Fifteen competitive cyclists and 15 subjects not involved in competitive cycling were studied to determine the relationship between VO2max, lactate threshold (LT), fixed blood lactate concentrations, body composition parameters, and maximal effort bicycle ergometer performance. The subjects were assessed for VO2max, LT, VOLT, and VO2 associated with blood lactate concentrations of 3, 4, 5, and 6 mM/l (VO2 3 mM-VO2 6 mM/l), using an incremental protocol on the bicycle ergometer. Body composition was determined by underwater weighing. Subjects also completed two 10-min drop-off performance tests (starting at 70 rpm) at the same absolute power output (4.5 kg resistance, 1890 kgm/min) (ABS) and at the same relative power output (the highest power output completed for 3 min on the VO2max test) (REL). Metabolic measures and revolution scores were collected on a minute-by-minute basis during the performance tests. The results indicated that the competitive cyclists had higher VO2max (4.25 +/- 0.39 vs 3.50 +/- 0.54 l/min); VO2 LT (2.91 +/- 0.55 vs 1.66 +/- 0.49 l/min); VO2 3 mM, VO2 4 mM, VO2 5 mM, VO2 6 mM, VO2 LT/VO2max (68.5 +/- 11.2 vs 47.2 +/- 10.9 %); max resistance (5.70 +/- 0.56 vs 4.63 +/- 0.67 kg); and resistance at LT (3.57 +/- 0.70 vs 1.93 +/- 0.68 kg) as compared to the noncompetitive subjects (P less than 0.05). Correlational analysis revealed poor prediction between metabolic measures and the homogeneous cumulative rpm scores during the REL test.2+ subjects (r = 0.60 to 0.90).(ABSTRACT TRUNCATED AT 250 WORDS)