Reliability and Validity of Different Models of TKK Hand Dynamometers

Cristina Cadenas-Sanchez; Guillermo Sanchez-Delgado; Borja Martinez-Tellez; José Mora-Gonzalez; Marie Löf; Vanesa España-Romero; Jonatan R Ruiz; Francisco B Ortega

doi:10.5014/ajot.2016.019117

Reliability and Validity of Different Models of TKK Hand Dynamometers

Am J Occup Ther. 2016 Jul-Aug;70(4):7004300010. doi: 10.5014/ajot.2016.019117.

Authors

Cristina Cadenas-Sanchez¹, Guillermo Sanchez-Delgado¹, Borja Martinez-Tellez¹, José Mora-Gonzalez¹, Marie Löf², Vanesa España-Romero³, Jonatan R Ruiz⁴, Francisco B Ortega⁴

Affiliations

¹ Cristina Cadenas-Sanchez, MSc; Guillermo Sanchez-Delgado, MSc; Borja Martinez-Tellez, MSc; and José Mora-Gonzalez, MSc, are PhD Students, PROFITH (PROmoting FITness and Health through physical activity) Research Group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain; address correspondence to cadenas@ugr.es.
² Marie Löf, PhD, is Senior Researcher, Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
³ Vanesa España-Romero, PhD, is Lecturer, Department of Physical Education, School of Education, University of Cádiz, Puerto Real, Spain.
⁴ Jonatan R. Ruiz, PhD, and Francisco B. Ortega, PhD, are Senior Researchers, PROFITH Research Group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain, and Senior Researchers, Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.

PMID: 27294996
DOI: 10.5014/ajot.2016.019117

Abstract

Objective: We examined the reliability and validity of the analog and digital models of TKK handgrip dynamometers using calibrated known weights.

Method: A total of 6 dynamometers (3 digital and 3 analog; 2 new and 1 old for each model) were used in this study.

Results: Intrainstrument reliability was very high; systematic error for test-retest reliability was ≤|0.3 kg|. The systematic error among different instruments (same model) and between different models (digital vs. analog) ranged between |0.4 kg| and |0.6 kg|. The systematic error between new and old dynamometers ranged from |0.8 kg| to |1 kg|. All dynamometers provided lower values for the same known weights than a SECA scale, with a systematic error ranging from -0.94 to -2.64 kg.

Conclusion: This study indicates that clinicians and investigators who provide treatment to address handgrip strength should use the same instrument and model for repeated measures. Distinguishing meaningful change from dynamometer variability is discussed.