The Effect of Shoulder Mobilization on Muscle Strength and Proprioception: a Randomized Double-blind Study

Acibadem University48 enrolled

Overview

This randomized, double-blind study examines the acute effects of shoulder mobilization on muscle strength and proprioception in healthy individuals. Forty-eight participants (aged 18-25) were randomly assigned to either a mobilization or sham intervention group. Muscle strength and proprioception were assessed before and after treatment. The mobilization group received passive shoulder joint glides, while the sham group underwent a placebo procedure. The study aims to determine whether mobilization affects strength and proprioception immediately.

Summary of the Study This randomized, double-blind study investigates the acute effects of shoulder joint mobilization on muscle strength and proprioception in healthy individuals compared to a sham intervention. Background: The shoulder joint is highly mobile and prone to injury, with rehabilitation often including manual therapy techniques like joint mobilization. Mobilization may enhance joint stability, neuromuscular control, and proprioception by stimulating mechanoreceptors. However, its immediate effects on shoulder proprioception and strength remain unclear. Methods: Participants: 48 healthy university students (aged 18-25) randomly assigned to either the mobilization or sham group. Assessments: Muscle strength (using a handheld dynamometer) and proprioception (laser pointer-assisted joint position reproduction test) were measured before and after the intervention. Intervention: The mobilization group received passive shoulder joint glides, while the sham group underwent a placebo procedure without actual joint movement. Conclusion: This study aims to determine whether shoulder mobilization has immediate effects on proprioception and strength.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Interventions

Joint mobilizationOTHER

Participants receive passive shoulder joint mobilization on the dominant-side glenohumeral joint. The mobilization includes inferior, anterior, and posterior glide techniques, each performed for 1 minute at a frequency of 0.5 Hz, with a 30-second rest between each mobilization. The participant is positioned comfortably to support the joint's range of motion.

ShamOTHER

In the sham intervention, the practitioner mimics the technique of shoulder mobilization but does not apply any actual movement or glide effect on the joint. The procedure is designed to closely resemble the real intervention in terms of duration, rhythm, and the practitioner's handling of the participant's shoulder. The practitioner will use superficial touch on the glenohumeral joint without applying any of the mobilizing forces necessary to move the joint.

Outcomes

Primary Outcomes

Proprioception

Laser pointer-assisted joint position reproduction test for shoulder: A laser pointer is strapped 5 cm above the lateral epicondyle. Participants actively move their arm to a predefined position (90° flexion or abduction), and the laser projection is marked. After lowering their arm and closing their eyes, they attempt to replicate the same position. The difference between the initial and reproduced positions (in millimeters) is measured

Time frame: Before the intervention

Proprioception

Time frame: Immediately after intervention

Secondary Outcomes

Muscle Strength

Hand-held dynamometer (Lafayette) Muscle strength will be measured using a hand-held dynamometer (Lafayette). The assessment will focus on the shoulder flexors, abductors, internal rotators, and external rotators. Three measurements for each muscle group will be taken, and the average value will be recorded in kilograms (kg).