Preview
Hüseyin Akbulut, MSc (2026). Trunk Flexion Endurance Test: Protocol and Application. Sporeus. Retrieved, November 8, 2026. https://sporeus.com/en/egzersiz-testleri-en/trunk-flexion-endurance-test/
Measures: Abdominal endurance (static flexion)
Table of Contents
Difficulty: Moderate | Category: Strength
Protocol
The Trunk Flexion Endurance Test is the flexor test of the trunk endurance battery of McGill et al. (1999). It measures static endurance of the abdominal muscles.
Preparation: The participant sits with knees and hips at 90°, leaning back against a support set at 60°. Arms are crossed over the chest and the feet are secured. A 5-minute warm-up is performed.
Test Procedure: The support is moved back about 10 cm and the stopwatch starts. The participant holds the 60° trunk angle without support. The test ends when the trunk falls below this angle (back towards the support).
Data Recording: Duration is recorded in seconds.
Interpretation: McGill et al. (1999) reported mean times of about 136 s in men and 134 s in women in healthy young adults. In the battery the flexion/extension ratio is expected to be below 1.0 (longer extensor endurance).
Post-Test: Results are interpreted together with the Sorensen (extension) and side bridge tests.
Formula
Flexion/extension ratio = flexion_s / Sorensen_s; below 1.0 expected
Equipment Required
exercise mat, stopwatch, support angled at 60° (for the McGill version)
Interpretation
There is no single widely accepted normative table for this test. Results are best interpreted against the person’s previous measurements with the same protocol and equipment (and, where relevant, left-right comparison).
Practical Applications
This test is applied as part of the McGill battery in lower back pain risk assessment. The flexion/extension ratio indicates muscular balance and guides treatment planning.
Limitations
Standardization of 60° support position is difficult. Differences in starting position between participants affect results.
Related Tests: Back Extension Endurance Test (Sorensen Test), Side Plank Test, Plank Hold Test
Sources: McGill SM et al., 1999, Arch Phys Med Rehabil; McGill SM, 2002, Low Back Disorders
Hüseyin Akbulut is the founder of Sporeus and author of THRESHOLD (EŞİK), a 540-page Turkish-language book on endurance science.
- 540pp THRESHOLD Book
- MSc Sport Sciences
- Marmara University
Protocol The Trunk Flexion Endurance Test is the flexor test of the trunk endurance battery of McGill et al. (1999). It measures static endurance of the abdominal muscles. Preparation: The participant sits with knees and hips at 90°, leaning back against a support set at 60°. Arms are crossed over the chest and the feet are secured. A 5-minute warm-up is performed. Test Procedure: The support is moved back about 10 cm and the stopwatch starts. The participant holds the 60° trunk angle without support. The test ends when the trunk falls below this angle (back towards the support). Data Recording: Duration is recorded in seconds. Interpretation: McGill et al. (1999) reported mean times of about 136 s in men and 134 s in women in healthy young adults. In the battery the flexion/extension ratio is expected to be below 1.0 (longer extensor endurance). Post-Test: Results are interpreted together with the Sorensen (extension) and side bridge tests. Formula
Flexion/extension ratio = flexion_s / Sorensen_s; below 1.0 expected
Equipment Required
exercise mat, stopwatch, support angled at 60° (for the McGill version)
Interpretation
There is no single widely accepted normative table for this test. Results are best interpreted against the person's previous measurements with the same protocol and equipment (and, where relevant, left-right comparison).
