The literature contains limited evidence on how our brains control eccentric movement. A higher activation is expected in the contralateral motor cortex (M1) but consensus has not yet been reached. Therefore, the present study aimed to compare patterns of M1 activation between eccentric and concentric movements. Nine healthy participants performed in a randomized order three sets of five repetitions of eccentric or concentric movement with the dominant elbow flexors over a range of motion of 60° at two velocities (30°/s and 60°/s). The tests were carried out using a Biodex isokinetic dynamometer with the forearm supported in the horizontal plane. The peak torque values were not significantly different between concentric and eccentric movements (p = 0.42). Hemodynamic responses of the contralateral and ipsilateral M1 were measured with a near-infrared spectroscopy system (Oxymon MkIII, Artinis). A higher contralateral M1 activity was found during eccentric movements (p = 0.04, η² = 0.47) and at the velocity of 30°/s (p = 0.039, η² = 0.48). These preliminary findings indicate a specific control mechanism in the contralateral M1 to produce eccentric muscle actions at the angular velocities investigated, although the role of other brain areas in the motor control network cannot be excluded.

Eccentric, compared to concentric muscle contraction, is thought to be attributed to different strategies of neuro-motor processing and a higher level of mental demand. This study aimed to evaluate the mental demand and related-cortical activation patterns to eccentric and concentric cycling at matched perceived effort and torque. Nineteen healthy men (30+/-6 yrs) performed four different 5-min cycling exercise conditions on a semi-recumbent isokinetic cycle ergometer: 1) concentric at a moderate perceived effort (23 on the CR100 scale) without torque feedback; 2) concentric and 3) eccentric at the same average torque produced in the first condition; and 4) eccentric at the same moderate perceived effort than the first concentric condition. The order of conditions 2-4 was ran-domised. After each condition, mental demand was monitored using the NASA-TLX scale. Changes in oxy- (O2Hb) and deoxy- (HHb) haemoglobin during cycling exercise were measured over the two prefrontal cortices and the right parietal lobe from a 15-probe layout using a continuous-wave NIRS system. Mental demand was significantly higher when performing eccentric compared to concentric cycling (p = .012) and when the intensity was fixed by the torque rather than the perceived effort (p < .001). For both torque- or perceived effort-matched exercises, O2Hb was significantly greater (p < .001) in both prefrontal cortices and right parietal lobe, and HHb decreased in the left and right prefrontal cortices during eccentric compared to concentric cycling. The current study supports that acute eccentric cycling involves a higher mental demand and frontoparietal network activation compared to concentric cycling.