractures occur without any significant back pain. If pain medication, progressive activity, or a brace or support does not help with the fracture, two minimally invasive procedures - vertebroplasty or kyphoplasty - may be options.
  
  Ankles can be stabilized by lightweight orthoses, available in molded plastics as well as softer materials that use elastic properties to prevent foot drop. Additionally, shoes can be fitted with traditional spring-loaded braces to prevent foot drop while walking. Regular exercise is usually prescribed.
   Section::::Core.:Backpacks.
  
  Using weighted backpacks is a very common form of weight. It is like clothing when properly affixed, although some backpacks require tension in the pectorals or being held on the arms to keep from sliding off if not properly affixed.
   BULLET::::- "Non-weight-bearing" (NWB): The leg must not touch the floor and is not permitted to support any weight at all. The patient may hop on the other leg or use crutches or other devices for mobility. In this grade, 0% of the body weight may be rested on the leg.
  
  BULLET::::- "Touch-down weight-bearing" or "Toe-touch weight-bearing:" The foot or toes may touch the floor (such as to maintain balance), but not support any weight. Do not place actual weight on the affected leg. Imagine having an egg underfoot that one is not to crush.
   Section::::Hard-bearing vs. soft-bearing.
  
  There are two main types of balancing machines, hard-bearing and soft-bearing. The difference between them, however, is in the suspension and not the bearings.
   Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Others define it as the magnitude of the reaction force exerted on a body by mechanisms that keep it in place: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall, the weight would be zero. In this sense of weight, terrestrial objects can be weightless: ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, would be weightless.
   One major advantage to ankle weights, unlike wrist weights, is that it adds a whole new component to exercises that wrist weights do not, since we can't grip dumbbells with our feet like we can with our hands. It is a major advantage in training rotational hip stabilizers, to work on turnout for martial arts and dance postures. To do this, the leg is bent 90 degrees at the knee, and then rotated inwards and outwards to bring the foot upwards. This is commonly seen in footbag kicks and holds.
  