Author(s): SENTIJA, D., KOLIC, L., BABIC, V., Institution: FACULTY OF KINESIOLOGY, UNIVERSITY OF ZAGREB, Country: CROATIA, Abstract-ID: 1767

INTRODUCTION:
Standard treadmill stress test protocols used in clinical settings are designed to progressively increase intensity to reach maximum cardiopulmonary capacity, making them effective for testing both walking and running. However, those test protocols are poorly suited for race walking, since there is an exponential growth of energy consumption with increasing walking speed, which significantly shortens test duration and compromises the reliability of anaerobic threshold (respiratory compensation point, AnT) detection. We investigated the influence of two different race walking treadmill test protocols to exhaustion on determination of the anaerobic threshold and associated parameters.
METHODS:
Thirty five amateur race walkers (20 men and 15 women) preformed two different graded race walking tests to exhaustion (at 1% treadmill grade), in random order: 1. with speed increments of 0.5 km/h every 30 sec (standard protocol otherwise used for running, T05) and 2. with speed increments of 0.3 km/h every 30 sec (finely graded load increments, T03). Quark b2 (Cosmed, Italy) metabolic cart was used for breath-by-breath data collection and analysis. Data were averaged for each step, at 30 sec periods, and the modified V-slope method was used for gas exchange anaerobic threshold determination. Student's t-test was used to determine differences in functional parameters between the tests at the speed of the anaerobic threshold and the Pearson correlation coefficient (r) was used to determine the relationship between parameters of the two tests.
RESULTS:
In two cases, the shorter (T05) test failed to yield a reliable anaerobic threshold detection. In the finely graded test (T03) a significantly lower walking speed at the anaerobic threshold was found compared to T05 (8.69±0.77 : 9.06±0.83 km/h, p = 0.008), while the mean heart rate (157.2±17 : 157.8±19 b/min, p = 0.79), VO2 (2.48±0.61 : 2.48±0.66 L/min, p = 0.97) and ventilation (63.1±17 : 63.8±19 L/min, p = 0.77) at the gas exchange anaerobic threshold were almost identical in both tests. Significant, moderate to high relationships were found between anaerobic threshold parameters of the tests (r = 0.60-0.85, p < 0.05).
CONCLUSION:
Graded exercise test protocols used for running are based on the linear relationship between running speed and the metabolic cost of running. This relationship is nonlinear for walking, what makes those protocols less suitable for anaerobic threshold determination in walking. Graded treadmill race walking tests with smaller workload increments provide a more accurate and objective anaerobic threshold estimation. The heart rate at the ventilatory anaerobic threshold can be used as an objective measure of working intensity regardless of the protocol used, while the determination of the speed of walking at the anaerobic threshold is protocol dependent.
Sentija D. et al., 2009.
Rakovac M. et al., 2025.