The goal of this clinical trial is to learn if yoga or stretching-strengthening exercises are more effective in sedentary young adults who are currently healthy but at risk due to inactivity. The main questions it aims to answer are:

Which exercise type leads to better improvements in physical fitness, mental well-being, and sleep quality based on a person's starting profile?

How do initial levels of balance and muscle strength affect how well a person responds to these exercises?

Researchers will compare a yoga group to a stretching-strengthening exercise group to see if one approach is more effective than the other for specific types of individuals.

Participants will:

Be evaluated for their starting physical fitness (balance and strength) and psychological health.

Perform either yoga or stretching-strengthening exercises regularly during the study period.

Complete surveys about their mood, stress levels, and sleep quality.

Be re-tested at the end of the program to measure changes and improvements.

Sedentary lifestyle has become increasingly prevalent among young adults, leading to decreased physical fitness levels and negatively affecting psychological well-being. Although exercise-based interventions are widely recognized as effective strategies to mitigate these risks, there is limited comparative evidence regarding the differential effects of distinct exercise paradigms in healthy sedentary young individuals.

Yoga, as a mind-body intervention, integrates physical postures, breathing techniques, and mindfulness practices, and has been shown to improve flexibility, balance, muscular endurance, and psychological outcomes such as stress and well-being. On the other hand, traditional exercise programs focusing on stretching and strengthening target musculoskeletal functions more directly and are known to enhance muscle strength, endurance, and functional performance. However, studies directly comparing these two approaches under equivalent conditions (i.e., duration, frequency, and intensity) in a young, healthy sedentary population are scarce.

The primary aim of this randomized controlled trial is to compare the effects of a structured yoga program and a combined stretching and strengthening exercise program on physical fitness and psychological well-being in sedentary young adults. Additionally, the study aims to investigate how baseline physical and psychosocial profiles influence individual responses to these exercise interventions.

The study is designed as a two-arm, parallel-group randomized controlled trial. A total of 50 healthy sedentary individuals aged 18-30 years will be recruited and randomly assigned to either the yoga group or the stretching-strengthening exercise group. Both interventions will be conducted over a 6-week period, with sessions held twice per week, each lasting approximately 50 minutes.

The yoga intervention will consist of three main components: (1) breathing awareness and preparation, including pranayama and low-intensity mobility exercises; (2) a structured sequence of yoga postures (asanas) involving standing poses, balance poses, forward bends, backbends, and core stabilization exercises; and (3) a relaxation and mindfulness phase, including Savasana. The program will follow a progressive structure, gradually increasing intensity and complexity over the 6-week period.

The stretching-strengthening program will include core stabilization exercises, upper and lower extremity strengthening, and flexibility exercises. Exercises will target major muscle groups using body weight, resistance bands, and free weights, with progressive increases in repetitions, sets, and resistance. Each session will conclude with static and dynamic stretching exercises.

Outcome measures will be assessed at baseline and after the 6-week intervention period. Physical fitness parameters will include muscle strength (hand-held dynamometry), muscular endurance (sit-up test and plank duration), flexibility (sit-and-reach test), and dynamic balance (Y-Balance Test). Psychological outcomes will include psychological well-being and sleep quality, assessed using validated questionnaires. Additionally, participants' expectations regarding the intervention and their adherence and satisfaction levels will be evaluated.

Inclusion Criteria:

• Being between 18 and 30 years of age,
• Having a body mass index (BMI) of less than 30 kg/m²,
• Being healthy (having no known systemic, neurological, psychological, or orthopedic diseases),
• Not having participated in regular exercise within the last six months,
• Having a sedentary lifestyle according to the World Health Organization (WHO) definition (not performing at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week),
• Agreeing not to participate regularly in any other physical activity or exercise program for the duration of the study,
• Voluntarily participating in the study and agreeing to sign the written and verbal informed consent form in accordance with the principles of the Declaration of Helsinki.

Exclusion Criteria:

• Individuals with a history of injury, surgery, or pain complaints affecting the musculoskeletal system within the last six months,
• Individuals with neurological, cardiovascular, respiratory, endocrine, psychiatric, or metabolic diseases,
• Individuals who participate in any regular sporting activity,
• Female participants who are pregnant or have a suspected pregnancy,
• Individuals who state that they will not be able to participate regularly in the exercise program or will not be able to complete the study,
• Individuals who do not provide written and verbal informed consent to participate in the study.