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Europa Medicophysica 2001 September;37(3):161-70

Copyright © 2001 EDIZIONI MINERVA MEDICA

lingua: Inglese

The hand grip: gender, dominance and age considerations

Sella G. E.

From the Ohio Valley Disability Institute Martins Ferry, OH, USA

Back­ground. ­This ret­ro­spec­tive ­study of the ­hand ­grip eval­u­ated the ­hand ­grip ­strength and the var­i­ables of ­hand dom­i­nance and ­gender dif­fer­ences in a ­large pop­u­la­tion ­sample of USA ­adult men and ­women.
­Methods. Experi­mental ­design: ­this eval­u­a­tion was ­based on ret­ro­spec­tive ­data of ­hand ­grip ­tests per­formed by 875 indi­vid­uals (1750 ­hands) of ­both gen­ders, ­ranging in age ­from 19-91. The ­testing was ­done ­with ­Jamar dyna­mom­e­ters on ­both ­hands (­average ­values) at ­handle ­levels I, III & V. Set­ting: the ­testing was con­ducted in an occu­pa­tional ­physician’s ­office. Par­tic­i­pants: ­hand ­grip was per­formed rou­tinely on eva­luees for the pur­pose of dis­ability eval­u­a­tion and in the ­course of ­annual phys­ical exam­ina­tions of ­patients. No par­tic­i­pant had any ­upper ­limb ­pathology or dys­func­tion. The par­tic­i­pants ­were eval­u­ated ­also in ­terms of the ­body ­mass ­index (B.M.I). No ­gender dif­fer­ence was ­found in the BMI Inter­ven­tions: the ­hand ­grip ­testing was not inva­sive. ­None of the par­tic­i­pants had any reac­tions, ­side ­effects or symp­toms ­related to the ­hand ­grip ­testing. Meas­ures: (1) anthro­po­metric ­data on the ­sample of 875 per­sons (1750 ­hands); (2) sta­tis­tical ­data gath­ered on the ­right and ­left ­hand ­grip (kgs) at ­three ­handle posit­iors of the ­Jamar ­hand dyna­mom­eter. ­They ­included the fol­lowing param­e­ters: (a) ­average ­hand ­grip ­strength strat­i­fied for age ­groups (b) stan­dard devi­a­tion and co-effi­cient of vari­a­tion for the ­same strat­ifi­ca­tions; (c) ­left ­versus ­right ­hand ­grip ­strength ­ratio (%) for the gen­ders and the strat­i­fied ­groups; (d) ­female/­male ­ratio (%) of ­grip ­force at the 6 dyna­mom­eter posi­tions.
­Results. The ­results of ­this ­study ­done on 1750 ­hands indi­cated the fol­lowing: a) The ­hand ­grip ­strength and pat­tern of the ­male ­gender (964 ­hands) was 30.6 kg, 37 kg & 25.9 kg at ­handle posi­tions I, III & V respec­tively. b) The ­hand ­grip ­strength and ­pattem of the ­female ­gender (794 ­hands) was 16.3 kg, 19.2 kg & 13.8 kg at ­handle posi­tions I, III & V respec­tively. c) ­When the ­grip pat­tern by posi­tion ­data ­were nor­mal­ized to the ­grip ­value of posi­tion III, ­both gen­ders dem­on­strated a sim­ilar “­umbrella pat­tern”. ­Thus for 1750 ­hands, the nor­mal­ized ­grip ­pattern is 76%, 100% & 69% for posi­tions I, III & V respec­tively. ­Even ­though the ­grip ­strength was dif­ferent for the two gen­ders, the ­study ­showed ­that the ­human ­hand had the ­above nor­mal­ized pat­tern for the ­three ­handle posi­tions, irre­spec­tive of ­gender. d) The ­study ­showed ­that the ­hand ­grip ­varied ­with age. It ­increased to max­imum ­till the age ­group 30-39 in the ­female ­gender and ­decreased there­after. The pat­tern was sim­ilar in the ­male ­gender ­although the max­imal ­grip ­strenght was ­shown in the age ­group 20-29. e) A ­greater ­strength was ­shown by ­hand dom­i­nance in ­only 53% of ­cases. 32% of ­cases ­showed ­greater ­strength for the non-domi­nant ­hand. 15% of ­cases ­showed ­equal ­hand ­grip ­whether the per­sons ­were ­right or ­left ­hand dom­i­nant. ­These find­ings ­were irre­spec­tive of ­gender.
Con­clu­sions. ­This is the ­largest ­study of the ­hand ­grip by ­gender, age and ­hand dom­i­nance to ­date in ­terms of the gen­eral pop­u­la­tion. The ­data ­shown in the ­results sec­tion and in the ­text ­tables can be uti­lized as nor­ma­tive ­data ­until ­larger ­studies are ­done. The ­results ­showed ­that men and ­women ­have a sim­ilar ­grip pat­tern in ­terms of ­hand dyna­mom­etry on the ­Jamar dyna­mom­eter, ­when the ­testing is ­done in stan­dard­ized ­fashion. The ­study dis­pelled the old ­myth of the ­greater ­strength “by 10%” of the dom­i­nant ­hand. Dyna­mom­etry is an objec­tive ­method ­which ­allows indi­vidual com­par­ison ­with the data­base by age and ­gender.