Abstract
The functional threshold power field test
exceeds laboratory performance in junior road cyclists. J Strength Cond Res XX(X): 000–000, 2022—The functional threshold power
(FTP) field test is appealing for junior cyclists, but it was never investigated in this age category, and even in adults, there are fewdata on
FTP collected in field conditions. Nine male junior road cyclists (16.9 6 0.8 years) performed laboratory determination of maximal
aerobic power (MAP), 4-mMlactate threshold (P4mM), critical power (CP), and the curvature constant (W9), plus a field determination of
FTP as 95% of the average power output during a 20-minute time trial in an uphill road. The level of significance was set at p , 0.05.
Outdoor FTP (269 6 34 W) was significantly higher than CP (236 6 24W) and P4mM (233 6 23 W). The V_O2peak of the field FTP test (66.964.4ml·kg21·min21)was significantly higher than theV_O2peak assessed in the laboratory (62.763.7ml·kg21·min21). Functional threshold power was correlated, in descending order, withMAP (r50.95), P4mM (r50.94), outdoor and indoor V_O2peak (r50.93 and 0.93, respectively), CP (r 5 0.84), and W9 (r 5 0.66). It follows that in junior road cyclists, the FTP field test was feasible and related primarily to aerobic endurance parameters and secondarily, but notably, to W9. However, the FTP field test significantly exceeded all laboratory performance tests. When translating laboratory results to outdoor uphill conditions, coaches and sport scientists should consider this discrepancy, which may be particularly enhanced in this cycling age category