Interobserver and intraobserver reliability in lower-limb flexibility measurements

Area of Science:

• Sports Medicine
• Biomechanical Analysis
• Rehabilitation Science

Background:

• Assessing lower extremity flexibility is crucial for injury prevention and performance enhancement in athletes.
• Understanding the reliability of flexibility tests across different activity levels is essential for accurate clinical evaluation.

Purpose of the Study:

• To evaluate the inter- and intraobserver reliability of lower extremity flexibility tests.
• To investigate the impact of varying sports activity levels on the reliability of these flexibility measurements.

Main Methods:

• Sixty-six participants (professional athletes, active individuals, controls) underwent standardized hamstring, quadriceps, and hip adductor flexibility tests.
• Interobserver reliability was assessed by two blinded examiners, and intraobserver reliability by one examiner after a one-week interval.
• Intraclass correlation coefficient (ICC), coefficient of variation (CV), and critical difference (CD) were used for statistical analysis.

Main Results:

• All flexibility measurements demonstrated satisfactory inter- and intraobserver reliability (ICC).
• Professional athletes exhibited superior reliability (lower CV and CD) compared to active and control groups (P<0.05).
• The popliteal angle test was the most reliable hamstring flexibility measure, while the chair sit and reach test was the least reliable across all groups.

Conclusions:

• This study provides extensive reliability data for flexibility tests in individuals with diverse sports activity levels.
• Quadriceps and hip adductor flexibility measurements are reliable for clinical application.
• The intensity of sports participation significantly affects the reliability of lower extremity flexibility tests.