Blood Flow-Restricted Training and Time Trial Performance: A Cohort Study of World-Class Rowers.

Introduction: This study aimed to explore the potential impact of incorporating blood flow restriction (BFR) training within a training block characterized by minimal high-intensity work on 2000-m rowing ergometer time trial (TT) performance in elite/world-class rowers. Physiological markers often associated with endurance performance (maximal aerobic capacity, V̇O 2max ; blood lactate thresholds and hemoglobin mass, Hb mass ) were measured to determine whether changes are related to an improvement in performance.

Methods: Using a quasi-experimental, observational study design (no control group), 2000-m TT performance, V̇O 2max , submaximal work rates eliciting blood lactate concentrations of ~2 and ~4 mmol·L -1 , and Hb mass were measured before and after 4 wk of noncompetitive season training, which included BFR rowing. BFR training consisted of 11 sessions of 2 × 10 min of BFR rowing at a workload equating to blood lactate concentrations of ~2 mmol·L -1 . Paired t -tests were used to compare pre-/postvalues, and Pearson correlation was used to examine whether physiological changes were associated with changes to TT performance.

Results: TT performance improved in both female (1.09% ± 1.2%, ~4.6 ± 5.2 s; P < 0.01) and male (1.17% ± 0.48%, ~4.5 ± 1.9 s; P < 0.001) athletes. V̇O 2max increased in female rowers only ( P < 0.01), but both sexes had an increase in work rates eliciting blood lactate concentrations of 2 mmol·L -1 (female: 184 ± 16 to 195 ± 15 W, P < 0.01; male: 288 ± 23 to 317 ± 26 W, P = 0.04) and 4 mmol·L -1 (female: 217 ± 13 to 227 ± 14 W, P = 0.02; male: 339 ± 43 to 364 ± 39 W, P < 0.01). No changes in Hb mass (both sexes, P = 0.8) were observed. Improvements in TT performance were not related to physiological changes (all correlations P ≥ 0.2).

Conclusions: After 4 wk of training with BFR, the improvement in TT performance was greater than what is typical for this population. Physiological variables improved during this training block but did not explain improved TT performance.