The self selected speed of running in recreational long distance runners

The aim of this study was to test the hypothesis that the self selected spe ed in running (v(ss)) is dependent upon the same factors that determine max imal speed in endurance events (e.g. the anaerobic threshold). Experiments were carried out on 8 recreational long distance runners (42.1 +/- 8.6 year s of age, 70.1 +/- 10.6 kg of body mass, 1.74 +/- 0.06 m of body height) wh ile they were participating in a 14 day relay race. During the "race" the s ubjects were not requested to perform maximally but only to cover their run ning turn (1 hour per day) at their preferred pace. The relationships betwe en heart rate (HR), perceived exertion (RPE), blood lactate concentration ( [La](b)) and speed (v) were determined in each subject, before the race, du ring an incremental running test. From these relationships the speed corres ponding to a 4 mM concentration of lactate in blood (v(4mM)) was calculated and found to be 14.3 +/- 1.8 km x h(-1) (n = 8). At this speed the RPE and HR values were 13.6 +/- 1.4 and 156.4 +/- 12.8 bpm, respectively. The aver age values of speed (v(ss), 13.4 +/- 0.6 km x h(-1)), RPE (13.5 +/- 1.4) an d HR (154.4 +/- 7.6 bpm) measured during the race (n = 47) were not signifi cantly different from those measured at the lactate threshold (v(4mM), RPE4 mM and v(4mM)). However, v(ss) and the average HR during the race showed si gnificantly lower variances than v(4mM) and HR4mM suggesting that, besides the need of avoiding lactate accumulation in blood, other factors must be i nvolved in the choice of speed in running.