This study aims to compare the effects of concentric and eccentric full can exercises on supraspinatus muscle architecture in individuals with partial rotator cuff tears. Rotator cuff tears are a common cause of shoulder pain and functional limitation. The supraspinatus muscle plays a key role in shoulder movement and stability, and its structure may be affected in individuals with partial tears. Exercise-based rehabilitation is widely used in the conservative management of these conditions. The full can exercise is commonly prescribed to selectively activate the supraspinatus muscle. However, the effects of different contraction types, specifically concentric and eccentric exercises, on muscle structure and clinical outcomes are not fully understood. In this study, participants will be randomly assigned to either a concentric or eccentric full can exercise group. Both groups will receive a standard physiotherapy program, including therapeutic ultrasound and transcutaneous electrical nerve stimulation (TENS), in addition to the assigned exercise protocol. The intervention will last for 6 weeks, with sessions performed three times per week. Outcomes will be assessed before and after the intervention. The primary outcome is the change in supraspinatus muscle pennation angle measured by ultrasound imaging. Secondary outcomes include muscle architecture parameters, pain intensity, range of motion, muscle strength, functional status, and kinesiophobia. The findings of this study may help improve exercise selection in the rehabilitation of individuals with rotator cuff tears.
Study Design and Setting This study is designed as a prospective, randomized, assessor-blinded, parallel-group clinical trial. The study will be conducted at Firat University Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, and Fethi Sekin City Hospital, Department of Physical Medicine and Rehabilitation. Participants A total of 60 individuals aged between 18 and 65 years with a diagnosis of partial supraspinatus tendon tear confirmed by ultrasound or magnetic resonance imaging will be included. Participants will be randomly allocated into two groups (n=30 per group). Randomization and Blinding Participants will be assigned to groups using a computer-generated randomization sequence. Allocation will be concealed using sealed, opaque envelopes. Outcome assessments will be performed by a blinded assessor. Interventions Both groups will receive a standard physiotherapy program including: Therapeutic ultrasound Transcutaneous electrical nerve stimulation (TENS) Standard shoulder rehabilitation exercises The only difference between groups will be the contraction type of the full can exercise: Concentric Group: Emphasis on the lifting phase (approximately 2 seconds), with minimal eccentric loading Eccentric Group: Emphasis on the lowering phase (approximately 4 seconds), with minimal concentric loading All interventions will be applied 3 times per week for 6 weeks (total of 18 sessions). Outcome Measures Primary Outcome: Supraspinatus muscle pennation angle measured by B-mode ultrasonography Secondary Outcomes: Muscle architecture parameters (fiber length, physiological cross-sectional area) Pain intensity (Visual Analog Scale) Range of motion (goniometric assessment) Muscle strength (hand-held dynamometry) Functional status (DASH, SPADI) Kinesiophobia (Tampa Scale of Kinesiophobia) Assessments will be performed at baseline (T0) and at the end of the 6-week intervention (T1). Sample Size and Statistical Analysis Sample size calculation was based on the primary outcome (pennation angle change), assuming an effect size of 0.70, alpha of 0.05, and power of 80%. A minimum of 26 participants per group was required; therefore, 30 participants per group will be recruited to account for potential dropouts. Data will be analyzed using appropriate statistical methods including mixed-design ANOVA for group and time comparisons. Non-parametric tests will be used if assumptions are not met. Intention-to-treat analysis will be applied. Ethical Considerations The study will be conducted in accordance with ethical principles for human research. Informed consent will be obtained from all participants prior to inclusion.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
60
A strengthening exercise performed in the scapular plane with emphasis on the eccentric phase. The lowering phase is performed slowly in approximately 4 seconds against resistance, while the concentric phase is minimized. Exercises are performed 3 times per week for 6 weeks.
A strengthening exercise performed in the scapular plane with emphasis on the eccentric phase. The lowering phase is performed slowly in approximately 4 seconds against resistance, while the concentric phase is minimized. Exercises are performed 3 times per week for 6 weeks.
Includes therapeutic ultrasound, transcutaneous electrical nerve stimulation (TENS), and standard shoulder rehabilitation exercises applied to all participants.
Firat University
Elâzığ, MErkez, Turkey (Türkiye)
Change in Supraspinatus Muscle Pennation Angle
The pennation angle of the supraspinatus muscle will be measured using B-mode ultrasonography. Measurements will be obtained at baseline (T0) and after 6 weeks (T1). The change between time points will be analyzed. Supraspinatus Muscle Pennation Angle: * Assessed by B-mode ultrasonography. * Pennation angle will be measured in degrees (°). * Higher values indicate greater muscle architectural adaptation. * Measured at baseline (T0) and after 6 weeks of intervention (T1).
Time frame: Baseline and 6 weeks
Change in Supraspinatus Muscle Fiber Length
Measured using B-mode ultrasonography at baseline and after 6 weeks. Supraspinatus Fascicle Length: * Measured using B-mode ultrasonography in millimeters (mm). * Greater fascicle length may indicate improved muscle architectural properties. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Physiological Cross-Sectional Area of Supraspinatus
Measured via ultrasound imaging at baseline and after 6 weeks. Physiological Cross-Sectional Area (PCSA): * Measured using ultrasonography in cm². * Higher values indicate greater muscle size. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Pain Intensity (VAS)
Pain intensity will be assessed using the Visual Analog Scale (0-10 cm). Visual Analog Scale for Pain: * Pain intensity will be assessed using the Visual Analog Scale (VAS). * The scale ranges from 0 to 10. * 0 indicates no pain and 10 indicates worst imaginable pain. * Higher scores indicate worse pain severity. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Shoulder Range of Motion
Measured using a goniometer for flexion, abduction, internal and external rotation. Shoulder Range of Motion: * Active shoulder flexion, abduction, internal rotation, and external rotation will be measured using a universal goniometer in degrees (°). * Higher values indicate greater joint mobility. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Shoulder Muscle Strength
Measured using a hand-held dynamometer during isometric contraction. Shoulder Muscle Strength * Isometric muscle strength will be assessed using a handheld dynamometer. * Measurements will be recorded in kilograms or Newtons. * Higher values indicate greater muscle strength. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Functional Status (DASH Scores)
Functional status will be assessed using DASH questionnaires. Disabilities of the Arm, Shoulder and Hand (DASH) Score * Functional disability will be assessed using the DASH questionnaire. * Scores range from 0 to 100. * Higher scores indicate greater disability. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Functional Status (SPADI Scores)
Functional status will be assessed using SPADI questionnaires. Shoulder Pain and Disability Index (SPADI): * Shoulder-related pain and disability will be assessed using SPADI. * Scores range from 0 to 100. * Higher scores indicate greater pain and disability. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
Change in Kinesiophobia (Tampa Scale)
Measured using the Tampa Scale of Kinesiophobia. Tampa Scale for Kinesiophobia: * Fear of movement will be assessed using the Tampa Scale for Kinesiophobia. * Scores range from 17 to 68. * Higher scores indicate greater kinesiophobia. * Assessed at baseline and 6 weeks.
Time frame: Baseline and 6 weeks
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