l"" <J ( MEDICINE AND SCIENCE IN SPORTS Vol. 11, No.4, pp. 338-344, 1979 Plasma lactate accumulation and distance running performance ABSTRACT FARRELL, PETER A., JACK H. WILMORE, EDWARD F. COYLE, JOHN E. BILLING, and DAVID L. COSTILL. Plasma lactate accumulation and distance running performance. Med. Sci. Sports. Vol. 11, no. 4, pp. 338-344, 1979. Laboratory and field assessments were made on eighteen male distance runners. Per- formance data were obtained for distances of 3.2,9.7, 15, 19.3 km (n = 18) and the marathon (n = 13). Muscle fiber composition ex- pressed as percent of slow twitch fibers (%ST), maximal oxygen consumption (V02max), running economy (V02 for a treadmill ve- locity of 268 m/min), and the V02 and treadmill velocity corre- sponding to the onset of plasma lactate accumulation (OPLA) were determined for each subject. %ST (R2: .47), V02max (r2: .83), running economy (r2:.49), V02 in mllkg min corresponding to the OPLA (r2: .91) and the treadmill velocity corresponding to the OPLA (r2:.91) were significantly (p<.O5) related to perform- ance at all distances. Multiple regression analysis showed that the treadmill velocity corresponding to the OPLA was most closely related to performance and the addition of other factors did not significantly raise the multiple R values suggesting that these other variables may interact with the purpose of keeping plasma lactates low during distance races. The slowest and fastest mar- athoners ran their marathons 7 and 3 m/min faster than their treadmill velocities corresponding to their OPLA which indi- cates that this relationship is independent of the competitive level of the runner. Runners appear to set a race pace which al- lows the utilization of the largest possible V02 which just avoids the exponential rise in plasma lactate. MUSCLE FIBER COMPOSITION, RUNNING ECONOMY, VOzMAX Many factors have been identified as having an influ- ence on success in distance running. The observation of significant relationships between Vozmax, fraction of slow twitch fibers, the fraction of Vozmax which can be utilized and performance have implicated these factors as being associated with success in distance running (6,7,8,9,11, 19,42,56,57). Daniels (15) has suggested that running econ- omy may be related to performance, with running econ- omy defined as the oxygen consumption (mllkg min) for a given standardized submaximal treadmill velocity. Several investigations have demonstrated large individual varia- tions in running economy between subjects (14,15,37) yet this factor has not been investigated in terms of perform- ance. Exhaustive exercise of a prolonged duration is charac- terized by relatively low plasma lactate levels (1,7,12,30). Another common finding is that individuals can exercise Submitted for publication December. 1978. Accepted for publication August, 1979. PETER A. FARRELL, JACK H. WILMORE, EDW ARD F. COYLE, JOHN E. BILLING, and DAVID L. COSTILL Exercise and Sport Science Laboratory The University of Arizona Tucson, AZ 85721 up to a certain critical intensity with little or no accumu- lation of lactate in the plasma (16,31,33,44,52). However, when this critical intensity is surpassed, lactate begins to accumulate exponentially (24,44). Costill and Fox (12) have demonstrated that experienced marathoners utilize approximately 75 percent of their Vozmax during their best marathons. Later, Costill et al. (14) demonstrated that experienced runners can utilize approximately 70% of their Vozmax before lactate begins to accumulate in the plasma. . The above findings suggest that many factors are related to success in distance running and that runners may set a race pace which closely approximates the running velocity at which lactate begins to accumulate in the plasma. The present investigation was undertaken to investigate these factors as correlates to performance at several race dis- tances. METHODS Eighteen experienced male distance runners volun- teered to participate in the study. Table 1 summarizes their physical characteristics and responses to maximal ex- ercise. Running experience ranged from one to ten years. Body composition was determined by body density as- sessment using the hydrostatic weighing procedures of Behnke and Wilmore (2). Residual lung volume was deter- mined by the nitrogen dilution technique (54). The Siri (49) equation was used to estimate relative fat from total body density. The procedures of Bergstrom (3) were employed to obtain muscle biopsies from the lateral head of the gas- trocnemius. This muscle was chosen based on the report of Costill et al. (10) that this muscle is metabolically more ac- tive than are the thigh muscles during distance running. Tissue slices were stained by the following procedures: 1) NADHz Tetrazolium Reductase (41), 2) Myosin ATPase, pH 4.3, 4.5, 4.6 pre-incubations (35), and 3)Alpha-Glycer- ophosphate Dehydrogenase (53). The primary stain used for fiber typing was the Alpha-Glycerophosphate Dehy- drogenase stain and when the typing of anyone fiber was questionable the other stains were used as cross references. The mean number of fibers counted per subject was 391 :J:168 SD fibers. 338