Effects of Unilateral Compound Training on Lower-Limb Strength Asymmetry and Athletic Performance in Female Handball Players

Effects of a Six-Week Unilateral Compound Training Program on Lower-Limb Strength Asymmetry and Athletic Performance in Competitive Female Handball Players: A Randomized Controlled Trial

Lower-limb strength asymmetry is common among female handball players and may negatively affect athletic performance while increasing injury risk. This randomized controlled trial was designed to investigate the effects of a six-week unilateral compound training program on lower-limb strength asymmetry, isokinetic muscle strength, hamstring-to-quadriceps ratio, body composition, and physical performance in competitive female handball players. Participants were randomly assigned to either an experimental group receiving unilateral compound training in addition to regular handball training or a control group continuing regular handball training only. It was hypothesized that unilateral compound training would reduce strength asymmetry and improve neuromuscular performance compared with regular training alone.

emale handball requires repeated sprinting, jumping, rapid changes of direction, and unilateral movements that may contribute to the development of lower-limb strength asymmetries. Such asymmetries have been associated with impaired athletic performance and an increased risk of injury. Although unilateral resistance and plyometric exercises have shown beneficial effects individually, evidence regarding the effectiveness of unilateral compound training in female handball players remains limited.

This randomized controlled trial aimed to evaluate the effects of a six-week unilateral compound training program on lower-limb strength asymmetry, isokinetic knee extensor and flexor strength, hamstring-to-quadriceps ratios, body composition, sprint performance, change-of-direction ability, countermovement jump performance, and single-leg jump performance in competitive female handball players.

Thirty competitive female handball players were randomly assigned to an experimental group or a control group. The experimental group completed unilateral resistance and plyometric exercises three times per week for six weeks in addition to regular handball training, whereas the control group continued regular handball training only. Outcome measures were assessed before and after the intervention using standardized laboratory procedures. The findings of this study are expected to provide evidence regarding the effectiveness of unilateral compound training for reducing lower-limb asymmetry and improving sport-specific performance in female handball athletes.

Inclusion Criteria:

• Female handball players aged 18-25 years.
• Competing in the Turkish Women's 2nd Handball League.
• Regular participation in team training (4 sessions/week) and official matches.
• Voluntary participation with written informed consent.

Exclusion Criteria:

• Current musculoskeletal injury or pain preventing participation in training.
• History of lower-limb surgery within the previous 12 months.
• Neurological, cardiovascular, or other medical conditions affecting exercise participation.
• Failure to complete the intervention or assessment procedures.