Validation of a Methodology Using Isometric Dynamometer for Ankle STrength Assessment to Quantify LDH-induced Paresis

NCT07763522 | Enrolling By Invitation

• 1 other identifier: HUS/418/2026
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

Lumbar disc herniation (LDH) is a common condition that may cause lower limb motor weakness (paresis), particularly affecting ankle dorsiflexion and plantarflexion. Although motor deficits are clinically important and may influence treatment decisions, objective and standardized methods for quantifying the severity of paresis are lacking. Current clinical assessment mainly relies on manual muscle testing, which is subjective and has limited sensitivity, while isokinetic dynamometry, the reference standard for muscle strength assessment, is expensive and impractical for routine clinical use. This prospective validation study aims to evaluate a clinically feasible isometric ankle strength measurement method based on a handheld dynamometer fixed with an external strap to eliminate examiner-dependent resistance. The study will be conducted in two sequential phases. First, validity and reliability of the method will be established in healthy adult volunteers by comparing measurements with those obtained using an isokinetic dynamometer. Second, the method will be applied in patients with LDH-induced lower limb paresis to determine its performance across a broader range of muscle strength values and its clinical applicability. Outcome measures include maximal isometric ankle dorsiflexion and plantarflexion force, time to peak force, manual muscle testing (Medical Research Council scale), patient-reported weakness using a Numeric Rating Scale, Lower Extremity Functional Scale (LEFS) scores, and functional ankle strength tests. Validity will be assessed using correlation analyses and Bland-Altman agreement analysis, while intra- and inter-rater reliability will be evaluated using intraclass correlation coefficients, coefficient of variation, standard error of measurement, and minimum detectable change. The study seeks to establish a reliable, valid, and clinically practical method for objective assessment of ankle muscle strength in patients with LDH-induced paresis. Such a method could improve clinical evaluation, enable objective monitoring of recovery, facilitate future clinical research, and support treatment decision-making.

Conditions

Paresis; Lumbar Disc Herniation

Keywords

dynamometry; paresis; strength measurement

Outcome Measures

Primary Outcomes (4)

• Criterion validity of the isometric handheld dynamometer

  Agreement between the investigational isometric handheld dynamometer (HHD) measurement method and the reference standard isokinetic dynamometer (IKD) for maximal ankle dorsiflexion and plantarflexion strength.

  At baseline (first measurement session; Day 0)

• Construct validity of the handheld dynamometer

  Correlation of HHD measurements with patient-reported weakness (Numerical Rating Scale), Lower Extremity Functionality Scale questionnaire, manual muscle testing (Medical Research Council grade) and functional ankle performance tests.

  At baseline (first measurement session; Day 0)

• Intra-rater reliability of the handheld dynamometer

  Test-retest reliability of ankle dorsiflexion and plantarflexion strength measurements obtained by the same examiner.

  At baseline (Day 0) and at the second measurement session, within 7 days after baseline

• Inter-rater reliability of the handheld dynamometer

  Agreement between measurements performed by different examiners

  At the second measurement session, within 7 days after baseline

Other Outcomes (8)

• Maximal isometric ankle dorsiflexion strength

  At baseline (first measurement session; Day 0)

• Maximal isometric ankle plantarflexion strength

  At baseline (first measurement session; Day 0)

• Time to peak force

  At baseline (first measurement session; Day 0)

Study Arms (1)

Study participant

OTHER

Person participating in validity and reliability assessment

Device: Strength test validity and reliability

Interventions

Strength test validity and reliability DEVICE

Ankle dorsiflexion and plantarflexion isometric maximal voluntary contraction strength test

Study participant

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged 18-65 years old
• No pathology affecting ankle dorsiflexion or plantarflexion strength

You may not qualify if:

• \- Pathology affecting ankle dorsiflexion or plantarflexion strength
• Second phase
• Aged 18-65 years old
• LDH-induced muscle weakness of ankle dorsiflexion or plantarflexion
• \- No muscle weakness induced by herniated lumbar disc

Sponsors & Collaborators

• Helsinki University Central Hospital: lead

Study Sites (1)

Helsinki University Central Hospital

Helsinki, Uusimaa, 00290, Finland

Location

MeSH Terms

Conditions

Paresis; Intervertebral Disc Displacement

Condition Hierarchy (Ancestors)

Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Spinal Diseases; Bone Diseases; Musculoskeletal Diseases; Hernia; Pathological Conditions, Anatomical

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: OTHER
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: July 8, 2026
• First Posted: August 13, 2026
• Study Start: August 10, 2026
• Primary Completion: October 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: August 13, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: 10 years after publication
• Access Criteria: Researchers who provide a methodologically sound research proposal. Data will be available upon reasonable request to the principal investigator, subject to institutional approval, applicable legislation, and a data sharing agreement.

Locations

FI (1)