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Results for “Muscle Strength”

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At least 19 recordsLinked to original sources

PubMed1979

Muscle strength and muscle characteristics in monozygous and dizygous twins.

Muscle strength and electrical activity were investigated on 31 pairs of young male and female monozygous (MZ) and dizygous (DZ) twins. The measurements included leg forces, force-time, running velocity, muscular power, maximal integrated electromyographic activity (IEMG) and chronaximetry of the quadriceps muscle group. In each parameter the intrapair variance was computed and the differences were tested between the MZ and DZ twins. The variance ratio (MZ vs. DZ) was statistically significant only for muscular power confirming an earlier finding which has demonstrated a genetic component for the variable. In addition to the various performance variables several key enzymes involved in ATP turnover during muscle contraction and in glucose residue metabolism were analyzed from the muscle biopsy samples (m. vastus lateralis). A genetic component could not be observed in any of their activities or their relationships to performance variables.

Adolescent↗

PubMed2025

Impact of Muscle Quality on Muscle Strength and Physical Performance Beyond Muscle Mass or Diabetes Status.

BACKGROUND: Muscle quality, represented by myosteatosis, is recognized as an important factor in sarcopenia. In this study, we aimed to determine the associations between myosteatosis, muscle strength and physical performance among the elderly South Korean population. METHODS: We included 1440 participants (mean age 62.7 ± 6.2 years) from the Korean Genome and Epidemiology Study (KoGES). Based on the computed tomography attenuation of mid-thigh imaging, the total muscle area (TMA), normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA) and inter-intramuscular adipose tissue (IMAT) and its indices were used to evaluate myosteatosis. Muscle strength was evaluated using hand grip strength, whereas physical performance was evaluated through 4-m gait speed, a 30-s sit-to-stand test and 2-min walking test. RESULTS: Of the 1440 patients, 51.5% were women, and 37.2% had diabetes. With aging, the LAMA index gradually increased, and the NAMA index gradually decreased in both men and women (p for trend < 0.001). The NAMA index was positively associated, whereas the LAMA and IMAT indices were negatively associated with muscle strength and physical performance after adjusting for age and sex. Higher tertiles of the NAMA index were consistently associated with improved physical performance across all appendicular skeletal muscle tertiles. The relationship between the NAMA index or LAMA index and muscle strength and physical performance did not differ according to diabetic status. Regular exercise was associated with a higher NAMA index and a lower LAMA index in the non-diabetic group; however, no significant difference in muscle quality was observed in the diabetic group in relation to exercise. CONCLUSIONS: Reduced myosteatosis was positively associated with greater muscle strength and better physical performance in both men and women, regardless of muscle mass or diabetes status; improving myosteatosis may be a therapeutic target for the prevention of sarcopenia.

Humans↗

PubMed1977

Effect of acute infectious disease on isometric muscle strength.

Isometric strength of different muscle groups was recorded in thiryty-nine patients suffering various acute infectious diseases, predominantly of viral or mycoplasma aetiology. Recordings were performed after subsidence of fever, and 1, and 4 months thereafter. A control group of twenty-two healthy men, confined to bed for the same period of time as the patients, were investigated at the same time intervals. In addition, control measurements were performed after 1 year in the patients, prior to bed rest in the control subjects. As a result of illness muscle strength was decreased significantly to 85.4-95.3% of that recorded at 4 months. In the control subjects strength did not change significantly, the corresponding percentages being 96.3-102.5. Thus, the present data indicate that these illnesses in themselves may bring about isometric muscle strength reduction.

Adult↗

PubMed1977

Assessment of muscle strength in Duchenne muscular dystrophy.

Muscle strength in 23 patients with Duchenne dystrophy was tested against gravity and manual resistance during an 8-year period. The data show striking linearity in rate of loss of strength with age for any given patient. The tempo does not appear altered during growth spurts, bracing, or loss of ambulation. Variability in disease severity was documented clearly by 7 years of age and appears to be related to earlier age at onset of symptoms. This long ignored method of muscle strength assessment provides a precise measure of disease progression and, since the technique is widely used by physical therapists, it should be incorporated in clinical studies and therapeutic trials.

Age Factors↗

PubMed1979

Influence of muscle temperature on maximal muscle strength and power output in human skeletal muscles.

The influence of muscle temperature (Tm) on maximal muscle strength, power output, jumping, and sprinting performance was evaluated in four male subjects. In one of the subjects the electromyogram (EMG) was recorded from M. vastus lateralis, M. biceps femoris, and M. semitendinosus. Tm ranged from 30.0 degrees C to 39 degrees C. Maximal dynamic strength, power output, jumping, and sprinting performance were positively related to Tm. The changes were in the same order of magnitude for all these parameters (4-6% x degrees C-1) Maximal isometric strength decreased by 2% x degrees C-1 with decreasing Tm. The force-velocity relationship was shifted to the left at subnormal Tm. Thus in short term exercises, such as jumping and sprinting, performance is reduced at low Tm and enhanced at Tm above normal, primarily as a result of a variation in maximal dynamic strength.

Adult↗

PubMed2025

Exercise Therapy in Down Syndrome: A Systematic Review and Meta-Analysis Focused on Muscle Strength, Redox Balance, and Inflammatory Profile.

OBJECTIVE: This study systematically reviewed and meta-analyzed randomized and quasi-randomized controlled trials investigating the impact of exercise therapy on muscle strength, redox balance, and inflammatory profile in individuals with Down syndrome. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, SPORTDiscus, EMBASE, and PEDro. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomized and quasi-randomized controlled trials exploring exercise therapy effects on muscle strength and redox balance in individuals with Down syndrome. Although no initial restrictions on age, gender, or health condition were applied during the search process, all included studies focused on adult participants (>18 yr old). No language restrictions were applied, and the search covered the period from 1970 to 2021. RESULTS: We assessed the abstract of 1964 studies. Of the 46 studies meeting the inclusion criteria for the period 2004-2021, 32 focused on muscle strength, and 14 examined redox balance and inflammation. A total of 1611 participants with a mean age of 27 yr were included. This review confirmed that different exercise modalities are prone to improve muscle strength (random effect (95% confidence interval): 0.66, 0.54 to 0.78), redox balance and inflammatory profile (random effect (95% confidence interval): -1.04, -1.31 to -0.76) in this population. The multimodel inference suggested that the frequency of training (times per week) might play a significant role in the main effect. Unsupervised machine learning algorithms displayed a pattern-based graphic representation to assess heterogeneity. CONCLUSIONS: Exercise training demonstrated a positive impact on muscle strength in adults with Down syndrome. The review provides valuable insights into the effects of exercise therapy on individuals with Down syndrome, emphasizing the need for tailored training prescriptions.

Humans↗

PubMed1978

Muscle strengths in relation to fat storage rate in young men.

Hand-grip strength, elbow flexion strength, trunk extension strength and knee extension strength, and body composition (measured by densitometry) were measured in 59 male students (mean 19.2 years) in order to compare the muscle strength of obese men, in relation to fat storage rate (% fat), with those of non-obese men. Their % fat ranged from 6.2-35.6%. Correlations of body weight and lean body mass were found to be significant with each muscle strength. Our findings presented that obese men had lower muscle strengths for body weight and lean body mass than non-obese men do. This might be the result of two characteristics, inactivity and weak willpower, of obese men. Besides, the 20% fat of threshold of obesity for men proposed by Behnke and Wilmore was reasonable from the viewpoint of the muscle strength because of the differences between group D (18.8% fat) and group E (23.8% fat).

Adipose Tissue↗

PubMed1978

Swelling of the upper extremity, function and muscle strength of shoulder joint following mastectomy combined with radiotherapy.

Swelling of the arm, mobility of the shoulder joint and muscle strength were examined in 76 patients with breast cancer 4.5 to 14 years (mean 8 years) after primary therapy. Marked arm swelling was found on the operated side in 31% of the patients operated by radical mastectomy and in 18% of those having undergone total mastectomy. The swelling was more marked in the upper arm than in the forearm. Patients irradiated postoperatively with a megavoltage technique showed more often and more oedema than those treated with a kilovoltage technique. Obese patients had more swelling than patients of normal weight. Of the various movements of the shoulder joint, abduction, adduction, flexion, extension, horizontal extension and internal rotation were significantly reduced on the operated side in comparison with the non-operated side, but the differences were not great. Neither swelling of the arm nor the patient's weight had any effect on the function of the shoulder joint, as expressed in terms of abduction. Of the muscle groups in the shoulder joint adductors, flexors and extensors were significantly weaker on the operated than on the non-operated side. The muscle strength of the operated side averaged 25% weaker than that of the control side. Swelling of the arm did not reduce the muscle strength of the shoulder joint.

Adult↗

PubMed1979

Method for measurement of maximal isometric muscle strength with special reference to the fingers.

A method for measurement of the maximal isometric muscle strength in the fingers is presented. Details of the apparatus designed for avoidance of hysteresis in mechanical components on measurement of low strengths are given. The measurement of low strengths is described. The measurement procedure is simple both for examiner and for the subject. Values for finger muscle strength in normal persons are presented.

Equipment and Supplies↗

PubMed1977

Voluntary isometric muscle strength of patients undergoing rehabilitation following fractures of the lower limb.

Isometric muscle strength was measured in 32 servicemen recovering from fractures of the lower limb. At the time when patients were admitted for rehabilitation there were marked reductions of strength in the injured limb of muscles acting at the hip, knee and ankle joints. Marked improvement of strength occurred during rehabilitation, but there were still significant differences between the limbs at the time of discharge from the rehabilitation unit.

Ankle Joint↗

PubMed2026

Colocalization and functional analyses identify GBE1 as a gene linking muscle strength and cardiometabolic fitness.

Handgrip strength is a proxy for muscular fitness, an indicator for general health status, and is associated with cardiometabolic health. The mechanisms connecting handgrip strength to skeletal muscle function are incompletely understood. We applied integrated linkage-disequilibrium-adjusted colocalization analysis of genome-wide association study summary statistics for handgrip strength, combined with expression and splicing quantitative trait loci from skeletal muscle, and identified glycogen branching enzyme 1 (GBE1) as a candidate gene for handgrip strength. CRISPR-interference knockdown of GBE1 in immortalized human skeletal muscle cells (HMCL-7304) demonstrated decreased glycogen content and accumulation of polyglucosan bodies. Knockdown of GBE1 led to increased oxygen consumption rate, oxidative stress, and changes in mitochondrial morphology. Transcriptomic profiling of GBE1 knockdown cells identified upregulation of the human superoxide dismutase 2 and enrichment of pathways related to muscle contraction and oxidative stress responses. These functional genomic analyses prioritize GBE1 as a muscle-relevant candidate gene for handgrip strength and provide mechanistic insights to muscle fitness.NEW & NOTEWORTHY Colocalization of genome-wide association study (GWAS) loci with quantitative trait loci (QTL) in skeletal muscle tissue identified GBE1 as a candidate for handgrip strength. Cellular phenotypes with GBE1 knockdown in immortalized human skeletal muscle cells include decreased glycogen content, accumulation of polyglucosan bodies, changes in mitochondrial function and morphology, and increased expression of reactive oxygen species (ROS) scavengers. Transcriptomic changes suggest a role for GBE1 in muscle contraction and oxidative stress-mediated responses.

Humans↗

PubMed2026

Effects of exercise on muscle strength and characteristics in rheumatic diseases and sarcopenia: Protocol for the Care for Muscle (C4M) Study.

OBJECTIVE: Muscle weakness is prevalent in rheumatoid arthritis (RA), osteoarthritis (OA) and sarcopenia (SARC). Endurance exercises may improve mitochondrial function and oxidative capacity, while strength exercises are thought to stimulate myofibrillar protein synthesis. This study aims to compare the effects of strength and endurance exercise and explore the association between muscle characteristics and exercise outcomes in patients with RA, OA and SARC. We hypothesize that responses to endurance and strength exercises in patients with muscle weakness are influenced by intramuscular pathology including muscle morphology, mitochondrial function, and systemic inflammation, based on their disease pathology, potentially requiring personalized training schedules. METHODS: This two-arm, parallel-group exploratory trial will enroll 69 patients (23 RA, 23 OA, 23 SARC), randomized to endurance (n = 35) or muscle strength exercises (n = 34), using minimization to balance disease type and gender. The 8-week intervention includes two supervised sessions per week using a controlled cable pulley device (Reforter™) and fitness equipment, plus one weekly home-based session. The primary outcome is isokinetic muscle strength (peak torque), measured with the Biodex system®. Secondary outcomes include muscle morphology, mitochondrial function, systemic inflammation and muscle endurance (by Biodex and 6 Minute Walk test). Muscle morphology will be assessed via 3D ultrasound imaging of the vastus lateralis. Mitochondrial function will be analyzed using high-resolution respirometry on muscle biopsies. Systemic inflammation will be measured using multiplex assays or ELISA on serum samples. DISCUSSION: This study will explore differential responses to muscle endurance and muscle strength exercises in patients with RA, OA, and SARC, offering novel insights into the molecular mechanisms of muscle weakness. The findings may help identify potential mechanisms underlying variability in exercise response and provide effect size estimates to guide future confirmatory studies and more targeted exercise interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT06480643 (date of registration28-06-24).

Humans↗

PubMed1979

Muscle strength and speed of movement in relation to age and muscle morphology.

Maximum values for isometric strength, dynamic strength, and speed of movement (MEV) in the quadriceps muscle were measured in 114 male subjects who were between 11 and 70 yr. Biopsy samples were taken from the quadriceps muscle in 51 of the subjects (22-65 yr. old). Isometric and dynamic strength increased up to the third decade, remained almost constant to the fifth decade, and then decreased with increasing age. However, no measurable external atrophy of the quadriceps muscle, explaining the decline in strength, could be seen in old age. Histochemical changes in the muscle tissue such as decreased proportion of type II fibers and a selective atrophy of type II fibers, were seen with increasing age. The strength decline in old age was also observed to correlate significantly with the type II fiber area. Multiple regression analyses indicated, however, that mechanisms other than the type II fiber atrophy might be responsible for the decline in strength performance during aging. The implications of these findings are discussed.

Adolescent↗

PubMed1976

Ventilatory muscle strength and endurance training.

We studied respiratory mechanics in young volunteers before and after 5-wk training programs limited to the ventilatory muscles. Four strength trainers (S) performed repeated static maximum inspiratory and expiratory maneuvers against obstructed airways. Four endurance trainers (E) performed voluntary normocarbic hyperpnea to exhaustion. Subjects spent 30-45 min each day in these exercises, 5 days a week. Four control subjects (C) did no training. We attempted to minimize the effect of learning. S increased pressure maximums by about 55%, but vital capacity and total lung capacity by only about 4%. Initially all subjects could sustain hyperpnea at about 81% of their control 15-s maximum voluntary ventilation (MVV) for 15 min; E increased this to about 96% and increased their MVV by 14% as well. No other statistically significant changes were recognized in any group. We conclude that ventilatory muscle strength or endurance can be specifically increased by appropriate ventilatory muscle training programs.

Adult↗

PubMed1977

Muscle strength and fiber composition in athletes and sedentary men.

Members of Swedish national teams in track and field events (sprinting and jumping), downhill skiing, race walking, orienteering, and a group of sedentary men were studied to examine the relationship between muslce fiber characteristics in needle biopsy samples form m. vastus lateralis and muscle strength measured as peak torque during isokinectic knee extensions. In comparison with the sedentary group the following differences were found: a) percentage fast twitch fibers was lower in the endurance athetes, b) fast to slow twitch muscle fiber area ratio was higher in the track athletes, c)track athletes and downhill skier attained higher peak torque values at all angular velocities examined. The track athletes had, however, higher torque values at the fastest angular velocity as compared to the downhill skiers, whereas there was no differnce under isometric conditions. The proportion of fast twitch fibers was related to torque produced, especially at high motion velocity. The training also appeared to affect the force-velocity relationship.

Adult↗

PubMed1975

Back pain and isometric back muscle strength of workers in a Danish factory.

105 factory workers (38 females and 67 males) have been questioned about their frequency of back pain. 60% of the females and 61% of the males have previously experienced episodes of back pain. 21% of the females and 37% of the males have been absent from work due to back pain. The incidence of back pain is not related to age, height, sort of work, or isometric muscle strength of the back (IS). For the males the incidence rises with increasing weight, i.e. combination of height and obesity, but is not related to any two single factors. For the females there is no correlation between the incidence of pain and weight. IS is correlated to height and age in the males but not in the females. Standards for IS are presented and suggested as a guide to evaluation of the working capabilities of individual subjects with back pain.

Adult↗

PubMed2026

Effects of blood flow restriction training combined with plyometric training on lower limb muscle strength and motor unit recruitment in basketball players: An experimental study.

OBJECTIVE: Previous studies have shown that plyometric training (PT) improves neuromuscular function and explosive power but not maximal strength. Blood flow restriction training (BFR) combined with low-intensity resistance training (RT) increases muscle mass and strength. This study investigated the effects of PT, and BFR combined with PT on lower-limb muscle function. METHODS: Twenty elite basketball players were randomly assigned to two groups: PT-alone group (PT, n = 10) and BFR combine with PT group (PT-BFR, n = 10). All participants underwent bodyweight-based plyometric training three times per week for eight weeks. Peak torque values for hip and knee flexion and extension, as well as root mean square (RMS) values derived from electromyography, were measured before and after the intervention. RESULTS: After the 8-week intervention, both groups showed significant improvements in knee flexion and extension peak torque at 180°/s (all p < 0.01). Between-group comparisons revealed greater gains in the PT-BFR group for hip extension and flexion at 60°/s (p = 0.036-0.002; ηp2 = 0.225-0.233). RMS of the rectus femoris increased significantly more in the PT-BFR group than in the PT group (right: p = 0.004, ηp2 = 0.385; left: p = 0.020, ηp2 = 0.266), whereas no significant changes were observed in the gastrocnemius, tibialis anterior, or biceps femoris (all p > 0.05). CMJ height also improved more in the PT-BFR group, with a significant group × time interaction (p = 0.042, ηp2 = 0.210). CONCLUSION: Both training protocols enhanced bilateral lower-limb strength, with notable gains in the non-dominant leg; however, the magnitude did not differ substantially between groups. In contrast, compared with PT alone, BFR combined with PT produced superior enhancements in lower-limb muscle strength and neuromuscular recruitment. These findings suggest that when PT is employed to improve explosive power, it may be effectively combined with BFR to further augment muscular strength.

Humans↗

PubMed1977

[Biomechanical viewpoints on variation in muscle strength].

Explore the source record for details and available documents.

Biomechanical Phenomena↗