To evaluate exercise procedures to test the endurance capacity during soccer, individual results in laboratory and field tests were compared to physical performance during the match and further to performance during long term, intermittent exercise. Twenty professional soccer players were video-taped during competitive soccer matches, and the longest total distance (match-distance) and high intensity distance were determined. Blood lactate and maximum oxygen uptake (VO2max) were measured during treadmill running. The subjects also carried out a continuous and an interval field test. Furthermore, eight players performed a prolonged, soccer-specific, intermittent test to exhaustion. Muscle enzymes and morphological characteristics were determined in biopsy samples obtained from the m. gastrocnemius. The distance covered during the prolonged, intermittent test (mean: 16.3 km; range: 14.8-18.5 km) was not related to match-distance (r = 0.16), however, its correlation coefficient with high intensity distance covered during the match was 0.70. The interval field test distance was strongly correlated (r = 0.83) with the distance covered during the prolonged, intermittent test distance. VO2max (r = 0.64) and blood lactate concentrations during submaximal running (r = 0.58) were related to match-distance, but not to the prolonged intermittent test distance (r = 0.18 and r = 0.27, respectively). The muscle enzyme activities and the morphological variables were not related to match activities nor to prolonged, intermittent exercise performance.(ABSTRACT TRUNCATED AT 250 WORDS)