The Effect of Lower Leg Sensory Impulses on the Force Sense of Knee Extensor Muscles in Healthy Adults: The Accuracy of Sense-of-Force Studies

Abstract Background Producing the target force of a muscle group by using visual feedback and reproducing the same force fully blind are regarded as a common approach for quantifying the sense of force. Force sense error is considered to be the difference between the produced target force and reproduced force. The present study aimed to evaluate the effects of tactile sensory feedback in the lower leg on the perceived magnitude of force sense. Methods and materials In this cross-sectional study, 18 healthy men (mean age 24.31 ± 3.94 years) were selected based on a simple randomized method. First, the quantity of force sense error of the knee extensor muscle group was measured before and after manipulating the tactile inputs of the leg. Then, methods A, B, and C were applied to measure force sense errors. In addition, the tactile impulses were manipulated in methods B and C by placing a piece of thick foam between the distal portion of lower leg among the subjects and the dynamometer. The tactile inputs remained intact during method A. Results The accuracy of the reproduced target force was significantly affected following the disturbance of tactile inputs in the lower leg in methods B and C, compared to method A (p  Conclusion Altering tactile inputs in the lower leg can affect the force sense of the knee extensor muscles. The received somatosensory inputs across the lower leg can affect the whole process of force perception at this joint.