Reliability and validity of the soccer specific INTER field test.

Area of Science:

• Sports Science
• Exercise Physiology
• Soccer Performance Analysis

Background:

• Soccer demands intermittent high-intensity efforts.
• Existing tests may not fully replicate game-specific physiological and performance loads.
• A need exists for reliable field tests reflecting soccer's unique demands.

Purpose of the Study:

• To detail the execution of the Intermittent Endurance Running (INTER) test.
• To describe physiological responses during the INTER test.
• To evaluate the reliability and content validity of the INTER test for soccer players.

Main Methods:

• The INTER test involves 20m shuttle runs with interspersed sprints, agility drills, walking, and rest.
• Players progressed through increasing shuttle run speeds until exhaustion.
• Physiological markers (heart rate, blood lactate) and performance metrics (time, distance, sprint/agility) were recorded.

Main Results:

• Players achieved an average exercise tolerance time of 25:51 min and covered 2892 m.
• Mean blood lactate and heart rate were 5.5 mmol·L⁻¹ and 161 bpm, respectively.
• Sprint and agility performance declined at higher intensities; test-retest reliability was high (ICC=0.75 for time, CV<1% for sprints/agility).

Conclusions:

• The INTER test accurately simulates soccer's distance/time ratio, sprint frequency, and physiological demands.
• It demonstrates strong reliability and content validity for assessing key physical performance aspects in soccer.
• The INTER test serves as a viable alternative field test for soccer player evaluation.