Jamar dynamometer

This is a test that shows the maximal grip strength in kilograms (Kg) using a hand dynamometer. The device used was the Jamar^® dynamometer (Lafayette Instrument Company, IN, USA). The subject was placed in a seated position with the arms supported, ensuring 90° elbow flexion with the wrists in a neutral position. Three measurements were taken for both the dominant and non-dominant arms, with a one-minute rest between measurements. The mean between the three measurements of each hand was calculated and the hand that obtained the best results was chosen. The validity and reliability of this device has been evaluated in previous studies (ICC = 0.98) [35 (link)].

The evaluation of sensory‐motor impairments included grip force and somatosensory function (i.e., two‐point discrimination and stereognosis). Grip force was evaluated with the Jamar dynamometer (Lafayette Instrument Company, Lafayette, IN, USA), using the mean of three maximum contractions of each hand. Two‐point discrimination and stereognosis were assessed according to Klingels et al. (2010 (link)) Briefly, two‐point discrimination was examined distally at the index finger using an aesthesiometer to identify the minimal distance at which one or two points could be correctly distinguished. Stereognosis was evaluated via tactile identification of six familiar objects.
At activity level, bimanual performance was assessed using the Assisting Hand Assessment (AHA) (Holmefur & Krumlinde‐Sundholm, 2016 (link); Krumlinde‐Sundholm et al., 2007 (link)). During a video‐recorded semi‐structured play session, the AHA evaluates the spontaneous use of the impaired hand during bimanual activities. Afterward, 22 items were scored and converted to 0–100 logit‐based AHA units. Unimanual capacity was assessed at both hands with the Jebsen‐Taylor Hand Function Test (JTHFT), evaluating movement duration during the execution of six unimanual tasks (Araneda et al., 2019 (link)).

Isometric knee extension strength (Strength measuring device FK, Sauter GmbH, Balingen, Germany) was measured according to the protocol described by Gandevia [19 (link)]. Briefly, knee strength was assessed with the patient in a seated position with a strap around the leg 10 cm above the ankle joint with the hip and knee joint angles positioned at 90 degrees. Handgrip strength (HGS) was assessed using a Jamar dynamometer (Lafayette Instrument Company, Lafayette, IN, USA). Handgrip and knee strengths were measured three times at the dominant or unaffected side of hand/leg and the maximum score was recorded.

We used the free online calculator specific for men and women to calculate both continuous and categorical frailty scores based on the answers to four self-report questions and grip strength measurement [12 (link)]. Fatigue was measured as a yes/no response to whether the respondent has too little energy to complete desired tasks. Appetite was measusured as self-reported food intake over the last month (diminished, same, or increased). Weakness was assessed by two repetitions of grip dynamometry on each hand using a Jamar dynamometer (Lafayette Instruments, USA). Walking difficulties were assessed by self-report of the ability to walk 100 m and climb one flight of stairs. Physical activity was measured via self-report of frequency of engagement in low to moderately intense physical activities.

Grip strength was assessed with a JAMAR® dynamometer; (Model 5,030 J1; Lafayette instrument Co.; Lafayette, IN, United States), adjusted to fit participants’ hands as described elsewhere (Wages et al., 2020 (link)). Three trials per arm were obtained and average grip strength calculated. Lean mass was assessed via dual-energy X-ray absorptiometry (DXA) (Hologic discovery QDR model Series, Waltham, MA, United States) (Wages et al., 2020 (link)). Forearm lean tissue mass was extracted from the whole-body scan (upper extremities distal to the elbow) using manufacturer’s software (Hologic APEX, Version 4.0.2). Grip strength was subsequently expressed relative to forearm lean tissue mass, which controls for between subject differences in lean mass and will conceptually be more reflective of neurological mechanisms of grip strength. It should be noted that while DXA-derived measures of lean mass are not sensitive to change in muscle mass, that it does serve as a reasonable proxy for cross-sectional studies (r = 0.89 when compared to MRI-derived muscle volume; Tavoian et al., 2019 (link)).