TAPER IMPROVES RUNNING ECONOMY BUT NOT VELOCITY AT LACTATE THRESHOLD IN DISTANCE RUNNERS

Abstract

The mechanisms associated with potential improvements in running performance following a training taper (TT) are unclear. Recent investigations suggest that improved running economy (RE) and/or improved lactate threshold (LT) may be potential mechanisms through which performance may be improved following a TT. PURPOSE To examine the effects of a 14-day TT on RE and LT in trained distance runners. METHODS Ten well-trained male distance runners (20.1 ± 0.1 yrs, mean ±SE) were tested following 15 weeks of summer base/early season training (BT), five weeks of mid-season training (MT) and after a 14-day TT. Oxygen consumption (indirect calorimetry) was monitored during four, 5-minute submax treadmill running efforts (11.3, 12.9, 14.5, and 16.1 km/h) and a max run to volitional exhaustion. A finger stick blood sample was collected at the conclusion of each submax effort and at 1, 3, 5 and 7 minutes post max run. The running velocity at a fixed blood lactate level of 4 mM (defined as LT) was interpolated from a lactate profile. RESULTS No change was observed in LT following TT. RE at 11.3 km/h following TT improved when compared to BT and MT (32.33 ± 0.81 vs. 33.43 ± 0.49 and 33.22 ± 0.58 ml/kg/min, respectively p < 0.05). RE at 12.9 km/h following TT also improved when compared to BT and MT (37.52 ± 0.87 vs. 38.31 ± 0.46 and 38.19 ± 0.74 ml/kg/min, respectively, p < 0.05). Interestingly, RE at 14.5 km/h following MT was worse when compared to BT (44.32 ± 0.79 vs. 43.64 ± 0.63 ml/kg/min, p < 0.05). However, RE at 14.5km/h following TT improved when compared to MT (43.30 ± 0.90 vs. 44.32 ± 0.79 ml/kg/min, p < 0.05). No Change in RE was observed at 16.1 km/h. Furthermore, no change in VO2 max was found following TT. CONCLUSION A 14-day TT appears to have no effect on LT. However, TT may result in improved RE at running speeds common to training paces incorporated by distance runners. Improvements in RE, such as those observed in this study, have been associated with improved running performance and may help to explain improvements in racing performance commonly noted by coaches and athletes following a TT.