## 4 Discussion and Conclusions
However, based on the fact that the EMG amplitude normalized to M\({}_{\text{max}}\) and the relative voluntary muscle activation (estimated using the interpolated twitch technique) significantly reduced after stretching [104; 105], there seem to be other potential neurophysiological mechanisms that may influence the effective, voluntary neural drive. For example, afferent signals from some peripheral proprioceptive structures, such as muscle spindles, Golgi tendon organs, and free nerve endings, are likely integrated in the process of muscle force control (for review see [106]). In particular, the amplification of the motor command provided by persistent inward currents in motor neurons seems to be reduced after static stretching, which might prevent the motoneurons from discharging at higher firing rates (for review see [31]). Indeed, [PERSON] et al. [107] reported that the magnitude of neural drive (estimated from the cumulative spike train) to the plantar flexors significantly increased after static stretching, albeit during low isometric contraction at 10% of MVIT. Future studies are required to study the effects of static stretching on spinal motoneuron firing behaviors and the association between motoneuron excitability and stretch-induced force loss. The present review has several limitations. First, this review does not include all the relevant studies, probably due to the limitations in the keyword searches and search engine algorithms used. This may have biased the results of the current meta-analyses. Second, the static stretching protocols in each of the studies varied in terms of dosage, intensity, and target joint and muscle, and this was not considered in the meta-analyses. Third, the participants in the studies were mostly young healthy male individuals, so the current results may not be generalizable to other populations, such as older adults, female individuals, and patients with neurologic diseases or musculoskeletal injuries. Lastly, many data points in the meta-analyses came from the same articles or research teams, which may lead to an overestimation of the effect size. In conclusion, static stretching may be effective for increasing range of motion and reducing muscle, tendon, and muscle-tendon unit stiffness. However, the reduced stiffness of tendons and the muscle-tendon units is likely an acute response, suggesting that long-term (chronic) static stretching may be beneficial for improving the flexibility of joint and muscle tissue than the flexibility of tendons and the muscle-tendon units. Moreover, static stretching alone may not significantly change neural excitability and muscle architecture. Given that long-term disuse (e.g., due to neurological diseases) likely leads to measurable changes in neural excitability and muscle contractile properties, further studies are required to explore the impact of various aspects of static stretching protocols, such as intensity, duration, and dosage. Furthermore, it is essential to investigate how the integration of static stretching with various sensorimotor stimuli can reshape the neuromuscular systems. Conceptualization, J.S. ; methodology, R.S., M.W.S. and J.S. ; software, J.S. ; validation, R.S., M.W.S. and J.S. ; formal analysis, J.S. ; investigation, R.S., M.W.S. and J.S. ; resources, J.S. ; data curation, R.S., M.W.S. and J.S. ; writing--original draft preparation, R.S., M.W.S. and J.S. ; writing--review and editing, [PERSON]; visualization, [PERSON]; supervision, [PERSON]; project administration, J.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The authors declare no conflict of interest.