OBJECTIVE: A novel walk test is proposed to assess the ability of elderly subjects to sustain a submaximal effort in ecological surroundings. Vo(2) uptake during this test was compared with that of a six-minute walk test and maximal exercise test. DESIGN: Descriptive laboratory study. SETTING: Rehabilitation department, Dijon University Hospital. SUBJECTS: Thirty-one subjects, aged from 70 to 85 years, free from any chronic disease. INTERVENTION: Three tests to assess physical capacities: the 200-m fast walk test (200 mFWT), the six-minute walk test (6 MWT) at self-paced speed, and one maximal cardiorespiratory exercise test on an ergocycle. MAIN MEASURES: Distance walked on the 6 MWT, time to perform the 200 mFWT. Heart rate (HR) and oxygen uptake (Vo(2)) were measured for each test. RESULTS: All subjects successfully completed the two walk tests without any complaints. They walked more quickly during the 200 mFWT than during the 6 MWT (mean (SD) speed respectively 1.60 (0.17) versus 1.23 (0.16) m/s, P<0.001). Compared with the maximal exercise test, the relative intensity was much higher during the 200 mFWT than during the 6 MWT (mean (SD) Vo(2) uptake 86.8 (8.9)% versus 67.4 (10.7)% of peak Vo(2), mean (SD) HR 89.9 (9.4) versus 76.2 (0.8)% of peak HR; P<0.001). CONCLUSION: In healthy elderly subjects, the 200 mFWT requires a more sustained effort than the 6 MWT. This test is simple, ecological and well tolerated. In addition to the 6 MWT, the 200 mFWT could be a useful tool to build up and evaluate training or rehabilitation programmes, especially when interval training is planned.