Norms of walking speed and grip strength in Constances

The methods used to develop the norms available via this application are described in detail in an article on walking speed. In that article, we defined norms that take into account level of education (1). The methodology is the same for the other norms (walking speed without taking into account level of education, grip strength), and the corresponding results are described on the corresponding pages.

Please quote this reference when using these standards.

Tests of walking speed and grip strength at inclusion in Constances

The walking speed and grip strength tests were part of a set of cognitive and motor tests performed by Constances participants aged 45 to 69 years at the time of inclusion in the study, in the examination and health centres (Centre d’examen de santé, CES). The tests were administered under the supervision of neuropsychologists using a standardised protocol.

Walking speed

The procedures for the walking speed tests are as follows:

Distance

Walking speed is measured over a distance of 3 meters, starting 1 meter before the measurement zone and stopping 1 meter after it, to allow acceleration and deceleration on either side of the measurement zone.

Speed

At usual speed, participants were asked to walk at their ‘usual pace’.
At fast speed, participants were asked to walk ‘as fast as possible but without running’.
Measurements were taken first at normal pace and then at fast pace.

Measuring device

Walking speed was measured using Racetime2 kit light radio, MicroGate® photoelectric cells placed on either side of the 3-metre distance, with a measurement accuracy of one hundredth of a second.
We have previously shown that measurements taken over 3 meters using photoelectric cells correlate very well with measurements taken using manual stopwatches (intraclass correlation coefficient: normal speed = 0.93, 95% confidence interval = 0.90-0.95; fast speed = 0.92, 95% confidence interval = 0.88-0.95). In addition, for the same person, manual measurements of walking speed over 3 and 5 meters highly correlated (normal speed = 0.84; fast speed = 0.82) (2).

Conditions of the test

Participants were asked to come to the examination and health centres (Centre d’examen de santé, CES) comfortably shod. Those wearing heels were asked to remove their shoes and to complete the walking speed test barefoot.
The use of a walking stick was permitted.
The walking speed norms available via this app were estimated for people who took the test with comfortable shoes and who did not use a walking stick.
Taking the test :

The test was described by the neuropsychologist.
An initial trial was carried out at both paces (usual and fast).
If the instructions were not clearly understood, the neuropsychologist demonstrated them.
Walking speed was then recorded, first at usual speed and then at fast speed.

Grip strength

The procedures for the grip strength test are as follows:

Measuring device

· From 2012 to 2014, grip strength was measured using the JAMAR ® PLUS + handheld force gauge, using a sealed hydraulic system. In 2014, the equipment was replaced by the JAMAR ® PLUS + digital hand dynamometer using electronic cells that increase the accuracy of grip force measurements.

Conditions of the test

The grip strength norms available in this application correspond to estimates obtained with an electronic dynamometer.
Taking the test :

o For both materials, the handle was adjusted to the participant's preferred hand to rest on the second phalanx of the index finger and the next finger.

o The instructions were to squeeze the handle as hard as possible for two seconds before releasing it, in a standing position, keeping the arm tight along the body with the forearm at a 90° angle.

o The measurement was taken three times with a one-minute pause in between and reported in kilograms as an integer value.

o In our analyses, we used the maximum force of the three tests, i.e. the highest value.

Extrapolation

The norms were estimated for a population of people whose height was between 133 and 198 cm for women and between 145 and 203 cm for men. Estimates of norms for people outside the height ranges available in our sample are therefore extrapolations and should be interpreted with caution.

References

1. Santos F, Renuy A, Ozguler A, Ribet C, Goldberg M, Zins M, Artaud F, Elbaz A. Norms for usual and maximum walking speed in adults 45-69 years old from the French general population: Constances study. JAMDA (2023): https://doi.org/10.1016/j.jamda.2023.10.001

2. Santos F, Ozguler A, Lenain M, Zins M, Artaud F, Elbaz A. Comparison of manual and automated measures of walking speed: Distance and pace matter. Experimental Gerontology (2022): https://doi.org/10.1016/j.exger.2022.111987