Most Effective Knee Joint Angle Pair for Isometric Exercise

NCT07207135 | Completed DMC

• 1 other identifier: FU_MGBeydagi_Isometric
• Study Type: interventional
• Target: 44
• Locations: 1 country
• Sites: 1

Brief Summary

This study investigated the effects of isometric exercises applied to the quadriceps and hamstring muscles at different knee joint angles on balance, joint position sense, and functional performance in healthy individuals. Thirty participants aged 20-30 years were randomized into four groups and performed an eight-week training program, three times per week. Outcome measures included the Y Balance Test, digital goniometer assessments for joint position sense, and functional performance tests (stair climb and 30-second sit-to-stand). The results aim to identify which knee joint angles are most effective for improving neuromuscular function and may guide future rehabilitation and training protocols.

Conditions

Isometric Exercise; Exercise Training; Musculoskeletal Function; Balance, Proprioception, and Functional Performance; Healthy Volunteers

Keywords

Isometric Exercise; Knee Joint Angles; Joint Position Sense; Balance; Functional Performance; Exercise Therapy

Outcome Measures

Primary Outcomes (3)

• Balance Performance

  Balance will be assessed using the Y Balance Test, which measures dynamic postural control in anterior, posteromedial, and posterolateral directions. Normalized reach distances will be recorded.

  Baseline and after 8 weeks of intervention

• Joint Position Sense

  Proprioception will be evaluated using a digital goniometer at predetermined knee joint angles (15°, 30°, 45°, 60°, 90°, and 120°). Absolute angular error between target and reproduced angles will be calculated.

  Baseline and after 8 weeks of intervention

• Functional Performance- Stair Climb Test

  unctional performance will be assessed using the Stair Climb Test (time to ascend and descend 9 steps)

  Baseline and after 8 weeks of intervention

Secondary Outcomes (1)

• Functional Performance - 30-Second Sit-to-Stand Test

  Baseline and after 8 weeks.

Other Outcomes (1)

• Sociodemographic and Anthropometric Characteristics

  Baseline (prior to intervention)

Study Arms (4)

Group 1

EXPERIMENTAL

Isometric Exercise at 15° and 90° Knee Angles

Other: Isometric Exercise at 15° and 90° Knee Angles

Group 2

EXPERIMENTAL

Isometric Exercise at 30° and 105° Knee Angles

Other: Isometric Exercise at 30° and 105° Knee Angles

Group 3

EXPERIMENTAL

Isometric Exercise at 45° and 120° Knee Angles

Other: Isometric Exercise at 45° and 120° Knee Angles

Group 4

EXPERIMENTAL

Isometric Exercise at 60° and 135° Knee Angles

Other: Isometric Exercise at 60° and 135° Knee Angles

Interventions

Isometric Exercise at 15° and 90° Knee Angles OTHER

Participants performed quadriceps and hamstring isometric contractions at 15° and 90° of knee flexion. Each contraction lasted 10 seconds against resistance, three times per week for eight weeks, with progressive repetitions. Hip and ankle strengthening was also included.

Group 1

Isometric Exercise at 30° and 105° Knee Angles OTHER

Same protocol as Group 1, but at 30° and 105° of knee flexion.

Group 2

Isometric Exercise at 45° and 120° Knee Angles OTHER

Same protocol as Group 1, but at 45° and 120° of knee flexion.

Group 3

Isometric Exercise at 60° and 135° Knee Angles OTHER

Same protocol as Group 1, but at 60° and 135° of knee flexion.

Group 4

Eligibility Criteria

• Age: 20 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age between 20 and 30 years
• Voluntary participation with signed informed consent
• No history of knee pain
• No history of knee surgery
• No musculoskeletal pathology preventing ambulation

You may not qualify if:

• Presence of cardiovascular or pulmonary diseases that prevent exercise
• Inflammatory or infectious pathology of the knee joint
• Uncontrolled endocrinological disorders or significant systemic/organ insufficiency
• Neurological disorders affecting knee joint innervation

Sponsors & Collaborators

• Firat University: lead

Study Sites (1)

Fırat Üniversitesi

Elâzığ, Merkez, 23200, Turkey (Türkiye)

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Participants were randomly assigned to one of four parallel groups. Each group performed an eight-week exercise program consisting of progressive resistance training for the hip and ankle combined with isometric quadriceps and hamstring exercises at specific knee joint angles (15°-90°, 30°-105°, 45°-120°, and 60°-135°). The intervention was delivered three times per week under the supervision of physiotherapists.

Study Record Dates

• First Submitted: September 25, 2025
• First Posted: October 3, 2025
• Study Start: March 15, 2024
• Primary Completion: May 12, 2025
• Study Completion: May 30, 2025
• Last Updated: October 3, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)