Authors' reply to the comment by Zhu et al.

Abstract

We appreciate the comment on our article ‘The effect of stretching intensity on pain sensitivity: A randomized crossover study on healthy adults’ (Støve, Hansen, et al., 2024) by Zhu et al. (Binbin, 2024). We want to acknowledge the authors for initiating an important discussion on how stretching intensity and body position influence the stretching effects.

We agree that, for pain modulation, our findings indicate that gentler, lower-intensity stretching may be preferable to high-intensity stretching, particularly in clinical populations (Støve, Hansen, et al., 2024). This could apply both to pain modulation and to exercise adherence. However, it is important to note that stretching exercises are employed in various clinical contexts and are not always primarily aimed at modulating pain. By way of illustration, current evidence shows a dose–response relationship between stretching intensity and flexibility, with higher-intensity stretching yielding greater acute flexibility gains (Thomas et al., 2018).

In our study, we utilized a seated stretching position in the Biodex as it ensured good experimental control. However, this approach may have limited clinical applicability. Although the effect of different body positions during stretching on pain modulation was beyond the scope of the present study, current evidence indicates that comparable pain modulation effects from static stretching exercises can be achieved across various delivery methods, including home-based, therapist-guided and machine-assisted stretching approaches (Støve et al., 2021; Støve, Hirata, & Palsson, 2024; Støve, Thomsen, et al., 2024).

We agree that the clinical implications of our findings go beyond basic static stretching and may extend to various exercise modalities that incorporate stretching elements, such as yoga, proprioceptive neuromuscular facilitation (PNF) and Tai Chi. However, additional work is needed to explore the factors that determine the analgesic effect of stretching exercises in different populations to enable the adaptation of interventions for diverse patient populations. The present results invite the hypothesis that the sensory perception of the stretching stimuli (e.g. the sensation of stretch, stiffness, discomfort or tightness) and the stretch duration may be key factors in determining the magnitude of stretch-induced hypoalgesia.

MPS wrote the first draft, which AR, LØH, KKE, JLT and SPM critically revised. All authors have read and approved the final manuscript.

This project was funded by the Frimodt-Heinecke Foundation. The funding body had no role in the design, collection, analysis, interpretation of data or in writing the manuscript.

The authors declare that they have no competing interests.