Strength Training With and Without Blood Flow Restriction on Shoulder Muscle Strength in Healthy Adults

Comparative Effects of Blood Flow Restriction and Traditional Strength Training on Proximal Shoulder Musculature: A Randomized Clinical Trial

The goal of this clinical trial is to compare two types of shoulder strength training: low-load training with blood-flow restriction (BFR) and high-load training without BFR. The study includes healthy adults.

The main questions it aims to answer are:

Are changes in shoulder strength, power, endurance, and muscle mass similar with low-load BFR and high-load training?

Researchers will compare strength training with BFR to strength training without BFR to see whether changes in shoulder muscle performance are similar.

Participants will:

• Provide basic personal details, body measurements (e.g., height and weight), and a brief medical history before starting.
• Train in one of the two programs (BFR or no BFR) two times per week for 4 weeks.
• Complete tests of shoulder maximum strength, power, endurance, and muscle mass at the start and at the end of the protocol.

All outcome assessments were conducted after a standardized warm-up to minimize measurement variability. The warm-up comprised light aerobic activity, followed by dynamic mobility exercises for the shoulder girdle and upper limbs, and targeted stretching of the shoulder and elbow/forearm muscle groups (two sets of 20-30 seconds per muscle group). Safety procedures included monitoring for adverse symptoms during testing and training; sessions were paused or discontinued according to predefined criteria.

Inclusion Criteria:

• Body Mass Index between 18.5 and 30 kg/m²

Exclusion Criteria:

• participation in sports that heavily involve the dominant arm (e.g., tennis, volleyball, or handball) and do not engage in strength training exercises on the upper limb;
• history of trauma or surgery affecting the dominant upper limb;
• acute or chronic shoulder pain,;
• radiating pain;
• cervical disc herniation;
• previous neck surgeries,;
• upper limb edema;
• history of deep vein thrombosis;
• history of oncologic or metabolic conditions;
• pregnancy;
• experience of persistent symptoms such as numbness, tingling, or pain exceeding 7/10 on a numeric scale during the training (applicable to BFR group);
• missed more than one session during the study.