BACKGROUND: Recent research highlights the importance of muscular strength as a key factor in physical fitness, a strong indicator of overall mortality risk, and a vital target for preventing chronic diseases. This study used a proteome-wide Mendelian randomization analysis plus colocalization analysis for low hand grip strength to explore potential therapeutic targets for muscle weakness.
METHODS: We conducted two two-sample Mendelian randomization analyses from four cohorts to identify and validate the causal relationship between plasma proteins and low grip strength. We also employed bidirectional Mendelian randomization analysis with Steiger filtering, Bayesian co-localization, and phenotype scanning to detect reverse causality, thereby consolidating our Mendelian randomization findings. Downstream analyses were also undertaken of identified proteins, including knockout models, enrichment analyses, and protein-protein interaction networks. Finally, we assessed the druggability of the identified proteins.
RESULTS: At Bonferroni significance (P < 6.82 × 10-5), Mendelian randomization analysis revealed that three proteins were causally associated with low grip strength. Increased MGP (OR = 0.85) and HP (OR = 0.96) decreased the risk of low grip strength, whereas elevated ART4 (OR = 1.06) increased the risk of low grip strength. None of the three proteins had reverse causality with low grip strength. Bayesian co-localization suggested that MGP shared the same variant with low grip strength (coloc.abf-PPH4 = 0.826). Further downstream analyses showed that MGP, which is highly expressed in musculoskeletal system, is a potential novel target for muscle weakness.
CONCLUSIONS: The proteome-wide Mendelian randomization investigation identified three proteins associated with the risk of muscle weakness. MGP, HP, and ART4 deserve further investigation as potential therapeutic targets for muscle weakness.

BACKGROUND: Frailty is a geriatric syndrome characterized by increased individual vulnerability with an increase in both dependence and mortality when exposed to external stressors. The use of Frailty Indices in routine clinical practice is limited by several factors, such as the cognitive status of the patient, times of consultation, or lack of prior information from the patient.
OBJECTIVE: In this study, we propose the generation of an objective measure of frailty, based on the signal from hand grip strength (HGS).
METHODS: This signal was recorded with a modified Deyard dynamometer and processed using machine learning strategies based on supervised learning methods to train classifiers. A database was generated from a cohort of 138 older adults in a transverse pilot study that combined classical geriatric questionnaires with physiological data.
METHODS: Participants were patients selected by geriatricians of medical services provided by collaborating entities.
RESULTS: To process the generated information 20 selected significant features of the HGS dataset were filtered, cleaned, and extracted. A technique based on a combination of the Synthetic Minority Oversampling Technique (SMOTE) to generate new samples from the smallest group and ENN (technique based on K-nearest neighbors) to remove noisy samples provided the best results as a well-balanced distribution of data.
CONCLUSIONS: A Random Forest Classifier was trained to predict the frailty label with 92.9% of accuracy, achieving sensitivities higher than 90%.

UNASSIGNED: Previous observational studies have demonstrated an association between grip strength and detrimental pregnancy and perinatal outcomes. However, the causality of this relationship remains uncertain.
UNASSIGNED: This study aims to investigate if there is a causal relationship between grip strength and adverse pregnancy and perinatal outcomes, providing evidence to support active intervention for adverse pregnancy outcomes.
UNASSIGNED: A two-sample Mendelian randomization method was used to select GWAS data from the UK Biobank and the FinnGen Biobank as data sources. The inverse variance weighting method was used as the main analysis method. The reliability of the results was verified through sensitivity analysis, including Cochran\'s Q test, MR-egger intercept regression analysis, leave-one-out analysis, and funnel plot. Independent queues are also used to verify the reliability of the results.
UNASSIGNED: The study demonstrated a significant positive correlation between genetically predicted hand grip strength and offspring birth weight, specifically left-hand grip strength (β = 0.193, 95 % CI: 0.099-0.286, p = 0.0001) and right-hand grip strength (β = 0.310, 95 % CI: 0.235-0.384, p = 3.27E-16). Sensitivity analysis indicated no horizontal multi-effect, and leave-one-out analysis along with the funnel plot showed no abnormalities. The verification queue also yielded similar results.
UNASSIGNED: This study revealed a significant association between grip strength-related traits and offspring birth weight, suggesting a potential protective effect. Moreover, a negative predictive trend was observed for other adverse pregnancy outcomes. Modifying grip strength through an active lifestyle and continuous monitoring of pregnant women\'s grip strength may have implications for improving pregnancy outcomes. However, further research is warranted to investigate these findings more comprehensively.

UNASSIGNED: Health-related fitness directly depends on the level of physical activity of the individual. Inactivity contributes to around 3.3% of all deaths, making the lack of exercise and sedentary lifestyles among the young generation a current source of concern. There is a paucity of research on the association between PA and health-related physical fitness among young people. In the perspective of this, the objective of this research was to find out the effect of PA levels on physical fitness in healthy adults.
UNASSIGNED: A total of 419 students between the ages of 18 and 25 participated in this cross-sectional survey. The \"Global Physical Activity Questionnaire (GPAQ)\" was used to evaluate the PA. Their body fat percentage was measured using a skin fold caliper, followed by measurement of VO2max using a gas analyzer and hand grip strength and endurance assessment with the help of a computerized dynamometer. For statistical analysis, Karl Pearson\'s correlation coefficients and the ANOVA test were utilized.
UNASSIGNED: PA was positively correlated with VO2 max (r=0.429), and handgrip strength (r=0.408) while negatively correlated with body fat % (r=-.315). VO2 max, body fat, and hand grip strength differ significantly amongst participants having different physical activity levels. (p-value =<0.05).
UNASSIGNED: This research concludes that PA is associated with physical fitness. PA will lead to a definite improvement in overall physical fitness. With the help of the results of this study, young adults can be motivated for physical fitness.

UNASSIGNED: Iron deficiency affects more than 60% of colorectal cancer patients at the time of diagnosis. Iron deficiency ultimately leads to anemia, but additionally, iron deficiency might impact other domains of colorectal cancer patients\' health and well-being. The aim of this study was to evaluate the impact of iron deficiency on fatigue, quality of life, cognition, and physical ability in patients undergoing evaluation for colorectal cancer.
UNASSIGNED: Multicenter, prospective, observational cross-sectional study (2021-2023). Fatigue was the primary outcome, measured using the Focused Assessment of Cancer Treatment-Anemia questionnaire (FACT-An). Quality of Life, Cognition, Aerobe capacity, mobility, and peripheral muscle strength were tested as secondary outcomes. Multivariate analysis was performed to estimate the impact of iron deficiency on all outcomes.
UNASSIGNED: Two hundred and one patients were analyzed, 57% being iron deficient. In multivariate regression analysis, iron deficiency was not associated with fatigue: FACT-An (r = -1.17, p = 0.57, 25% CI: -5.27 to 2.92). Results on quality of life, cognition, and mobility were non-significant and with small regression coefficients. Iron deficiency showed a nearly significant association with reduced hand-grip-strength (r = -3.47 kg, p = 0.06, 25%CI -7.03 to 0.08) and reduced 6 min walking distance (r = -40.36 m, p = 0.07, 25%CI: -84.73 to 4.00).
UNASSIGNED: Iron deficiency in patients undergoing evaluation for colorectal cancer was not associated with fatigue, quality of life, or cognition, but might affect aerobic endurance and peripheral muscle strength to a degree that is clinically relevant.

OBJECTIVE: Recently, handgrip, knee extensor and respiratory muscle strength were proposed as candidate biomarkers to assess the neuromuscular function of vitality capacity in older persons. This umbrella review aims to provide an overview of the available instruments and their measurement properties to assess these biomarkers.
METHODS: The databases PubMed, Web of Science and Embase were systematically screened for systematic reviews and meta-analyses reporting on handgrip, knee extensor or respiratory muscle strength assessments, resulting in 7,555 articles. The COSMIN checklist was used to appraise psychometric properties and the AMSTAR for assessing methodological quality.
RESULTS: Twenty-seven systematic reviews were included in this study. Some of the identified reviews described the psychometric properties of the assessment tools. We found five assessment tools that can be used to measure neuromuscular function in the context of healthy ageing. Those are the handheld dynamometer for handgrip strength, the dynamometer for knee extensor strength and regarding respiratory muscle strength, the sniff nasal inspiratory pressure, maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP).
CONCLUSIONS: The handheld dynamometer for hand grip strength, the dynamometer for knee extensor strength, sniff nasal inspiratory pressure, MIP and MEP were identified. Therefore, these assessments could be used to identify community-dwelling older adults at risk for a declined neuromuscular function in the context of vitality capacity.

UNASSIGNED: This study aimed to assess the possible association of adherence to the Mediterranean diet (MD) with muscle strength and body composition.
UNASSIGNED: The cross-sectional study evaluated 112 postmenopausal women (aged 41-71 years). Fasting blood samples were obtained for biochemical/hormonal assessment. The Mediterranean Dietary Score (MedDietScore) was calculated and used to stratify adherence by tertiles (low [T1], moderate [T2] or high [T3]). Handgrip strength (HGS) was measured by dynamometry and body composition with dual-X-ray absorptiometry.
UNASSIGNED: Women with low-moderate MedDietScore (T1/T2) had lower HGS values than those with higher scores (19.5 ± 4.9 kg vs. 21.9 ± 3.9 kg, p = 0.023). A linear stepwise increase of HGS values per MedDietScore tertile was found (T1 vs. T2 vs. T3: 18.4 ± 4.4 kg vs. 20.6 ± 5.2 kg vs. 21.9 ± 3.9 kg, ANOVA p-value for linear trend = 0.009, ANCOVA p-value = 0.026). Multivariable models confirmed that HGS values were independently associated with the MedDietScore (β-coefficient = 0.266, p = 0.010). Lean mass values were associated with the MedDietScore (β-coefficient = 0.205, p = 0.040). All models were adjusted for age and cardiometabolic risk factors.
UNASSIGNED: The data suggest that the higher the adherence to the MD, the better the muscle strength and lean mass in postmenopausal women. Prospective studies are required to evaluate the significance of these observations in cardiovascular prevention strategies at midlife.

BACKGROUND: Handgrip strength (HGS) is an indicator of muscular strength, used in the diagnosis of sarcopenia, undernutrition, and physical frailty as well as recovery. Typically, the maximum HGS value is used; however, recent evidence suggests the exploration of new indicators provided based on the force-time curve to achieve a more comprehensive assessment of muscle function. Therefore, the objective was to identify indicators of the HGS profile beyond maximum HGS, based on force-time curves, and to systematize knowledge about their applications to various types of samples, health issues, and physical performance.
METHODS: A systematic review was performed including studies whose participants\' HGS was assessed with a digital or adapted dynamometer. The outcome measures were HGS profile indicators calculated from the force-time curve.
RESULTS: a total of 15 studies were included, and the following indicators were identified: grip fatigue, fatigability index, fatigue rate, fatigue resistance, time to 80% maximal voluntary contraction, plateau coefficient of variability, time to maximum value, T-90%, release rate, power factor, grip work, average integrated area, endurance, cycle duration, time between cycles, maximum and minimum force-velocity, rate of grip force, final force, inflection point, integrated area, submaximal control, and response time.
CONCLUSIONS: Various indicators based on the force-time curve can be assessed through digital or adapted dynamometers. Future research should analyze these indicators to understand their implications for muscle function assessment, to standardize evaluation procedures, to identify clinically relevant measures, and to clarify their implications in clinical practice.

BACKGROUND: Emerging evidence suggests that alterations in BCAA metabolism may contribute to the pathogenesis of sarcopenia. However, the relationship between branched-chain amino acids (BCAAs) and sarcopenia is incompletely understood, and existing literature presents conflicting results. In this study, we conducted a community-based study involving > 100,000 United Kingdom adults to comprehensively explore the association between BCAAs and sarcopenia, and assess the potential role of muscle mass in mediating the relationship between BCAAs and muscle strength.
METHODS: Multivariable linear regression analysis examined the relationship between circulating BCAAs and muscle mass/strength. Logistic regression analysis assessed the impact of circulating BCAAs and quartiles of BCAAs on sarcopenia risk. Subgroup analyses explored the variations in associations across age, and gender. Mediation analysis investigated the potential mediating effect of muscle mass on the BCAA-muscle strength relationship.
RESULTS: Among 108,017 participants (mean age: 56.40 ± 8.09 years; 46.23% men), positive associations were observed between total BCAA, isoleucine, leucine, valine, and muscle mass (beta, 0.56-2.53; p < 0.05) and between total BCAA, leucine, valine, and muscle strength (beta, 0.91-3.44; p < 0.05). Logistic regression analysis revealed that increased circulating valine was associated with a 47% reduced sarcopenia risk (odds ratio = 0.53; 95% confidence interval = 0.3-0.94; p = 0.029). Subgroup analyses demonstrated strong associations between circulating BCAAs and muscle mass/strength in men and individuals aged ≥ 60 years. Mediation analysis suggested that muscle mass completely mediated the relationship between total BCAA, and valine levels and muscle strength, partially mediated the relationship between leucine levels and muscle strength, obscuring the true effect of isoleucine on muscle strength.
CONCLUSIONS: This study suggested the potential benefits of BCAAs in preserving muscle mass/strength and highlighted muscle mass might be mediator of BCAA-muscle strength association. Our findings contribute new evidence for the clinical prevention and treatment of sarcopenia and related conditions involving muscle mass/strength loss.

OBJECTIVE: To describe hand grip strength, walking speed, functional mobility, and postural control at one year following intensive care unit admission for COVID-19, and to find any predictors that are associated with impaired hand grip strength, walking speed, functional mobility, or postural control at the 1-year follow-up.
METHODS: Retrospective cross-sectional and longitudinal observational study.
METHODS: Intensive care unit and outpatient research clinic at Sahlgrenska University Hospital.
METHODS: Of the 105 individuals in \"The Gothenburg Recovery and Rehabilitation after COVID-19 and Intensive Care Unit\" cohort, 78 participated in this study.
METHODS: Descriptive statistics for hand grip strength, walking speed, functional mobility, and postural control were presented and binary logistic regressions were performed to find their significant predictors.
RESULTS: At 1-year following intensive care unit admission for COVID-19, impaired hand grip strength was found in 24.4% for the right hand and 23.1% for the left hand. Walking speed, functional mobility, and postural control were found to be impaired in 29.5%, 21.8%, and 5.1%, respectively. For impaired walking speed, longer length of stay at intensive care unit and presence of diabetes mellitus were risk factors. Diabetes mellitus was found to be the risk factor for impaired functional mobility.
CONCLUSIONS: In this study, 45% of the participants showed impairment in function, activity capacity or both. These results suggest that individuals who recovered after intensive care unit admission for COVID-19 would benefit from receiving long-term follow-up to enable identification of those with need of physical health assistance and rehabilitation.