Median grip strength peaks at about 51 kg in men and 31 kg in women, in their thirties

12 British studies pooled: 60,803 observations from 49,964 people aged 4–90. Devices were Jamar (7 studies), Smedley, Nottingham electronic and Takei. Most studies used the maximum of six trials across both hands.

Centiles in kg (P10 / P25 / P50 / P75 / P90). Men at 45: 36 / 42 / 49 / 56 / 61. Men at 65: 31 / 37 / 43 / 48 / 53. Men at 85: 19 / 24 / 29 / 33 / 38. Women at 45: 22 / 26 / 30 / 34 / 38. Women at 65: 17 / 21 / 25 / 29 / 33. Women at 85: 11 / 14 / 17 / 20 / 23.

Weak grip (T-score of −2.5 or lower) is 27 kg or less in men and 16 kg or less in women. At 80, 23.0% of men and 26.6% of women were below it.

The authors write that their cross-sectional centiles should not be used to monitor an individual’s change over time, because cross-sectional data are likely to underestimate individual decline.

British data only. The authors found the centiles robust to device type (differences under 10%). Cross-sectional: the curve compares different people at different ages, not the same people ageing.

The app’s grip table follows these centiles by decade of age. Because the authors warn against reading a cross-sectional chart as a rate of change, the app shows your percentile as a reference point each quarter and tracks change from your own results, not from the slope of this curve.