Core Endurance: McGill Tests and Their Ratios

Students run through the four McGill core endurance tests and calculate the ratios between flexors, extensors and side muscles, which tell us more about a healthy back than maximum strength does. They use the results to choose which basic exercises to prioritize.

How to play

1. Explain why, for back health, endurance and balance between trunk muscles matter more than maximum strength (3 min).
2. Spine warm-up: slow cat-camel, alternating bird dog and glute bridge (4 min).
3. In groups of three (tested, timer and observer), do the four tests with rest between them: flexors sitting at 60 degrees without support, extensors with the trunk off the end of the bench and the ankles held by the partner, and a side plank on each side; stop the clock when the position breaks, with a 2-minute cap (14 min).
4. Calculate the ratios on the worksheet: flexors/extensors under 1, right/left side between 0.95 and 1.05, and side/extensors under 0.75 (4 min).
5. Each student practices the big three (McGill curl-up, side plank and bird dog), with extra work on the one that matches their worst ratio (5 min).

Rules

• In the extensor test, the partner holds the ankles firmly for the whole test and warns before letting go.
• Stop immediately if any back pain appears and write it down.
• Each test is capped at 2 minutes to avoid excessive fatigue.
• The observer stops the test when the pelvis drops or the trunk bends, even if the student wants to keep going.

Variations

Adaptations

• Overweight: does the knee-supported versions and is judged on their own ratios, not times.
• Limited mobility: does seated versions (resisted trunk leans in the wheelchair) and times classmates.
• Diagnosed low back pain: only practices the basic exercises without timing, with medical clearance.

Learning goals

• Assess trunk muscle endurance with standardized tests.
• Interpret muscle ratios linked to back health.
• Perform the basic core stability exercises with correct technique.

Equipment for a class of 25

• exercise mats: 10
• gym benches: 4
• stopwatches: 10
• worksheets: 28

Teacher tip

One bench per group of three is enough for the extensor test if you stagger the test order. Ratios motivate more than times because they don't just reward the strongest.

More main activities for High School