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

The aim of the present study was to determine the effect of dynapenia on posture, spinal muscle elasticity, strength and endurance in young adults.

Skeletal muscle plays an important role in general health and physical development throughout the life cycle \[1\]. Skeletal muscle strength and performance are of critical importance in performing daily activities, maintaining mobility, and maintaining general health. Therefore, changes in general muscle strength and performance due to various reasons differentiate muscle contraction quality and neural activation, facilitating for the concept of 'dynapenia' \[2,3\].

Dynapenia is defined as a decrease in performance and/or strength without loss of muscle mass \[4\]. Although dynapenia, which facilitates for morbidity and mortality \[5,7\], is a well-defined condition in the elderly, there is very limited information about its prevalence and causes in young people \[8\]. Dynapenia, which has many negative effects on quality of life and daily functioning for the general population \[9\], is considered a form of accelerated muscle aging and can be defined as the "pre-sarcopenia stage" \[10\].

When other causes of dynapenia are examined in the literature; age and chronic diseases have been emphasized, but it has been overlooked that one of the most important modifiable factors, inadequate physical activity, can facilitate for dynapenia, especially in young people \[4\]. The COVID-19 pandemic that started in 2020 and the quarantine and similar measures taken subsequently have led to a decrease in physical activity levels in young people and an increase of approximately 28% in daily sitting time \[11\]. Low physical activity levels and the resulting decrease in muscle strength and performance can facilitate for dynapenia in young individuals \[4,12\].

Individuals who spend a long time in front of the computer also struggle with many health problems caused by being inactive for a long time, especially in the neck and waist \[13,14\]. Posture that is disrupted by the side effects of sitting for a long time can cause a decrease in muscle length and/or elasticity in certain groups of muscles \[15\]. Changes in the muscle also lead to a decrease in muscle strength over time \[16,17\], which can be an accelerating factor for dynapenia.

In the literature, many studies have addressed postural disorders, spinal muscle elasticity, muscle strength and endurance with the functional strength parameter handgrip strength \[18,21\], but no study has examined these parameters in young individuals with dynapenia. When deciding on the presence of dynapenia, handgrip strength is the most important parameter that provides information about general muscle strength. However, changes in the spine in individuals with dynapenia, whose handgrip strength and general muscle performance are reduced, have been ignored in the literature.

Evaluating posture, spinal muscle strength, elasticity and endurance in individuals with dynapenia can be a fundamental step in preparing preventive and therapeutic algorithms against dynapenia. The strength and endurance of spinal muscles can play a critical role in providing postural control, preserving movement functions and reducing the risk of injury, especially in individuals with dynapenia. Therefore, examining factors related to the spine in the presence of dynapenia in young individuals can make significant contributions to developing preventive health strategies, increasing functional capacities and improving quality of life.

According to above information; The aim of the present study was to determine the effect of dynapenia on posture, spinal muscle elasticity, strength and endurance in young adults.

Data collection will be carried out as follows: Participants' height, weight, body mass index and smoking, average time spent in front of the screen during the day (hours of daily use x years of use), presence of Covid-19, number of cases and when it occurred will be recorded verbally. Physical activity level will be assessed with the International Physical Activity Questionnaire - Short Form (IPAQ-SF) \[22,23\]; average smartphone usage time with the Smartphone Addiction Scale Short Form \[24\], and sleep quality (Pittsburgh Sleep Quality Index) \[25\]. Those with no decrease in muscle mass but a decrease in muscle strength and/or performance will be included in the 'dypenia group', and those with no decrease in muscle mass, muscle function and performance will be included in the 'control group'.

Eligibility Criteria:
Inclusion Criteria:

* Being between the ages of 18-25
* Filling out all the survey questions

Exclusion Criteria:

* Presence of chronic diseases that may affect the musculoskeletal system (diabetes, heart disease, neurological disorders)
* Use of medications that may affect muscle functions (corticosteroids, muscle relaxants)
* Presence of serious musculoskeletal injury within the last six months
* Presence of surgery and/or pain related to the musculoskeletal system
* History of eating disorders such as anorexia nervosa, bulimia nervosa were defined as exclusion criteria