Reduced plantar sensation causes a cautious walking pattern
Introduction
Human movement is the result of a complex interaction of neural, motor and skeletal functions that are controlled by the central nervous system. Spinal locomotor patterns are modified by afferent information due to the external requirements [1], [2] and different sensory systems, visual, vestibular and somatosensory, contribute to the overall control of human movement. The role of the visual and the vestibular system have been well documented [3], [4], [5], [6], [7], [8], whereas information about the influence of the somatosensory system is less well described. The consequences of reduced influence of the somatosensory system in its entirety has been investigated for the regulation of posture and gait using ischaemic block technique or in patients with diabetic neuropathy [9], [10], [11]. The somatosensory system consists of different types of sensors providing information from muscles, tendons, ligaments, and joint capsules, as well as cutaneous and subcutaneous structures of the skin. The influence of each single sensory system on movement control still remains unclear because of the difficulties in disabling or reducing these systems selectively.
The plantar afferents of the foot are important for the control of posture and gait because the foot is usually the only part of the body that is in direct contact with its environment. One possibility to impair information from the sole of the foot is to use an ice immersion approach. It has been shown that reduced plantar information by such an approach leads to an increased body sway in standing, an increased variation in foot contact in gait termination and a modified pressure distribution pattern in walking [4], [12], [13], [14], [15]. Eils et al. showed that roll-over in walking was substantially modified after ice immersion of the sole of the foot compared with normal conditions [15]. However, the cause of the modified roll-over remained unclear because the proximal joints were not considered.
In general, the complex control mechanisms of body segments movement under reduced plantar sensation conditions has not been well described. Knowledge of how information from plantar afferents triggers and modulates human gait patterns has important implications for the rehabilitation of gait disorders. Therefore, the aim of this investigation was to selectively reduce the cutaneous information from the plantar surface of the foot using an ice immersion approach to study the effects on ground reaction forces, muscle activation patterns and segment movements of the lower extremity in barefoot walking. Our hypothesis was that reduced cutaneous information of the plantar surface of the foot results in a substantially modified gait strategy by characteristic changes in the horizontal and vertical components of the ground reaction forces, reduced electromyography (EMG) activity of specific muscles of the lower extremities, and modified segment angles of the lower extremities during the phases of walking.
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Materials and methods
Twenty healthy subjects (25.9±1.2 years, 61.6±11.5 kg, 178±9.5 cm) participated in the study. All subjects signed an informed consent form and filled out a short questionnaire before participation. All experimental procedures were performed in accordance to the principles of the Declaration of Helsinki. Subjects with a history of neurological disease or diabetes were excluded. Force plate measurements; (EMG) measurements and three-dimensional movement analysis were performed simultaneously during
Results
The analysis of ground reaction force parameters showed significant changes for almost all parameters under the iced condition (Table 1). The second peak of the vGRF was significantly decreased and the minimum between peaks was significantly increased under iced conditions. The absolute ground contact time did not change significantly between both normal and iced conditions (744 ms versus 758 ms, P>0.05). The timing of first and second peak was significantly modified under iced conditions. The
Discussion
This investigation has shown that altered plantar sensation using an ice immersion approach leads to a substantially modulated gait strategy indicating a more cautious ground contact and push-off with accordingly modified EMG and motion patterns. Furthermore, these results explain previous observations where a characteristically modified roll-over pattern from pressure distribution measurements was found under iced conditions [15].
Plantar sensation was reduced using a 10 min ice immersion
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2021, Gait and PostureCitation Excerpt :It was concluded that these results may have been observed due to the less use of the affected side and less weight bearing transferred to that side. Eils et al. [28] achieved a decrease in plantar sensation with the ice technique in healthy individuals and examined the effects of decreased plantar sensation on gait patterns. They concluded that decreased plantar sensation causes negative changes in the ankle, knee, and hip joints, and the gait patterns.