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«A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agricultural Mechanical College in partial fulfillment of the ...»

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As illustrated in Figures 2.8 and 2.9, the attachment proposed by Famolare is different from the removable heel evaluated in this study, in that it has a sliding mechanism, rather than being screwed to the sole. Moreover, the bowling shoe is modified by increasing the height of the sole together with that of the heel. In contrast, the track-and-field spike shoes considered in this thesis were modified exclusively at the heel area, since the purpose is to establish a balance of the foot, which is lost in the use of the original curved, spiked, track shoe.

The sliding mechanism is commendable in that it requires less effort – and less time – to install than the time required to screw a removable heel underneath a track spike shoe. However, this action requires a perfect match in dimensions, whereas the screw-on removable heel evaluated here can adapt to different models of spike shoes.

2.6.3. Basketball In 1996, Lombardino proposed a removable heel for athletic shoes. Even though this invention represents the closest model to the modified spike shoes evaluated in this thesis, one major difference is that Lombardino designed a shoe with two heel options. In other words, the athlete can choose between two shapes of heels to fit the activity, whether it is plyometric training or general use. Another difference is that these shoes are better suited for basketball practice, as shown in Figures 2.10 through 2.12, whereas this thesis evaluates a shoe specifically designed for track.

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The above figures display an attachment that slides in and locks at the sole. Again, this marks another difference with the removable heel of the track spike shoe.

2.6.4. Ladies‟ High Heel Shoes with Removable Heels Numerous patents have been filed for such shoes. This feature is popular as it enables ladies to wear shoes that combine the aesthetics and professionalism of high heels, while relieving them from the resulting discomfort when not needed. Koehl et al. (1989), SchneiderLevy (2001), and Rodriguez Colon (1994) provide typical examples of studies of removable high heel characteristics.

Koehl et al. (1989) designed a heel that could be removed in case the original heel is damaged, or if the owner wants to change the shape and color of the heel, as illustrated by the

drawing they included in the patent:

Figure 2.13: Shoe construction with self-seating removable heel

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As one can see on sections 5 and 6 of Figure 2.14, the heel attaches to an adapter (number 18) that connect the heel to various types of removable heels. One of the shortcomings of such a system is that the shoe is not designed to adapt to different heights of heel. Nevertheless, this is extremely useful for aesthetic, versatility purposes, and could help those who cannot wear thin high heels, such as people with diabetes, as it creates minimal pressure points, where all the body weight is forced (Ahroni and Scheffler, 2006).

High heels have been found responsible for serious foot and leg conditions, including pain, instability / imbalance, deformity, and hampered mobility (Dawson et al., 2002; Menz and Morris, 2005). Problems with high heel shoes are not always presently visible among younger ladies, but problems do tend to manifest later on, as seen in research among older women who wore high heels in the past. Dawson et al. (2002) studied the origin of problems of osteoarthritis of the knee among older women (age 50-70). The results of their survey showed that all women with the condition had worn heels over many years. Although the exact height of the high heel hasn‟t been conclusively found to be a determining factor in this etiological analysis, additional studies such as Menz and Morris (2005) show the effects of wearing high heels in older people.

Menz and Morris state that repetitively wearing shoes with heels higher than 25 mm causes bunion and big toe inward deviation (hallux valgus) and other callosities (note that such data helps set design limitations on the height of the removable heel assessed in this thesis).

Nyska et al. (1996) experimented by treadmill with women walking in high heels versus women walking in low heels. The experiment indicated that such a phenomenon is due to the high total weight-load on the forefoot, having shifted from the hindfoot while wearing the high heel shoe.

To help remedy this problem, Rodriguez Colon (1994) submitted a patent for a low-heel shoe that transforms into a high-heel one. This design provides more flexibility than that of Koehl et al., in the sense that his invention enables the owner of the shoe to alternate the height of her heels.

Since high heel soles are curved, it seems that removing the heel should trigger an imbalance and unevenness of the foot during stance, which would impose stress on the Achilles tendon similar to that of walking in sprint spike shoes without a removable heel. With this rationale, inventors / designers such as Rodriguez Colon apply the removable heel to shoes manufactured in flexible material, or adapt a shank to change the shape of the shoe, thus enabling the toes to lay flat during stance, as the heel is removed. Such a technique allows the foot to change to an appropriate, more comfortable position. The following figures provide an illustration of the shank mechanism as it is used to safely modify the angle of the sole.

Figure 2.15: Side view of shoe with high heel and low heel Source: Rodriguez Colon (1994)

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Figures 2.15 through 2.

18 display the different features of the convertible shoe. By principle and design, it is quite comparable to the track spike shoe evaluated in this study, though the goal, in essence, becomes the inverse of the convertible high heel shoe design. In effect, this thesis assesses a shoe with a biomechanical modification aimed to remedy problems caused by a lowpositioned heel, whereas Rodriguez Colon‟s invention was intended to remedy problems caused by a high-positioned heel.

2.7 Summary Thus, one can summarize the literature on track-and-field and footwear and the relatable

scientific research in the following terms:

Excessive stress related to inappropriate wear of track spike shoes, such as wearing them during walking despite the fact that they are designed for running, causes inflammation of heels, toes, shins, Achilles tendons, cartilage under the kneecaps, and thighs (McGrath and Finch, 1996). Almost all athletes develop

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competition (Elliott, 2007; Runners‟ Lane, 2005; Smith, 2007).

Definitions and explanations of walking and running techniques show a contrast

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For instance, tibialis anterior fatigue among track-and-field runners was demonstrated to frequently be due to switching from plantar flexion (running) to

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heel pressure (Tortora, 2002; Donley and Leyes, 2001; Segers et al., 2006).

Electromyography is an appropriate device for identifying ergonomic problems and generating solutions, along with statistical evaluation of EMG data to prove

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Literature research reveals the effects and origins of common running injuries that affect track and field athletes. These problems are both internal (runner‟s gait, frequency of exercise, and category, i.e., long/mid distance) and external (shoes). In regard to the factors mentioned in causing runners‟ injuries, the literature tends to coincide with the notion of a spike shoe with a removable as an a priori efficient solution to the extreme and repetitive dorsiflexion that characterizes mid and long distance running techniques.

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The rationale behind this project is that by allowing the runner‟s feet to remain at an even level, a removable heel helps avoid the foot‟s excessive abduction upward when walking before and after practice or competition.

Based on Alangari (2006) and measurements from the Nike spike shoes with and without the removable heel, the regular spike shoe elevates the toes and the front half of the foot (see Figure 1.1). Such elevation alters phases 2 and 3 of the walking stance, as it increases the angle of the toes to about 25 degrees. Thus, phases 2 and 3 exert an enormous stretch on the Achilles tendon, as well as stress on extrinsic foot muscles. On the other hand, when wearing the spike shoes with a removable heel, the toes are still slightly elevated, but as the heel restores some of the balance lost to this elevation, the elevation is about 10 degrees less than when the heel is not present (see Figure 5.1). Therefore, Achilles tendon stretch and stress on extrinsic foot muscles is reduced in phases 2 and 3. Actually, when wearing the heel, only phase 2 differs from normal walking (see Figure 2.2) after balance is restored with the removable heel.

The removable heel is meant to offer the flexibility required to eliminate extensive stress.

Effectively, this feature will reduce pressure from the exterior digitorum longus (the in-step part of the foot), as well as from the backward part of the abductor digitii, thereby avoiding injuries and inflammations such as Achilles tendonitis, calcaneal apophysitis, and stress fractures of the metatarsals. Furthermore, the removable heel would relieve the stress and pressure from the patella (at the lower section of what is commonly called the “knee-cap”), as well as from the anterior tibial area (commonly called the shin), and the posterial tibial area (the calf). By doing so, a heel that may be removed, according to the track-and-field activity, would help prevent tibial compartment syndromes and patello-femoral syndromes, discomforts so common among

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The purpose of this study is to evaluate a shoe that mid-distance and short-distance runners may use when moving to and from the track before and/or after practice or competition.

The focus and baseline is that though athletes do not always have the time to change shoes immediately after practice or competition, they need shoes that are appropriate for the activity being performed, whether it is running or walking. Consequently, the keywords to the biomechanically modified spike shoes are flexibility and adaptability.

The objectives can therefore be listed as such:

Decrease the risk of injury among track athletes, which implies protecting their

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This means that the kind of spike shoe runners may wear is one flexible enough to be adjusted in order to adapt to and enhance each runner‟s performance. In other words, the shoe should adapt to the runner, not the other way around.

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3 non-athlete subjects who exercise regularly (two males and one female) All participants are between the ages of 19 and 29 years old, with a mean age of 25.2 years and a standard deviation of 3.07, a mean stature of 175.0 cm and a standard deviation of 7.11, and a mean whole body mass of 80.5 kg and a standard deviation of 6.50. They were selected based on different physiological factors and physical abilities to observe the effects of using regular spike shoes, as well as to ensure that the modified shoe accommodates the majority

of its users, regardless of gender. The following table provides details for each participant:

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The diversity of backgrounds, including gender, is intended to demonstrate the difference of impact of the removable heel according to athletic history, as well as to provide comparative ground to sprinter participants, the group targeted by the biomechanical modification of the track shoe. While the electromyographic study of Zeller et al. (2003) indicate that muscle activity generates a heavier strain in women than it does in men, this experiment shows that women, despite their distinct gait, suffer discomfort when walking in regular spike shoes, and that they can benefit from a removable heel. Further series of experiment as a continuation of this thesis could assess the benefits of the heel according to gender.

On the other hand, Lynch et al. (1998) show that it is important to select participants of the same age group for data consistency, as their weight training program reported that age brings about loss of muscle mass and muscle function. Therefore, delimiting the participants‟ age is essential to ensure that muscle activity data remains untainted by such type of nonpathological muscle condition.

5.2. Equipment / Apparatus Spike shoes with removable heel

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5.3. Task Design The participants were asked to walk on a treadmill, wearing the original shoes for a first session and biomechanically modified shoes for a second, comparative, session. No preliminary trimming or warm-up was implemented except the fact that participants walked on the treadmill for one to two minutes to get accustomed to the equipment. The treadmill was set to two different speeds, 2 mph and 3 mph, which the literature (Gross and Shi, 2001) and LSU track athletes‟ testimonials report as speeds at which athletes are comfortable walking before or after running in general, while the EMG apparatus was set to measure specific muscle activity in all sessions. Each session lasted one minute, with a lapse of 2 minutes in between. Participants were then asked to rate their pain or discomfort on their body map areas 20 to 27 on a scale from 0 to 10 (see Figure 5.11, page 58).

5.3.1. Installation of the Heel A heel compatible with a men‟s size 10 Nike pair of spikes was designed and built. The plastic heel is of a texture flexible enough to adjust to most walking techniques. With the help of a professional shoemaker, Velcro fabric was sewn on to the sole of the spike and the top of the removable heel, while holes were drilled to fit with the spikes‟ screws. The following figures display pictures of the modified track spike with a removable heel. There are pictures of the track spike with and without the heel. There is also a comparison with one track spike with the heel on and one without, so as to provide a visual notion of the appearance of the shoe once altered with a removable heel.

Figure 5.1: Spike shoe with removable heel - side view The following picture provides a comparative view of the alteration.

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