Effect Of The Presence Of Dynapenia On Posture, Spine Muscle Elasticity, Strength And Endurance In Young Adults

Bioelectrical Impedance Analysis

Bioelectrical impedance analysis is a method used to evaluate body composition \[30\]. Impedance refers to the resistance of tissue to electric current and is inversely proportional to conductivity. For example, components with high specific resistance such as bone and fat tissue make it difficult for electric current to pass, while components with low resistance such as skeletal muscle and visceral organs can easily conduct electric current. This principle forms the basis of bioelectrical impedance analysis \[31,32\]. Values of \< 8.87 kg/m2 in men and \< 6.42 kg/m2 in women were considered low muscle mass \[9\]. The Tanita BC 401 device will be used in the current study. Participants will be informed before the BIA measurement and will be asked not to drink alcohol for up to 48 hours, not to eat or drink 4 hours before, not to consume tea, coffee and cola for 12 hours before, and not to exercise. In addition, women's measurements will be taken outside of the menstrual period \[33,34\].

Assessment of Muscle Strength

Grip strength, will be measured using the JAMAR hand dynamometer and standardized protocol \[37\]. The JAMAR hand dynamometer is a reliable and most widely used measurement tool for measuring static grip strength \[35,38\]. Measurements are based on the principle of compressing two parallel bars. The participant is given a position suitable for holding and grip strength and the evaluation is made \[38,41\]. The needle of the JAMAR Hand Dynamometer can measure up to 90 kg \[37,39,42\]. The person should sit on a seat without arm support, with the arm in adduction and neutral rotation, the elbow in 90-degree flexion and the forearm in a neutral position \[43,44\]. The average of three trials for each hand was used to determine general grip strength. Inadequacy in hand grip strength was determined as less than 20 kg for women and less than 30 kg for men \[45\].

Assessment of Muscle Performance: 4-Meter Walk Test(4-MWT)

4-Meter Walk Test(4-MWT): (4-MWT) is a walking speed test that evaluates functional limitations and physical performance. (4-MWT) is a widely used test due to its simplicity and high test-retest reliability \[46\]. Test walking speed is the most commonly used and practical method for evaluating muscle performance in the clinic. A normal value is approximately 3.57 seconds. Additionally, walking speeds of less than 0.8 m/s have been associated with a risk of falling \[46,49\].

Assessment of Muscle Performance: Sit-to-Stand Test(SST)

Sit-to-Stand Test(SST): The participant is asked to stand up and sit down completely from a chair for one minute with the arms crossed at chest height from a standard chair height of 45 cm. The number of times the person stands up and sits down completely constitutes the total score \[50\]. During the test, the participant is seated upright on a chair with their feet touching the floor. The person's arms are crossed in front of their chest. The test is started with the command and the number of times the person gets up completely within 30 seconds is recorded. Only a chair and a stopwatch are required for the test. In the evaluations made for young adults, while for men, results below 15 repetitions in the 30-second sit-to-stand test can be considered as poor performance, this limit is determined as 12 repetitions for women \[51\].

Assessment of Posture Angles

The camera, which is placed perpendicular to the floor with a tripod, will be placed 80 cm away from the participant, at the level of the participant's shoulders. The participant is asked to focus on a point at eye level. After taking a lateral photo of the participants while standing, the following posture angles will be calculated using a special software \[52,58\].

Evaluation of Spinal Muscle Elasticity

The stiffness and elasticity of the relevant muscles will be evaluated using the MyotonPRO device, which provides information about the stiffness and elasticity of the muscle \[59,60\]. The participant will be asked to sit on a chair for the assessment. In this way, the participant will be able to reveal his/her completely comfortable position \[60\]. The relevant points will be marked and the measurement will be carried out perpendicular to this point with MyotonPRO. The measurement will be performed bilaterally on the right and left sides, and the data obtained will be recorded.

Evaluation of The Strength And Endurance of The Spine Stabilization Muscles

The Stabilizer Pressure Biofeedback Unit will be used to measure the strength with Posterior pelvic tilt movement, isolated Transversus Abdominis strength measurement and Deep Cervical Flexors strength and endurance assessment will be performed using the Stabilizer Pressure Biofeedback Unit \[61,62\]. The McGill protocol will be used to evaluate core endurance \[63\].

Measurement of The Strength With The Posterior Pelvic Tilt Movement

The participant is placed on his back, with the midpoint of the cuff placed on the midpoint of the line connecting both crista iliacae. The manometer valve is closed and the cuff is inflated to a pressure of 40 mm-Hg, and the participant is asked to press his/her waist down without moving his/her head, shoulders and knees, and to wait for 10 seconds without holding his/her breath. The pressure value on the manometer is recorded. The measurement is repeated 3 times with 30-second rest periods, and the maximum value is accepted as the Posterior pelvic tilt muscle strength \[64,65\].