Effect of 5-day dry immersion on the human foot morphology evaluated by computer plantography and soft tissues stiffness measuring

Abstract

Abstract16 participants have been subjected to Dry Immersion model (DI) for 5 days. DI reproduces the space flight factors such as lack of support, mechanical and axial unloading, physical inactivity, elimination of vertical vascular gradient. Long-term bed rest is also associated with similar factors, so the results of the study may be useful for clinical medicine. Computer plantography and measuring the stiffness of the soft tissues of the foot and superficial muscles of the shin (mm. tibialis anterior and peroneus longus) were performed twice before DI exposure, on the 2nd and 4th days of DI exposure, as well as on the 2nd day of the recovery period. DI exposure effects the parameters under study in two ways: by raising the longitudinal arch and by flattening the transverse arch, which is accompanied by a decrease in the soft tissues stiffness of the foot and superficial muscles of the shin. The work reveals the phenomenon of compensating the longitudinal arch state by changing the characteristics that reflect the transverse arch state. The results of the study for the first time demonstrate the correlation of the foot morphological characteristics with a decrease in stiffness of mm. peroneus longus and tibialis anterior.

Impact of different ground-based microgravity models on human sensorimotor system

“…Moreover, a study of muscle tone in a long-term 21-day DI showed a decrease in the tibialis anterior muscle and an increase in the soleus and gastrocnemius muscles, which may be the result of functional compensation through increasing fascial contractility ( Amirova et al, 2020 ). A similar phenomenon was also observed in a study of the dynamics of the morphological and functional characteristics of the foot structure in a 5-day DI ( Saveko et al, 2021 ), as well as in the rectus femoris muscle in a 3-day DI ( Demangel et al, 2017 ). Furthermore, Reschke et al (2009) noted a decrease in the stretch reflex parameters of the postural muscles after exposure to long-duration head-down bed rest: a decrease in start latency and peak latency of the monosynaptic stretch reflex, peak magnitude and latency of the functional stretch reflex ( Reschke et al, 2009 ).…”