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About this tool
Time a front plank with the built-in stopwatch and compare the hold against an age-adjusted core endurance target.
The Plank Hold Benchmark Tool times a front plank with a built-in stopwatch and compares the hold against an age-adjusted target. The target starts from a 120-second reference — the figure spine biomechanist Stuart McGill treats as a reasonable front-plank standard for a healthy adult — and reduces it by 1% for each year over 39, matching the roughly 1% per year decline in muscular endurance after 40. Results are expressed as a percentage of that target, with bands from Needs work through to Exceptional, plus how many more seconds would reach the next band.
Open Plank Hold Benchmark Tool on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
The reference hold, the 1%-per-year age adjustment and the band thresholds are all spelled out rather than presented as a mystery norm.
The stopwatch writes into the result panel as it runs, so you can see the percentage climb while you hold.
Tells you exactly how many more seconds would move you into the next band.
Around two minutes is a reasonable standard for a healthy adult under 40, and it is the reference this tool uses. Holding much longer adds little: beyond roughly two minutes the test stops distinguishing core endurance and starts measuring shoulder tolerance and pain tolerance instead.
No. In the trunk endurance testing this benchmark descends from, women match or exceed men on flexor and extensor endurance holds — unlike maximal strength lifts, where a sex difference is large. This tool therefore applies no sex adjustment; the target depends only on age.
No. Once you can hold a clean two-minute plank, extra time gives diminishing returns and often comes at the cost of form. Progress instead with harder variations — long-lever planks, single-arm or single-leg holds, or adding load — which keep the hold in the 30-60 second range where quality is easier to maintain.
Forearms under the shoulders, a straight line from ears through hips to heels, glutes and abdominals braced, ribs pulled down rather than flared, and neutral neck. Stop the clock the moment the hips drop or the lower back arches — a sagging plank loads the spine instead of training the core. Stop entirely and get advice if you feel back pain, numbness or pins and needles.