The hand grip force test as a measure of physical function in women with fibromyalgia

Reliability and validity of the K-force grip dynamometer in healthy subjects: do we need to assess it three times?

Introduction

Digital dynamometers to assess grip strength are becoming more common in research and clinical settings. The aim of the study was to assess validity and reliability of the K-force dynamometer compared to the Jamar dynamometer. We also aimed to assess differences over the course of three measurements.

Methods

Twenty-seven healthy participants were included. Three trials with the K-force and Jamar dynamometers were completed. Testing order was randomised. Intraclass correlation coefficients (ICCs) with absolute agreement assessed reliability and validity. Standard error of the measurement (SEM) and minimal detectable change (MDC95) were calculated. Concurrent validity was assessed using Pearson's correlations and ICCs. Differences between the three repetitions were assessed using one-way repeated measures ANOVAs.

Results

Both the K-force and the Jamar presented excellent intra-rater reliability with ICCs ranging from 0.96 to 0.97. The SEM ranged from 1.7 to 2 kg and the MDC from 4.7 to 5.7 kg for both dynamometers. The concurrent validity of the K-force was high (r ≥ 0.89). However, the K-force underestimated the grip strength by 4.5-8.5 kg. There was no change in grip strength with either dynamometer over the course of three trials.

Conclusions

The K-force is reliable, but it underestimates grip strength by 4.5-8.5 kg compared to the Jamar dynamometer. K-force can be used to monitor progress over time but cannot be used to compare results against normative data. The use of a single measurement when assessing grip strength is sufficient when assessing healthy subjects.

Convergent Validity between Electromyographic Muscle Activity, Ultrasound Muscle Thickness and Dynamometric Force Measurement for Assessing Muscle

Muscle fatigue is defined as a reversible decline in performance after intensive use, which largely recovers after a resting period. Surface electromyography (EMG), ultrasound imaging (US) and dynamometry are used to assess muscle activity, muscle morphology and isometric force capacity. This study aimed to assess the convergent validity between these three methods for assessing muscle fatigue during a manual prehension maximal voluntary isometric contraction (MVIC). A diagnostic accuracy study was conducted, enrolling 50 healthy participants for the measurement of simultaneous changes in muscle thickness, muscle activity and isometric force using EMG, US and a hand dynamometer, respectively, during a 15 s MVIC. An adjustment line and its variance (R²) were calculated. Muscle activity and thickness were comparable between genders (p > 0.05). However, men exhibited lower force holding capacity (p < 0.05). No side-to-side or dominance differences were found for any variable. Significant correlations were found for the EMG slope with US (r = 0.359; p < 0.01) and dynamometry (r = 0.305; p < 0.01) slopes and between dynamometry and US slopes (r = 0.227; p < 0.05). The sample of this study was characterized by comparable muscle activity and muscle thickness change between genders. In addition, fatigue slopes were not associated with demography or anthropometry. Our findings showed fair convergent associations between these methods, providing synergistic muscle fatigue information.

Efficacy of Dry Needling and Acupuncture in Patients with Fibromyalgia: A Systematic Review and Meta-Analysis

Fibromyalgia (FM) is a syndrome that involves chronic pain, fatigue, sleep disturbance and impaired quality of life and daily functioning. In addition to medical and psychological therapies, other therapies including acupuncture and dry needling aim to reduce pain and disability in patients with FM. The aim of this study was to investigate the efficacy of dry needling and acupuncture in patients with FM regarding pain, function and disability in both the short and the long term. MEDLINE, PubMed, SCOPUS and Web of Science databases were systematically searched for randomized controlled trial studies evaluating efficacy data of dry needling or/and acupuncture treatments to improve pain, fatigue, sleep disturbance and impaired quality of life and/or daily function. A qualitative analysis including the methodological quality and a systematic data synthesis was performed. A total of 25 studies addressed the selection criteria. Most studies had an acceptable methodological quality. Four studies assessed the effect of dry needling, and twenty-one studies assessed the effect of acupuncture. In general, both interventions improved pain, anxiety, depression, fatigue, stiffness, quality of sleep and quality of life. However, both techniques were not compared in any study. Acupuncture and dry needling therapies seems to be effective in patients with FM, since both reduced pain pressure thresholds, anxiety, depression, fatigue, sleep disturbances and disability in the short term. It is still required to compare both techniques and their application in the long term.

Relationship between Kinesiophobia and Mobility, Impact of the Disease, and Fear of Falling in Women with and without Fibromyalgia: A Cross-Sectional Study

Background: Kinesiophobia is defined as fear of movement due to the painful experience of it. The main symptom of fibromyalgia is persistent and widespread pain associated with other symptoms. This study analyzes the kinesiophobia between women with fibromyalgia and apparently healthy women and investigates the relationship between kinesiophobia and physical fitness tests, fear of falling, and the impact of the fibromyalgia. Methods: Fifty-one women participated in this study were divided into two groups: (1) women with fibromyalgia and (2) apparently healthy women. Participants completed questionnaires to assess kinesiophobia, fear of falling, and the impact of fibromyalgia. Subsequently, participants completed the physical tests Timed Up and Go, 10-step stair ascent, and handgrip strength. Results: Women with fibromyalgia had significant differences in kinesiophobia and fear of falling compared to apparently healthy women. Similarly, performance in the physical tests was lower, except for the handgrip strength, which maintained similar values to the apparently healthy women. Significant relationships were found only in the fibromyalgia group between kinesiophobia, the impact of the disease, fear of falling, and the Timed Up and Go and 10-step stair ascent tests. Conclusions: Women with fibromyalgia showed higher kinesiophobia scores, worse performance in mobility tests, and higher fear of falling than apparently healthy women. Kinesiophobia score is related to Timed Up and Go performance, the 10-step stair ascent, the fear of falling, and the impact of the disease in women with fibromyalgia.