Grip Strength in Healthy Israeli Adults: Comparison to Internationally Reported Normative Data
Background: Reference values are essential when evaluating the normality of an individual's grip strength (GS) relative to the healthy population. Studies have shown that normative GS data vary in different cultures 1,2,3 and therefore it is important to establish the accurate reference value when evaluating an individual's GS. Normative data for GS have never been described for Israel.
Objectives: This study had two primary objectives. The first was to establish normative data for GS for the adult population in Israel. The second objective was to compare the results of this derived Israeli normative data to internationally reported measures. Two published studies were used for comparison. One study consolidated data from twelve different studies that originated from eight different countries4. The other study was limited to data from Australia3.
Methodology: 574 healthy adult volunteers had their grip strength tested. This study was conducted over a three-year period (2013-2015). Testing with regard to position and technique was performed in accordance with recommendations of the American Society of Hand Therapists. Grip strength was determined using the Jamar dynamometer from the average of three trials for each hand. Normative data was established based on age, handedness and sex. More specifically, to allow comparison to international data, the age was subdivided in both 5 and 10 year intervals. The results from this study were then compared to international standards using a one sample t-test.
Results: Looking first at Israeli normative data, across ages and handedness, males were 45% stronger than females. Right-handed people were on average 9% stronger on their right compared to their left side. Left-handed people had the similar average strength on both side. Compared to the Australian data, Israeli men were 3% weaker and Israeli women were 15% weaker. When the data was subdivided based on age, the Israeli population was weaker but statistical significance was reached only for men below the age of 30 and for women below the age of 60. When the Israeli data was compared to the consolidated norms, Israeli men were 10% weaker and women were 23% weaker.
Conclusion: Normative data for grip strength was established for the Israeli population and compared to internationally published data. The lower grip strength of the Israeli population we speculate may be related to the lower demands placed on the hands for “white-collar” occupations relative to manual labor. It may also be related to lower average population size, weight or hand girth when comparing the populations.