Role of Rate of Force Development in Mediating the Relationship Between Task-Specific Fear and Chronic Low Back Pain Among Japanese Caregivers - Pilot Cross-Sectional Mediation Study

Sep 29, 2026

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Chronic low back pain (CLBP) is common among caregivers, yet the pathways connecting psychological fear of movement to pain remain unclear. This pilot cross-sectional mediation study tested whether rate of force development (RFD), reflecting explosive strength, mediates links between task-specific fear and CLBP intensity. Thirty-two Japanese care workers completed sit-to-stand and stand-to-sit tasks on a force plate after fear ratings.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Abstract

Background

Methods

Results

Conclusion

Introduction

Chronic low back pain and kinesiophobia

Role of task-specific fear and movement patterns

Sit-to-stand, early-phase RFD, and clinical relevance

Review began 11/06/2025 Review ended 12/01/2025 Published 12/05/2025 © Copyright 2025 Abiko et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. DOI: 10.7759/cureus.98512 Open Access Original Article Role of Rate of Force Development in Mediating the Relationship Between Task-Specific Fear and Chronic Low Back Pain Among Japanese Caregivers: A Pilot Cross-Sectional Mediation Study Teppei Abiko 1, 2, Shin Murata 1, Hayato Shigetoh 1, Norihisa Matsumoto 3, Yamaguchi Hideaki 4 , Michie Ohyama 5, Eiji Sakata 5, Wayne Hing 2 1. Department of Physical Therapy, Faculty of Health Sciences, Kyoto Tachibana University, Kyoto, JPN 2. Faculty of Health Sciences and Medicine, Bond University, Gold Coast, AUS 3. Faculty of Rehabilitation, Reiwa Health Sciences University, Fukuoka, JPN 4. Research Consultancy, Kyoto Tachibana University, Nagoya, JPN 5. Welfare Equipment, NPO (Non-Profit Organization) Fukushiyogunet, Fukuoka, JPN Corresponding author: Teppei Abiko, [abiko@tachibana-u.ac.jp](abiko@tachibana-u.ac.jp) Abstract Background Chronic low back pain (CLBP) is prevalent among caregivers; however, the mechanisms linking psychological factors like fear of movement to pain are unclear. This study investigated whether the rate of force development (RFD), a measure of explosive strength, mediates the relationship between task-specific fear and CLBP intensity in this high-risk population. Methods Thirty-two Japanese care workers (13 CLBP, 19 healthy) performed sit-to-stand and stand-to-sit tasks on a force plate after rating their task-specific fear. Vertical ground reaction force was used to calculate earlyphase RFD (0-100 ms) during stand-to-sit, the prespecified mediator. CLBP was defined as pain persisting for >3 months. Associations were analyzed using Spearman 's correlation and a 1,000-sample bootstrap mediation model. Results Early-phase RFD (0-100 ms) during stand-to-sit correlated negatively with both task-specific fear (ρ = -0.43) and CLBP intensity (ρ = -0.51) . The mediation analysis confirmed a significant indirect effect of fear on CLBP through RFD (B = 0 .39, 95% CI (0 .06, 1.30)) . The total effect of fear on pain was also significant (B = 5.58, 95% CI (0 .39, 18.61)) . Conclusion In caregivers, higher task-specific fear is associated with suppressed RFD during the stand-to-sit task, reflecting a force-control deficit linked to CLBP. Early-phase RFD is a promising biomarker for identifying fear-driven motor inhibition. These findings suggest that workplace interventions that combine graded exposure with explosive-strength training may effectively reduce the risk of chronic pain. Categories: Physical Medicine & Rehabilitation, Pain Management, Healthcare Technology Keywords: chronic low back pain, kinesiophobia, mediation analysis, rate of force development, sit-to-stand Introduction Chronic low back pain (CLBP) is a major contributor to occupational disability and economic loss worldwide [1] . It is especially prevalent among individuals in physically demanding occupations, such as healthcare, caregiving [2], manufacturing, and construction [3], where frequent lifting and repetitive trunk movements are common. In these settings, CLBP contributes to absenteeism and job turnover, leading to staff shortagesand reduced efficiency. While physical loading is a key factor, psychological contributors, such askinesiophobia, defined as the fear of movement due to anticipated pain or re-injury, have also been implicated in the development of disabilities [4], a contributing factor of CLBP and work absence [5,6] . Kinesiophobia has been linked to altered lumbar kinematics during movement tasks [7,8] . Individuals with a higher fear of movement often demonstrate slower movement initiation,

FAQs

What was the study designed to test about caregivers with chronic low back pain?

The study examined whether the rate of force development (RFD) mediates the relationship between task-specific fear and CLBP intensity in Japanese caregivers.

How were task-specific fear and chronic low back pain defined and measured?

Participants rated task-specific fear before performing tasks. CLBP was defined as pain persisting for more than three months.

What main mediation findings were reported regarding fear, RFD, and pain intensity?

Early-phase RFD during stand-to-sit correlated negatively with both task-specific fear and CLBP intensity, and mediation analysis confirmed a significant indirect effect of fear on CLBP through RFD.

Sep 29, 2026

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