Comprehensive Evaluation of Three Training Modalities: Plyometric, Traditional, and Combined, on Reducing the Incidence and Severity of Lower and Upper Limb Injuries, Improving Performance, and Enhancing Quality of Life in Male Professional Volleyball Players

Comparing the effects of eight weeks of plyometric, traditional, and combined training on reducing the incidence and severity of upper and lower limb injuries, improving sports performance, and enhancing quality of life in professional male volleyball players aged 18‑30 years.

Randomized controlled trial, single‑blind (outcome assessors), parallel three‑intervention‑group, pre‑test/post‑test, sample size 45, software randomization, phase not applicable.

Professional volleyball clubs. After screening and consent, 8‑week intervention in standard hall under expert trainer supervision. Assessments by blinded assessors at pre‑test and post‑test.

Inclusion: male volleyball players 18‑30 years; at least 3 years of professional league experience; no acute injury in last 4 weeks; medical clearance; consent. Exclusion: history of knee, ankle, shoulder, or spine surgery in last 12 months; uncontrolled chronic disease; use of stimulants or steroids; inability to balance for 30s.

Plyometric group: 8 weeks, 3×45min/week, explosive exercises including vertical jumps, box jumps, single‑leg hops, and rapid bounding with emphasis on landing technique. Traditional group: 8 weeks, 3×45min/week, strength training with weights including squats, lunges, bench press, and rotator cuff exercises. Combined group: 8 weeks, 3×45min/week, 50% plyometric and 50% traditional training.

Incidence and severity of upper and lower limb injuries using injury registration form and OSTRC questionnaire; shoulder pain and functional disability using SPADI; foot and ankle pain and functional disability using FADI; sports performance using vertical jump test and T‑test agility; quality of life using SF‑36 questionnaire.

After initial screening and confirmation of eligibility, eligible participants will be randomly assigned to three intervention groups (Plyometric, Traditional, and Combined) using randomization software. The randomization method is simple randomization with individual as the unit of randomization. No stratification is used. The random sequence is generated by software. Allocation concealment is ensured using sealed envelopes.

In this study, due to the nature of the exercise intervention, complete blinding is not possible. However, outcome assessors who are responsible for administering the questionnaires and assessments related to injury, pain, functional disability, sports performance, and quality of life will be blinded to participants' group allocation. Participants, the principal investigator, and trainers are aware of the intervention type. Outcome assessors are blinded through participant coding and lack of access to group allocation information.

De-identified individual participant data, study protocol, statistical analysis plan, informed consent form, clinical study report, and data dictionary: All collected data related to outcome variables (incidence and severity of upper and lower limb injuries, pain and functional disability, sports performance, and health-related quality of life) will be shared completely without identifying information. Documentation regarding methodology, forms used, and analysis plan will also be provided.

Six months after publication of study results

Researchers affiliated with reputable academic and scientific institutions who have an approved research proposal by their institutional ethics committee.

Data may be used solely for research purposes and secondary analyses related to injury prevention and exercise physiology. Commercial use of the data is not permitted. All users must adhere to ethical requirements and maintain data confidentiality, and must report any findings from their analyses to the primary authors. Requests must include a detailed description of the project and its objectives.

To request data, please contact the corresponding author, Mr. Abbas Hasan Al-Qazzaz, via email at abbas.hasan@modares.ac.ir. Requests may also be submitted through the Department of Exercise Sciences at Tarbiat Modares University.

Upon submission of a request via email, the corresponding author will review the application. After approval by the university ethics committee, the request will be forwarded to the research team. If finally approved, de-identified data will be provided within two to four weeks via email or a secure data-sharing platform.

Data will be provided solely for non-commercial purposes, with full adherence to ethical principles and confidentiality of participant information.