(Bal et al., 2025)

Purpose

To determine whether adding structured strength training to regular soccer practice improves performance indicators such as jump height, aerobic capacity, and match running metrics in female players under 18.

Methods

• Participants: 32 U18 Danish elite female players divided into:
  • Experimental group (EG) – added two weekly strength sessions
  • Control group (CG) – regular soccer training only
• Tests:
  • Countermovement jump (CMJ) for lower-body power
  • Yo-Yo Intermittent Recovery Test Level 2 for aerobic fitness (VO₂max estimate)
  • GPS-based match data for total distance, high-speed distance (>23 km/h), and maximum velocity.
• The strength program emphasized major muscle groups using half of the maximum possible repetitions per set (e.g., 6 of 12 reps at ~70% 1RM), minimizing fatigue while maintaining intensity.

Results

• Experimental group:
  • CMJ ↑ 16.3%
  • Estimated VO₂max ↑ 5.8%
  • Total match distance ↑ 19.4%
  • Very-high-speed running almost doubled (+97%)
  • Maximum velocity ↑ 13.5%
  • All with large effect sizes (ES ≈ 1.1–1.5)
• Control group: no meaningful changes.
• Between-group analyses confirmed significant advantages for the strength-training group (p = 0.001 for all variables).

Conclusions

Implementing a short, structured in-season strength training program significantly enhanced both physical performance and match running output in young elite female soccer players. Performing only half of the possible repetitions per set proved to be efficient and non-fatiguing, suggesting a practical model for integrating strength work into congested soccer schedules.

Practical Application

Coaches and conditioning staff should incorporate lower-limb–focused strength sessions twice weekly during the season to improve jumping ability, aerobic fitness, and high-speed match performance — all crucial determinants of success in modern women’s football.