Reliability of Standardised High-Intensity Static Stretching on the Hamstrings over Multiple Visits

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Static stretching (SS) is a common practice in athletic training.
• Recent research explores the impact of SS intensity on range of motion (ROM), strength, and passive stiffness.
• The reliability of high-intensity SS across repeated testing sessions remains under-investigated.

Purpose of the Study:

• To assess the reliability of high-intensity static stretching (SS) of the hamstrings.
• To evaluate the consistency of measurements for ROM, strength, power, and passive stiffness across five laboratory visits.
• To determine if high-intensity SS protocols are reproducible in a controlled setting.

Main Methods:

• Thirteen physically active males participated in five laboratory testing sessions.
• High-intensity SS involved a 30-second stretch at 120% of the point of discomfort (POD).
• Measurements were taken using an isokinetic dynamometer to assess ROM, strength, power, and passive stiffness.

Main Results:

• Good reliability (intraclass correlation coefficient > 0.80) was found for knee extension ROM, knee flexion strength, and passive stiffness.
• No significant differences were observed in the ROM achieved at the POD across the five testing sessions (p = 0.370).
• These results indicate consistency in the measured outcomes under the tested high-intensity SS protocol.

Conclusions:

• High-intensity static stretching (SS) to 120% of the point of discomfort, when performed on an isokinetic dynamometer, is reliable across multiple laboratory sessions.
• The protocol shows consistent effects on hamstring range of motion, strength, and passive stiffness.
• Further research is needed to determine the reliability of high-intensity SS in applied, real-world athletic scenarios.