The Yo-Yo IR2 test: physiological response, reliability, and application to elite soccer

Area of Science:

• Sports Science
• Exercise Physiology
• Biomechanics

Background:

• Optimal training methods are crucial for enhancing athletic performance in female soccer players.
• Investigating the impact of training surfaces on strength and performance metrics is essential for program design.

Purpose of the Study:

• To compare the effects of resistance training on stable versus unstable surfaces on key performance indicators in female soccer players.
• To determine if unstable surface training offers benefits over traditional stable surface training for soccer-specific skills.

Main Methods:

• Nineteen NCAA Division II female soccer players were divided into unstable (UST) and stable (ST) training groups.
• Both groups underwent a 5-week periodized resistance training program, with UST performing some exercises on an unstable surface.
• Performance tests included sprint speed, planned and reactive agility, aerobic capacity, and countermovement vertical jump (CMJ) before and after training.

Main Results:

• Both groups showed significant improvements in straight-line sprint speed, planned agility, and reactive agility.
• The stable training (ST) group demonstrated a significant increase in countermovement vertical jump (CMJ), while the unstable training (UST) group showed a decline.
• No performance advantages were observed for the unstable training group in speed, agility, or aerobic capacity.

Conclusions:

• Resistance training on an unstable surface provides no additional benefits for improving speed, agility, or aerobic capacity in female soccer players compared to stable surfaces.
• Utilizing unstable surfaces during resistance training may potentially hinder improvements in vertical jump height, a critical component of soccer performance.