Effect of 0° and 50° N-K Table Load Angles on Quadriceps Activation in Knee Osteoarthritis

NCT07456254 | Completed

• 1 other identifier: 1207/UN2.F1/ETIK/PPM.0002/2023
• Study Type: interventional
• Target: 43
• Locations: 1 country
• Sites: 1

Brief Summary

Knee osteoarthritis (OA) is a common degenerative joint disease that leads to pain, reduced mobility, and functional limitation. Quadriceps femoris weakness plays a significant role in disease progression and disability. Isotonic strengthening using the N-K Table allows adjustment of load angles to optimize muscle activation; however, the effect of different load angles on quadriceps activation in patients with knee osteoarthritis remains unclear. This study aims to compare quadriceps femoris activation at 0° and 50° N-K Table load angles in patients with knee osteoarthritis using surface electromyography (sEMG). A randomized cross-over experimental design is applied to determine whether adjusting the load angle improves maximum voluntary contraction (MVC) during isotonic knee extension exercise.

Conditions

Knee Osteoarthritis; Osteearthritis

Keywords

Knee Osteoarthritis; Quadriceps Femoris; Isotonic Muscle Strengthening; Maximum Voluntary Contraction; Surface Electromyography

Outcome Measures

Primary Outcomes (1)

• Maximum Voluntary Contraction (MVC) of Quadriceps Femoris Muscles

  Maximum voluntary contraction (MVC) of the quadriceps femoris muscles (vastus medialis, rectus femoris, and vastus lateralis) measured using surface electromyography (sEMG) during isotonic knee extension exercise performed on the N-K Table at 0° and 50° load angles. MVC is defined as the highest sEMG amplitude recorded from three maximal voluntary contraction trials for each muscle.

  Day 1

Study Arms (2)

0° Load Angle NK Table

EXPERIMENTAL

Participants performed isotonic knee extension exercise using the N-K Table adjusted to a 0° load angle. Exercise intensity was set at 75% of the individual 10-repetition maximum (10RM). Each participant performed controlled knee extension movements from 90° flexion to near full extension. At each load angle, three maximal voluntary contractions were recorded with 3-second rest intervals between trials. Surface electromyography (sEMG) was used to measure maximum voluntary contraction (MVC) of the vastus medialis, vastus lateralis, and rectus femoris muscles.

Other: Isotonic Quadriceps Exercise Using NK Table

50° Load Angle NK Table

EXPERIMENTAL

Participants performed isotonic knee extension exercise using the N-K Table adjusted to a 50° load angle. Exercise intensity was set at 75% of the individual 10-repetition maximum (10RM). Each participant performed controlled knee extension movements from 90° flexion to near full extension. At each load angle, three maximal voluntary contractions were recorded with 3-second rest intervals between trials. Surface electromyography (sEMG) was used to measure maximum voluntary contraction (MVC) of the vastus medialis, vastus lateralis, and rectus femoris muscles.

Other: Isotonic Quadriceps Exercise Using NK Table

Interventions

Isotonic Quadriceps Exercise Using NK Table OTHER

Isotonic knee extension exercise performed using the N-K Table device at specified load angles (0° and 50°) with resistance set at 75% of 10RM.

0° Load Angle NK Table; 50° Load Angle NK Table

Eligibility Criteria

• Age: 50 Years - 65 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Diagnosed with unilateral or bilateral knee osteoarthritis (OA), grade 2 or 3, in the subacute or chronic phase based on the criteria of the American College of Rheumatology (ACR) and Kellgren-Lawrence classification.
• Female, aged 50-65 years, based on ACR diagnostic criteria.
• Knee flexion-extension range of motion of at least 0-120 degrees.
• Normal cognitive function as assessed using the Montreal Cognitive Assessment Indonesia Version (MoCA-INA) (score ≥26-30)

You may not qualify if:

• Knee joint instability due to ligament laxity in the cruciate or collateral ligaments obtained from physical examination (valgus/varus test and anterior/posterior drawer test) or previous supporting examination.
• Presence of deformity in the form of genu varus, genu valgus, or genu recurvatum (Q angle 12-20°).
• History of knee injury (fracture, ligament rupture, or meniscus) or having undergone knee surgery.
• Pain or instability of the ankle joint obtained from physical examination.
• Stroke or disorders of the central and peripheral nervous system.
• Patients with metabolic diseases such as diabetes mellitus and heart disease or other autoimmune diseases based on medical records in unstable condition with pre-prandial capillary blood glucose ≠ 80-130 mg/dL or 1-2 hours post-prandial capillary blood glucose ≠ \<180 mg/dL, systolic blood pressure ≠ 90-140 mmHg and diastolic blood pressure ≠ 60-90 mmHg.
• Pain durin loaded knee extension exercise greatetr than 3 on the Visual Analogue Scale (VAS)

Sponsors & Collaborators

• Indonesia University: lead

Study Sites (1)

Department of Physical Medicine and Rehabilitation, Dr. Cipto Mangunkusumo General Hospital

Jakarta, DKI Jakarta, 10430, Indonesia

Location

MeSH Terms

Conditions

Osteoarthritis, Knee

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This is an open-label study. Due to the nature of the exercise intervention, participants and investigators are aware of the load angle applied during testing.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: researcher

Model Details: This study uses a randomized cross-over design in which all participants perform isotonic knee extension exercises at two N-K Table load angles (0° and 50°) in random order. Each participant serves as their own control, and sufficient rest intervals are provided between testing conditions to minimize fatigue effects.

Study Record Dates

• First Submitted: February 25, 2026
• First Posted: March 6, 2026
• Study Start: January 20, 2024
• Primary Completion: June 5, 2024
• Study Completion: May 25, 2025
• Last Updated: March 6, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

ID (1)