Year: 2026
Type: article
Abstract: Background/Objectives: Spinal excitability may undergo adaptive modulation in response to training load, sport-specific demands, and fatigue. While high-impact sports are known to influence reflex responsiveness, the extent to which these changes differ from athletes in lower-impact disciplines remains unclear. This study aimed to investigate post-exercise changes in Hmax/Mmax ratio among trained runners with varied sport backgrounds, and to identify emergent physiological profiles that may reflect differential spinal adaptation to fatigue. Methods: Twenty-two trained athletes underwent unilateral H-reflex testing before and after treadmill running performed to voluntary exhaustion. Amplitudes of the H-reflex and M-wave were recorded, and Hmax/Mmax ratios were analyzed. Based on a physiologically relevant threshold commonly used to distinguish normal from suppressed reflex amplitudes, participants were post hoc classified into three groups: Group A (pre- and post-test ratios above threshold), Group B (pre above, post below), and Group C (both below). A two-way repeated-measures ANOVA was used to assess between-group effects. Results: Significant differences were found across groups and conditions (p < 0.001). Group A maintained reflex ratios above the threshold, indicating stable excitability. Group B showed the greatest suppression (approximately 66%), transitioning from normal to subthreshold values. Group C remained consistently below-threshold. A significant interaction (p < 0.0001) confirmed that reflex modulation varied by physiological profile. A small but statistically significant reduction in H-reflex latency was also observed; however, this change remained within normal physiological variability. Conclusions: Postexercise H-reflex modulation revealed heterogeneous neuromuscular responses among athletes. These findings may contribute to understanding how sport-specific demands and fatigue shape spinal excitability and may help identify individuals with adaptive or potentially pathological profiles relevant to sports diagnostics.
Source: Journal of Clinical Medicine
DOI: 10.3390/jcm15031297
Institutions: University of Sri Jayewardenepura, Gdansk University of Physical Education and Sport, Bogomoletz Institute of Physiology, National University of Ukraine on Physical Education and Sport, Vinnytsia Mykhailo Kotsiubynskyi State Pedagogical University, National Academy of Medical Sciences of Ukraine, State Institution “National Institute of Traumatology and Orthopedics of the National Academy of Medical Sciences of Ukraine”, Lesya Ukrainka Volyn National University
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7127889088