Comparison of plyometric training using differential learning versus nonlinear pedagogy on functional, biomechanical factors in athletes at high risk of A. C. L. injury: protocol for aparallel-group randomized controlled trial.

The trial will enroll 48 male athletes identified as being at high risk for ACL injury.

• Participants will be aged 18-26 years.
• Athletes participate in ball sports.
• Participants are identified as being at high risk for ACL injury prior to enrollment.
• The study uses a single-assessor blind randomized controlled trial design.

Participants will be randomly allocated to one of three parallel groups of equal size.

• Group 1: NLP combined with plyometric training (n = 16).
• Group 2: DL combined with plyometric training (n = 16).
• Group 3: a control group (n = 16, implied by equal allocation from total of 48).
• Outcome assessors will be blinded to group allocation.

The intervention consists of 24 sessions delivered over 8 weeks at a frequency of three sessions per week for both active intervention groups.

• Both the NLP and DL groups undergo the same total number and frequency of sessions.
• Plyometric exercises are performed under variable conditions.
• The protocol is designed for practical application in both clinical and field settings.
• Physiotherapists, athletic trainers, coaches, and return-to-sport specialists are identified as potential implementers.

Primary outcomes include kinematic and kinetic variables, while secondary outcomes assess functional performance.

• All outcomes will be measured at baseline and following the 8-week intervention period.
• Kinematic and kinetic variables relate to biomechanical risk factors for ACL injury.
• Functional performance constitutes the secondary outcome domain.
• The design aims to capture modifiable risk factors associated with ACL injury.

Emerging evidence cited in the paper suggests that integrating movement variability effectively reduces modifiable risk factors for ACL injuries.

• Injury prevention strategies have recently emphasized the integration of multidimensional training with motor learning approaches.
• Both NLP and DL are described as approaches that incorporate movement variability.
• The incidence of ACL ruptures is described as 'notably high' among young athletes participating in ball sports.
• The study was prospectively registered with the Iranian Registry of Clinical Trials (IRCT) on March 15, 2025, under identifier IRCT20210602051477N3.