If You Can Do This Many Sit-ups After 55, Your Arm Core Endurance Is Elite

By Jarrod Nobbe, MA, CSCS

February 7, 2026

Core strength gets plenty of credit for protecting your back and improving posture, but core endurance often matters just as much once you pass 55. Endurance reflects how long your core muscles can stay engaged while supporting your spine and transferring force. That ability shows up every time you walk uphill, carry groceries, get out of bed, or stay upright during long periods of standing or sitting. When endurance fades, fatigue sets in fast, and movement quality usually follows.

Strength and endurance aren’t interchangeable. Strength reflects how much force your core can produce in a short burst. Endurance reflects how long those muscles can keep working without losing control. After 55, endurance tends to decline faster than strength, especially if training focuses only on brief, heavy efforts or isolated movements.

Sit-ups provide a simple way to test that endurance. When performed with clean technique, sit-ups challenge your ability to repeatedly flex and stabilize your trunk while managing fatigue. A strong score shows that your core can keep producing force, maintain coordination, and support your spine across repeated efforts. Below, you’ll learn why sit-ups matter, how to perform them correctly, how to interpret your score, and how to build elite-level core endurance.

Why Sit-Ups Provide a Functional Core Exercise

Sit-ups train one of the core’s primary roles: repeated, controlled trunk flexion. This pattern occurs more often than people realize, especially during daily transitions such as getting out of bed, rising from the floor, or sitting up from a reclined position. Practicing this movement helps maintain strength and endurance in a range that many adults slowly lose with age.6254a4d1642c605c54bf1cab17d50f1e

From a muscular standpoint, sit-ups target the rectus abdominis while engaging the hip flexors and deeper stabilizing muscles. Performing them repeatedly challenges the core’s ability to sustain tension without relying on momentum. That sustained tension plays a major role in posture, spinal support, and efficient movement.

Sit-ups also expose endurance limitations quickly. As fatigue builds, poor control shows up through jerky movement, shortened range, or excessive strain in the neck and hips. Being able to maintain smooth, repeatable reps signals that your core muscles can resist fatigue and continue doing their job when it counts.

How to Perform the Best Sit-Up Technique

Proper technique keeps the test honest and your spine safe. Clean reps ensure you’re measuring core endurance rather than bouncing through reps or pulling with your neck. A consistent setup also allows your score to reflect real progress over time.

How to Do It:

1. Lie on your back with your knees bent and your feet flat on the floor.
2. Place your hands lightly across your chest or with fingertips touching your temples.
3. Brace your core by tightening your midsection before starting the movement.
4. Curl your torso upward until your chest reaches your thighs or your elbows pass your knees.
5. Lower back down under control until your shoulder blades touch the floor.
6. Repeat each rep with the same tempo and range of motion until your form breaks down.

If you begin pulling on your neck, shortening the range, or bouncing out of the bottom, the set is complete. Clean reps matter more than chasing a higher number.

Sit-Up Endurance Score Rankings After 55

This test measures how many controlled sit-ups you can perform consecutively without rest. Use a steady pace and stop when technique declines.

• Under 15 reps: Needs Improvement: This range suggests limited core endurance. Daily tasks that require repeated trunk movement may feel fatiguing or unstable.
• 15 to 25 reps: Average: You’ve built a functional base. Your core can handle everyday demands, but endurance likely drops off during longer efforts.
• 26 to 40 reps: Above Average: This score reflects solid endurance and good trunk control under fatigue.
• 41+ reps: Elite: This level shows exceptional core endurance for your age. Your trunk muscles maintain coordination, control, and force output even as fatigue builds.

The Best Tips for Building Elite Core Endurance After 55

Improving core endurance comes from frequent, repeatable training rather than max-effort sets. These strategies help raise your sit-up score while keeping your spine healthy.

• Train your core three to four times per week: Regular exposure improves fatigue resistance without excessive soreness.
• Use moderate rep ranges: Sets of 15 to 30 reps build endurance more effectively than very low-rep work.
• Control every rep: Slowing the lowering phase increases time under tension and improves muscular control.
• Strengthen supporting muscles: Exercises like dead bugs, planks, and carries improve overall trunk stability and reduce weak links.
• Adjust volume when fatigue lingers: Persistent soreness or back discomfort signals that recovery needs more attention.

Core endurance reflects how well your body holds together under repeated effort. If your sit-up score climbs, you’re building a core that supports movement, posture, and confidence well into your later years.

References

1. Kang, Kwon-Young. “Effects of core muscle stability training on the weight distribution and stability of the elderly.” Journal of physical therapy science vol. 27,10 (2015): 3163-5. doi:10.1589/jpts.27.3163
2. Childs, John D et al. “Effects of sit-up training versus core stabilization exercises on sit-up performance.” Medicine and science in sports and exercise vol. 41,11 (2009): 2072-83. doi:10.1249/MSS.0b013e3181a84db2