Athletic-footwear companies are playing a major role in lower limb injury prevention, not necessarily for altruistic reasons, but because the market is so competitive these days they have to stay a step ahead of the field. The industry is spending millions of dollars each year to produce the perfect shoes to give different athletes ultimate performance. Just as automobile racers rely on certain tires for a competitive edge, so athletes rely on footwear to give them an advantage over the competition.
Certain athletic events require different types of shoes because stresses and ground surfaces may differ. And, since every athlete has a different foot, a single shoe last may suit one but not another. The end result is that, except for children who are not playing a specific sport, there is no longer any such thing as the all-purpose sneaker or running shoe.
All this competitiveness and research has led to a much better product for the athlete, but usually at a higher price per pair of shoes. However, let me assure you that when it comes to athletic shoes, you do get what you pay for, almost all the time. The major problem for the athletic consumer today is how to choose the proper pair of shoes from among the proliferation of models and manufacturers.
Because athletic shoes today are sports-specific, you would be well advised to find a store that carries a wide variety of shoes for all sorts of activities and that employs sales personnel who are familiar with the merchandise and the needs of specific athletes. If you have a definite biomechanical problem in your lower limbs, you would be wise to consult first with a podiatrist who is an expert in sports medicine. Then you will know better exactly what type of shoe to look for.
You must also take into consideration the type of surface on which you will be exercising. Different terrains, court surfaces, or playing fields will call for different types of shoes. Avoid buying the best-looking or highest-priced athletic shoe without taking the above into consideration. If you have any doubts at all, keep shopping until you find a knowledgeable salesperson. Remember, although a certain shoe may feel okay when you try it on in the store, it may be totally inadequate for your needs when you are exercising.
The three major factors to consider when purchasing athletic shoes are, as for non-athletic shoes, cushioning (shock absorption), stability, and flexibility. Recent developments in designing and manufacturing these shoes have resulted in footwear that is far superior to that of 20 years ago, and their increased stability, flexibility, and shock absorption provide more comfort than any other type of shoe made today. That is why it is not unusual to see business executives, both male and female, wearing running shoes to work, switching to regular shoes only when they reach their offices. Let's take a closer look at a typical modern running shoe to find out exactly why it helps protect the feet and legs from injury.
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The following has been excerpted from Healthy Feet: The Foot Doctor's Complete Guide for Men and Women, by Glenn Copeland, DPM, with Stan Solomon. Available in bookstores August 2004. Published by Key Porter Books.
Cushioning (shock absorption)
Most of the shock on a foot is absorbed through the midsole that spans the length of the shoe (see Diagram 15-1). The thickness of the highly resilient material used for cushioning is generally approximately one inch (2.5 cm) at the heel and a third to half an inch (8 to 13 mm) at the forefoot. The additional thickness at the heel allows for the extra stress created during the heel-strike phase of the gait cycle. It reduces the risk of trauma to the heel and to the Achilles tendon. Some shoes also have a built-in cushioning system on the outer sole, where contact is made with the ground during the running stride. This space-age cushioning has certainly cut down the number of traumatic overuse injuries to runners' feet, particularly in the heel area. Depending on the make and style of the shoe, the cushioning in today's athletic footwear can range from air to water to gel.
The modern running shoe also features high-tech extra stability devices to improve foot control. The more foot control the shoe offers, the less chance there is of wear-and-tear disorders caused by stressful, repetitive motions. Because of great improvements in the materials used, running shoes can now provide better stability with more motion control. Many insoles have a material on the outside that is harder than in the middle, to help prevent rolling of the foot when it strikes the ground. Much better control of torsion (twisting from the front of the shoe to the back) helps prevent biomechanical abnormalities.
Although running shoes are constantly improving, manufacturers are still having trouble providing maximum stability without sacrificing cushioning properties, and vice versa. Also, stability is often traded off for a lighter-weight shoe, as many runners would rather have the comfort of a lighter shoe than the added stability. If they do not have any foot problems, they can easily get away with this trade-off.
A lot of shoe manufacturers have combined different densities of foam in the midsole to provide greater rigidity in various areas. Firm internal and external heel counters have also been added in some shoes for more rearfoot control. The plethora of new designs is seemingly endless as manufacturers vie for a healthy share of the athletic-footwear market. In the long run, the winner will be the athlete, as the competition will ensure continuous improvements in these shoes.
One of the most important factors determining stability in a shoe is the last. As I mentioned earlier, the last refers to the shape of the sole, and can be compared to the frame of an automobile before the chassis is mounted on it. The two most common types of lasts are straight and curved, and a few rules govern the choice of type. First, if the shape of your foot is basically straight and if you have a low arch, the straight-lasted shoe is best for you, because it offers more support on the inside of the foot and will help prevent you from overpronating, enabling you to minimize overpronation injuries.
If your foot is slightly curved, if you have a higher than normal arch when standing, and if you have been diagnosed as having a rigid foot, you will probably feel more comfortable in curve-lasted shoes. These shoes offer more cushioning but still retain rearfoot stability. People who oversupinate often find that curve-lasted shoes are much better for them because the shape of their feet and that of the shoe are compatible.
If you are uncertain as to which type of last to get, you might want to seek expert advice before buying your next pair of athletic shoes. Many runners, though, can tell whether they require a straight or a curved last just by walking in the shoes for a few minutes.
Flexibility in a running shoe is necessary to take excessive strain off the muscles in the lower leg while you are running. Most flexible shoes today provide better shock absorption than inflexible ones, with little loss in stability. When shopping for a pair of running shoes, you should try bending the shoe in half at the midfoot area. If this cannot be done easily, try another pair. You can also determine flexibility by examining the forefoot outsole patterns on the bottom of the shoe and looking for flex notches on the sides. These patterns and notches are not there for aesthetic purposes; they are designed to provide the required flexibility - most importantly, in the area of the metatarsal heads and toes.
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Other footwear factors
There are a few other factors to consider when purchasing a running shoe, particularly the breathability of the shoe, and especially in the upper, forefoot part. You do not want too much moisture to be trapped inside your shoe, as fungi and blisters thrive in hot, moist areas. You will also want to know what sort of traction the outer sole provides. You do not want to be slipping and sliding when you are running.
Is the shoe you are choosing light in weight, but still able to provide the stability you need? Generally speaking, the lighter the shoe, the less stability it has to offer. Is there cushioning around the ankle that includes an Achilles pad, to prevent irritation to this area and consequent skin eruption? Is the tongue of the shoe padded to prevent the laces from pressing on the top of the foot? Finally, is there a removable inner sole in case you must add prescribed orthotics?
Racquet sports and aerobics shoes
Many of the remarks I have made above refer specifically to running shoes, which are designed to support a foot that is constantly moving forward. They are not designed for repeated bouncing up and down on one's toes or for quick lateral movements. Sports activities that require a lot of lateral movements necessitate a shoe that provides more lateral support for the foot. And many activities, such as aerobics exercises, place additional stresses on the forefoot, so they require shoes with additional shock absorptive qualities in the front.
Racquet sports involve repeated, quick, stop-and-go movements in all directions. Running shoes do not provide for such movements, particularly because of the added cushioning in their heels and a lack of lateral stability in the forefoot. Raised heels make the back part of the foot less stable, and quick lateral movements can result in sprained ankles. So if you wish to minimize the risk of a lower limb injury while playing racquet sports, buy shoes specifically designed for such activities. The court is no place for a running shoe. And shoes for racquet sports are now becoming surface-specific, with tennis shoes for clay surfaces, as well as those for “tartan” or asphalt courts.
Many problems make foot and leg injuries constant companions of aerobics exercisers. The exercises are usually done on a fairly hard surface. Exercisers may spend a lot of time on their toes and, depending on the instructor's routines, moving laterally. Lateral movement is particularly accentuated when aerobics are combined with dancing, as in dancercise. So an aerobics exerciser must have a shoe that combines added forefoot cushioning with flexibility and stability.
Manufacturers of aerobics shoes are continuing their research to develop the perfect product, and for people who are not prone to leg and foot problems and who exercise on surfaces that have some resilience, the modern aerobic shoe is fine. But if you are constantly plagued by problems such as shin splints or are forced to exercise on hard, unyielding surfaces, I recommend that you stick to good running shoes, because you require cushioning that even the best aerobic shoe cannot yet offer. Definitely avoid wearing a racquet-sports shoe for aerobics, because they are made for lateral mobility and fail to provide adequate flexibility and the shock absorption required for aerobic exercising.
If you do a lot of step aerobics, you require shoes that grip better and have more flexibility in the front part of the foot. Because of the pull on the Achilles tendon, stair-climbers need exercise shoes that have higher heels, particularly if they have a history of Achilles problems due to a shortened tendon.
Hiking is also a popular aerobic pastime these days. Stability is very important for hikers because they are constantly walking or climbing on uneven surfaces. High-top hiking shoes provide much of the additional stability they require.
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Other Sports Footwear
A few years ago the major manufacturers of athletic shoes began branching out. High-top basketball-type shoes became popular, particularly when they were advertised by hoop superstars. Now, not only do the manufacturers make running, aerobics, and racquet-sports shoes, they produce footwear for every imaginable athletic activity and for all types of surfaces. Baseball players, for example, now have shoes designed specifically for use on artificial turf to protect them from injuries such as turf toe. It is not feasible for this book to discuss in detail every type of sports shoe on the market today. I can only advise athletes to consult with their trainer, coach, or a knowledgeable sports-shoe salesperson, and to try on the models available for their specific sport in order to determine the best possible shoe to buy. The rule should be that if shoes do not feel comfortable during the physical activity, do not wear them at all. The lower limbs could be injured and overall performance will suffer if the shoes do not fit comfortably. Many of the major athletic-footwear stores now provide various surfaces on the premises to allow customers to try out the shoes under typical conditions for their type of activity.
Some athletes worry about whether they should buy all-leather shoes or shoes that are half leather and half nylon mesh. All-leather shoes are more durable, obviously, but they are also heavier. The half-and-half shoes are lighter and provide greater breathability for the foot. You must weigh the trade-offs for yourself and buy the shoes in which you feel the most comfortable. There is no noticeable difference in performance between the two types.
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The asphalt jungle
Humans may be the only animals that do most of their running and walking on hard, man-made surfaces like concrete and asphalt. Of course, I am referring to modern man, particularly people who live and work in urban areas and rely on roads and sidewalks for level surfaces on which to exercise or get back and forth. This is a shame, because grass or a level dirt path would provide far more shock absorption than pavement. In most urban areas, a nice level path of grass or dirt to run on is difficult or impossible to find, so runners train on sidewalks or roadways.
It is imperative that the surface on which you run should at least be free of potholes and sudden, sharp dips, and not be overly canted. One bad step on an uneven surface could result in a severe ankle or knee-joint injury. As well, runners often neglect to take into serious consideration the pounding to which their bodies are being subjected as they run on hard surfaces. The added shock of a hard landing on the foot accentuates biomechanical foot faults, and can lead to injuries such as stress fractures. The most important thing runners can do is wear running shoes that provide the best shock absorption. Extra shock-absorbing material in running shoes will considerably reduce the jarring forces to which the body is subjected with each stride.
The floors on which aerobic exercises are often done have also been blamed by sports medicine specialists for development of problems caused by excessive shock to the foot and leg. One common injury is shin splints. Fortunately, good fitness clubs have recognized the problem and have sought more resilient surfaces to install in their exercise areas. They have found that not only do their members remain more injury-free, but their instructors miss fewer classes because of shin splints and other overuse problems. As I mentioned above, if you do aerobic exercises on a very hard floor, you should wear running shoes, because they provide the best shock absorption for your feet. And, as I noted in the previous chapter, switching to low-impact and step aerobics will dramatically reduce the number of stress fractures, shin splints, and knee and iliotibial band injuries.
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