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Background: The purpose of this systematic review was to compare various methods for measuring hand grip strength to provide data for the development of a standardized protocol for such a measurement based on epidemiologic studies of sarcopenia in older population., Methods: Systematic review and meta-analysis were performed using 34 available epidemiologic studies., Results: The choice of hand dynamometer and measurement protocols for measuring hand grip strength was not consistent among studies. Mean values of hand grip strength in older population were also different by study area (Europe, America, and Asia) and gender., Conclusion: This systematic review demonstrated that various grip strength measurement methods were used in different epidemiologic studies. A standardized method is needed to enable more consistent measurement of grip strength and better assessment of sarcopenia., (© 2018. European Geriatric Medicine Society.)

Amino acid (AA) availability is a rate-limiting factor in the regulation of muscle protein metabolism and, consequently, a risk factor for age-related decline in muscle performance. AA transporters are emerging as sensors of AA availability and activators of mTORC1 signalling, acting as transceptors. Here, we evaluated the association of 58 single nucleotide polymorphisms (SNPs) in 10 selected AA transporter genes with parameters of physical performance (Hand Grip, Activity of Daily Living, Walking time). By analysing a sample of 475 subjects aged 50-89 years, we found significant associations with SLC7A5 /LAT1, SLC7A8 /LAT2, SLC36A1 /PAT1, SLC38A2 /SNAT2, SLC3A2 /CD98, SLC38A7 /SNAT7 genes. Further investigation of the SNPs in a cross-sectional study including 290 subjects aged 90-107 years revealed associations of SLC3A2 /CD98, SLC38A2 /SNAT2, SLC38A3 /SNAT3, SLC38A9 /SNAT9 variability with longevity. Finally, a longitudinal study examining the survival rate over 10 years showed age-dependent complexity due to possible antagonistic pleiotropic effects for a SNP in SLC38A9 /SNAT9, conferring a survival advantage before 90 years of age and a disadvantage later, probably due to the remodelling of AA metabolism. On the whole, our findings support the hypothesis that AA transporters may impact on the age-related physical decline and survival at old age in a complex way, likely through a mechanism involving mTORC1 signalling.

Background: Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable., Objective: To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning., Methods: Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions., Results: The group mean EMG amplitudes for resisted wrist extension were 1.2-1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip., Conclusions: The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.

Objectives: Studies on grasping and limb posture during arboreal locomotion in great apes in their natural environment are scarce and thus, attempts to correlate behavioral and habitat differences with variation in morphology are limited. The aim of this study is to compare hand use and forelimb posture during vertical climbing in wild, habituated mountain gorillas (Gorilla beringei beringei) and semi-free-ranging chimpanzees (Pan troglodytes) to assess differences in the climbing styles that may relate to variation in hand or forelimb morphology and body size., Materials and Methods: We investigated hand use and forelimb posture during both ascent and descent vertical climbing in 15 wild mountain gorillas and eight semi-free-ranging chimpanzees, using video records obtained ad libitum., Results: In both apes, forelimb posture was correlated with substrate size during both ascent and descent climbing. While climbing, both apes used power grips and diagonal power grips, including three different thumb postures. Mountain gorillas showed greater ulnar deviation of the wrist during vertical descent than chimpanzees, and the thumb played an important supportive role when gorillas vertically descended lianas., Discussion: We found that both apes generally had the same grip preferences and used similar forelimb postures on supports of a similar size, which is consistent with their overall similarity in hard and soft tissue morphology of the hand and forelimb. However, some species-specific differences in morphology appear to elicit slightly different grasping strategies during vertical climbing between mountain gorillas and chimpanzees., (© 2017 Wiley Periodicals, Inc.)

Background Finger amputations aim at preserving function and optimizing cosmesis. The crucial decision here is whether to preserve a stump or to do a ray amputation. The present study aimed to compare the functional outcome and postoperative quality of life after ray amputation or amputation through the proximal phalanx.

This study evaluates whether the existing force-endurance relationship models are predictive of endurance time for overweight and obese individuals, and if not, provide revised models that can be applied for ergonomics practice. Data was collected from 141 participants (49 normal weight, 50 overweight, 42 obese) who each performed isometric endurance tasks of hand grip, shoulder flexion, and trunk extension at four levels of relative workload. Subject-specific fatigue rates and a general model of the force-endurance relationship were determined and compared to two fatigue models from the literature. There was a lack of fit between previous models and the current data for the grip (ICC = 0.8), with a shift toward lower endurance times for the new data. Application of the revised models can facilitate improved workplace design and job evaluation to accommodate the capacities of the current workforce.

This study aims to evaluate the effects of strengthening exercises on wrist flexor and extensor strength, hand grip strength, and counter-stroke performance. Thirty amateur table tennis players were recruited and randomly allocated into two groups: the control and the training group (n = 15/group). Pre- and post-data were collected. The training group performed home exercises for six weeks using a bucket filled with water, while the controls were asked to keep their lifestyle as usual. The general characteristics were no significant differences. The training group showed significantly higher levels of wrist flexor and extensor strength than the control group (p < 0.05). However, the difference in hand grip strength was not statistically significant. Both groups showed significant improvement in counter-stroke performance (p < 0.05), however, there was no difference between the groups. In conclusion, specific strengthening exercises increase wrist flexor and extensor strength, but they have no effect on either hand grip strength or counter-stroke performance., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: Optimal strength and flexibility are essential for performance enhancement and injury prevention in hockey, and anthropometry is known to influence these parameters., Aim: To find anthropometric correlates for strength and flexibility score in young Indian field hockey players., Materials and Methods: Thirteen female and 19 male subjects volunteered for the study. Selected anthropometric variables: lengths, breadths, girths and body composition; strength and sit and reach score were measured for each subject., Results: Males were taller, leaner and stronger with longer upper limbs and broader chests. With few exceptions, taller, heavier and leaner players with longer trunks and limbs, broader chest and hip, and bulkier arms and lower limbs had stronger grip, back, upper and lower limbs. Heavier and taller players with longer trunk and more percentage of body fat were more flexible. Also, the stronger players had more percentage body fat and body mass index, which might be due to the strong positive correlation of percentage body fat and body mass index with fat free mass., Conclusion: Anthropometric variables, especially heights, breadths and body composition, show significant correlation with strength and flexibility, and hence may serve as monitoring tool and for talent identification.

The current study examined the relationship between vitamin D status and muscle strength in young healthy adults: residents (>6 months) and newcomers (0-3 months), originally from sunny climate countries but currently living in the northeast of Scotland. Our longitudinal data found a positive, albeit small, relationship between vitamin D status and knee extensor isometric strength., Introduction: Vitamin D has been suggested to play a role in muscle health and function, but studies so far have been primarily in older populations for falls prevention and subsequent risk of fractures., Methods: Vitamin D status was assessed in a healthy young adults from sunny climate countries (n = 71, aged 19-42 years) with 56% seen within 3 months of arriving in Aberdeen [newcomers; median (range) time living in the UK = 2 months (9-105 days)] and the remainder resident for >6 months [residents; 23 months (6-121 months)]. Participants attended visits every 3 months for 15 months. At each visit, fasted blood samples were collected for analysis of serum 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), carboxy-terminal collagen crosslinks (CTX) and N-terminal propeptide of type I collagen (P1NP). Maximal voluntary contractions (MVC) were performed for grip strength (both arms) and for maximal isometric strength of the knee extensors (right knee)., Results: There were small seasonal variations in 25(OH)D concentrations within the newcomers and residents, but no seasonal variation in bone turnover markers. There was a positive, albeit small, association between 25(OH)D and knee extensor maximal isometric strength. Mixed modelling predicted that for each 1 nmol/L increase in 25(OH)D, peak torque would increase by 1 Nm (p = 0.04)., Conclusions: This study suggests that vitamin D may be important for muscle health in young adults migrating from sunnier climates to high latitudes, yet the potential effect is small.

The goal of this study was to (i) assess the physical and anthropometric differences between three levels of climbers and (ii) predict climbing ability by using a multiple regression model. The participants were divided into novice (n = 15), skilled (n = 16), and elite (n = 10) climbers. Anthropometric characteristics such as height, weight, percentage of body fat and muscle, bi-acromial breath, arm span, and ape index were measured. General and specific strength were assessed through an arm jump test, a bench press test, and a hand and finger grip strength test in maximal and endurance conditions. All variables were combined into components via a principal component analysis (PCA) and the components used in a multiple regression analysis. The major finding of this study is that climbing ability is more related to specific rather than general strength. Only finger grip strength shows a higher level of initial strength between all samples while the arm jump test discriminates between climbers and non-climbers. The PCA reveals three components, labeled as training, muscle, and anthropometry, which together explain 64.22% of the variance. The regression model indicates that trainable variables explained 46% of the total variance in climbing ability, whereas anthropometry and muscle characteristics explain fewer than 4%., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Repetitive movements and poor posture are associated with over-use of smartphones when texting or playing games and significantly contribute to the symptoms of pain and discomfort in the upper extremities., Objective: This study investigated the effect of exercise training and postural correction on disabilities of the arm, shoulder, and hand (DASH), hand grip and key pinch strength among smartphone users., Methods: One hundred university students were randomly divided into two groups; the experimental group participated in a 12-week programme of exercise training and postural corrections. The control group were instructed to follow their usual routine for smartphone utilization. Measurements of DASH scores, hand grip strength, and key pinch grip strength were conducted before and after 12 weeks for both groups., Results: There were no significant differences between the start values of both groups for DASH scores, hand grip strength, and key pinch strength ( p > 0.05). However, there was a significant improvement in all outcomes measured in the experimental group ( p < 0.05), with significant changes in the outcomes of the control group., Conclusion: Postural correction combined with a selected exercise training programme improved the hand grip, key pinch grip strength, and upper extremity disability and symptoms associated with smartphone use among university students., Competing Interests: Conflicts of interest: The authors have no conflict of interest to declare.

Background: This study aimed to examine the relationship between hand-grip force and maximum inspiratory pressure (PImax) in healthy young and middle-age individuals., Methods: All individuals underwent assessment of inspiratory muscle strength by maximum inspiratory pressure using a U-type water manometer and evaluation of hand-grip force by a hydraulic hand dynamometer., Results: The correlation of PImax and hand-grip force was strong (r = 0.76). A multilinear regression model was built to investigate the ability of various parameters, such as hand-grip force, sex, and body mass index measurements, to predict PImax. PImax can be accurately predicted by 80% (r = 0.76) with a simple equation of easily evaluable factors, such as hand-grip force, body mass index, and sex., Conclusion: The results showed significant correlation between hand flexors' force and strength of inspiratory muscles in healthy individuals. This appears to be an easy way to evaluate the results indirectly and can help to assess the relationship between hand flexor and inspiratory muscle capacity, especially the diaphragm. Our study should be viewed as a hypothesis-generating one, and further studies are required in the population of critically ill or difficult-to-wean patients. (ClinicalTrials.gov registration NCT02423616.)., (Copyright © 2016 by Daedalus Enterprises.)

Background: Shoulder pain as a result of rotator cuff pathology is one of the most common musculoskeletal complaints presenting within primary care. Assessment of hand grip strength has been proposed as an indicator of rotator cuff function. This experimental study assessed the relationship between grip strength and shoulder lateral rotator muscle strength in a number of different shoulder positions, aiming to investigate whether such a relationship existed and whether grip strength could be used as a functional assessment tool for the posterior cuff., Methods: Twenty-seven healthy, physically active, volunteers (19 males, eight females) with no history of shoulder, upper limb or neck injury comprised the study group. The mean (SD) age was 19.8 (5.7) years (range 18 years to 23 years). Grip strength (measured with hand grip dynamometer) and lateral rotator strength (measured with a hand held dynamometer) was measured at neutral, 90° abduction, and 90° abduction with 90° external rotation., Results: The correlation between grip strength and shoulder lateral rotation strength ranged between r = 0.91 (r (2 )= 0.84) and r = 0.72 (r (2 )= 0.52) across all positions., Conclusions: A strong correlation between grip strength and lateral rotator strength was shown at all positions for both left and right hands, suggesting that assessment of grip strength could be used as a rotator cuff monitor of recruitment function.

Objectives: The aim of this prospective study was to evaluate muscle force of the hand, thumb, and forefinger in patients with prolonged radial occlusion after transradial percutaneous coronary procedures., Background: There are no data on hand strength and function in patients with prolonged radial occlusion after percutaneous coronary procedures., Methods: Elective patients with chronic stable angina undergoing percutaneous coronary procedures were evaluated the day before the procedure for radial artery patency, Allen test, hand grip, and thumb and forefinger pinch tests. The same measures were performed the day after the procedure and at follow-up. At follow-up, patients were divided in two groups according to the radial patency (group 1) or occlusion (group 2)., Results: Of the 99 patients included in the study, 90 patients had a patent radial artery (group 1), and nine (9.1%) patients had an occluded artery (group 2). At baseline, there were no significant differences in hand grip test between the two groups (42 ± 11 kg in group 1 and 41 ± 17 kg in group 2, P = 0.74). In both groups, after the procedure, the hand grip test values was significantly reduced compared with baseline values (40 ± 11 kg in group 1, P < 0.0001 and 37 ± 17 kg in group 2, P = 0.007). Finally, at follow-up, in both groups, the hand grip test values returned to baseline values. Thumb and forefinger pinch tests did not show significant differences after the procedure and at follow-up, compared with baseline., Conclusions: Radial artery occlusion after percutaneous coronary procedures was not associated with a reduction in hand and finger strength., (© 2015 Wiley Periodicals, Inc.)

Risk of bone fractures in patients with HIV infection is greater than in the general population, particularly in those co-infected with hepatitis viruses. We compared bone mineral density (BMD) and muscular strength, measured by hand grip test (HG), in HIV mono-infected and co-infected patients. T-score values were lower in HIV patients co-infected with hepatitis viruses vs. mono-infected individuals. Since no significant correlations between HG and T-scores were found, we hypothesize that these factors belong, at least in part, to independent pathways, so both should be taken into account as risks for fragility fractures. Larger prospective studies are needed to confirm this hypothesis.

Many stroke survivors suffer from impaired hand function. Biomechanics of hand grip suggests that abnormally directed grip force can hamper gripping abilities and hand function. This study examined the relation between the ability to precisely direct fingertip force and clinical hand function scores among individuals affected by stroke. Specifically, clinical hand function tests of the Fugl-Meyer, Chedoke McMaster, and Box and Block Test were used, since they involve various hand movements required for activities of daily living. Digit force direction during static grip was recorded using multiaxial load cells. Data for 59 chronic stroke survivors were analyzed. We found that larger angular deviation of digit force from the normal direction was significantly associated with lower hand functional levels (p<.001 for all three clinical tests). Particularly, stroke survivors whose digit force deviated more than 21° from the normal direction could not achieve the normal level of Fugl-Meyer or Chedoke or move more than 4 blocks in a minute. The biomechanics of the way digit force direction affects hand grip function is described. In addition, underlying mechanisms for altered digit force direction post stroke are postulated, including impaired somatosensation and abnormal neural input to muscles. In summary, this study identifies a new biomechanical marker for hand functional level and recovery. Future interventions may focus on correcting digit force direction to improve hand functional outcome., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: Assessing the clinical effectiveness of measuring grip strength as a prognostic tool in recovering ambulation in bed-confined frail elderly patients., Methods: A prospective study was carried out with 50 elderly inpatients (mean age: 81.6 years old). Manual muscle test was used for checking strength of hip flexor muscles, hip abductor muscles and knee extensor muscles. Grip strength was assessed by hydraulic dynamometer. Walking ability was assessed by functional ambulation categories and Functional Classification of Sagunto Hospital Ambulation. Existence of cognitive impairment (Short Portable Mental Status of Pfeiffer) and comorbidity (abbreviated Charlson index) were considered to be confounding variables., Statistical Analysis: Simple comparisons and mixed models of multiple ordinal regression., Results: The sample presented generalized weakness in scapular (mean 4.22) and pelvic (mean 3.82) muscle. Mean hand grip values were similar: 11.98 kg right hand; 11.70 kg left hand. The patients had lost walking ability. After treatment, there was a statistically significant for scapular waist strength (P=0.001), pelvic waist strength (P=0.005) and walking ability (P=0.001). A statistically significant relationship in the regression analysis was found between the grip (right and left hands) and walking ability post-treatment (P=0.009; odds ratio 1.14 and P=0.0014 odds ratio 1.113 for each walking scale). The confounding variables showed no statistical significance in the results., Conclusion: Grip strength is associated with walking ability in hospitalized frail elderly. Grip strength assessment by hydraulic dynamometry is useful in patients with poor collaboration. Walking ability training in frail elderly inpatients is useful.

Background: Evidence suggests CaHMB may impact muscle mass and/or strength in older adults, yet no long-term studies have compared its effectiveness in sedentary and resistance training conditions. The purpose of this study was to evaluate the effects of 24 weeks of CaHMB supplementation and resistance training (3 d wk(-1)) or CaHMB supplementation only in ≥65 yr old adults., Methods: This double-blinded, placebo-controlled, trial occurred in two phases under ad libitum conditions. Phase I consisted of two non-exercise groups: (a) placebo and (b) 3 g CaHMB consumed twice daily. Phase II consisted of two resistance exercise groups: (a) placebo and resistance exercise and (b) 3 g CaHMB consumed twice daily and resistance exercise (RE). Strength and functionality were assessed in both phases with isokinetic leg extension and flexion at 60°·s(-1) and 180°·s(-1) (LE60, LF60, LE180, LF180), hand grip strength (HG) and get-up-and-go (GUG). Dual X-Ray Absorptiometry (DXA) was used to measure arm, leg, and total body lean mass (LM) as well as total fat mass (FM). Muscle Quality was measured for arm (MQ(HG)=HG/arm LM) and Leg (MQ60=LE60/leg LM) (MQ180=LE180/leg LM)., Results: At 24 weeks of Phase I, change in LE60 (+8.8%) and MQ180 (+20.8%) for CaHMB was significantly (p<0.05) greater than that for placebo group. Additionally, only CaHMB showed significant (p<0.05) improvements in total LM (2.2%), leg LM (2.1%), and LE180 (+17.3%), though no treatment effect was observed. Phase II demonstrated that RE significantly improved total LM (4.3%), LE60 (22.8%), LE180 (21.4%), HG (9.8%), and GUG (10.2%) with no difference between treatment groups. At week 24, only CaHMB group significantly improved FM (-3.8%) and MQHG (7.3%); however there was no treatment main effect for these variables., Conclusion: CaHMB improved strength and MQ without RE. Further, RE is an effective intervention for improving all measures of body composition and functionality., (© 2013. Published by Elsevier Inc. All rights reserved.)

Study Design: Repeated measures design., Introduction: Mirror activity refers to emergence of motion not only in the intended, but also in the contralateral limb., Purpose: To characterize post-stroke mirror activities across multiple muscles during unilateral pinch., Methods: Chronic stroke survivors performed unilateral pinch grip using the paretic and nonparetic hand, while four muscles' EMGs were recorded for both hands., Results: During the paretic hand grip, the relaxed nonparetic hand showed mirror activity that was more pronounced for the intrinsic (FDI and thenar eminence) than extrinsic muscles (FDS and EDC). During the nonparetic hand grip, mirror activity in the paretic hand was suppressed for the intrinsic than extrinsic muscles., Conclusion: Chronic stroke survivors' relaxed hand did not mirror the task hand's muscle activation pattern, but displayed altered muscle activation patterns depending on muscles and sides, possibly mediated by disturbed interhemispheric inhibition and relative reliance on corticospinal tracts among muscles., Level of Evidence: N/A., (Copyright © 2013 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.)

In this nonexperimental study, videofilmed, self-selected housework activities of rheumatic women were analyzed. The women gripped and manipulated objects in their homes. The activities were analyzed under the headings Activity, Actions, Objects, and Grip. The films were viewed frame by frame, and the data was computerized for statistical analysis. The women performed five self-selected housework activities and eight groups of actions (n = 340). During the actions the women handled 12 groups of objects using the eight grip classes of Sollerman's grip classification. The diagonal volar grip was the most common grip (20%), and the tripoid pinch was the least common (0.29%); 34% of the actions were right-handed, 19% left-handed, and 47% bimanual. No clear grip pattern was revealed by the activity analysis.