A Field-Based Cycling Test to Assess Predictors of Endurance Performance and Establishing Training Zones

Abstract

This study evaluates the relationship between a field-based 8-min time trial (8MTT) and physiological endurance variables assessed with an incremental laboratory test. Secondly, lactate thresholds assessed in the laboratory were compared to estimated functional threshold power (FTP) from the 8MTT. Nineteen well-trained road cyclists (aged 22 ± 2 yr, height 185.9 ± 4.5 cm, weight 72.8 ± 4.6 kg, VO2max 64 ± 4 ml·min·kg) participated. Linear regression revealed that mean 8MTT power output (PO) was strongly to very strongly related to PO at 4 mmol[BULLET OPERATOR]L, PO at initial rise of 1.00 mmol[BULLET OPERATOR]L, PO at Dmax and modified (mDmax) (r = 0.61 - 0.82). Mean 8MTT PO was largely to very largely different compared to PO at fixed blood lactate concentration (FBLC) of 2 mmol·L (ES = 3.20) and 4 mmol·L (ES = 1.90), PO at initial rise 1.00 mmol[BULLET OPERATOR]L (ES = 2.33), PO at Dmax (ES = 3.47) and mDmax (ES = 1.79) but only trivially different from maximal power output (Wmax) (ES = 0.09). The 8MTT based estimated FTP was moderate to very largely different compared to PO at initial rise of 1 mmol[BULLET OPERATOR]L (ES = 1.37), PO at Dmax (ES = 2.42), PO at mDmax (ES = 0.77) and PO at 4 mmol[BULLET OPERATOR]L(ES = 0.83). Therefore, even though the 8MTT can be valuable as a performance test in cycling shown through its relationships with predictors of endurance performance, coaches should be cautious when using FTP and PO at laboratory-based thresholds interchangeably to inform training prescription.

Functional Threshold Power in Cyclists: Validity of the Concept and Physiological Responses

“…ods in the laboratory. Although FTP 8 was equivalent to LT 2 determined as blood lactate concentration [La] of mmol.L − 1 in one study [14], FTP 8 overestimated by ~6 % the same LT 2 index in the other [25]. These contrasting results might be explained by the use of fixed blood lactate concentrations, because they poorly reflect interindividual differences in lactate kinetics [13].…”

“…However, FTP 8 was higher than other LT methods: visual determination (LT visual ) (280 ± 15 W), 1 mmol.L − 1 or greater than the previous stage (LT ∆1 ) (268 ± 18 W), and 1 mmol.L − 1 above baseline (LT + 1 ) (250 ± 24 W) [14]. Accordingly, Sanders et al [25] found that FTP 8 overestimated several LT methods in well-trained cyclists, with mean differences ranging from 21 to 62 W. In contrast to Gavin et al [14], Sanders et al [25] reported FTP 8 was 6 ± 6 % (21 ± 20 W) higher than [La] of 4 mmol.L − 1 . Of note, the use of fixed [La] probably explains this inconsistency, as interindividual differences in lactate kinetics are not taken into account [13].…”

“…Of note, the use of fixed [La] probably explains this inconsistency, as interindividual differences in lactate kinetics are not taken into account [13]. Moreover, the differences between FTP 8 and several LT approaches found by Gavin et al [14] and Sanders et al [25] are not surprising. For example, Gavin et al [14] used LT + 1 while Sanders et al [25] used LT + 1 and 2 mmol.L − 1 [La] to compare with FTP 8 .…”

“…However, in order to decrease the effort time and to improve practicality for regular evaluations, Allen and Coggan [2] have suggested FTP 60 could be determined as 95 % of the mean PO in a 20-min TT (FTP 20 ). A couple of studies have also estimated FTP 60 as 90 % of the mean PO in an 8-min TT (FTP 8 ) [14,25]. Although FTP is widely used in cycling to define target intensity zones and to monitor changes in performance over a season [2], FTP research is still incipient.…”

“…Both Gavin et al [14] and Sanders et al [25] have assessed the agreement between FTP 8 and LTs determined by different meth-…”