The participant arrived at the laboratory at ~13:00 following a 4 hr fast, having abstained from smoking, alcohol, and caffeine for the preceding 16 hrs. Routine bowel management was completed >24 hrs prior to each trial. Upon arrival, the participant emptied his bladder and confirmed compliance with these pre-exercise requirements. The participant was fitted with surface electrodes to record EMG (Bagnoli; Delsys Inc) signals across multiple muscles, a 12 lead ECG (Cardio-card; Nasiff Associates Inc) and heart rate monitor (T1; Polar) prior to testing (A). We took three resting brachial blood pressure (BP) measurements (Dinamap Pro 300V2; General Electric) before an un-blinded clinician adjusted the neurostimulator (B, C), as per the trial allocation, while investigators left the room. We attached a facemask to an online metabolic cart (TrueOne 2400®; ParvoMedics) to capture breath-by-breath variables. Following a 5 min rest, whereby BP measurements were recorded every minute (D), the participant performed a two-minute warm-up with no resistance (0W) on an arm-crank ergometer (Angio; Lode). We increased power output by 10W/minute, until the participant reached volitional exhaustion (E). The participant cycled at 50 revolutions per minute (rpm) throughout. During every minute of the test we recorded the participants global rating of perceived exertion (RPE) using a (Borg 6 -20) RPE scale. We defined peak oxygen uptake (V̇O2peak) and ventilation as the highest 15-breath rolling averages recorded during exercise. A schematic of the trial day is shown in panel (F).