TY - JOUR T1 - Perception of effort during an isometric contraction is influenced by prior muscle lengthening or shortening JF - bioRxiv DO - 10.1101/2021.03.29.437599 SP - 2021.03.29.437599 AU - Benjamin Kozlowski AU - Benjamin Pageaux AU - Emma F. Hubbard AU - Benjamin St. Peters AU - Philip J. Millar AU - Geoffrey A. Power Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/03/31/2021.03.29.437599.abstract N2 - Purpose Following a shortening or lengthening muscle contraction, the torque produced in the isometric steady state is distinctly lower (residual torque depression; rTD) or higher (residual torque enhancement; rTE), respectively, compared to a purely isometric contraction at the same final muscle length and level of activation. This is referred to as the history dependence of force. When matching a given torque level, there is greater muscle activation (electromyography; EMG) following shortening and less activation following lengthening. Owing to these differences in neuromuscular activation, it is unclear whether perception of effort is altered by the history dependence of force.Methods Experiment 1 tested whether perception of effort differed between the rTD and rTE state when torque was matched. Experiment 2 tested whether perception of effort differed between the rTD and rTE state when EMG was matched. Finally, experiment 3 tested whether EMG differed between the rTD and rTE state when perception of effort was matched.Results When torque was matched, both EMG and perception of effort were higher in the rTD compared to rTE state. When EMG was matched, torque was lower in the rTD compared to rTE state while perception of effort did not differ between the two states. When perception of effort was matched, torque was lower in the rTD compared to rTE state and EMG did not differ between the two states.Conclusion The combined results from these experiments indicate that the history dependence of force alters one’s perception of effort, dependent on the level of motor command.Competing Interest StatementThe authors have declared no competing interest. ER -