The study aimed to investigate the effect of stretching the sternocleidomastoid, pectoralis major and iliopsoas muscles on 800 meters freestyle swimming performance in master swimmers.

The benefits of swimming are almost endless. Swimming is important not only as a sport but also for evaluating leisure time, building strength, and recuperating. It even allows some muscles to grow symmetrically and consistently. There is no malfunctioning muscle group in swimming. Even when swimming with minimal effort, one can move with relatively little force and easily. Besides this, it establishes a sense of trust.

Sportive swimming is described as the athlete's ability to complete specific distances in water in the quickest amount of time using freestyle, backstroke, breaststroke, or butterfly strokes. The backstroke technique is performed in supine posture, while the other techniques are swum in facedown, horizontal, and near-horizontal positions. Variable approaches have varied characteristics in terms of body position, leg kick, arm pulling, head position, respiration, and condition.

Biomechanically, our myofascial connections also helps swimmers while they swim. Tightening Superficial Front Line (SFL) causes flexion of the hips and trunk in motion also produces hyperextension at the top of the neck. The large muscles of the pectoralis and latissimus provide the motive force for the large movements of adduction and extension, such as a swimming stroke. Vertical fibers in the fascia on the profound side of the epimysium of the pectoralis major, which does indeed connect from the rectus attachment to the lower part of the fascia colli superficialis (and sternocleidomastoid (SCM)). Lower extremity also coordinates stability while upper part of the body initiates movements between phases İliopsoas starts the hip flexion and is followed up by the rectus femoris initiates knee extension to continue horizontal movement in the water.

Because of the demands of the sport, swimmers have a more rounded forward posture. When the head is forward, the cervical spine is hyperextended, the thoracic spine is in slight flexion, and the lumbar spine is in slight extension, this is known as forward posture. Muscle imbalances in the shoulders are to blame for this forward posture. In the recovery phase of swimming, the scapula must retract and protract along the thoracic wall. The subacromial space reduces with protraction because of the swimmer's adaptation due to sport. Stretching the scapular protractors such as the pectoralis major muscle has been shown to have a considerable impact on the degree of forwarding shoulder posture (FSP) in healthy people. Besides this adaptation also, swimmers with shoulder pain because of more active trigger points can lead to the development of mechanical hypersensitivity compared to ones that do not have any shoulder pain.

As summarized above, swimming athletes generally have a forward posture due to their adaptation to water. In our opinion, this posture may be due to the tension of the anterior group myofascial structures, and releasing the fascia by stretching might affect swimmers' performance. Master swimmers have that adaptation far more compared to young swimmers. Therefore, we can better observe the effects of Sternocleidomastoid, Pectoralis major, and İliopsoas muscle stretching on swimming performance by testing swimmers at distances such as 800 meters.

H0: There is no significant difference between the 800-meter performance measurements of the people in the group that added stretching of specific muscles to their normal training and those in the group that did not add stretching.

H1: There is a significant difference in the 800-meter performance measurements of the group with specific muscle stretching added to their normal training and the people in the group without stretching.

Inclusion Criteria:

• Participants in the study voluntarily,
• Participants in ages over 25 years of age,
• Participants must swim at least two days a week.

Exclusion Criteria:

• Presence of chronic disease,
• Participants have undergone surgery in relevant regions in the last 2 years,
• Participants have had injuries in the relevant regions in the last 2 years.