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

Purpose: 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.

Methods: Thirty young adults performed CONC and two bouts of ECC (ECC1 and ECC2) for 20 min at a similar workload (227.5 ± 51.5 W) with 1-week apart. Cognitive load during exercise was assessed by the average error from the target torque over 1200 (60 rpm × 20 min) 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 15 min for 60 min after exercise or sitting (control).

Results: Heart rate was lower during ECC1 (115.5 ± 20.3 bpm) and ECC2 (116.7 ± 21.0 bpm) than CONC (156.9 ± 19.4 bpm). 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 ± 122.6 ms) 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 ± 0.37 µM) and ECC2 (- 0.40 ± 0.40 µM) than CONC (0.10 ± 0.40 µM) and control (- 0.21 ± 0.28 µM). 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 30 min after ECC1 or 60 min after CONC and ECC2.

Conclusion: Cognitive load was greater during ECC than CONC, but post-exercise attention and vigilance changes were not largely different between ECC and CONC.