[Purpose] To assess the influence of plantar sensory input and task guidance produced by
a protrusion on lower limb joint dynamics during gait by changes in muscle activity and
two-dimensional motion analysis. The protrusion seals on the soles of the feet, named
“Perceptual Stimulus Protrusion” were used in this study. [Participants and Methods] In
this study, 40 and 42 healthy adults were recruited for muscle activity and
two-dimensional analysis, respectively. In addition to walking without perceptual stimulus
protrusion (“Control” condition), the testing conditions included attachment of the
protrusion to the heel (“Heel Condition”) and the hallucal (“Hallucal Condition”). As task
guidance, participants were orally instructed how to walk for each conditions. The muscle
activities of the rectus femoris, vastus medialis, tibialis anterior, and medial head of
the gastrocnemius were measured. The two-dimensional analysis was compared with the angle
of ankle dorsiflexion and plantarflexion, the toe height during the swing phase between
the test conditions, respectively. [Results] In the Heel Condition, the tibialis anterior
and vastus medialis activity in the stance and swing phases, toe height, and angle of
ankle dorsiflexion and plantarflexion increased. In the Hallucal Condition, tibialis
anterior activity during the stance and swing phases, gastrocnemius activity during the
stance phase, toe height, and angle of ankle plantarflexion increased. [Conclusion]
Plantar sensory input and task guidance using perceptual stimulus protrusion influences
active motion control. Therefore, the application of this procedure can be expected to
support motion guidance, such as gait and load practice.