Background: Resistance training (RT) improves muscle strength and overall physical function in older adults. RT may be particularly important in the obese elderly who have compromised muscle ...function. Whether caloric restriction (CR) acts synergistically with RT to enhance function is unknown. Objective: As the primary goal of the Improving Muscle for Functional Independence Trial (I’M FIT), we determined the effects of adding CR for weight loss on muscle and physical function responses to RT in older overweight and obese adults. Design: I’M FIT was a 5-mo trial in 126 older (65–79 y) overweight and obese men and women who were randomly assigned to a progressive, 3-d/wk, moderate-intensity RT intervention with a weight-loss intervention (RT+CR) or without a weight-loss intervention (RT). The primary outcome was maximal knee extensor strength; secondary outcomes were muscle power and quality, overall physical function, and total body and thigh compositions. Results: Body mass decreased in the RT+CR group but not in the RT group. Fat mass, percentage of fat, and all thigh fat volumes decreased in both groups, but only the RT+CR group lost lean mass. Adjusted postintervention body- and thigh-composition measures were all lower with RT+CR except intermuscular adipose tissue (IMAT). Knee strength, power, and quality and the 4-m gait speed increased similarly in both groups. Adjusted postintervention means for a 400-m walk time and self-reported disability were better with RT+CR with no group differences in other functional measures, including knee strength. Participants with a lower percentage of fat and IMAT at baseline exhibited a greater improvement in the 400-m walk and knee strength and power. Conclusions: RT improved body composition (including reducing IMAT) and muscle strength and physical function in obese elderly, but those with higher initial adiposity experienced less improvement. The addition of CR during RT improves mobility and does not compromise other functional adaptations to RT. These findings support the incorporation of RT into obesity treatments for this population regardless of whether CR is part of the treatment. This trial was registered at clinicaltrials.gov as NCT01049698.
Muscle strength assessment is important in predicting clinical and functional outcomes in many disorders. Manual muscle testing, although commonly used, offers suboptimal accuracy and reliability. ...Isokinetic dynamometers (IKDs) have excellent accuracy and reliability; but are bulky and expensive, offering limited accessibility. This study aimed to design a portable dynamometer that is accessible, accurate and reliable, and to validate the device in a general population. The portable articulated dynamometry system (PADS) is a portable device with an embedded high-precision load cell, designed to measure muscle strength with optimal accuracy. Seventy-two participants underwent maximal isometric and isokinetic knee extensor torque measurement with the PADS and IKD, respectively. The PADS results were cross-validated against IKD results using change in mean (CIM). Interrater and intra-rater reliabilities were assessed using intraclass correlation coefficients, standard error of measurement, and minimal detectable change. The PADS maximal knee extensor strength results were not significantly different from those by IKD (CIM: - 2.13 Nm; 95% CI - 4.74, 0.49 Nm). The PADS showed interrater reliability (Pearson's r: 0.958; ICC: 0.979; SEM: 5.51%) and excellent intra-rater reliability (Pearson's r: 0.912; ICC: 0.954; SEM: 8.38%). The proposed PADS may be an effective alternative to IKD, offering good accuracy, reliability, and potentially better accessibility.
We compared the effects of two resistance training (RT) programs only differing in the repetition velocity loss allowed in each set: 20% (VL20) vs 40% (VL40) on muscle structural and functional ...adaptations. Twenty‐two young males were randomly assigned to a VL20 (n = 12) or VL40 (n = 10) group. Subjects followed an 8‐week velocity‐based RT program using the squat exercise while monitoring repetition velocity. Pre‐ and post‐training assessments included: magnetic resonance imaging, vastus lateralis biopsies for muscle cross‐sectional area (CSA) and fiber type analyses, one‐repetition maximum strength and full load‐velocity squat profile, countermovement jump (CMJ), and 20‐m sprint running. VL20 resulted in similar squat strength gains than VL40 and greater improvements in CMJ (9.5% vs 3.5%, P < 0.05), despite VL20 performing 40% fewer repetitions. Although both groups increased mean fiber CSA and whole quadriceps muscle volume, VL40 training elicited a greater hypertrophy of vastus lateralis and intermedius than VL20. Training resulted in a reduction of myosin heavy chain IIX percentage in VL40, whereas it was preserved in VL20. In conclusion, the progressive accumulation of muscle fatigue as indicated by a more pronounced repetition velocity loss appears as an important variable in the configuration of the resistance exercise stimulus as it influences functional and structural neuromuscular adaptations.
To systematically review (1) psychometric properties of criterion isokinetic dynamometry testing of muscle strength in persons with poststroke hemiplegia (PPSH); and (2) literature that compares ...muscle strength in patients poststroke with that in healthy controls assessed by criterion isokinetic dynamometry.
A systematic literature search of 7 databases was performed.
Included studies (1) enrolled participants with definite poststroke hemiplegia according to defined criteria; (2) assessed muscle strength or power by criterion isokinetic dynamometry; (3) had undergone peer review; and (4) were available in English or Danish.
The psychometric properties of isokinetic dynamometry were reviewed with respect to reliability, validity, and responsiveness. Furthermore, comparisons of strength between paretic, nonparetic, and comparable healthy muscles were reviewed.
Twenty studies covering 316 PPSH were included. High intraclass correlation coefficient (ICC) inter- and intrasession reliability was reported for isokinetic dynamometry, which was independent of the tested muscle group, contraction mode, and contraction velocity. Slightly higher ICC values were found for the nonparetic extremity. Standard error of the mean (SEM) values showed that a change of 7% to 20% was required for a real group change to take place for most muscle groups, with the knee extensors showing the smallest SEM% values. The muscle strength of paretic muscles showed deficits when compared with both healthy and nonparetic muscles, independent of muscle group, contraction mode, and contraction velocity. Nonparetic muscles only showed minor strength impairments when compared with healthy muscles.
Criterion isokinetic dynamometry is a reliable test in persons with stroke, generally showing marked reductions in muscle strength of paretic and, to a lesser degree, nonparetic muscles when compared with healthy controls, independent of muscle group, contraction mode, and contraction velocity.
There is a growing body of evidence that links nutrition to muscle mass, strength and function in older adults, suggesting that it has an important role to play both in the prevention and management ...of sarcopenia. This review summarises the discussions of a working group ESCEO working group meeting 8th September 2016 that met to review current evidence and to consider its implications for preventive and treatment strategies. The review points to the importance of ‘healthier’ dietary patterns that are adequate in quality in older age, to ensure sufficient intakes of protein, vitamin D, antioxidant nutrients and long-chain polyunsaturated fatty acids. In particular, there is substantial evidence to support the roles of dietary protein and physical activity as key anabolic stimuli for muscle protein synthesis. However, much of the evidence is observational and from high-income countries. Further high-quality trials, particularly from more diverse populations, are needed to enable an understanding of dose and duration effects of individual nutrients on function, to elucidate mechanistic links, and to define optimal profiles and patterns of nutrient intake for older adults.
Although the 5 times stand-to-sit test (5TSST) is indicated for screening for muscle weakness in older adults, its validity is based only on the correlation with quadriceps muscle strength or with ...the muscle strength of a few muscle groups of the lower limbs. Thus, the objective of the present study was to verify whether in independent older women, the 5TSST can really estimate global muscle strength, considering the sum of muscle strength of the trunk, hip, knee and ankle, which are important for functional activities.
119 independent older women participated in this cross-sectional study, undergoing the 5TSST and an isometric muscle strength assessment of the trunk, hip, knee and ankle, using an isokinetic dynamometer. The accuracy of the 5TSST for the discrimination of older women with reduced global muscle strength was evaluated by the ROC curve.
The ROC curve showed that the 5TSST may discriminate older women with reduced global muscle strength with moderate accuracy (AUC = 0.783; 95 % CI = 0.681–0.886; p < 0.001). The 5TSST score with the best accuracy (sensitivity: 80.0 % and specificity: 61.8 %) to evaluate global muscle strength was 11.64 s.
5TSST can be used to identify reduced global muscle strength in independent older women, standing out as an accessible tool for the screening of muscle weakness.
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•The 5 times stand-to-sit test (5TSST) is tool for the screening of muscle weakness.•The 5TSST can estimate global muscle strength in independent older women.•The cutoff point that identifies the reduction of global muscle strength is 11.64 s.
The primary purpose of this study was to examine whether grip strength is related to total muscle strength in children, adolescents, and young adults. The second purpose was to provide reference ...charts for grip strength, which could be used in the clinical and research setting. This cross-sectional study was performed at primary and secondary schools and the University of Applied Sciences. Three hundred and eighty-four healthy Dutch children, adolescents, and young adults at the age of 8 to 20 years participated. Isometric muscle strength was measured with a handheld dynamometer of four muscle groups (shoulder abductors, grip strength, hip flexors, and ankle dorsiflexors). Total muscle strength was a summing up of shoulder abductors, hip flexors, and ankle dorsiflexors. All physical therapists participated in a reliability study. The study was started when intratester and intertester reliability was high (Pearson correlation coefficient >0.8). Grip strength was strongly correlated with total muscle strength, with correlation coefficients between 0.736 and 0.890 (
p
< 0.01). However, the correlation was weaker when controlled for weight (0.485–0.564,
p
< 0.01). Grip strength is related to total muscle strength. This indicates, in the clinical setting, that grip strength can be used as a tool to have a rapid indication of someone’s general muscle strength. The developed reference charts are suitable for evaluating muscle strength in children, adolescents, and young adults in clinical and research settings.
•Most frequently used outcome measures of muscle strength in patients with DM1.•Left ventricular ejection fraction was the preferred cardiac strength measure.•Isometric torque and medical research ...council were the skeletal measures chosen.•Maximal inspiratory and expiratory pressure were the respiratory measures chosen.
Measurement of muscle strength is fundamental for the management of patients with myotonic dystrophy type 1 (DM1). Nevertheless, guidance on this topic is somewhat limited due to heterogeneous outcome measures used. This systematic literature review aimed to summarize the most frequent outcome measures to assess muscle strength in patients with DM1. We searched on Pubmed, Web of Science and Embase databases. Observational studies using measures of muscle strength assessment in adult patients with DM1 were included. From a total of 80 included studies, 24 measured cardiac, 45 skeletal and 23 respiratory muscle strength. The most common method and outcome measures used to assess cardiac muscle strength were echocardiography and ejection fraction, for skeletal muscle strength were quantitative muscle test, manual muscle test and maximum isometric torque and medical research council and for respiratory muscle strength were manometry and maximal inspiratory and expiratory pressure. We successfully gathered the more consensual methods and measures to evaluate muscle strength in future clinical studies, particularly to test muscle strength response to treatments in patients with DM1. Future consensus on a set of measures to evaluate muscle strength (core outcome set), is important for these patients.
Evaluation of muscle strength imbalance can be an important element in optimizing the training process of soccer players. The purpose of the study was to examine isokinetic peak torque (PT) and total ...work (TW) exerted by both knee extensors (quadriceps or Q) and flexors (hamstrings or H), intra-limb imbalance and the magnitude and direction of inter-limb asymmetry in top elite senior (n = 109) and junior (n = 74) soccer players. An isokinetic dynamometry was used to measure maximum peak torque of quadriceps (PT-Q) and hamstrings (PT-H) at an angular velocity of 60° ·s-1, as well as the total work for extensors (TW-Q) and flexors (TW-H) at an angular velocity of 240° ·s-1 in the dominant (DL) and non-dominant leg (NDL) during concentric muscle contraction. Intra-limb imbalance and inter-limb asymmetries were calculated using a standard equation. Statistical analysis using t-test and Mann-Whitney U-test revealed: (a) no differences (p > 0.05) between groups for PT-Q and PT-H, (b) greater strength levels (p < 0.05) for TW-Q and TW-H of senior players than juniors, and (c) no differences (p > 0.05) between groups for intra-limb imbalance and inter-limb asymmetry. Additionally, Pearson's chi-kwadrat (χ2) analysis showed no differences (p > 0.05) between groups for intra-limb imbalance and inter-limb asymmetry in relation to the 'normative' values accepted in the literature that indicate an increase in the risk of knee injury. This study shows that isokinetic assessment can be an important tool to identify imbalances/asymmetries and to develop strategies to reduce the risk of muscle injury.