Foure, A. | Search bioRxiv

bioRxiv2026

Bioimpedance spectroscopy assessment of skeletal muscle tissue properties after muscle damage

High intensity and unaccustomed physical activity can induce skeletal muscle damage, while even routine movements can cause similar alterations in patients with neuromuscular disease. However, reliable assessment of muscle damage using indirect markers such as muscle function evaluation, invasive measurements, or imaging techniques is difficult to implement in routine clinical follow-up and sport field settings. Bioimpedance spectroscopy appears as a promising non-invasive, easy-to-use and transportable tool to assess indirect markers of muscle damage. The aim of this study was to determine whether bioimpedance spectroscopy data are sensitive to eccentric exercise-induced muscle damage and if these potential changes mirror responses in muscle function and tissue mechanical properties. Changes in knee extensors maximal isometric contraction torque, muscle soreness, resting rigidity of the quadriceps femoris muscle tissue, and bioimpedance parameters at rest and during maximal isometric contraction were assessed in nine healthy males before, immediately after and in the three days following 120 maximal isokinetic eccentric contractions. Maximal contraction torque was significantly reduced during the three days following the eccentric exercise (up to -24.2%) while muscle soreness and rigidity of the quadriceps femoris were elevated until the second day (+494.4% and +7.6%). Changes in bioimpedance spectroscopy parameters were transiently observed at rest immediately after the damaging exercise, but not in the days that followed. Although the changes in bioimpedance parameters correlated with that of the indirect markers of muscle damage, they had already returned to baseline while functional and mechanical impairments persisted. Therefore, bioimpedance spectroscopy measurements may represent a suitable and cost-effective means of monitoring muscle fatigue.

physiology↗

bioRxiv2025

Decoding hypnotic consciousness: neural and experiential insights into induced and ideomotor suggestions

Hypnotic induction and ideomotor suggestions provide a powerful framework for investigating the remarkable capacity of verbal influence to reshape conscious experience, cognition, and motor control. We employed a multimodal approach combining high-density EEG, respiratory and behavioral monitoring, and first-person reports across three conditions: baseline resting state, progressive hypnotic induction (Light and Deep states), and an ideomotor task comparing a hypnotically suggested arm catalepsy to a voluntary simulation. EEG results revealed that light hypnosis was associated with early parieto-occipital alpha suppression and increased theta-band activity. As hypnosis deepened, frontoparietal connectivity increased in the theta while parasympathetic activation declined, challenging the view of hypnosis as a passive, low-arousal state and instead pointing to active top-down reorganization of large-scale brain networks. During the ideomotor state, participants exhibited distinct patterns of behavioral responsiveness, classified as tremblers and non-tremblers, despite reporting comparable disruptions in the sense of agency. Phenomenological analyses corroborated these distinctions, revealing that Tremblers attempted to move despite experiencing the action as involuntary or constrained, whereas Non-Tremblers refrained from acting due to a perceived impossibility or an inability to initiate the motor command. EEG connectivity analysis in Tremblers showed an increased frontoparietal gamma activity and reduced delta connectivity, suggesting heightened sensorimotor integration and greater executive monitoring under motor conflict. Together, these findings demonstrate that hypnosis engages dynamic top-down processes that reconfigure both neural connectivity and subjective experience depending on suggestion-types. They support predictive coding accounts of agency disruption and underscore the value of neurophenomenological methods for advancing consciousness science and informing clinical applications.

neuroscience↗