**4. Assessment of asymmetry in permanent muscles based on isokinetic test results**

The asymmetry observed in the skeletal system can be caused by both mechanical effects and genetic factors. Asymmetry is used in the skeletal system as a method that best reflects the variations that may occur in the study of the limbs. Asymmetry, especially in the upper extremities, is due to the fact that there is more freedom of movement. On the other hand, if the symmetry of the upper extremities is broken in favor of one side, the contralateral side is superior and advanced in the lower extremities. Numerous experiments on the upper extremities have shown that the main cause of bilateral asymmetry is side choice [18–20].

Asymmetry in the muscles can damage not only the esthetic structure, but also health. Muscles of different strengths can cause damage to the spine and other structures by creating completely different pressure points.

This condition is most often seen in people who have an inversely proportional shortness on one side of the hamstring muscles.

In isokinetic compression, the rate of skeletal muscle contraction is constant. In isokinetic compressions, each movement is performed at a constant speed due to the destination. On the contrary, in isotonic compression, it is impossible to keep the speed constant in a certain motion.

In isokinetic compressions, motion occurs in three separate phases.


Since the speed is not constant during the acceleration and deceleration phases, the physical activity performed at this stage cannot be considered isokinetic. Since the optimal test speeds for each joint movement are not known, it is important to find the angular velocities with the isokinetic loading range of the joints. In this regard, the estimates made with an isokinetic dynamometer calculate the peak torque, work, and power parameters corresponding to the isokinetic range.

#### *Complementary Therapies*

As the speed of the dynamometer increases, the time of the compression and deceleration phases increases, and the phase time with the main isokinetic load decreases. Studies have shown that serious errors in assessment can occur if these three phases are not taken into account during flexion-extension movements performed at different angular velocities. Therefore, the assessment of the isokinetic loading phase, especially at high angular velocities, may be important for the correct interpretation of the data.

With the development of technology, as in many areas, there have been developments in the field of strengthening and rehabilitation of human muscles. In general, isometric and isotonic (concentric- eccentric) compression types are used to strengthen the muscle. This is especially important in the assessment of dynamic neuromuscular capabilities in sports and in the quantitative assessment of outcomes. In order to determine the muscle capacity that can occur during dynamic muscle contraction (construction), it is necessary to measure the force and force exerted at a certain angular velocity. These values are quantified with an isokinetic dynamometer [21–24].

The purpose of the research and the problem statement.

Formulas used in the calculation of muscle strength and research-related terms. Force (F) is defined as a physical quantity that stops motion or turns stagnation into motion, the unit of which is Newton (N).

Work (W) is the force applied at a certain distance; the unit is the Newtonmeter (Nm) or Coul. The work done does not depend on time. Mathematical formula: W = F�d (where d is the distance).

The moment of force (torque) is the force that creates a rotation by applying a point or axis, the unit of which is the Newton-meter.

Power (P) is the work done in a single time; the unit is Watt (W).

$$\mathbf{P} = \mathbf{W}/\ \mathbf{t}; \ \mathbf{P} = \mathbf{F} \cdot \mathbf{d}/\mathbf{t}; \ \mathbf{P} = \mathbf{F} \cdot \mathbf{t}.$$

Angular velocity is the distance traveled in a single time; the unit is degrees/second (°/sec).

Factors affecting measurements when measuring muscle strength. Personal characteristics:


#### *Methods and Tools for Assessing Muscle Asymmetry in the Analysis of Electromyographic… DOI: http://dx.doi.org/10.5772/intechopen.103061*

Muscle movement: With isokinetic devices, force, work and force can be measured in both concentric and eccentric compressions. Most studies have shown that the force at eccentric compression is greater than that at concentric compression. This is because in eccentric compression, both contractile and non-contractile elastic components are involved in the formation of force, while in concentric compression only contractile structures are involved.

Test type: Isometric, isotonic, or isokinetic compression types are measured with an isokinetic dynamometer.

Bicycle ergometer is used for the lower extremity and arm ergometer for the upper extremity for warm-up (muscle training) (**Table 6**).

The experiments are warm-up exercises for 5 minutes on a bicycle ergometer with 55 5 rpm. Warm-up loads are regulated according to a person's heart rate, and the heart rate is recorded by a telemetry monitor (S810, Polar, Finland) that visualizes the heartbeat. During the warm-up period, the heart rate is maintained between 100 and 120 beats per minute. The arm ergometer is used in the same way for the upper circumference. Stretching exercises are performed for 5 minutes before and after the test to prevent possible injuries.

As shown in **Table 1**, a protocol of test results is prepared. To allow individuals to adapt to the isokinetic measurements, the test is repeated on the isokinetic dynamometer at 210°/sec and 180°/sec at five maximum positions, with 45 seconds rest between repetitions. Concentric peak values of torque of the Working and power variables. Using a Cybex Norm dynamometer, the angular velocity is measured three times with an increase of 30°/s in each set from 30°/s to 450°/s. There is a time of 30 seconds for a break between measurements. Which of the three iterations has the highest peak torque is used in data analysis.


**Table 6.**

*Test protocol.*


#### **Table 7.**

*Foot-thigh abduction.*

Foot (thigh) abduction: The movement is performed with 59.00 8.2 degrees of articular movement (**Table 7**).
