Reliability and criterion validity of a low-cost handgrip dynamometer: The Camry

Background Handgrip strength has been related with multiple health outcomes, including all-cause mortality and morbidity. Handgrip testing is a highly valid and reliable method, included in evidence-based fitness test batteries from preschool to older ages. Previously, Jamar and TKK dynamometers have shown good reliability and validity against known weights. However, the cost of these dynamometers is the major limitation for implementing handgrip strength testing in certain countries and settings, as well as at large scale. Recently, a ten times cheaper model (Camry Dynamometer) has been used in fitness surveillance systems, though its reliability and validity, compared to known weights and other well-validated dynamometers, remains unknown. Therefore, the aims of the current study were to test to examine test-retest reliability, inter-model reliability (comparing a Camry dynamometer with 3000 uses versus a new Camry dynamometer), and inter-instrument reliability (Camry versus TKK dynamometer) of Camry dynamometer, using calibrated known weights.