Introduction
Handgrip strength (HGS) is a strong predictor and easily applicable assessment, indicating a person's physical condition and health. However, many dynamometers are available; therefore, it is essential to ensure that the results of HGS testing using different dynamometers can be used interchangeably. The primary purpose of this study was to investigate the inter-instrument agreement and criterion validity of the Baseline BIMS Digital Grip Dynamometer in comparison with the Jamar electronic dynamometer (Jamar+).

Methods
Seventy participants, aged between 23–88 (five men and five women in each decade from 20 to 80+), performed three attempts with each dynamometer (30-sec break between attempts) in a randomized order and separated with a 5-minute break between dynamometers. Intraclass correlation coefficient (3.1), standard error of measurement and minimal detectable change were used for comparison of the strongest and average strength measured with dynamometers. Jamar+ and Baseline BIMS Digital Grip Dynamometer were new dynamometers and considered calibrated by the manufacturer.

Results
The overall Intraclass correlation coefficient was excellent (0.98). An average (SD) difference of 0.68 (2.2) kg (p = 0.04) was seen for the comparison of the strongest attempt for Baseline BIMS minus Jamar+, Correspondingly, for the average of three attempts, it was 0.37 (2.29, p = 0.2) kg. The standard error of measurement (%) and minimal detectable change (%) of the strongest attempt was 1.64 kg (4.2%) and 3.55 kg (9.0%), respectively.

Conclusions
Findings indicate low measurement error with high agreement and criterion validity for the comparison of Baseline BIMS Digital Grip Dynamometer and Jamar+ and that results of the two dynamometers can be used interchangeably.