Cumulative endpoint and reconstructed 500-m energy-system contributions from individualized pacing-matched trials in 2000-m rowing ergometry.

Abstract

Objective: To evaluate the accuracy with which 500-, 1000-, and 1500-m endpoint trials reproduced each rower's individualized 2000-m pacing template, estimate cumulative energy-system contributions at 500, 1000, 1500, and 2000 m, and reconstruct contributions across four successive 500-m segments.

Methods: Twelve trained male provincial-team rowers completed a 2000-m all-out rowing-ergometer reference trial to establish individualized cumulative time, mean power, and mean stroke-rate targets, followed by pacing-matched 500-, 1000-, and 1500-m endpoint trials. Pacing-replication accuracy was evaluated using achieved-minus-target bias, MAE, MAPE, concordance, and Bland-Altman limits of agreement. Energy-system contributions were estimated indirectly using the PCr-La-O₂ framework. Cumulative endpoints and within-rower reconstructed 500-m segments were analyzed separately using repeated-measures analyses with Holm-adjusted comparisons.

Results: At 500, 1000, and 1500 m, time MAE was 0.050, 0.092, and 1.258 s; power MAE was 0.667, 0.917, and 5.083 W; and stroke-rate MAE was 0.750, 0.396, and 0.359 spm, respectively. Corresponding MAPE values were 0.053-0.431% for time, 0.157-1.339% for power, and 1.239-2.483% for stroke rate. No stable group-level systematic bias was detected after Holm adjustment, although statistical equivalence was not tested. Reconstruction showed a higher estimated phosphagen contribution during 0-500 m, glycolytic contribution concentrated mainly within the first 1000 m, and a higher aerobic contribution after the opening segment. No robust segmental difference in total estimated contribution was concluded.

Conclusions: Individualized known-endpoint trials can closely reproduce a rower's 2000-m pacing template while providing endpoint-specific post-exercise inputs for cumulative indirect energy-system estimation. Within-rower reconstruction offers a transparent way to describe successive 500-m energetic patterns alongside actual kinematics, but these reconstructed segments should not be interpreted as direct physiological measurements of continuous race phases or as a validated training prescription.