Self-Paced Cycling at the Highest Sustainable Intensity With Blood Flow Restriction Reduces External but Not Internal Training Loads

Purpose: This study compared training loads and internal:external load ratios from an aerobic interval session at the highest perceptually sustainable intensity with and without blood flow restriction (BFR). Methods: On separate days, 14 endurance cyclists/triathletes completed four 4-minute self-paced aerobic cycling intervals at their highest sustainable intensity, with and without BFR (60% of arterial occlusion pressure). Internal training load was quantified using 3 training impulses (TRIMP; Banister, Lucia, and Edwards) and sessional ratings of perceived exertion. External load was assessed using total work done (TWD). Training load ratios between all internal loads were calculated relative to TWD. Results: Lucia TRIMP was lower for the BFR compared with non-BFR session (49 [9] vs 53 [8] arbitrary units [ au], P =.020, dz = -0.71). No between-conditions differences were observed for Banister TRIMP (P =.068), Edwards TRIMP (P =.072), and training load in sessional ratings of perceived exertion (P =.134). The TWD was lower for the BFR compared with non-BFR session (223 [52] vs 271 [58] kJ, P <.001, d(z) = -1.27). Ratios were greater for the BFR session compared with non-BFR for Lucia TRIMP:TWD (0.229 [0.056] vs 0.206 [0.056] au, P <.001, d(z) = 1.21), Edwards TRIMP:TWD (0.396 [0.105] vs 0.370 [0.088] au, P =.031, d(z) = 0.66), and training load in sessional ratings of perceived exertion: TWD (1.000 [0.266] vs 0.890 [0.275] au, P =.044, d(z) = 0.60), but not Banister TRIMP:TWD (P =.306). Conclusions: Practitioners should consider both internal and external loads when monitoring BFR exercise to ensure the demands are appropriately captured. These BFR-induced changes were reflected by the Lucia TRIMP: TWD and Edwards TRIMP: TWD ratio, which could be used to monitor aerobic BFR training loads. The Lucia TRIMP:TWD ratio likely represents BFR-induced changes more appropriately compared with ratios involving either Edwards or Banister TRIMP.

Automated summary

This study compared training loads and internal:external load ratios from an aerobic interval session at the highest perceptually sustainable intensity with and without blood flow restriction (BFR). The results showed that the session with BFR had lower Lucia TRIMP and total work done (TWD), indicating lower internal and external loads. The study suggests that the Lucia TRIMP:TWD and Edwards TRIMP:TWD ratios can be used to effectively monitor aerobic BFR training loads.