A grip-strength number is only comparable when the measurement setup is comparable. Changing the device, handle, posture, or trial rule can produce a different result without a true change in strength.
Equipment and setup
The Fitness Age Advanced protocol requires a hydraulic hand dynamometer that reports kilograms. Sit in a stable chair with feet supported. Keep the shoulder close to the body, the elbow flexed, and the forearm in a neutral position. Adjust the handle to fit the hand so the grip is secure rather than stretched or cramped.
The reference approach is informed by the Dodds et al. life-course analysis, which harmonized grip data across multiple British studies. Harmonization does not remove every difference between devices and protocols, so the product records the method and applies narrow eligibility rules.
Testing steps
Explain and demonstrate the squeeze before recording a trial. Test both hands, alternating sides if practical. Complete three attempts per hand with enough rest to avoid obvious fatigue. Squeeze firmly and smoothly without holding the breath or changing body position.
Record every attempt and the device, handle setting, posture, date, and any deviation. The Fitness Age input uses the maximum observed result in kilograms, but keeping all six trials helps reveal a mistyped or inconsistent value.
Do not test through pain, acute hand or arm injury, recent surgery, or a condition for which forceful gripping is not appropriate. A painful or modified attempt can be saved as context but should not be presented as a protocol-valid score. Review the general exercise safety guidance before any self-test.
Making repeat tests comparable
Use the same dynamometer and handle setting at a similar time of day. Keep posture, warm-up, instruction, rest between trials, and recorded statistic unchanged. If you switch equipment, start a new series rather than pretending the values continue seamlessly.
Strength can vary with fatigue, recent training, pain, illness, and familiarity with the device. A small difference between sessions may be ordinary variation. Look for a sustained pattern across repeat tests and consider the plausible range of the combined Fitness Age result.
What grip cannot tell you
Grip does not replace assessment of leg strength, power, balance, mobility, or task-specific ability. The US Physical Activity Guidelines recommend strengthening all major muscle groups, not only the hands.
Read what grip contributes, see the exact inclusion logic in the methodology, and use the safety screen whenever a test involves effort.