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Most Effective Knee Joint Angle Pair for Isometric Exercise

F

Firat University

Status

Completed

Conditions

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

Treatments

Other: Isometric Exercise at 30° and 105° Knee Angles
Other: Isometric Exercise at 15° and 90° Knee Angles
Other: Isometric Exercise at 60° and 135° Knee Angles
Other: Isometric Exercise at 45° and 120° Knee Angles

Study type

Interventional

Funder types

Other

Identifiers

NCT07207135
FU_MGBeydagi_Isometric

Details and patient eligibility

About

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.

Full description

Isometric exercises applied to the quadriceps and hamstring muscles are widely used both in rehabilitation programs and in improving physical fitness in athletes. Isometric contractions occur when the muscle generates tension without changing its length, making them especially suitable in conditions where joint movement is limited or contraindicated. Previous studies have demonstrated the benefits of isometric training in increasing muscle strength, enhancing proprioception, and supporting functional performance. However, there is no clear consensus regarding the effects of isometric exercises performed at different knee joint angles on balance, joint position sense, and functional capacity.

The aim of this study was to investigate the effects of isometric exercises applied to the quadriceps and hamstring muscles at different knee angles (15°-90°, 30°-105°, 45°-120°, 60°-135°) on balance, joint position sense, and functional performance in healthy individuals. Participants aged 20-30 years, without knee pain, previous knee surgery, or pathologies preventing ambulation, were included. All participants were randomized into four groups. Each group performed progressive resistance exercises for the hip and ankle, combined with isometric exercises of the quadriceps and hamstring muscles at the specified knee angles.

The training program lasted eight weeks, with sessions three times per week. During each session, isometric contractions were performed against resistance for 10 seconds at the assigned knee angles, with standardized rest periods between sets. The number of repetitions was progressively increased throughout the program.

Assessments were conducted at baseline and after eight weeks. The following outcome measures were used:

Balance: Y Balance Test

Joint position sense: Digital goniometer measurements

Functional performance: Stair climb test and 30-second sit-to-stand test

The hypothesis of the study was that isometric exercises performed at different knee joint angles would result in different responses in balance, joint position sense, and functional performance. The findings are expected to provide valuable insights both for improving physical fitness in healthy populations and for guiding rehabilitation protocols in clinical populations.

Enrollment

44 patients

Sex

All

Ages

20 to 30 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

  • 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

Exclusion criteria

  • 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

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

None (Open label)

44 participants in 4 patient groups

Group 1
Experimental group
Description:
Isometric Exercise at 15° and 90° Knee Angles
Treatment:
Other: Isometric Exercise at 15° and 90° Knee Angles
Group 2
Experimental group
Description:
Isometric Exercise at 30° and 105° Knee Angles
Treatment:
Other: Isometric Exercise at 30° and 105° Knee Angles
Group 3
Experimental group
Description:
Isometric Exercise at 45° and 120° Knee Angles
Treatment:
Other: Isometric Exercise at 45° and 120° Knee Angles
Group 4
Experimental group
Description:
Isometric Exercise at 60° and 135° Knee Angles
Treatment:
Other: Isometric Exercise at 60° and 135° Knee Angles

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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