Dr Helen Roberts is a Senior Lecturer in Academic Geriatric Medicine at the University of Southampton.
Older (and middle-aged) people with low muscle strength are at risk of poor current and future health. Grip strength is often used as a proxy for general muscle strength and is most easily measured using the maximum grip strength a participant can generate when asked to squeeze the handle of a small hand held device (see photograph) with each hand while seated, using a standard protocol (see our research paper). Research among people living in their own homes has shown that low grip strength, defined as < 20kg for women and < 30kg for men, is associated with a higher risk of frailty, difficulty walking, falls and fractures, more admissions to hospital, poor quality of life and an increased risk of death. This is costly to both the individual and to society. However the grip strength of people who need rehabilitation or live in care homes has been little studied.
We measured the grip strength of three groups of people in one market town in England: 100 people in a community hospital rehabilitation ward, 47 receiving out-patient physiotherapy, and 100 people living in nursing homes. They were all aged 70 years and over and we also measured their body size, physical and cognitive function, nutritional status and number of falls.
Grip strength was simple to measure and highly acceptable to all the participants including those with the weakest grip. Lower grip strength was associated with older age, smaller body size, female gender, worse physical and cognitive function, worse nutritional status and more falls. Combining these factors showed that physical function was the factor most strongly associated with grip strength for both men and women in each group after age, gender and body size.
There was a substantial difference in grip strength between the three groups, with the out-patient physiotherapy group having the highest grip strength and those in the nursing homes the weakest grip strength. This difference between the groups remained significant even after adjustment for all of the other factors including age, body size and physical function, and the reasons behind this are unclear.
Importantly the grip strength values in this study were lower than those reported for people living in their own homes and, using these existing values for low grip strength, half of the out-patient physiotherapy group and most of the rehabilitation inpatients and nursing home residents in this study would have been defined as simply having low grip. This would be unhelpful since there was considerable variation in grip strength within each group and there is evidence that grip strength can be discriminatory even at low values: for example lower grip strength was associated with longer length of stay within the in-patient rehabilitation group. Further research is required to ascertain whether grip strength can help identify people at risk of adverse health outcomes within different healthcare settings.