Vastus medialis H-reflex reliability during standing.

Area of Science:

• Neuromuscular physiology
• Rehabilitation science
• Biomedical engineering

Background:

• The vastus medialis H-reflex is a valuable tool for assessing quadriceps voluntary activation and inhibition, particularly following knee injuries.
• Establishing the reliability of this measure across repeated testing sessions is crucial for its clinical application.
• Previous research has not comprehensively evaluated the reliability of vastus medialis H-reflex amplitude recordings during dynamic postural tasks.

Purpose of the Study:

• To determine the intrasession and intersession reliability of vastus medialis H-reflex amplitude measurements.
• To investigate the reliability of these recordings across different knee flexion angles (0, 30, 45, 60 degrees) while standing.
• To validate the recording of four H-reflex traces per trial for enhanced accuracy.

Main Methods:

• Utilized an electromyography unit to elicit and record the vastus medialis H-reflex from healthy subjects.
• Stimulated the femoral nerve with standardized pulses (0.5 ms at 0.2 pps of H-maximum).
• Collected data over two consecutive days, with multiple trials at each of the four knee flexion angles within each session.

Main Results:

• Demonstrated high intrasession reliability for vastus medialis H-reflex amplitude recordings across varied knee angles (ICC [2, 4] range: 0.76–0.98).
• Showed moderate to high intersession reliability for these measurements (ICC [2, 1] range: 0.51–0.84).
• Confirmed that recording four H-reflex traces per trial is a reliable method.

Conclusions:

• Vastus medialis H-reflex amplitude recordings are reliable within a single testing session.
• These measurements also demonstrate good reliability between different testing sessions.
• The findings support the use of vastus medialis H-reflex amplitude during standing with varied knee flexion as a dependable clinical and research tool.