Effects of feet warming on plantar pressure distribution, pain threshold, and skin sensitivity

Abstract-Text (inkl. Referenzen und Bildunterschriften)

Introduction: The sensory inputs from the feet are essential for gait and posture. It was shown that temperature interventions can alter foot afferent inputs, improving tactile sensitivity [1], with potentially positive effects on postural control [2]. Further effects of temperature interventions could effect pain sensitivity and plantar pressure.

Aim: To investigate whether improved tactile sensitivity following foot warming induces changes in foot pain sensitivity and plantar pressure distribution in adults.

Materials & Methods: Twenty-five adults (22.52 ± 3.27 yrs) were evaluated for tactile sensitivity (monofilaments), pain threshold (mechanical pain pressure), and plantar pressure (instrumented mat) during single-leg stance. This parameters were measured before and after a foot-warming protocol that increased foot temperature by ~6 °C [3]. Sensitivity, pain thresholds, and plantar pressure were analyzed for the forefoot, midfoot, and rearfoot.

Results: Foot warming improved tactile sensitivity (Table 1) and reduced pain thresholds (Table 2). However, plantar pressure distribution measurements did not differ between pre- and post-warming conditions.

Summary: Warming the feet improved cutaneous afferent information but did not change plantar pressure distribution in young adults. Improving sensitivity without changing plantar pressure distribution can be interesting in developing orthoses and footwear with clinical applications in sports, rehabilitation, and ergonomics.

[1] Schmidt et al., Clin Neurophysiol Pract. 27;2:38-43 (2017).

[2] Machado et al., The Foot, 50; 0958-2592, (2022).

[3] Machado et al., Gait Posture, 102:132-138, (2023).

Table 1: Mean ± SD of skin sensitivity (Log10). Pre- and post-heating assessments: * p < 0.05.

Table 2: Mean ± SD of pressure pain threshold (N/cm²). Pre- and post-heating assessments:* p < 0.05.