Cognitive demand of eccentric versus concentric cycling and its effects on post-exercise attention and vigilance

Abstract

This study tested the hypotheses that eccentric cycling (ECC) would be more cognitively demanding than concentric cycling (CONC), and attention and vigilance would improve more after ECC than CONC. Thirty young adults performed CONC and two bouts of ECC (ECC1 and ECC2) for 20min at a similar workload (227.5 ± 51.5W) with 1-week apart. Cognitive load during exercise was assessed by the average error from the target torque over 1200 (60rpm × 20min) revolutions, choice reaction time (CRT), the NASA-task load index (NASA-TLX), and prefrontal cortex oxygenation and deoxygenation (HHb) by near-infrared spectroscopy. Attention and vigilance were assessed by a sustained attention to response task (SART) before, immediately, and at every 15min for 60min after exercise or sitting (control). Heart rate was lower during ECC1 (115.5 ± 20.3bpm) and ECC2 (116.7 ± 21.0bpm) than CONC (156.9 ± 19.4bpm). The torque error was greater for ECC1 (26.1 ± 9.0%) and ECC2 (19.4 ± 9.0%) than CONC (10.8 ± 3.7%). CRT (CONC: 602.8 ± 69.0, ECC1: 711.1 ± 113.0, ECC2: 693.6 ± 122.6ms) and mental demand in NASA-TLX (46.8 ± 25.8, 80.0 ± 15.3, 60.3 ± 17.6) were greater for ECC1 and ECC2 than CONC. Decreases in HHb were greater for ECC1 (- 0.41 ± 0.37µM) and ECC2 (- 0.40 ± 0.40µM) than CONC (0.10 ± 0.40µM) and control (- 0.21 ± 0.28µM). Attention and vigilance decreased 2-8% after 20-min sitting, but improved 2-10% immediately after ECC2, and did not decline from the baseline for 30min after ECC1 or 60min after CONC and ECC2. Cognitive load was greater during ECC than CONC, but post-exercise attention and vigilance changes were not largely different between ECC and CONC.