Increase the speed of the gears in the cycle the speed

Gait studies project

Table of Contents

1 The gait cycle
1.1 Reciprocal ground contact
1.2 Structure of the gait cycle
1.3 Step and double step

2 The gait phases
2.1 Initial ground contact
2.2 Stress response
2.3 Middle stance phase
2.4 Terminal stance phase
2.5 Pre-swing phase
2.6 Initial swing phase
2.7 Middle swing phase
2.8 Terminal swing phase

3 Study design and goal of the gait analysis carried out
3.1 Evaluation of the data series
3.1.1 Thesis 1: The double step length increases with increasing speed.
3.1.2 Thesis 2: The contact time increases with increasing speed.
3.1.3 Thesis 3: With increasing speed, the number of steps / min increases.
3.1.4 Thesis 4: Both sexes differ significantly in terms of double step length, contact time and cadence.
3.2 Conclusion

bibliography

1 The gait cycle

Is characterized by a repetitive movement pattern of the extremities and in which the entire body is balanced over the standing surface. In order to be able to guarantee this stability, the information of the bones, muscles, tendons and ligaments of the lower extremity with that of the upper extremity is synthesized via the junction of the brain. The result of this complex relationship is the gait. In order to be able to analyze it scientifically, it must be viewed from different points of view so that individual processes can be worked out and their contribution to the overall movement made visible. According to Dr. Jacquelin Perry (2003, p. 1), this analysis can be carried out under three aspects. A priori, the corridor is subdivided based on the variations in the reciprocal ground contact of both feet. The duration and length of a double step are also used as a basis. The functional significance of the individual events within the gait cycle is determined a posteriori, and the respective intervals are recorded as functional gait phases.

1.1 Reciprocal ground contact

In the dynamic movement of walking or running, each leg fulfills a specific role; a precisely regulated division of labor is carried out with constant changes in the area of ​​responsibility. Thus, one leg corresponds to a movable support, while the other swings to a new location and vice versa. Only when the body weight is transferred from one leg to the other do both feet come into contact with the ground. The term gait cycle (GZ) (Fig. 1) describes a single sequence of this function of a leg, in which each action flows smoothly into the next. In principle, when the heel comes into contact with the ground, the gait cycle begins. Since certain acute or pathological clinical pictures cannot always guarantee heel contact, the more general term initial ground contact (IBK) is used in biomechanics as the beginning of a gait cycle (Perry, 2003, p. 1).

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Illustration 1. Rough structure of the gait cycle (Perry, 2003, p. 1)

1.2 Structure of the gait cycle

Each gait cycle is divided into two parts, these are called the stance and swing phases. The term phase describes a functional sub-unit of the total activity of a leg within the gait cycle. The term stance phase describes the entire period in which the foot rests on the ground. It begins with the initial contact with the ground and ends with the impression of the forefoot. This imprint is in turn the beginning of the swing phase. The term swing phase describes the period of time during which the foot is in the air and swings forward (Perry, 2003, p. 2).

The stance phase is divided into three sub-phases (Fig. 2). Both at the beginning and at the end of the stance phase, both feet have contact with the ground (bipedal stance), whereas in the middle stance phase only one foot is in contact. A gait cycle begins with the initial bipedal stance phase (Fig. 3). At this point, both feet are on the ground. The monopedal stance phase begins as soon as the contralateral foot is lifted for the swing. During the monopedal stance phase, the entire body load rests on the extremity in question. The duration of the monopedal stance phase (Fig. 3) is the best indicator of the support capacity of the leg in question. The terminal bipedal stance phase makes up the third subunit. It begins with the ground contact of the contralateral foot and lasts until the original supporting leg is lifted for the swing. In the gait cycle, 60% of the time is normally spent on the stance phase and 40% on the swing phase. The stance phase consists of the bipedal (2 x 10%) and the monopedal (40%) stance phase. From the preceding explanations it can be seen that the percentage of the monopedal stance phase of one leg has to correspond to the swing phase of the other leg.

The duration of the two gait phases is inversely proportional to the gait speed. The stance and swing phase shorten as the pace increases. Conversely, the stance and swing phase take longer, the slower the person walking becomes. There are different relationships between the sub-units of the stance phase. Eliminating the bipedal stance phase is equivalent to changing the mode of locomotion, in short, the gait changes to running (Perry, 2003, p. 4).

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Figure 2. Structure of the gait cycle (Perry, 2003, p.4)

1.3 Step and double step

The term step refers to the timing of the action of both legs. Each double step consists of two steps. In the middle of a double step, the contralateral foot makes contact with the ground and begins its next stance phase. A step thus describes the interval between the initial contact with the ground, first of one foot and then the other. The double step corresponds exactly to a gait cycle in which the interval between the two successive initial contact with the same extremity determines the duration of a double step. While walking, the same temporal sequence is continuously repeated reciprocally (Perry, 2003, p. 4).

2 The gait phases

As already described, there is a constant change in alignment of the body in relation to the supporting foot as well as a selective forward movement of certain segments of a leg in the swing phase. There are currently eight functional sub-phases during the gait cycle. The general terminology used in this work for the functional gait phases is based on the guidelines developed by the Committee for Gait Analysis at Rancho Los Amigos. Each of the eight gait phases has a functional task and has a unique pattern in which certain movements occur synergistically in order to accomplish this task. Only through the correct timing of the phases are the lower extremities able to perform three basic functions:

1. Assumption of the body load, it initiates the stance phase and extends over the first two sub-phases (initial ground contact and load response);
2. Monopedal standing, characterized by the following two sub-phases (middle and terminal stance phase) and
3. Pre-swing of the leg, begins in the last section of the stance phase (pre-swing phase) and is continued through the three sub-phases of the swing phase (initial, middle and terminal swing phase) (Perry, 2003, p. 4).

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Figure 3. Proportion of bi- and monopedal stance phases in the gait cycle (Perry, 2003, p. 2)

2.1 Initial ground contact

This first sub-phase takes place in an interval of 0 - 2% at the beginning of the double step cycle. The initial contact with the ground marks the moment when the foot touches the ground (Fig. 4.1). The position of the joints at this point in time determines the pattern in which the leg's response to stress occurs. In 'healthy' people, the stance phase is initiated by rolling over the heel (Perry, 2003, p. 5).

2.2 Stress response

The exercise response occurs in the first tenth of the gait cycle. This is the initial bipedal stance phase (Fig. 4.2). The phase begins with the initial contact with the ground and continues until the contralateral foot is lifted for the swing. The foot or the arch of the foot takes on its actual function in this phase, that of a shock absorber. Adapting the arch of the foot to suit the situation ensures stability when taking on the body load and the continuity of locomotion (Perry, 2003, p. 5).

2.3 Middle stance phase

It characterizes the interval of 10 - 30% of the gait cycle and thus takes place parallel to the first half of the monopedal standing interval (Fig. 4.3). It begins when the contralateral foot is lifted and continues until the body weight is shifted to the forefoot. The locomotion should take place via the supporting foot, which can only be achieved through muscular stability of the leg and trunk (Perry, 2003, p. 5).

2.4 Terminal stance phase

Determines the section of about 30 - 50% of the gait cycle. The monopedal stance phase ends with this phase (Fig. 4.4). It begins with the heel peeling off and continues until the contralateral foot comes into contact with the ground. During the entire phase, the body weight is in front of the forefoot. The movement of the body continues (mainly) via the supporting foot (Perry, 2003, p. 6).

2.5 Pre-swing phase

In the interval between 50 - 60% of the gait cycle. This last section of the stance phase is the second (terminal) bipedal stance phase within the double step cycle (Fig. 4.5). It begins with the initial contact of the contralateral leg with the ground and ends with the toe detachment of the ipsilateral foot. In this phase, the relieved leg uses its leeway and prepares for the upcoming swing phase. All movements and muscle activity at this point relate to the task of positioning the leg for the swing (Perry, 2003, p. 6).

2.6 Initial swing phase

Takes place in the interval between 60 - 73% of the gait cycle. This first phase is about a third of the entire swing phase (Fig. 4.6). It begins when the foot is lifted off the ground and ends when the swinging foot is in opposition to the stand. This phase is characterized by the detachment of the foot from the floor and the forward movement of the leg from its hanging position (Perry, 2003, p. 6).

2.7 Middle swing phase

Occurs between 73-87% of the gait cycle. This second section of the swing phase begins when the swing leg is in opposition to the standing leg (Fig. 4.7). The interval ends when the hip and knee joint are in an even flexion position. In short, the leg swings forward and the foot releases from the floor (Perry, 2003, p. 8).

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