Competitive Swimming and Shoulder Adaptations: The Role of Stroke Specialty in Adolescent Swimmers (Shoulder)

March 27, 2025 updated by: SERCAN YILLI, Hacettepe University

Objectives: To examine the sport-specific adaptations and investigate the effect of swimming stroke specialization in shoulder complex among adolescent competitive swimmers.

Design: Observational study.

Setting: Athletic facilities.

Participants: A total of 76 adolescents participated including n = 28 non-swimmers as Control Group (CG) and n = 48 competitive swimmers as Swimmers Group (SWG).

Main Outcome Measures: Strength of glenohumeral (GH) and scapular muscles (SM), mobility of GH (GH ROMs) joint, proprioception, pectoralis minor length (PML), posterior shoulder tightness (PST) were evaluated for all participants. Kerlan Jobe Orthopaedic Score (KJOC) was sed to evaluate for SWG. The tested shoulder physical performance parameters were compared between the groups.

Study Overview

Status

Completed

Conditions

Study Type

Observational

Enrollment (Actual)

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Turkey
- - Istanbul, Turkey
    - Cebeci Sports Complex

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

Child
Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Probability Sample

Study Population

A total of 55 adolescent competitive swimmers and 40 non-athlete peers were screened. 48 swimmers and 28 non-athlete peers aged between 13 to 18 years met the inclusion criteria and participated in this study

Description

Inclusion Criteria for Swimmer Group:

aged between 13 to 18 years
the asymptomatic swimmers with no history of major upper limb injury or surgery and no injury history of upper limb in last 6 months
having experience in at least 5 years competitive swimming,
actively participating in competitive swimming at least 1 year,
competing at least in national level and having swimming stroke specialization in competitive swimming

Inclusion Criteria for Control Group:

aged between 13 to 18 years,
no competed in overhead sports like swimming, basketball, volleyball, tennis, baseball as professional or recreational,
no history of major upper limb injury or surgery in last 6 months.

Exclusion Criteria for all participants:

if they had at least two positive signs by shoulder screening tests (Hawkin's/Kennedy Subacromial Impingement Test, Jobe/Empty Can Test, External Rotation Resistance Test, Apprehension Instability Test, Speed Test and Gerber Lift-Off Test),
a BMI of 30 kg/m² or greater than 30 kg/m²,
competing in paralympic sports,
if they had any major upper limb injuries or surgeries,
if they had any systemic, neurological or rheumatological diseases,
being pre-pubertal stage (Tanner I) according to Tanner Scale,
indicated their unwillingness to participate to this study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Number of groups / cohorts

Cohorts and Interventions

Group / Cohort
Swimming Group (SWG) The asymptomatic swimmers with no history of major upper limb injury or surgery and no injury history of upper limb in last 6 months, having experience in at least 5 years competitive swimming, actively participating in competitive swimming at least 1 year, competing at least in national level and having swimming stroke specialization in competitive swimming were included
Control Group (CG) The non-athlete peers with no competed in overhead sports like swimming, basketball, volleyball, tennis, baseball as professional or recreational, no history of major upper limb injury or surgery and no injury history in last 6 months participated in this study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle Strength Time Frame: From October 2019 to September 2021	Muscle strength was assessed with break test by using hand-hold dynamometer (Jamaar Hand Dynamometer, USA). Assessments were applied for both shoulders and 3 times for each position. Shoulder flexion, extension, abduction, full-can, glenohumeral IR and ER, upper, middle and lower trapezius, serratus anterior muscle tests were applied. GH ER/IR ratio was calculated as well (21-26). Measurements were recorded in Newton (N).	From October 2019 to September 2021
Range of Motion Time Frame: From October 2019 to September 2021	Passive Range of Motion (PROM) of both shoulders was assessed using a digital inclinometer (Get My ROM, version 1.0.3 for iOS; Interactive Medical Productions, Hampton, NH, USA). Shoulder internal rotation (IR), external rotation (ER), and total-rotational ROM were assessed (ICC = 0.92-94). Shoulder IR and ER PROM were obtained with the participant lying supine on a standard examination table, with the shoulder initially abducted to 90° with 0° rotation and the elbow flexed to 90° with neutral pronation/supination. In addition, Total-rotational ROM was calculated by summing the IR and ER ROMs average degrees of each shoulder.	From October 2019 to September 2021
Pectoralis Minor Length Time Frame: From October 2019 to September 2021	Digitized 2 anatomical landmarks representing the length of the pectoralis minor. These 2 points were the medial-inferior angle of the coracoid process and just lateral to the sternocostal junction of the inferior aspect of the fourth rib. Measurements of pectoralis minor muscle length was taken with tape measure (ICC = 0.96). Because of height and muscle length variability among subjects, a normalization index was developed. The pectoralis minor index (PMI) was calculated by dividing the resting muscle length measurement by the subject height and multiplying by 100.	From October 2019 to September 2021
Proprioception Time Frame: From October 2019 to September 2021	For proprioception testing, participants attempted to reproduce 45° ER angle. Participants were positioned as lying supine with arm abducted to 90°, elbow flexed at 90°. The ''Get My ROM'' digital inclinometer was used to measure the angles; the iPhone was securely attached to participants forearm using a strap with the screen facing the tester (ICC = 0.87-89). The participant was instructed to close their eyes by using an eye patch throughout testing. The arm was passively rotated to 45° ER and held in this position for 3 seconds. The participant was asked to remember this position. Following the return to neutral the participant was asked to actively return the arm back to the angle shown. The amount of degrees away from 45° was recorded.	From October 2019 to September 2021
Posterior Shoulder Tightness Time Frame: From October 2019 to September 2021	Participants were positioned supine with both shoulders flush against a standard examination table. The tester stood at the head of the examination table toward the head of the subject and positioned the test shoulder and elbow in 90 of both abduction and flexion. To measure GH horizontal adduction, The ''Get My ROM'' digital inclinometer was aligned with the ventral midline of the humerus. The angle created by the end position of the humerus with respect to 0 of horizontal adduction was then recorded as the total amount of GH horizontal adduction motion (ICC = 0.79).	From October 2019 to September 2021

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Scapular Dyskinesis Time Frame: From October 2019 to September 2021	Each participant performed 5 repetitions of bilateral, active, weighted shoulder flexion and bilateral, active, weighted shoulder abduction (frontal plane) while they were observed from the posterior views. First of all, the scapula was observed while participants in rest and then weighted shoulder flexion and abduction movements from the posterior views. Kibler et al. reported the reliability of a visually based classification system for scapular dysfunction that defined 3 different types of motion abnormalities: Type 1 = inferior angle prominence, Type II = medial border prominence and Type III = excessive superior border elevation. Normal, symmetric scapular motion was considered Type IV (ICC = 0.32-42).	From October 2019 to September 2021
Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score (KJOC) Time Frame: From October 2019 to September 2021	KJOC has been designed specifically as a subjective assessment tool to measure functional status of the upper extremities in overhead athletes. The KJOC was translated from English to Turkish to enable use of questionnaires in Turkish overhead athletes by Turgut et al. KJOC was used to measure functional status of the upper extremities in competitive adolescent swimmers and the scores compared in different stroke specialty among the swimmers in this study.	From October 2019 to September 2021

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hacettepe University

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 16, 2019

Primary Completion (Actual)

September 10, 2021

Study Completion (Actual)

October 16, 2021

Study Registration Dates

First Submitted

March 20, 2025

First Submitted That Met QC Criteria

March 27, 2025

First Posted (Actual)

April 4, 2025

Study Record Updates

Last Update Posted (Actual)