Physiological and Perceptual Responses in Spinal Cord Injury Handcyclists During an Endurance Interval Training: The Role of Critical Speed.

Objective: This study sought to determine the physiological (oxygen uptake, heart rate, and blood lactate concentration) and perceptual (rating of perceived exertion) responses during an endurance interval training at the critical speed in elite handcyclists with spinal cord injury.

Design: Eight handcyclists performed an incremental test, three tests to exhaustion at a constant speed to determine critical speed, and the endurance interval training. The endurance interval training consisted of 6 × 5 mins at the individualized critical speed, with passive recovery of 50 secs. All testing was performed using their own handcycles on an oversized motorized treadmill. Physiological and perceptual responses were assessed during the incremental and endurance interval training tests.

Results: There was no significant difference in average oxygen uptake from the first to the sixth repetition. The mean ∆[La-]10_last between the 10th to the 30th minute of the exercise was -0.36 mmol·l-1, and no difference was detected from the first to the sixth repetition. The heart rate also remained stable during endurance interval training, whereas rating of perceived exertion increased significantly throughout the session.

Conclusions: Repetitions of 5 mins at the critical speed in elite handcyclists are associated with cardiorespiratory and lactate steady state, whereas the perceived exertion increased systematically.