Effects of an 8-week plyometric training programme on sprint, jump, and agility performance in recreational male football players aged 14-16 years: a randomized controlled trial

Technical Summary: Effects of an 8-Week Plyometric Training Programme on Recreational Male Football Players (Aged 14–16)

Problem Statement
Football is a high-intensity intermittent sport requiring recurrent explosive actions, including sprinting, jumping, acceleration, deceleration, and rapid changes of direction. While technical skills are central to performance, they are heavily dependent on physical capacities such as speed, explosive power, and agility. In adolescent players, these capacities develop alongside growth and maturation. Although plyometric training is widely recognized for enhancing explosive neuromuscular performance through the stretch-shortening cycle, there is a need for field-based evidence specifically regarding recreational adolescent football players. Practitioners require feasible training models that can be integrated into regular training schedules without specialized equipment to improve multiple performance parameters simultaneously.

Methodology
This study was a field-based, two-arm, parallel-group randomized controlled trial (RCT) conducted in Ankara, Türkiye.

• Participants: 28 male recreational football players (aged 14–16 years) who trained at least two days per week. Participants were randomly assigned to an experimental group (n=14) or a control group (n=14).
• Intervention: The experimental group underwent an 8-week plyometric training programme in addition to their routine football training. The control group continued with routine football training only. Both groups maintained their standard training exposure.
• Outcome Measures: Assessments were conducted pre- and post-intervention using standardized field tests:
  • Jump Performance: Vertical jump (measured via My Jump 2 app) and standing long jump.
  • Sprint Performance: 30 m sprint time.
  • Agility/Change of Direction: 505 agility test, quick feet (ladder-based), and zig-zag running test.
  • Anthropometry: Body Mass Index (BMI).
• Statistical Analysis: Data were analyzed using a two-way mixed ANOVA (Group × Time) as the primary decision criterion, supplemented by paired-samples t-tests (within-group), independent-samples t-tests (between-group), and change-score comparisons. Effect sizes were reported using Cohen's d and partial eta squared.

Key Results
The study observed significant Group × Time interactions for all performance outcomes, indicating that the experimental group improved significantly more than the control group.

• Jump Performance: The experimental group showed a mean increase of 15.86 cm in vertical jump compared to 4.50 cm in the control group. Standing long jump improved by 34.14 cm in the experimental group versus 10.29 cm in the control group.
• Sprint Performance: The experimental group reduced their 30 m sprint time by 0.73 seconds, whereas the control group reduced it by only 0.06 seconds.
• Agility and Change of Direction: The experimental group demonstrated substantial reductions in time for agility tests:
  • 505 Agility: -0.72 s (Experimental) vs. -0.09 s (Control).
  • Quick Feet: -1.67 s (Experimental) vs. -0.10 s (Control).
  • Zig-Zag: -2.72 s (Experimental) vs. -0.07 s (Control).
• Statistical Significance: All between-group comparisons for change scores were statistically significant (p < .001 for most variables), with large effect sizes (Cohen's d ranging from 1.16 to 8.42). Notably, baseline differences existed for sprint, 505 agility, and quick feet, but the post-test results favored the experimental group across all variables.

Key Contributions

• Evidence for Recreational Context: The study provides empirical support for integrating structured plyometric training into recreational adolescent football, a demographic often underrepresented in high-level sports science literature.
• Multidimensional Improvement: The intervention demonstrated simultaneous improvements in vertical and horizontal jump, linear sprint speed, and multidirectional agility, suggesting a transfer of neuromuscular adaptations to various football-specific movement patterns.
• Feasibility: The findings support the utility of plyometric exercises as a practical, equipment-light strategy that can be added to existing training regimens to enhance explosive and change-of-direction capacities.

Significance and Claims
The authors conclude that an 8-week plyometric training programme produces meaningful improvements in jump, sprint, and agility-related performance in recreational male football players aged 14–16. The findings suggest that such training is a practical and efficient component for developing explosive and multidirectional movement capacities in this population.

The paper explicitly states that these findings support the integration of structured plyometric exercises into youth recreational football training, provided that progression, supervision, and safety are carefully managed. The authors caution that while the study shows improvements in field-test performance, it did not directly assess technical skills, decision-making, or actual match-play performance; therefore, the results should be interpreted as enhancements in physical capacities rather than direct evidence of match-play improvement.

Limitations Noted by the Authors
The authors acknowledge several limitations:

• No formal a priori sample size calculation was performed; the study was powered to detect large effects only.
• The sample was limited to male recreational players aged 14–16, limiting generalizability to females, elite players, or other age groups.
• Baseline differences existed in some variables (30 m sprint, 505 agility, quick feet).
• Allocation concealment and assessor blinding were not implemented.
• Maturation status was not assessed.
• Long-term injury surveillance was not conducted, though no adverse events occurred during the 8-week period.