The FITP: A Controlled Intermittent Running Test for Futsal Athletes

Background: Futsal is a high-intensity, intermittent team sport, yet laboratory protocols that reproduce its substitution-based running demands remain scarce. This study examined the physiological, neuromuscular, and perceptual responses to the Futsal Intermittent Treadmill Protocol (FITP), a laboratory-based protocol designed to replicate the intermittent high-intensity running demands of futsal. Methods: Ten male, national-level (Tier 3) futsal players completed four bouts of intermittent running (6-20 km·h^-1) reflecting typical substitution patterns. Measurements included oxygen consumption (VO₂), heart rate (HR), blood lactate concentration ([BLa^-]), rating of perceived exertion (RPE), total quality recovery (TQR), and countermovement jump (CMJ) performance. Responses were analyzed using one-way repeated-measures ANOVA. Results: HR and %HRmax increased significantly across bouts (p < 0.001; η²p = 0.84 for both), reaching values typical of competitive matches. Relative VO₂ and %VO₂max remained stable, while RPE increased and TQR decreased progressively (p < 0.001; η²p = 0.59-0.62). Blood lactate levels and the CMJ mechanical variables showed no significant changes, indicating no systematic neuromuscular fatigue pattern. Conclusions: The FITP induces substantial cardiovascular and perceptual strain that is physiologically comparable to high-intensity futsal, while metabolic and neuromuscular responses remain stable. The protocol may provide a controlled, repeatable method for assessing intermittent running tolerance; however, optimizing its role in physical evaluation, top-up conditioning, and return-to-play monitoring will benefit from future research confirming its ongoing consistency and field application.