Pediatric Sarcopenia: What do We Know?

A Comparison of Aerobic Exercise and Resistance Training in Patients With and Without Chronic Kidney Disease

Adaptations and acute physiological effects of various resistance training programs in adolescent and elite athletes

Background:In adults, weight loss and sarcopenia are prognostic indicators of poor outcomes for patients awaiting liver transplant (LT). We tested the hypothesis that sarcopenia in children awaiting LT was related to poor outcomes.Methods:Children with end-stage chronic liver disease undergoing assessment for LT were recruited into an observational longitudinal study. Anthropometry and body composition (BC; whole-body dual-energy x-ray absorptiometry scan) were assessed before and, on average, 1 year after LT.Results:Eleven children (6 females:5 males) were assessed (4.7 to 17.2 years; median, 9.9) at baseline. Nine children went on to have an LT. The aspartate aminotransferase-to-platelet ratio index had a significant positive correlation with trunk lean mass and trunk lean mass index (LMI) SD score (SDS). At baseline, 4 patients were sarcopenic with appendicular LMI SDS less than −1.96. All fat mass and fat mass index (FMI) SDSs were within the normal range (above −1.96). There was a strong negative correlation between FMI SDS and height SDS. After transplant, there was a significant reduction in trunk LMI from 1.20 to −0.51 (95% CI, 1.03-2.4; P < 0.01). Body mass index SDS had a negative correlation with days to discharge after transplant. The majority of patients discharged after 16 days were sarcopenic. One year after transplantation, all patients were alive with normal graft function regardless of BC before LT.Conclusion:FMIs were normal regardless of LMIs and correlated negatively with height. BC was related to days to discharge after LT but not to outcomes a year after LT.

Background: Obesity, as a chronic disease, is becoming increasingly prevalent especially among women. Objectives: The purpose of this study was to evaluate and compare the effects of resistance training (RT), concurrent resistance training and aerobic training (RT + AT) on visfatin concentrations and body composition in overweight and obese women. Methods: An eight-week pretest-posttest design with two experimental exercising groups and one control group was used. 45 overweight and obese women were randomized into resistance training (RT), concurrent resistance and aerobic training (RT + AT) or an education-only groups (EDU). All participants received a dietary and education/counselling intervention. However, only the RT and RT + AT group participated in the eight-week exercise training. Results: Repeated measures analysis showed that visfatin was significantly decreased by 8.5% in the RT (P = 0.02) and 29.2% in the RT + AT (P < 0.001), but not in EDU (3.7%; P = 0.22). BMI was decreased in the RT (6.8%; P < 0.001), RT + AT (8.1%; P < 0.001) and EDU (4.4%; P < 0.001), while BF% decreased in the RT (6.9%; P = 0.001), RT + AT (13.1%; P= 0.001), and EDU (4.9%; P = 0.020). WHR was decreased in the RT (2.4%; P = 0.001), in the RT + AT (4.2%; P = 0.002) and EDU (2.5%; P = 0.02). VO2max (mL.kg-1.min-1) increased in the RT (16.3%; P = 0.004), RT + AT (37.7%; P = 0.001), but not in EDU (7.2%; P = 0.72). The absolute value of VO2max (L.min-1) also significantly increased in RT + AT (0.25%; P < 0.05) compared to baseline, but did not differ between the groups. Conclusions: While RT and education-alone improved body composition and aerobic capacity, structured regular exercise incorporating both RT and AT may be required to improve visfatin and VO2max in overweight and obese females.

BackgroundIndividuals with eating disorders may experience reduced bone mineral density and muscle mass, lower quality of life, and debilitating psychopathology. Abstinence from exercise has historically been recommended in the treatment of eating disorders. However, evidence shows that well-planned, supervised exercise can be safe and beneficial. Resistance training is an exercise modality of particular interest because of its ability to protect bone and muscle mass, in addition to its mental health and quality of life benefits. The purpose of this narrative review is to examine the use of resistance training in the treatment of eating disorders to determine whether its incorporation in treatment programs should be recommended.MethodsA search of the literature was conducted via PubMed, Web of Science, ScienceDirect, and Sage Journal. Articles published before the final database search (March 22nd, 2025) were considered. Inclusion criteria: Studies must examine how the use of resistance training affects people with anorexia nervosa, bulimia nervosa, or binge eating disorder, and must be published in English. Both quantitative and qualitative literature were included.ResultsA total of 17 studies were examined. Quantitative research revealed significant improvements in body composition, strength, and quality of life when resistance training was included in treatment. The available evidence suggests that higher loading is well-tolerated and is more effective than low loading at improving body composition. Qualitative research demonstrated participants’ positive attitudes toward the use of resistance training during treatment. The participants reported improved relationships with exercise, citing the emphasis on building strength as an empowering motivator that deemphasizes weight loss.ConclusionIn combination with a multidisciplinary team including a dietitian, psychologist, and medical provider, resistance training has the potential to play an important role in improving psychopathology, quality of life, and body composition in patients with eating disorders. More research is needed in this area before its inclusion in treatment can be confidently recommended.Plain english summaryPeople with eating disorders experience reduced bone mineral density muscle mass, and report low quality of life. Although abstinence from exercise has historically been recommended in the treatment of eating disorders, its intentional application may confer meaningful benefits to both physical and mental health. Resistance training is a modality that shows promise for improving many eating disorder symptoms, including protecting and increasing bone and muscle health and improving quality of life.

BackgroundWell programmed strength and conditioning training is an indispensable part of the long-term training process for athletes in individual and team sports to improve performance and prevent injuries. Yet, there is a limited number of studies available that examine the effects of resistance training (RT) on muscular fitness and physiological adaptations in elite female athletes.ObjectivesThis systematic review aimed to summarize recent evidence on the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes.Materials and MethodsA systematic literature search was conducted in nine electronic databases (Academic Search Elite, CINAHL, ERIC, Open Access Theses and Dissertations, Open Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, and SPORTDiscus) from inception until March 2022. Key search terms from the MeSH database such as RT and strength training were included and combined using the operators “AND,” “OR,” and “NOT”. The search syntax initially identified 181 records. After screening for titles, abstracts, and full texts, 33 studies remained that examined the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes.ResultsTwenty-four studies used single-mode RT or plyometric training and nine studies investigated the effects of combined training programs such as resistance with plyometric or agility training, resistance and speed training, and resistance and power training. The training duration lasted at least 4 weeks, but most studies used ~ 12 weeks. Studies were generally classified as ‘high-quality’ with a mean PEDro score of 6.8 (median 7). Irrespective of the type or combination of RT with other strength-dominated exercise regimens (type of exercise, exercise duration, or intensity), 24 out of 33 studies reported increases in muscle power (e.g., maximal and mean power; effect size [ES]: 0.23 < Cohen’s d < 1.83, small to large), strength (e.g., one-repetition-maximum [1RM]; ES: 0.15 < d < 6.80, small to very large), speed (e.g., sprint times; ES: 0.01 < d < 1.26, small to large), and jump performance (e.g., countermovement/squat jump; ES: 0.02 < d < 1.04, small to large).The nine studies that examined the effects of combined training showed significant increases on maximal strength (ES: 0.08 < d < 2.41, small to very large), muscle power (ES: 0.08 < d < 2.41, small to very large), jump and sprint performance (ES: 0.08 < d < 2.41, small to very large). Four out of six studies observed no changes in body mass or percentage of body fat after resistance or plyometric training or combined training (ES: 0.026 < d < 0.492, small to medium). Five out of six studies observed significant changes in muscle morphology (e.g., muscle thickness, muscle fiber cross-sectional area; ES: 0.23 < d < 3.21, small to very large). However, one study did not find any changes in muscle morphology (i.e., muscle thickness, pennation angle; ES: 0.1 < d < 0.19, small).ConclusionFindings from this systematic review suggest that RT or combined RT with other strength-dominated exercise types leads to significant increases in measures of muscle power, strength, speed, and jump performance in elite female athletes. However, the optimal dosage of programming parameters such as training intensity and duration necessary to induce large effects in measures of muscular fitness and their physiological adaptations remain to be resolved in female elite athletes.

Lesinski, M, Prieske, O, Chaabene, H, and Granacher, U. Seasonal effects of strength endurance vs. power training in young female soccer athletes. J Strength Cond Res 35(12S): S90-S96, 2021-This study examined the seasonal effects of strength endurance training (SET) vs. power training (PT) on physical fitness and body composition in young female soccer players. Thirty-six young female elite soccer players (15 ± 1 years; maturity offset +3 ± 1 years) were allocated to progressive SET (n = 19) or PT (n = 17). Over the course of one soccer season, SET performed slow movement velocity, moderate intensity (50-60% of the 1 repetition maximum [1RM]; 20-40 repetitions) strength exercises while PT performed moderate-to-high intensity (50-95% of the 1RM; 3-8 repetitions), high movement velocity strength exercises (2 sessions·wk-1). Before and after training, tests were performed for the assessment of muscle strength (1RM leg press), jump performance (countermovement jump [CMJ], drop jump [DJ]), muscular endurance (ventral Bourban test), linear speed (10 m, 20 m), change-of-direction (CoD) speed (T-test), dynamic balance (Y-balance test), sport-specific performance (kicking velocity), and body composition (lean body mass and fat mass). An analysis of covariance was used to test for between-group differences at post-test with baseline values as covariate. No significant between-group differences were observed in terms of total training volume over the respective soccer seasons (p = 0.069; d = 0.68). At post-test, SET showed significantly better ventral Bourban and T-test performances (d = 1.28-2.28; p = 0.000-0.001) compared with PT. However, PT resulted in significantly better 1RM leg press, DJ, 10-m, and 20-m sprint performances (d = 0.85-1.44; p = 0.000-0.026). No significant between-group differences were observed at post-test for CMJ, Y-balance test, kicking performance, and body composition (d = 0.20-0.74, p = 0.051-0.594). Our findings are mainly in accordance with the principle of training specificity. Both SET and PT are recommended to be implemented in young female elite soccer players according to the respective training period.

Data about effects of exercise training in adolescents with intellectual disability (ID) are very limited. This study investigated the effect of 2 different frequencies of the same intensity and total training volume of combined exercise training on indices of body composition, physical fitness, and lipid profile in overweight and obese adolescents with ID. A total of 45 overweight and obese adolescents with ID aged 14-22 years with a total IQ 45-70 received combined exercise training 3 times a week (CET3) for 30 sessions (10 weeks; n = 15), twice a week (CET2) for 30 sessions (15 weeks; n = 15), or no training (10 weeks; n = 15). Groups were matched for age, sex, and education form. Before and after the intervention period, indices of body composition, physical fitness and lipid profile have been evaluated. Compared to the control group, CET3 resulted in a significant improvement of physical fitness, obesity indices, and lipid profile of the participants. Comparing CET2 with CET3, no significantly different evolutions were noticed, except for lower limb strength in favor of exercising 3 times a week. In conclusion, exercising 2 times a week, which is more feasible and practical for participants and guidance, has the same health beneficial effects as 3 times per week in overweight and obese adolescents with ID in short-term training.

The significance of high bone density in children

Breast cancer treatments often lead to unfavourable changes in body composition, physical fitness, and quality of life (QoL). We compared the effects of resistance training (RT) and high-intensity interval training (HIIT) on these outcomes in survivors of breast cancer. Twenty-eight survivors of breast cancer, post-treatment (Stage I-III), aged 55.5 ± 8.8 years and body mass index 27.9 ± 5kg/m2 were randomly allocated to a 12-week supervised RT (n = 14) or HIIT (n = 14) intervention, 3 days per week. Body composition (dual energy x-ray absorptiometry), upper and lower body muscle strength (1-repetition maximum), cardiorespiratory fitness (CRF) (Ekblom Bak Cycle Test), and QoL domains (EORTC QLQ-C30 and EORTC QLQ-BR45) were assessed at baseline and 12 weeks. There were no significant differences between groups at baseline. Exercise attendance ranged from 81 to 85%. Between groups, there were significant differences (p ≤ 0.001) after 12 weeks in chest press strength for RT (mean difference [MD] = 4.7 kg) and CRF for HIIT (MD = 1.9ml/min/kg). Within groups, there were significant improvements (p < 0.05) for % lean mass and % fat mass in both RT and HIIT, as well as for upper and lower body muscle strength, CRF, and QoL domains. No major adverse events were noted. Both exercise groups improved body composition, physical fitness, and QoL domains over 12 weeks of RT or HIIT, although mode-specific benefits were apparent with more substantial improvements in lean mass and muscle strength with RT and reductions in % fat mass and improved CRF with HIIT. Tailored exercise programs should address the specific health needs of each patient.

Decreased Quality of Life Is Significantly Associated With Body Composition in Patients With Nonalcoholic Fatty Liver Disease

Sarcopenia is associated with poor clinical outcomes in chronic diseases. Our study aimed to characterize body composition (BC) parameters in patients with inflammatory bowel disease (IBD) and compare skeletal muscle mass (SMM) parameters with the healthy pediatric population. BC of healthy controls (HC) and of patients with IBD were measured via multifrequency bioelectrical impedance (InBody 720 device) in a cross-sectional manner. The effect of sex, age, height, weight, and body mass index (BMI) on BC parameters, with a special attention to SMM, was assessed. Reference tables from SMM were generated using a maximum-likelihood curve-fitting technique for calculating Z scores. BC parameters were associated with age, body size, and sex. SMM was lower in patients with IBD (n = 57, aged 6.71 ± 8.7 years) compared to unadjusted HC (n = 307, aged 9.9-19.3 years; 143 males; SMM: 22.34 ± 8.38 vs. 24.4 ± 6.3 kg; p = 0.03). SMM showed a moderately strong correlation with age, weight, height, and BMI (R = 0.65, 0.9, 0.87, and 0.66; p < 0.05 for each) in HC. In multivariate stepwise, ridge regression analysis, age, sex, and BMI remained the significant predictors of SMM (age β = 0.47, -0.31, and 0.38, respectively; p < 0.05). SMM of sex-, age-, and BMI-adjusted HC did not differ from IBD. Therefore, BMI Z score-based references were plotted for normalizing SMM, and SMM Z score was calculated and found to be similar to that of HC. BC is supposed to be an easy-to-measure and objective marker of sarcopenia in children with IBD. Adjustment of SMM for BMI Z score might be needed to avoid the overestimation of sarcopenia in this patient population.

Rheumatoid arthritis (RA) is characterised by functional disability and inflammation. This review explores the beneficial effects of exercise on function and cardiovascular disease risk in RA and explores the possibility that some of these beneficial effects may be moderated via exercise-induced improvements in body composition.

Timmons, JF, Hone, M, Duffy, O, and Egan, B. When matched for relative leg strength at baseline, male and female older adults respond similarly to concurrent aerobic and resistance exercise training. J Strength Cond Res 36(10): 2927–2933, 2022—Comparisons between sexes of adaptive responses with concurrent aerobic and resistance exercise training are largely unexplored. A supervised 12-week intervention of concurrent exercise training was used to investigate sex-specific differences, if any, in the response to concurrent exercise training in older adults. Community-dwelling men (n = 14; 68.0 ± 1.8 years; 27.8 ± 3.8 kg·m−2) and women (n = 14; 68.9 ± 3.8 years; 25.1 ± 3.8 kg·m−2) were pair-matched for relative leg strength expressed as leg press 1 repetition maximum per kg of leg lean body mass (LBM; assessed by dual-energy X-ray absorptiometry). Subjects undertook 24 minutes of concurrent aerobic (12 minutes) and resistance (12 minutes) exercise training 3 times per week i.e., 72 minutes of active exercise time per week. Muscle strength, physical function, and body composition were assessed before (PRE) and after 12 weeks (POST) of exercise training. The increase in absolute leg press strength was larger in men (mean difference ± SE, 25.3 ± 11.8 kg; p = 0.041, = 0.156), but when expressed as leg press strength relative to leg LBM, training-induced increases were not different between the sexes (mean difference ± SE, 0.30 ± 0.46 kg·kg−1; p = 0.526, = 0.016). No other measure of muscle strength (hand-grip and chest press), physical function (gait speed, timed-up-and-go, sit-to-stand, and Chester step test), or body composition (LBM and fat mass) differed in response to exercise training for between-sex comparisons. When male and female older adults are pair matched for relative leg strength at baseline before commencing exercise training, sex-specific adaptive responses to concurrent aerobic and resistance exercise training are largely similar for muscle strength, physical function, and body composition.

Current guidelines recommend individually adapted resistance training (RT) as a part of the exercise regime in patients with cardiovascular diseases. The aim of this review was to provide insights into current knowledge and understanding of how useful, feasible, safe, and effective RT is in patients with coronary artery disease (CAD), heart failure (HF), and valvular heart disease (VHD), with particular emphasis on the role of RT in elderly and/or frail patients. A review based on an intensive literature search: systematic reviews and meta-analyses published in 2010 or later; recent studies not integrated into meta-analyses or systematic reviews; additional manual searches. The results highlight the evaluation of effects and safety of RT in patients with CAD and HF with reduced ejection fraction (HFrEF) in numerous meta-analyses. In contrast, few studies have focused on RT in patients with HF with preserved ejection fraction (HFpEF) or VHD. Furthermore, few studies have addressed the feasibility and impact of RT in elderly cardiac patients, and data on the efficacy and safety of RT in frail elderly patients are limited. The review results underscore the high prevalence of age-related sarcopenia, disease-related skeletal muscle deconditioning, physical limitations, and frailty in older patients with cardiovascular diseases (CVD). They underline the need for individually tailored exercise concepts, including RT, aimed at improving functional status, mobility, physical performance and muscle strength in older patients. Furthermore, the importance of the use of assessment tools to diagnose frailty, mobility/functional capacity, and physical performance in the elderly admitted to cardiac rehabilitation is emphasized.