Grip Work Measurement with the Jamar Dynamometer: Validation of a Simple Equation for Clinical Use
Previously, we developed and validated an easy test to measure muscle fatigability during sustained maximal handgrip contraction in older persons using a Martin Vigorimeter device. This study aimed at validating the equation to estimate grip work (GW) during sustained maximal handgrip contraction, by monitoring continuously the grip strength (GS) decay using a Jamar Dynamometer-like (JD) device.
Cross sectional, explorative study.
Data collection took place at The National Research Centre for the Working Environment in Copenhagen, Denmark.
962 subjects, belonging to a subgroup of the Copenhagen Aging and Midlife Biobank, were enrolled.
GS was recorded continuously during sustained maximal contraction until it dropped to 50% of its maximum and fatigue resistance (FR, time to fatigue) was noted. GW, area under the force-time curve, was compared to its estimate which was calculated as GWestimated=GSmax*0.75*FR.
Excellent correlation was found between GWestimated and GWmeasured (R2=0.98 p<0.001). The equation slightly overestimated GW by 6.04 kg*s (95% CI[-0.08, 12.15]) with a coefficient of variation method error of 6%.
GW estimation is a valid parameter reflecting muscle work output during a sustained maximal grip effort in healthy middle-aged community-dwelling persons when using a JD. GW estimation is a promising outcome parameter in comprehensive geriatric assessment and its validation for commonly used instruments in geriatric practice will increase its clinical implementation.
Key wordsGrip work validity Jamar Dynamometer muscle fatigue grip strength
- 2.Bautmans, I., et al., Handgrip performance in relation to self–perceived fatigue, physical functioning and circulating IL–6 in elderly persons without inflammation. BMC Geriatrics, 2007. 7: p. 5.Google Scholar
- 3.Bautmans, I., et al., Surgery–induced inflammation in relation to age, muscle endurance, and self–perceived fatigue. Journals of Gerontology. Series A: Biological Sciences and Medical Sciences, 2010. 65(3): p. 266–73.Google Scholar
- 9.Desrosiers, J., et al., Comparison of the Jamar dynamometer and the Martin vigorimeter for grip strength measurements in a healthy elderly population. Scandinavian Journal of Rehabilitation Medicine, 1995. 27(3): p. 137–43.Google Scholar
- 12.Lund, R., et al., Cohort Profile: The Copenhagen Aging and Midlife Biobank (CAMB). Int J Epidemiol, 2016. 45(4): p. 1044–1053.Google Scholar