In addition to Classical Physiotherapy, Foundation Inspiratory Muscle Training (IKE) will be treated face to face for 30 sessions, 3 days a week, 10 weeks. On other days, IKE will be applied at home for 15 minutes in the morning and evening for a total of 30 minutes and will be followed up with a diary. IKE will be applied with a device that can load with threshold pressure. The IKE group will continue the exercise program for 10 weeks. The intensity of the exercise will be adjusted to 40-50% MIP for the exercise group. After 10 consecutive respiratory cycles, 3-4 respiratory controls will be asked. As tolerance increases, the consecutive respiratory cycle will be increased. The intensity will be adjusted by taking weekly MIP measurements. Daily monitoring forms will be created for each participant to ensure exercise follow-up.

Functional Inspiratory Muscle Training Group will receive functional inspiratory muscle training in addition to classical physiotherapy, 3 days a week, 10 weeks, 30 sessions in total, face-to-face treatment. On other days, foundation-ICE will be applied at home for 15 minutes in the morning and evening, for a total of 30 minutes, and will be followed with a diary. The same protocol will be applied with the foundation IKE group for teaching the respiratory cycle in the first 4 weeks, and resisted breathing will be worked simultaneously with the exercises in Table 2 in the last 6 weeks. The exercise program will be continued for a total of 10 weeks, including F-ICE, foundation IKE for the first 4 weeks, and F-ICE for 6 weeks thereafter. The intensity of the exercise will be adjusted to 40-50% MIP for the exercise group. After 10 consecutive respiratory cycles, 3-4 respiratory controls will be requested. As tolerance increases, the number of consecutive respiratory cycles will be increase

Respiratory muscle strength will be measured before and after interventions for peripheral muscle strength. Respiratory muscle strength will be measured with a portable device (Intraoral pressure measuring device) that can measure intraoral pressure electronically. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) will be recorded with intraoral pressure measurement, which is a non-invasive method .

Diaphragm thickness and mobility will be evaluated with ultrasonography Clarius C3HD, (Clarius Mobile Health, BC, Canada). Diaphragm thickness measurements will be made using 8-15 mHz linear probe from 8-9th intercostal space. Functional residual capacity (FRC) level will be measured at the end of maximum expiration and total lung capacity (TLC) level will be measured at the end of maximum inspiration. Thickening ratio will be calculated using end-inspiratory diaphragm thickness/end-expiratory diaphragm thickness formula, and thickening fraction will be calculated using end-inspiratory thickness-end-expiratory thickness/end-expiratory thickness formula. Diaphragm mobility will be evaluated using M-mode during rest and deep inspiration with 1-6 mHz convex probe.

Exercise capacity will be assessed with the "2-Minute Walk Test (2MWT)" before and after the interventions. The 2MWT is a frequently used, low-cost, clinically significant and recommended test for the assessment of functional exercise capacity. During the test, the person is asked to walk as fast as possible for two minutes in a 15-meter corridor. Before the test, the person is informed that they can stop and rest whenever they want, but this time will not be added. During the test, the person will be encouraged using standard expressions every minute. After the test, the total distance walked is recorded in meters.

The patient's flexibility will be assessed with the sit and reach test. The patient will be positioned with one foot resting on the S&R Sit and Reach® measuring table, the sole of the other foot on the floor, and the leg bent at the knee. The patient performing the application will place their hands on top of each other and stretch forward slowly and in a controlled manner. Then, the therapist will ask them to reach out with their hands on the S&R Sit and Reach® ruler three times and record the best degree. The data will be recorded in centimeters .

Patients' knee extensor and shoulder abductor muscle strengths will be measured using a portable handheld dynamometer. Measurements will be repeated three times for the dominant and non-dominant sides, and the highest values will be recorded in kgF.

The trunk flexor endurance test will be used to assess core endurance. Before the test begins, the head of the bed will be brought to 60°. The participant will lean their back against the head of the bed and then bring their knees and hips to 90° flexion. During this time, the participant's upper extremities will be crossed on the chest. With the start of the test, the head of the bed will be lowered and the participant will be asked to maintain their position. The time the participant spends without changing their position will be noted in seconds. The test will be repeated once.

Postural control will be evaluated with the Biodex® system, which is actively used in our clinic before and after the interventions. Increasing scores in the Biodex Balance System indicate that balance is deteriorating. After a 20-second trial period for statics, they will be asked to keep the circular ring in the center by moving it in the anteroposterior and mediolateral directions. Level 6 of the 8-level resistance (1 is the least stable, 8 is the most stable) will be used in the evaluation of dynamic balance. At the end of the 20-second test period, the general stability index, anteroposterior stability index, mediolateral stability index and general stability index scores of all individuals will be recorded for both static and dynamic balance.

Short Form-12 consists of 8 sub-dimensions and 12 items: physical functioning (2 items), physical role (2 items), body pain (1 item), general health (1 item), energy (1 item), social functioning (1 item), emotional role (2 items) and mental health (2 items). While the items related to physical and emotional role are answered as dichotomous (yes or no), other items have Likert-type options ranging from 3 to 6. The total score of the survey varies between 0-100, with higher scores representing better health.

The Tampa Kinesiophobia Scale (TKS) is a 17-question checklist used to assess acute and chronic low back pain, fibromyalgia, and musculoskeletal injuries and whiplash-related conditions. The scale uses a 4-point Likert scale (1 = Strongly disagree, 4 = Strongly agree). A total score is calculated after items 4, 8, 12, and 16 are reversed. The individual receives a total score between 17 and 68. A high score on the scale indicates that the individual has high kinesiophobia.

Pain catastrophizing of patients will be assessed using the "Pain Catastrophizing Scale (PCS)". The Turkish version of the "Pain Catastrophizing Scale", which has been reported to reliably predict certain variables such as fear, emotion or thought related to individuals' past pain experiences, severe pain, disability and emotional disturbances, will be assessed using the Pain Catastrophizing Scale (PCS). The scale consists of 13 questions scored from 0 to 4 (0=Not at all, 1=Somewhat. 2=Moderately, 3=Severely, 4=Always). An increase in the scale score indicates a high fear of experiencing pain .

The Hospital Anxiety and Depression Scale is used to determine the risk of anxiety and depression in patients and to measure their levels and changes in severity. The scale consists of a total of 14 questions. Seven of these (odd numbers) measure anxiety, and the other seven (even numbers) measure depression. The scale provides a four-point Likert-type measurement. Each item is scored differently. Items 1, 3, 5, 6, 8, 10, 11 and 13 are in decreasing severity and are scored as 3, 2, 1, 0. Items 2, 4, 7, 9, 12 and 14 are scored as 0, 1, 2, 3. The total scores of the subscales are obtained by adding these item scores. While items 1, 3, 5, 7, 9, 11 and 13 are added for the anxiety subscale, the scores of items 2, 4, 6, 8, 10, 12 and 14 are added for the depression subscale. Each heading is scored from 0 to 21. Higher scores indicate higher anxiety and depression.

Treatment satisfaction will be assessed with VAS. The patient will be asked to mark their level of satisfaction after treatment between 0-10 cm. A high score will indicate a high level of satisfaction.

Willingness for treatment will be assessed with VAS. The patient will be asked to mark their willingness level between 0-10 cm before treatment. A high score will indicate a high level of satisfaction.