**2.2 Changes in joint kinematic parameters**

The modifications of spatiotemporal parameters observed during gait of stroke patients are mainly caused by kinematic and kinetic alterations [19]. Global motor organization is given by the kinematic parameters, a segment rotation is characterized in function of the adjacent one, and joint angles are the main elements allowing the understanding of the gait. **Figure 2** illustrates the definition of joint angles of the lower limb.

### *2.2.1 Changes in movement at the hip*

The joint angle of the hip is defined as the relative angle between the pelvis and the femur. The flexion/extension of the hip occurs in the sagittal plane. The flexion of the hip propels the thigh toward the anterior surface of the body. In contrast, the extension of the hip throws the thigh toward the posterior surface of the body.

For the healthy subject, at the beginning of a cycle, the hip is in flexion. During the single support phase, the hip performs an extension. At the end of propulsion, the angle of the hip reaches a maximum extension of about −10°. During the oscillating phase, the maximum value of hip flexion can reach +45°.

Usually, a stroke patient exhibits both an insufficient hip flexion and a limitation of the hip extension, [20] which contribute to the decrease of the step length and of the gait speed.

## *2.2.2 Changes in movement at the knee*

The joint angle of the knee, defined as the relative angle between the tight and the shank, is close to +10° for the healthy subject at the beginning of a gait cycle. During the single support phase, this angle increases to a first maximum amplitude of about +20° and then decreases. At the beginning of the oscillating phase, the knee flexes quickly to prepare the oscillation of the body. We then observe a second local maximum with a value that can reach +60° followed by an extension.

**143**

everyday life.

*An Embedded Gait Analysis System for CNS Injury Patients*

For the stroke patient, the presence of a hyper-extension at the beginning of the single support phase due to the spasticity of the triceps surae or a decrease of peak knee flexion in swing phase is called stiff knee gait mainly due to a spasticity of the

The ankle joint angle is defined as the relative angle between the shank and the foot, the foot being considered as a single rigid segment. The dorsiflexion of the ankle in the sagittal plane traduces a flexion of the foot. In contrast, plantar flexion

During the gait cycle, the evolution of ankle angle is composed by three steps:

• During the initial double contact, the heel touches the ground with the foot in

• Then, the ankle makes a plantar flexion. When the entire foot is in contact with

• After this step, the foot makes a dorsiflexion to reach a peak whose value is about

• The last step corresponds to the toe off. The ankle makes, firstly, a plantar flexion

In stroke patients, a plantar flexion is often observed either during the initial double contact or during the single support phase or the swing phase. This decrease of dorsiflexion can be explained by a spasticity of the triceps surae muscle. This phenomenon is often associated with a reduction of the propulsive force and a

During an evaluation of the therapeutic management, the following are

• The relative segmental (articular kinematics) and the absolute displacements

• The movements of the segmental and/or global center of mass by using anthropometric data, kinetics, forces, moments, and articular powers by coupling

To allow appropriate management of the stoke patient, the 3D-GA system, considered de facto as the "gold standard," and the FGAs are the most used methods. However, the costs as well as the complexity of the use of optoelectronic 3D-GA systems reduce the use of this assessment of gait disturbance of patients with stroke sequelae to a limited number of laboratories/hospitals compared to the actual demand of patients. The studies presented in the following describe the design and implementation of a wireless embedded system for collecting gait parameters of pathological gait in

the ground, the ankle plantar flexion is about +10°.

*DOI: http://dx.doi.org/10.5772/intechopen.83826*

*2.2.3 Changes in movement at the ankle*

comes from a flexion of the foot.

neutral position (0°).

and, secondly, a dorsiflexion.

deficit of the gait velocity [21, 22].

(segmental kinematics)

dynamometric sensors (force platform type)

• Electromyographic muscular activities

+20°.

**2.3 Discussion**

considered:

rectus femoris muscle.

**Figure 2.** *Definition of the joint angles for the lower limb.*

For the stroke patient, the presence of a hyper-extension at the beginning of the single support phase due to the spasticity of the triceps surae or a decrease of peak knee flexion in swing phase is called stiff knee gait mainly due to a spasticity of the rectus femoris muscle.
