Impaired Muscle Performance Research Articles

A Single Dose of Microencapsulated Cocoa Supplementation Does Not Speed up Muscle Force Recovery after Eccentric Exercise-Induced Muscle Damage: A Placebo-Controlled, Double-Blind, Crossover Study

Exercise-induced muscle damage is associated with symptoms such as inflammation, delayed-onset muscle soreness, and impaired muscle performance. The intake of cocoa polyphenols has been suggested to improve muscle recovery due to their antioxidant and anti-inflammatory capacity. However, their bioavailability presents a challenge. Therefore, food microencapsulation may be an alternative to protect polyphenols, ensuring their biological effects. This study aimed to investigate the effect of a single dose of microencapsulated cocoa on the changes in muscle damage markers after eccentric exercise. In this randomized, double-blind, crossover study, fourteen healthy volunteers with previous resistance training experience performed 6 × 10 maximal isokinetic eccentric contractions of their elbow flexors using an isokinetic dynamometer after ingesting 25 g of microencapsulated cocoa or placebo. Peak isometric torque was measured using maximal voluntary isometric contractions, and pain was measured using a visual analogic scale both before and 24 h, 48 h, and 72 h after the damage protocol. Plasma glutathione and malondialdehyde levels were measured using high-performance liquid chromatography, and concentrations of myoglobin and C-reactive protein were determined using a fluorescence immunoassay analyzer. Significant decreases were seen in the peak isometric torque and pain measures from pre- to 72 h post-eccentric exercise. A significant main effect for time was found only for plasma myoglobin at 2 h, 48 h, and 72 h, and for C-reactive protein at 2 h, compared to the pre-eccentric exercise values. No significant time-treatment effects were observed (all p > 0.05). This study demonstrated that microencapsulated cocoa cannot improve muscle recovery after eccentric exercise, at least when a single dose is consumed.

Heterotopic Ossification in Hemophilia: A Multi-Center Case Series

CONCLUSION Heterotopic Ossification (HO), or Myositis Ossificans Traumatica, is the post-traumatic formation of unwanted abnormal benign lamellar ectopic bone within extra skeletal tissue locations. HO can form in varying sizes and sites in the body and can significantly impair muscle performance, range of motion (ROM), and function. Since the recent adoption of diagnostic musculoskeletal ultrasound (MSKUS) in hemophilia care, providers and physical therapists have deepened their understanding of hemarthropathic and hemarthrosis progression. MSKUS has also aided in detecting soft tissue injuries, muscle hematoma, and resultant HO formation. Despite advances in therapies for hemophilia, HO is emerging as an unforeseen complication of contusion and injury-related muscle bleeding in hemophilia. Its detection is important as delayed or inappropriate rehabilitation may prolong recovery and disability time. This multicenter retrospective case series sought to verify and confirm HO detection and investigate whether specific types and severities of hemophilia are at increased risk of HO. Deidentified data and MSKUS images from 29 cases were collected from 9 Hemophilia Treatment Centers from the USA, the Netherlands, and Canada from 2016 to June 2023. The case series was declared exempt from IRB approval. Diagnostic and evaluative data was compiled in Redcap. Images were reviewed and diagnostically confirmed by an RMSK-certified Doctor of Physical Therapy and a Radiologist. A single clinic subset was compared to the national hemophilia incidence taken from the ATHN dataset 2022. We detected HO formation in 29 patients across 9 HTCs. Trauma-induced HO was observed in all bleeding disorder types and severities. (See Table 1). The patients' ages at the time of the inciting injury ranged from 7-56 years, with a mean age of 22.3 and a median of 16.The study's highest incidence of HO cases occurred in patients with type A hemophilia totaling 22/29 subjects or 74.8% of all cases. Except for one severe A, one severe B and a moderate B, the patients were not on prophylactic hemostatic management at the time of injury. The majority of HO (n=24, 82.8%) occurred in the anterior and lateral compartments of the thigh and hip. There were 5 incidents in the upper extremity (4 in the upper anterior arm, 1 in the hand). 24 cases were due to blunt trauma except for 4 in the psoas at the level of the anterior hip and 1 in the elbow flexors of the upper arm. HO formation was mostly associated with deep muscle bleeds next to the bony cortex (n=24). HO was detected on average at 22.97 days after injury (median 21, range 11 to 60), with most detected with MSKUS (n=24) by the physical therapist (n=22) and physician (n=2) in clinic. At the Washington Center for Bleeding Disorders (WACBD), where strict MSKUS follow-up was possible in 7 patients, HO induction was confirmed at day 23, 26, 18, 11, 14, 20, and 22 for a mean of 19.14 days (SD = 5.24). Our study shows that HO occurs regularly in Hemophilia despite its omission in the recently revised 2020 World Federation of Hemophilia guidelines. Notably, the severity or type did not appear to be the sole determinant of HO formation, as the combined total of mild and moderate hemophilia genotypes was 21 (72.4%). Conversely, though limited by the study's small sample size, 74.8% of the HO incidence was reported in type A hemophilia, which appears to be an overrepresentation when compared to the ATHN dataset 2022 report, which indicates an overall 45.59% type A hemophilia incidence. The increased detection of HO in hemophilia may be explained by the growing use of MSKUS by HTC physicians and physical therapists. MSKUS has the advantages of safety and earlier HO detection than radiography. As shown in Fig. 1, HO bears the sonographic signature of hyperechoic contours and deeper acoustic shadowing. The WACBD conducted a review yielding an HO incidence of 23.68% (9 of 38 contusion events) compared to 9-17% in the non-hemophilia population. Though the single-center report is of limited significance, the suggestion of increased HO risk to hemophilia patients merits further study. This case series acknowledges HO as a complication of deep contusions in people with bleeding disorders, especially those not on hemostatic prophylaxis. Further study is needed to determine HO's incidence and risk in Hemophilia. Hemophilia treatment guidelines must be revised to include this complication.

The Effects of High-Load Slow-Velocity Resistance Exercise Training in Athletes With Tendinopathy: A Critically Appraised Topic.

Tendinopathy is a musculoskeletal pathological condition experienced by athletes that can result in pain, impaired muscle performance, and loss of physical function and can hinder return to sports. Various types of resistance exercise training are effective for treating tendinopathy, including isometric, concentric, eccentric, and high-load slow-velocity resistance exercise. What are the effects of high-load slow-velocity resistance exercise training, compared with other forms of resistance exercise, on tendon morphology and patient-reported outcomes in athletes with tendinopathy? The findings of 4 randomized clinical trials were included. One study compared high-load slow-velocity resistance exercise with moderate-load slow-velocity resistance exercise. Two studies investigated the effects of high-load slow-velocity resistance exercise versus eccentric resistance exercise. The fourth study compared high-load slow-velocity resistance exercise with inertia-based resistance exercise. In all of the studies, high-load slow-velocity resistance exercise was as effective as the other forms of resistance exercise for improving patient-reported outcomes and pain. Three studies found no significant differences in changes in tendon morphology between patients who received high-load slow-velocity resistance exercise versus those who received the other forms of resistance exercise. One study showed that high-load slow-velocity resistance exercise was more effective than eccentric exercise for improving tendon morphology outcomes. Current evidence supports the use of high-load slow-velocity resistance exercise as a treatment option for patellar and Achilles tendinopathy in athletes. Results from level 2 studies suggest grade B evidence in support of high-load slow-velocity resistance exercise for treating athletes with tendinopathy.

Chronic Intermittent Hypoxia-Induced Diaphragm Muscle Weakness Is NADPH Oxidase-2 Dependent.

Chronic intermittent hypoxia (CIH)-induced redox alterations underlie diaphragm muscle dysfunction. We sought to establish if NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS) underpin CIH-induced changes in diaphragm muscle, which manifest as impaired muscle performance. Adult male mice (C57BL/6J) were assigned to one of three groups: normoxic controls (sham); chronic intermittent hypoxia-exposed (CIH, 12 cycles/hour, 8 h/day for 14 days); and CIH + apocynin (NOX2 inhibitor, 2 mM) administered in the drinking water throughout exposure to CIH. In separate studies, we examined sham and CIH-exposed NOX2-null mice (B6.129S-CybbTM1Din/J). Apocynin co-treatment or NOX2 deletion proved efficacious in entirely preventing diaphragm muscle dysfunction following exposure to CIH. Exposure to CIH had no effect on NOX2 expression. However, NOX4 mRNA expression was increased following exposure to CIH in wild-type and NOX2 null mice. There was no evidence of overt CIH-induced oxidative stress. A NOX2-dependent increase in genes related to muscle regeneration, antioxidant capacity, and autophagy and atrophy was evident following exposure to CIH. We suggest that NOX-dependent CIH-induced diaphragm muscle weakness has the potential to affect ventilatory and non-ventilatory performance of the respiratory system. Therapeutic strategies employing NOX2 blockade may function as an adjunct therapy to improve diaphragm muscle performance and reduce disease burden in diseases characterised by exposure to CIH, such as obstructive sleep apnoea.

The Presence of Myosteatosis Is Associated with Age, Severity of Liver Disease and Poor Outcome and May Represent a Prodromal Phase of Sarcopenia in Patients with Liver Cirrhosis.

Myosteatosis implies impaired muscle quality. The aim of the study was to investigate the association of myosteatosis with other muscle abnormalities and its role in the prognosis of liver cirrhosis (LC). Skeletal muscle index (SMI) and myosteatosis were measured by computed tomography. Myosteatosis was defined as muscle radiodensity and evaluated according to dry body mass index (BMI). Median values and interquartile range were used for continuous and count (percentage) for categorical variables. A total of 197 consecutive patients were included (age 61 (IQR 52-68); 67% male; MELD score 11 (interquartile range 7.5-16)). Myosteatosis was identified in 73.6% and sarcopenia in 44.6% of patients. Myosteatosis was positively associated with age (p = 0.024) and Child-Pugh (p = 0.017) and inversely associated with SMI (p = 0.026). Patients with myosteatosis exhibited lower 360-day survival (log-rank p = 0.001) compared to those without it. MELD (p < 0.001) and myosteatosis (p = 0.048) emerged as negative prognostic factors of survival in multivariate model. Individuals combining low muscle strength and impaired muscle quality and quantity displayed more advanced LC, impaired muscle performance, lower BMI (p < 0.001 each) and a three times higher mortality rate compared to those with low muscle quality alone. The presence of myosteatosis was associated with advanced age, low skeletal mass and more severe LC. Myosteatosis was associated with poor prognosis and may represent a prodromal phase of muscle degeneration before the development of sarcopenia.

Spondyloarthritis and Sarcopenia: Prevalence of Probable Sarcopenia and its Impact on Disease Burden: The Saspar Study.

To evaluate the prevalence of probable, confirmed, and severe sarcopenia in spondyloarthritis (SpA), according to the European Working Group on Sarcopenia in Older People 2019 (EWGSOP2) definition. A total of 103 patients (51% women) with SpA, mean age 47.1 ± 13.7years, were included and compared to 103 age- and sex-matched controls. Grip strength was measured by dynamometry. Body composition was assessed by whole-body densitometry. In SpA patients gait speed was measured by the 4-m-distance walk test and quality of life was evaluated with a specific health-related questionnaire for sarcopenia (SaRQoL®). Twenty-two SpA patients (21%) versus 7 controls (7%) had a low grip strength, i.e., probable sarcopenia (p < 0.01), 15 SpA (15%) patients and 7 controls (7%) had low Skeletal Muscle mass Index (SMI) (ns), respectively, and 5 and 2% of SpA patients and controls had low grip strength and low SMI, i.e., confirmed sarcopenia (ns). All the sarcopenic SpA patients had a low gait speed, i.e., severe sarcopenia. Finally, probable sarcopenic SpA patients had significantly higher C-Reactive Protein (CRP, p < 0.001) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI score, p < 0.01), lower gait speed (p < 0.001), and SarQoL® score (p < 0.001) than SpA patients with normal grip strength. According to EWGSOP2 definition, the prevalence of probable sarcopenia was significantly higher in SpA patients compared to controls. Probable sarcopenia was associated with higher inflammation and disease activity, impaired muscle performance, and quality of life. These results suggest that muscle strength may be a salient hallmark in SpA.

HOW DID REHABILITATION PROGRAMME AFFECT CARDIORESPIRATORY FITNESS IN MULTIPLE SYSTEM ATROPHY? A CASE REPORT

Multiple System Atrophy (MSA) is a progressive neurodegenerative disorder with various symptoms that propose impaired muscle performance and loss of balance. A male 65 year old complaining of fatigue easily and dizziness when doing activities. He had walking difculty and limb weakness. The 6-minute walk test (6MWT) showed impaired cardiorespiratory tness with shortened walking distance and reduced maximal oxygen uptake (VO2max: 5,39, METs: 1,54). Moreover, there was decreasing thorax expansion (2-1.5-2.5), and balance instability measured by lower Time Up and Go test (17) and Berg Balance test (49). Cardiorespiratory Rehabilitation programs focus on physical therapy (passive and active strengthening exercise, treadmill aerobic cardiorespiratory exercise) and home program exercises. Three months after therapy, there were signicant improvement in cardiorespiratory tness characterized by improving VO2max (VO2max 9.07, Mets 2.59), increased thoracic expansion (2-4-4) and improving balance stability (TUG 11 s) although overall BBS score was reduced (45).

Postprandial glycemic responses to a high-protein dairy snack and energy-enriched berry snacks in older adults.

We have previously shown that regular consumption of high-protein dairy- and energy-enriched berry-based products consumed as snacks improved nutritional status, functional status, and quality of life among vulnerable older people. These products contain protein, sugar and other components which may have acute effects on glycemic control. The aim of the present study was to determine the effects of these snack products on postprandial glycemic responses in older adults. In a randomized, single-blinded crossover design, 25 subjects aged 71.4±4.6 years consumed either a high-protein dairy drink or one of the two energy-enriched berry purées, as well as corresponding reference products, as mid-morning snacks, each containing 25g of available carbohydrates. Baseline and postprandial blood samples for measurements of glucose, insulin, and non-esterified fatty acids (NEFA) were collected at regular intervals up to 3h. In comparison with a protein-free reference, consumption of the dairy product resulted in a remarkably high insulin response, a fall in glucose concentration and suppression of late postprandial NEFA rebound. In comparison with a low-berry reference, both berry products led to significantly lower glucose, insulin and NEFA responses. The high-protein dairy product which induces short-term hyperinsulinemia, accompanied with reduced glycemia, may help to improve muscle protein and energy metabolism. The energy-enriched berry products maintain balanced postprandial glycemia. These are beneficial effects in older adults who may suffer from impaired muscle performance or glycemic control. NCT04175353.

Influence Of Knee Extensor Strength On Spatiotemporal Gait Parameters In Adults With Prader-willi Syndrome

Adults with Prader-Willi Syndrome (PWS) are at greater risk for falls, which may be due to impaired muscle and gait performance. PURPOSE: To compare spatiotemporal gait parameters between adults with and without PWS, and to explore associations between knee extensor strength and spatiotemporal gait parameters in adults with PWS. METHODS: 10 adults with PWS, and 10 controls with and 10 without obesity completed isometric knee extensor (KE) strength assessments and gait analyses. Strength outcomes included peak KE torque, and early and late KE rate of torque development (RTD). Gait outcomes included speed, step length, step width, double support time, cadence, and gait-stability ratio (GSR). Step length and width were normalized to height, and strength outcomes were normalized to lean mass. Gait and strength outcomes were compared between groups with one-way MANOVA, and post hoc tests were made using Tukey’s HSD. Associations between strength and gait outcomes were explored using 1-tailed Pearson and Spearman correlations in the group with PWS. RESULTS: Gait (Pillai’s Trace = 0.86, p = 0.01) and strength outcomes (Pillai’s Trace = 0.52, p = 0.01) differed between groups. Adults with PWS had shorter step length (p < 0.01), longer double support (p = 0.01), and slower gait speed (p = 0.02) compared with controls without obesity, and higher GSR compared with controls without obesity (p = 0.01) and with obesity (p = 0.04). Adults with PWS had less KE torque (p < 0.01), early (p < 0.01) and late (p < 0.001) RTD compared with controls without obesity; and less KE torque (p = 0.01), less early (p = 0.03) and late (p = 0.01) RTD. In adults with PWS, greater KE torque was associated with faster speed (rho = 0.57, p < 0.01), smaller step width (r = -0.62, p = 0.03), shorter double support time (r = -0.57, p = 0.04), and lower GSR (rho = -0.79, p < 0.01). Greater late RTD was associated a faster speed (rho = 0.79, p = 0.01), lower GSR (rho = -0.71, p = 0.01), and longer step length (rho = 0.71, p = 0.01). CONCLUSIONS: Adults with PWS have different spatiotemporal gait parameters compared with controls that contribute to slower gait speed and reduced mobility. Larger GSR may reflect an adaptive strategy to increase ground contact time and avoid dynamic portions of the gait cycle. Improving knee extensor function may be useful to increase gait performance in adults with PWS.

Oral digoxin effects on exercise performance, K+ regulation and skeletal muscle Na+ ,K+ -ATPase in healthy humans.

We investigated whether digoxin lowered muscle Na+,K+‐ATPase (NKA), impaired muscle performance and exacerbated exercise K+ disturbances. Ten healthy adults ingested digoxin (0.25 mg; DIG) or placebo (CON) for 14 days and performed quadriceps strength and fatiguability, finger flexion (FF, 105%peak‐workrate, 3 × 1 min, fourth bout to fatigue) and leg cycling (LC, 10 min at 33% VO2peak and 67% VO2peak, 90% VO2peak to fatigue) trials using a double‐blind, crossover, randomised, counter‐balanced design. Arterial (a) and antecubital venous (v) blood was sampled (FF, LC) and muscle biopsied (LC, rest, 67% VO2peak, fatigue, 3 h after exercise). In DIG, in resting muscle, [3H]‐ouabain binding site content (OB‐Fab) was unchanged; however, bound‐digoxin removal with Digibind revealed total ouabain binding (OB+Fab) increased (8.2%, P = 0.047), indicating 7.6% NKA–digoxin occupancy. Quadriceps muscle strength declined in DIG (−4.3%, P = 0.010) but fatiguability was unchanged. During LC, in DIG (main effects), time to fatigue and [K+]a were unchanged, whilst [K+]v was lower (P = 0.042) and [K+]a‐v greater (P = 0.004) than in CON; with exercise (main effects), muscle OB‐Fab was increased at 67% VO2peak (per wet‐weight, P = 0.005; per protein P = 0.001) and at fatigue (per protein, P = 0.003), whilst [K+]a, [K+]v and [K+]a‐v were each increased at fatigue (P = 0.001). During FF, in DIG (main effects), time to fatigue, [K+]a, [K+]v and [K+]a‐v were unchanged; with exercise (main effects), plasma [K+]a, [K+]v, [K+]a‐v and muscle K+ efflux were all increased at fatigue (P = 0.001). Thus, muscle strength declined, but functional muscle NKA content was preserved during DIG, despite elevated plasma digoxin and muscle NKA–digoxin occupancy, with K+ disturbances and fatiguability unchanged. Key points The Na+,K+‐ATPase (NKA) is vital in regulating skeletal muscle extracellular potassium concentration ([K+]), excitability and plasma [K+] and thereby also in modulating fatigue during intense contractions. NKA is inhibited by digoxin, which in cardiac patients lowers muscle functional NKA content ([3H]‐ouabain binding) and exacerbates K+ disturbances during exercise.In healthy adults, we found that digoxin at clinical levels surprisingly did not reduce functional muscle NKA content, whilst digoxin removal by Digibind antibody revealed an ∼8% increased muscle total NKA content.Accordingly, digoxin did not exacerbate arterial plasma [K+] disturbances or worsen fatigue during intense exercise, although quadriceps muscle strength was reduced.Thus, digoxin treatment in healthy participants elevated serum digoxin, but muscle functional NKA content was preserved, whilst K+ disturbances and fatigue with intense exercise were unchanged. This resilience to digoxin NKA inhibition is consistent with the importance of NKA in preserving K+ regulation and muscle function.

Deleterious Effect of High-Fat Diet on Skeletal Muscle Performance Is Prevented by High-Protein Intake in Adult Rats but Not in Old Rats.

The phenotype of sarcopenic obesity is frequently associated with impaired muscle strength and performance. Ectopic lipid deposition may interfere with muscle anabolic response especially during aging. Evidence is scarce concerning the potential interplay among aging and nutrient imbalance on skeletal muscle functionality. The objective of the present study was to investigate the impact of protein intake in the context of an obesogenic diet on skeletal muscle functional properties and intramuscular lipid infiltration. Two groups of forty-two adult and thirty-seven old male Wistar rats were randomly divided into four groups: isocaloric standard diet (12% protein, 14% lipid, as ST12); isocaloric standard (high-protein) diet (25% protein, 14% lipid, ST25); hypercaloric high-fat (normal-protein) diet (12% protein, 45% lipid, HF12); and hypercaloric high-fat (high-protein) diet (25% protein, 45% lipid, HF25). The nutritional intervention lasted 10 weeks. Total body composition was measured through Echo-MRI. Lipids were extracted from tibialis anterior muscle and analyzed by gas-liquid chromatography. The functional properties of the plantarflexor muscles were evaluated in vivo on an isokinetic dynamometer. Maximal torque was assessed from the torque-frequency relationship in isometric condition and maximal power was evaluated from the torque-velocity relationship in concentric condition. In adult rats high-protein intake combined with high-fat diet determined a lower decrease in relative isometric torque, normalized to either FFM or body weight, compared with adult rats fed a high-fat normal-protein diet. High-fat diet was also detrimental to relative muscle power, as normalized to body weight, that decreased to a larger extent in adult rats fed a high-fat normal-protein diet than their counterparts fed a normal-fat, high-protein diet. The effect of high-fat diet observed in adults, with the enhanced protein intake (25%) conferring some kind of protection against the negative effects of HFD, may be linked to the reduced intramuscular fat in this group, which may have contributed to preserve, at least partly, the contractile properties. A potential role for high-protein diet in preventing ectopic lipid deposition needs to be explored in future research. Detrimental effects of high- fat diet on skeletal muscle performance are mitigated by high- protein intake in adult rats but not in old rats.

Intervention of Hydration Protocol on Strength, Endurance, and Muscle Power Performance

Water is a molecule that plays an essential role in the muscle contraction process because muscle is a tissue that mostly contains water (75-80%). Therefore, athletes need to maintain fluid intake to support their physical activities when competing and when training. Nevertheless, in several studies, it was noted that some athletes experienced hypohydration or dehydration, which ultimately impaired muscle performance. Therefore, this study was conducted to determine the hydration protocol intervention on muscle strength, endurance, and power performance. This research is an analytical study with quasi-experimental research methods, namely single-arm pre-post study design using secondary data. Subjects of this study were 69 athletes year 2020 (named consecutively: Muaythai 9, Pencak silat 12, wrestling 10, judo 18, and taekwondo 20 athletes). This research was conducted from December 2019 to January 2020. In the beginning, all athletes were tested for muscle strength using a leg dynamometer, then muscle endurance tests using push-up and sit-up tests, and muscle power tests using the triple hop test of the right and left legs. After the first test, all athletes were educated about the hydration protocol. The hydration protocol was determined based on each athlete's sweat rate (ISR) and the training characteristics of each sports division. Then, all athletes underwent the training for two months. After that, the same tests were performed. The result showed that hydration protocol influenced the performance of muscle strength, endurance, and power. Therefore, the hydration protocol is influential in maintaining a good hydration status in athletes so that the athlete does not experience hypohydration which will later impair the athlete's muscle performance. Therefore, it is crucial to apply hydration protocols individually according to the training program (volume of training), not only in martial arts sports but in all sports.

Characteristics of the Passive Muscle Stiffness of the Vastus Lateralis: A Feasibility Study to Assess Muscle Fibrosis.

Skeletal muscle fibrosis occurs with aging and has been suggested to impair muscle performance, thereby decreasing quality of life. Recently, muscle stiffness, a surrogate measure of muscle fibrosis, was noninvasively quantified as the shear modulus using ultrasound shear wave elastography (SWE) in humans. We aimed to investigate thigh muscle stiffness in females and males, respectively, across a broad range of ages by using SWE. Eighty-six community-dwelling Japanese people who were aged 30 to 79 years and did not regularly exercise participated in this study. The vastus lateralis (VL) shear modulus was measured at three different knee joint angles: full extension, 90° of flexion, and full flexion. There were no significant main effects of sex or age on the VL shear modulus in full extension or 90° of flexion of the knee. However, the VL shear modulus in knee full flexion was significantly smaller in females than in males and increased with age from 47.9 years. The results suggest that the accelerated increase in VL stiffness that occurs after an individual passes their late 40s may be an important therapeutic target for developing effective treatments and programs that preserve and improve quality of life.

Comparison of the effects of muscle-strengthening exercise using free weights and elastic resistance bands to maximum voluntary isometric contraction of the biceps brachii muscle on untrained subjects

Background: Impaired muscle performance, muscle weakness and atrophy, even sarcopenia (reduced muscle mass and strength) can be caused by injury, disease, immobilization, disuse, and inactivity. Resistance training is an appropriate therapeutic intervention to increase integrated muscle power, strength, and endurance during functional movement, to reduce the risk of injury or re-injury, and to improve physical performance. Objective: To compare the effectiveness of free weights (dumbbells) and elastic resistance bands in increasing the biceps brachii muscle strength on untrained subjects during four weeks of training. Methods: The study was conducted from February to March 2021. Twenty-four men with low and moderate activity levels were recruited and randomized into the dumbbell group (DB) and the elastic resistance bands (ERB) group. Each group was given a biceps brachii muscle strengthening exercise program for 4 weeks. Maximum voluntary isometric contraction (MVIC) of biceps brachii muscle was collected before and after treatment. Results: There was a significant difference in the MVIC value before and after 4 weeks of exercise in the DB group (right p-value 0.002 and left p-value 0.003) and the ERB group (right p-value 0.000 and left p-value 0.001), there was no difference significant difference in MVIC of the right and left biceps brachii muscles before and after 4 weeks of exercise between the two groups (right p-value 0.453 and left 0.714). Conclusion: Free weights and elastic resistance bands show the same effect in increasing MVIC on untrained subjects

The Validity of the Single-Leg Heel Raise Test in People With Multiple Sclerosis: A Cross-Sectional Study.

Background: The single-leg heel raise test is a common clinical assessment; however, little is known about its validity in people with multiple sclerosis (MS). This study investigated the validity of the single-leg heel raise test in a group of people with MS and a healthy control group (CTL).Materials and Methods: Twenty-one people with MS (49 ± 12 years, Expanded Disability Status Scale 1.5–5.5) and 10 healthy controls (48 ± 12 years) performed the single-leg heel raise test, ankle plantarflexion isometric strength assessment using electromechanical dynamometry, and mobility measures (Timed 25-Foot Walk, 2-Min Walk Test, Functional Stair Test).Results: Convergent validity between the heel raise test and strength was moderate for participants with MS completing <20 heel raises (r = 0.63, p = 0.001) but weak for the entire sample (r = 0.30, p = 0.020). Compared to the average CTL group values, the heel raise test differentiated between groups on the MS groups' weaker (p < 0.001) and stronger (p = 0.003) limbs, while strength only differentiated between groups on the weaker limb (p = 0.010). Considering the weaker and strong limbs from the MS group and the CTL group average values, the mobility measures had moderate-to-strong correlations with the heel raise test on the weaker MS limb + CTL (r = 0.71–0.78) and stronger MS limb + CTL (r = 0.62–0.70), and weak-to-moderate correlations with strength on the weaker MS limb + CTL (r = 0.49–0.58, p = 0.001–0.007).Discussion: In people with MS, the single-leg heel raise test may be clinically useful as it identified impaired muscle performance and differentiated muscle performance from a healthy control group and, together with the control group, correlated with functional mobility.

Association between mitochondrial function measured by 31P magnetic resonance spectroscopy and physical performance in older people with functional impairment

AbstractBackgroundMitochondrial dysfunction is a potential therapeutic target to improve skeletal muscle function, but the contribution of mitochondrial dysfunction to impaired skeletal muscle performance in older people remains unclear. The aim of this analysis was to test the association between measures of skeletal muscle mitochondrial function and physical performance in older people.MethodsWe analysed data from the Allopurinol in Functional Impairment trial. Participants aged 65 and over, who were unable to walk 400 m in 6 min, underwent 31P magnetic resonance spectroscopy of the calf after exercise at baseline and at 20 weeks follow up. The phosphocreatine recovery half‐life time (t1/2) was derived as a measure of mitochondrial function. Participants undertook the 6‐min walk test and the Short Physical Performance Battery. Muscle mass measured using the Akern 101 bio‐impedance analysis system. Bivariate correlations and multivariable regression analyses were conducted to determine associations between t1/2 and baseline factors.ResultsOne hundred and seventeen participants underwent baseline 31P magnetic resonance spectroscopy, mean age 80.4 years (SD 6.0); 56 (48%) were female. Mean 6‐min walk was 291 m (SD 80), mean SPPB score was 8.4 (SD 1.9); t1/2 correlated significantly with Short Physical Performance Battery score (r = 0.22, P = 0.02) but not with 6‐min walk distance (r = 0.10, P = 0.29). In multivariable linear regression, muscle mass and total body weight, but not t1/2, were independently associated with Short Physical Performance Battery score and with 6‐min walk distance. Change in t1/2 was not significantly associated with change in Short Physical Performance Battery score (r = 0.03, P = 0.79) or with change in 6‐min walk distance (r = −0.11, P = 0.28).ConclusionsMuscle mass, but not phosphocreatine recovery time, was consistently associated with Short Physical Performance Battery score and 6‐min walk distance in older people with functional impairment.

Impaired Muscle Strength and Performance in Patients With Mild Autonomous Cortisol Secretion

Background: Glucocorticoid-induced myopathy is well-recognized in overt Cushing syndrome (CS), but the impact of mild cortisol secretion on muscle is unclear. Recent data suggest that patients with mild autonomous cortisol secretion (MACS) are frailer and report more weakness than patients with non-functioning adrenal adenomas. We hypothesized that MACS is associated with 1) objective measures of impaired muscle strength and performance and 2) increased tissue accumulation of advanced glycation end products (AGEs), a measure of accelerated aging. Aim: To determine the effect of MACS on muscle mass, strength, performance, and tissue accumulation of AGEs. Methods: We conducted a cross-sectional analysis as part of an ongoing cohort study in patients with MACS compared to age and sex-matched referent subjects without cortisol excess. MACS was defined as serum cortisol >1.8 mcg/dL after the 1 mg overnight dexamethasone suppression test (DST), in the absence of overt signs and symptoms of CS. We measured hand grip strength with hand grip dynamometer and evaluated functional performance on the timed up and go test, 6 minute walk test, and gait speed assessment. Tissue accumulation of AGEs was measured with point-of-care AGE reader. Appendicular lean mass was calculated and adjusted for height in participants who underwent body composition scan. Results: A total of 23 patients with MACS and 23 age and sex-matched referent subjects without cortisol excess were enrolled. The median age of diagnosis was 63 years (range, 51–81), and 26 (56%) were women. In the MACS cohort, median cortisol following 1 mg DST was 2.6 µg/dL (range, 1.9–13.0), median DHEA-S 37 µg/dL (range, 5.0- 141.0), and median ACTH 8.5 pg/mL (range, 5.0–38.0). Patients with MACS had lower hand grip strength (median 29.3 vs. 32.5 kg, p=0.052), slower gait speed (median 1.1 vs. 1.4 m/s, p=0.001), covered less distance during the 6 minute walk test (median 453 vs. 510 m, p=0.001), and took longer to complete the timed up and go test (median 10.1 vs. 8.6 s, p=0.04) than referent subjects without cortisol excess. Accumulation of AGEs was higher in patients with MACS (median 2.9 vs. 2.4, p=0.01). No significant difference was observed in appendicular lean mass (n=19 pairs, 7.8 vs. 7.5 kg/m2, p=0.57). Conclusions: MACS is associated with decreased muscle strength and performance without a significant change in muscle mass, suggesting poor muscle quality. We also observed increased tissue accumulation of AGEs in MACS patients, consistent with our hypothesis of MACS-induced accelerated aging. These findings may help explain the increased frailty observed in MACS, and suggest muscle assessment be considered in all patients with autonomous cortisol secretion. Further studies should examine the impact of muscle and functional impairments on morbidity in MACS, and its possible reversal with either a structured exercise intervention or adrenalectomy.

42 Is Mitochondrial Function Measured by 31P Magnetic Resonance Spectroscopy Associated with Physical Performance in Older People with Functional Impairment?

Abstract Background Mitochondrial dysfunction has been proposed as a therapeutic target to improve muscle strength and endurance, but the contribution that mitochondrial dysfunction makes to impaired skeletal muscle performance in older people remains unclear. We studied the relationship between phosphocreatine recovery rate (a measure of skeletal muscle mitochondrial function) and physical performance in older people. Methods We analysed data from the Allopurinol in Functional Impairment (ALFIE) trial. Participants aged 65 and over, who were unable to walk 400 m in six minutes, underwent 31P magnetic resonance spectroscopy of the calf after exercise at baseline and at 20 weeks follow up. The phosphocreatine recovery half-life time (t-half) was derived as a measure of mitochondrial function. Participants also undertook the 6-minute walk distance, the Short Physical Performance Battery test (SPPB), and had muscle mass measured using bio-impedance analysis. Bivariate correlations and multivariable regression analyses were conducted to determine associations between t-half and baseline factors. Results One hundred and seventeen people underwent baseline 31P magnetic resonance spectroscopy, mean age 80.4 years (SD 6.0); 56 (48%) were female. Mean 6-minute walk was 291 m (SD 80) and mean SPPB score was 8.4 (SD 1.9). T-half was significantly correlated with SPPB score (r = 0.22, p = 0.02) but not with 6-minute walk distance (r = 0.10, p = 0.29). In multivariable linear regression, muscle mass and weight, but not t-half, were independently associated with SPPB score and with 6-minute walk distance. The change in t-half between baseline and 20 weeks was not significantly associated with the change in SPPB (r = 0.03, p = 0.79) or with the change in 6-minute walk distance (r = −0.11, p = 0.28). Conclusion Muscle mass, but not phosphocreatine recovery time, was associated with Short Physical Performance Battery score and 6-minute walk distance in this cohort of older people with functional impairment.

What is the impact of acute inflammation on muscle performance in geriatric patients?

There is growing evidence for a link between loss of skeletal muscle, impaired muscle performance, and systemic markers of acute inflammation in hospitalized geriatric patients. The present literature suggests a negative effect of acute inflammation at the time of hospital admission upon muscle performance and the change of this during the hospital stay, particularly in patients with persistent rather than resolved inflammation. Further, a few studies have reported a positive effect of anti-inflammatory medication upon recovery of muscle function in geriatric patients, but how this is mediated (e.g. inhibition of inflammatory cytokines) is not clear. In conclusion, a negative association between the presence of acute and persistent systemic markers of inflammation and various aspects of muscle function and its recovery after bedrest is observed in geriatric patients.

Impaired skeletal muscle performance as a consequence of random functional capillary rarefaction can be restored with overload-dependent angiogenesis.

Key points Loss of skeletal muscle capillaries is thought to contribute to a reduction in exercise tolerance, but the relative contribution of a compromised microcirculation with disease, in isolation of co‐morbidities, to impaired muscle function is unknown.We therefore developed a novel method to randomly occlude capillaries in the rat hindlimb to mimic the capillary rarefaction observed in many conditions.We demonstrate that muscle fatigue resistance is closely coupled with functional microvascular density, independent of arterial blood flow, while disturbance of the microcirculation leads to long‐term impairment of muscle function if left untreated.Mechanical stretch due to muscle overload causes a restoration of fatigue resistance via angiogenic remodelling.These observations highlight the importance of a healthy microcirculation and suggest that restoring impaired microvascular supply, regardless of disease co‐morbidities, will assist recovery of exercise tolerance in a variety of conditions that limit quality of life. To what extent microvascular rarefaction contributes to impaired skeletal muscle function remains unknown. Our understanding of whether pathological changes in the microcirculation can be reversed remains limited by a lack of basic physiological data in otherwise healthy tissue. The principal objectives here were to: (1) quantify the effect of random microvascular rarefaction on limb perfusion and muscle performance, and (2) determine if these changes could be reversed. We developed a novel protocol in rats whereby microspheres injected into the femoral artery allowed a unilateral reduction in functional capillary density in the extensor digitorum longus (EDL), and assessed acute and chronic effects on muscle function. Simultaneous bilateral EDL force and hindlimb blood flow measurements were made during electrical stimulation. Following functional capillary rarefaction there was an acute microsphere dose‐dependent reduction in muscle fatigue resistance (P < 0.001), despite preserved femoral artery perfusion. Histological analysis of EDL samples taken from injected animals confirmed a positive correlation between the proportion of functional capillaries and fatigue resistance (P = 0.002). Such impaired performance persisted for at least 2 weeks (P = 0.016). Concomitant mechanical overload improved both perfused capillary density and fatigue resistance (P<0.05), confirming that the capacity for muscle remodelling was retained following chronic distributed ischaemia, and that the impact of capillary rarefaction could be alleviated. These results demonstrate that loss of functional capillaries is detrimental to muscle function, even in otherwise healthy tissue, independent of arterial perfusion. Restoration of muscle performance following a mechanical overload stimulus indicates that angiogenic treatments to alleviate microvascular rarefaction may be key to restoring exercise tolerance.