The 30-15 Intermittent Fitness Test Provides Superior Sport-Specific Sensitivity to Treadmill Testing in Elite Female Footballers

Laboratory-based treadmill tests are commonly used to assess aerobic capacity in football players; however, they lack sport-specific characteristics such as intermittent running, accelerations, and changes of direction. The 30-15 Intermittent Fitness Test (30-15IFT) has been proposed as a more ecologically valid field-based alternative.

Twenty-seven elite female football players competing in the Turkish Women's Super League completed both the 30-15IFT and a standardized treadmill incremental protocol in a randomized crossover design. Tests were separated by 48 hours and performed under controlled environmental conditions. Physiological variables including VO₂max, maximal running speed, maximal heart rate, respiratory exchange ratio, lactate-derived thresholds (OBLA), metabolic load-dependent tolerance, and post-exercise recovery markers were assessed using breath-by-breath gas analysis, heart rate monitoring, and capillary blood lactate sampling.

The study aims to determine whether the 30-15IFT elicits more sensitive and sport-specific physiological responses compared with treadmill testing, thereby supporting its use in performance monitoring and individualized training prescription in elite women's football.

Inclusion criteria

• Female football players aged 18-35 years
• Competing in the Turkish Women's Super League
• Minimum of 3 years of professional football experience,
• Full participation in training and matches during the previous 6 months,
• Ability to perform maximal exercise testing

Exclusion criteria

• Musculoskeletal injury affecting performance within the last 3 months,
• Diagnosed cardiovascular, metabolic, or respiratory disease,
• Any condition limiting maximal physical effort