Elevated glucocorticoids alter the skeletal muscle transcriptome to induce a myopathy characterized by muscle atrophy, muscle weakness, and decreased metabolic function. These effects are more likely to occur and be more severe in aged muscle. Resistance exercise can blunt development of glucocorticoid myopathy in young muscle, but the potential to oppose the signals initiating myopathy in aged muscle is unknown. To answer this, young (4-month-old) and aged (24-25-month-old) male C57BL/6 mice were randomized to receive either an intraperitoneal (IP) injection of dexamethasone (DEX; 2 mg/kg) or saline as a control. Two hours post-injections, tibialis anterior (TA) muscles of mice were subjected to unilateral high force contractions. Muscles were harvested four hours later. The glucocorticoid- and contraction-sensitive genes were determined by RNA sequencing. The number of glucocorticoid-sensitive genes was similar between young and aged muscle. Contractions opposed changes to more glucocorticoid-sensitive genes in aged muscle, with this outcome primarily occurring when hormone levels were elevated. Glucocorticoid-sensitive gene programs opposed by contractions were primarily related to metabolism in young mice and muscle size regulation and inflammation in aged mice. In silico analysis implied Peroxisome proliferator-activated receptor gamma-1 (PPARG) contributed to the contraction-induced opposition of glucocorticoid-sensitive genes in aged muscle. Increasing PPARG expression in the TA of aged mice using Adeno-associated virus serotype 9 partially counteracted the glucocorticoid-induced reduction in Runt-related transcription factor 1 (Runx1) mRNA content, recapitulating the effects observed by contractions. Overall, these data contribute to our understanding of the contractile regulation of the glucocorticoid transcriptome in aged skeletal muscle.

BACKGROUND: Sarcopenia is common in children after liver transplantation (LTx). Resistance training (RT) may be effective in combating sarcopenia.
OBJECTIVE: The purpose of the study was to test the feasibility and impact of a 12-week RT program on skeletal muscle mass (SMM), muscle strength, physical performance (PP), and child-parent perspectives about RT.
METHODS: Children (6-18 years) post-LTx and healthy controls (HC) underwent progressive RT using resistance bands. SMM and adipose tissue (MRI: abdomen and thigh), muscle strength (handgrip, push-ups, sit-to-stand), and PP (6-minute walk test [6MWT], timed-up-and-down-stair test [TUDS]) were measured before and after 12-weeks of RT.
RESULTS: Ten children post-LTx (11.9 ± 3.5 years) and 13 HC (11.7 ± 3.9 years) participated. LTx children significantly increased abdominal SM-index (+4.6% LTx vs. a -2.7% HC; p = 0.01) and decreased visceral adipose tissue-index (-18% LTx vs. -0.8% HC; p = 0.04) compared to HC. No thigh SMI changes were noted. Significant increases in 6MWT distance (LTx; p = 0.04), number of push-ups (p = 0.04), and greater reduction times for TUDS (-10.6% vs. +1.7%; p = 0.05) occurred after 12 weeks. Higher thigh muscle-fat content was associated with worse physical performance. These results were impacted by adherence (≥75% vs. <75%) and family engagement.
CONCLUSIONS: RT in children post-LTx is feasible and effective. RT in children post-LTx may alleviate adverse outcomes associated with sarcopenia.

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) has emerged as a prevalent health concern, encompassing a wide spectrum of liver-related disorders. Insulin resistance, a key pathophysiological feature of MASLD, can be effectively ameliorated through dietary interventions. The Mediterranean diet, rich in whole grains, fruits, vegetables, legumes, and healthy fats, has shown promising results in improving insulin sensitivity. Several components of the Mediterranean diet, such as monounsaturated fats and polyphenols, exert anti-inflammatory and antioxidant effects, thereby reducing hepatic steatosis and inflammation. Furthermore, this dietary pattern has been associated with a higher likelihood of achieving MASLD remission. In addition to dietary modifications, physical exercise, particularly resistance exercise, plays a crucial role in enhancing metabolic flexibility. Resistance exercise training promotes the utilization of fatty acids as an energy source. It enhances muscle glucose uptake and glycogen storage, thus reducing the burden on the liver to uptake excess blood glucose. Furthermore, resistance exercise stimulates muscle protein synthesis, contributing to an improved muscle-to-fat ratio and overall metabolic health. When implemented synergistically, the Mediterranean diet and resistance exercise can elicit complementary effects in combating MASLD. Combined interventions have demonstrated additive benefits, including greater improvements in insulin resistance, increased metabolic flexibility, and enhanced potential for MASLD remission. This underscores the importance of adopting a multifaceted approach encompassing dietary modifications and regular physical exercise to effectively manage MASLD. This narrative review explores the biological mechanisms of diet and physical exercise in addressing MASLD by targeting insulin resistance and decreased metabolic flexibility.

UNASSIGNED: The Benchmarking Exercise Programme for Older People (BEPOP) service improvement project seeks to determine and promote the exercise training characteristics associated with positive outcomes for resistance exercise for older people living with, or at risk of, sarcopenia or physical frailty.
UNASSIGNED: Mixed-methods service improvement project. Ten UK National Health Service physiotherapist-led therapy services delivering exercise interventions for older people submitted anonymized data for up to 20 consecutive patients. A multidisciplinary expert panel generated a report and recommendations with site-specific benchmarking data and feedback. In parallel, participating physiotherapy team members were interviewed to elicit feedback on BEPOP rationale, processes and perceived value.
UNASSIGNED: Data from 188 patients were included, mean age 80 years (range 60-101). 115 (61%) received objective assessment of strength-based physical performance. Bodyweight exercises (173 [92%]) and resistance bands (49 [26%]) were the commonest exercise modalities. Exercises progressed predominantly through increased repetitions (163 [87%]) rather than increased load. 50 (30%) had no reassessment of outcomes; only 68 (41%) were signposted to follow-on exercise services. Staff interviews identified themes around knowledge, diagnosis, data collection and practice reflection.
UNASSIGNED: BEPOP was feasible to deliver and generated actionable insights for service improvement via improved diagnosis, measurement and progression of resistance exercise.

UNASSIGNED: Sarcopenia is a skeletal muscle mass (SMM) disease characterized by loss of strength with generalized loss of SMM. The aim of this study is to evaluate the effects of a 12-week intervention on SMM, strength, and functionally in older adults.
UNASSIGNED: This is a retrospective analysis of an intervention protocol with older adults at risk of sarcopenia who performed a daily intake of oral nutritional supplements (ONS) and resistance training exercise (RET), 3 times a week. Calf circumference (CC), bioelectrical impedance analysis (BIA), handgrip strength (HGS) and Timed Up and Go (TUG) were performed at baseline and at 12 weeks.
UNASSIGNED: Fifty-one older adults were included. The mean age was 76.3 ± 8.3 years and 68.6% were women. After 12 weeks, the study showed an increase of CC in cm (1.9 ± 2.5, p < 0.001), increase of strength in kg (5.4 ± 2.1, p < 0.001), reduction of TUG in seconds (-2.4 ± 4.8, p = 0.001), increase of free-fat mass in kg (1.0 ± 1.3, p < 0.001) and SMM in kg (0.9 ± 0.5, p < 0.001).
UNASSIGNED: Nutritional intervention with ONS associated with RET, can increase muscle strength, SMM and functionality among older adults at risk for sarcopenia.

This scoping review aims to summarize the literature on photobiomodulation (PBM) therapy as an adjunct to resistance exercise among older adults, focusing on its effects on muscle metrics, functional balance, capacity, and physical performance. The participants included were older adults aged ≥ 60 years and either gender. The concept was the application of PBM and resistance exercises with no limits on the context parameters. The databases Medline, Embase, Scopus and Web of Science were searched from inception till February 2024. Methodological quality was assessed using the Cochrane risk of bias 2.0. A total of 10 studies were included in the review. PBM, along with resistance training, was reported in six studies, whereas four reported PBM with isometric fatigue protocol. PBM with a wavelength of 808 nm was given on the belly of the rectus femoris muscle in most of the studies. The common dosimetry parameters used were- power density 35.7 W/cm2, energy density 250 J/cm2, 8 sites, energy per site 7 J, duration of 70 s per site, spot size per diode of 0.028 cm2, and stationary contact of application. The application of PBM therapy alongside resistance exercise has been found to improve muscle metrics, functional capacity, and functional performance and reduce fatigability when compared with the control group in most of the studies. When incorporating PBM therapy as an adjunct to resistance training, it is crucial to consider the dosimetry parameters involved-to achieve the intended therapeutic effect. Adjusting treatment parameters with this information can optimize the effectiveness of PBM therapy and improve treatment outcomes for patients.

The PUFA-derived lipid mediator response shifts from pro-inflammatory to inflammation resolution over time and may be modified by regular moderate exercise. This pre-post-test study aimed to compare the expression of PTGES2 (COX2) and ALOX15 in leucocytes and the plasma 5- and 15-HETE, 18-HEPE and 17-HDHA responses after unaccustomed resistance exercise between 18-35-year-old male recreational runners (n = 18) and less-active controls (n = 15). One repetition maximum (1RM) was determined for squats, 45° leg presses and leg extensions. Subsequently three sets of 8-10 repetitions were performed at 80 % 1RM and blood collected over 72 hours. PTGES2 and ALOX15 expression changed over time in runners (P = 0.016, P = 0.007) but not controls (P = 0.631, P = 0.539). 5- and 15-HETE changed over time in runners (P < 0.001, P = 0.022), but not controls (P = 0.457, P = 0.985). 18-HEPE changed in runners and controls (P < 0.001, P = 0.024), 17-HDHA changed borderline in runners (P = 0.076). In conclusion, pro-inflammatory and inflammation-resolving lipid mediators may respond sooner and more robust in recreational runners than less-active controls after strenuous resistance exercise.

Females historically experience sleep disturbances and overall poor sleep compared to males. Creatine has been proposed to impact sleep; however, the effects are not well known. The purpose of this study was to examine the effects of creatine supplementation on sleep among naturally menstruating females. Twenty-one participants completed a double-blind, randomized controlled trial in which they consumed 5 g creatine + 5 g maltodextrin or placebo, 10 g maltodextrin, daily for 6 weeks. Participants completed resistance training 2x/week using the TONAL® (Tonal Systems Inc., San Francisco, CA, USA) at-home gym. Pre- and post-testing assessed body composition, Pittsburgh Sleep Quality Index (PSQI), dietary intake, and muscular strength. Sleep was assessed nightly using an ŌURA® (Oulu, Finland) ring. Compared to the placebo group, those consuming creatine experienced significant increases in total sleep on training days (p = 0.013). No significant changes in chronic sleep and PSQI (pre-post) were observed. There was a significant increase in TONAL® strength score over time (p < 0.001), with no between-group differences. Participants reduced their total calorie (kcal) (p = 0.039), protein (g/kg) (p = 0.009), carbohydrate (g/kg) (p = 0.023), and fat (g) (p = 0.036) intake over time. Creatine supplementation increases sleep duration on resistance training days in naturally menstruating females.

The objectives of our study were 1) to examine whether the force-velocity-power (FvP) outcomes in the concentric and eccentric phases of flywheel (FW) squats differ among sports disciplines and 2) to investigate the association between FvP outcome variables and two key sport-performance indicators: countermovement jump height (CMJ) and change of direction (CoD) time involving 90° or 180° turns. Tests were performed by 469 athletes from five different sport disciplines and physical education students. Our results showed that FvP outcomes, when measured during the eccentric phase of the FW squat, effectively differed between athletes from different sports. However, during the concentric phase of the squat, only for the slope variable differences between sports were found. Contrary to our hypothesis, there were no statistically significant correlations between FW squat FvP outcomes and CMJ or CoD test results. These results suggest that FvP outcomes derived from FW squats may lack external validity and cannot be reliably used as a predictor of athletes\' jumping and agility performance. The paper discusses possible reasons for the larger differences between sports in eccentric FvP outcomes, as well as the absence of correlations between FvP outcomes and functional tests.

BACKGROUND: Resistance exercise leads to improved muscle function and metabolic homeostasis. Yet how circadian rhythm impacts exercise outcomes and its molecular transduction remains elusive.
METHODS: Human volunteers were subjected to 4 weeks of resistance training protocols at different times of day to assess training outcomes and their associations with myokine irisin. Based on rhythmicity of Fibronectin type III domain containing 5 (FNDC5/irisin), we trained wild type and FNDC5 knockout mice at late active phase (high FNDC5/irisin level) or late rest phase (low FNDC5/irisin level) to analyze exercise benefits on muscle function and metabolic homeostasis. Molecular analysis was performed to understand the regulatory mechanisms of FNDC5 rhythmicity and downstream signaling transduction in skeletal muscle.
RESULTS: In this study, we showed that regular resistance exercises performed at different times of day resulted in distinct training outcomes in humans, including exercise benefits and altered plasma metabolomics. We found that muscle FNDC5/irisin levels exhibit rhythmicity. Consistent with human data, compared to late rest phase (low irisin level), mice trained chronically at late active phase (high irisin level) gained more muscle capacity along with improved metabolic fitness and metabolomics/lipidomics profiles under a high-fat diet, whereas these differences were lost in FNDC5 knockout mice. Mechanistically, Basic helix-loop-helix ARNT like 1 (BMAL1) and Peroxisome proliferative activated receptor, gamma, coactivator 1 alpha 4 (PGC1α4) induce FNDC5/irisin transcription and rhythmicity, and the signaling is transduced via αV integrin in muscle.
CONCLUSIONS: Together, our results offered novel insights that exercise performed at distinct times of day determines training outcomes and metabolic benefits through the rhythmic regulation of the BMAL1/PGC1α4-FNDC5/irisin axis.