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A single bout of resistance exercise triggers mitophagy, potentially involving the ejection of mitochondria in human skeletal muscle
(Wiley, 2024-09-24) Díaz-Castro, Francisco; Tuñón-Suárez, Mauro; Rivera, Patricia; Botella, Javier; Cancino, Jorge; Figueroa, Ana María; Gutiérrez, Juan; Cantin, Claudette; Deldicque, Louise; Zbinden-Foncea, Hermann; Nielsen, Joachim; Henríquez-Olguín, Carlos; Morselli, Eugenia; Castro-Sepúlveda, Mauricio
Aim The present study aimed to investigate the effects of a single bout of resistance exercise on mitophagy in human skeletal muscle (SkM). Methods Eight healthy men were recruited to complete an acute bout of one-leg resistance exercise. SkM biopsies were obtained one hour after exercise in the resting leg (Rest-leg) and the contracting leg (Ex-leg). Mitophagy was assessed using protein-related abundance, transmission electron microscopy (TEM), and fluorescence microscopy. Results Our results show that acute resistance exercise increased pro-fission protein phosphorylation (DRP1Ser616) and decreased mitophagy markers such as PARKIN and BNIP3L/NIX protein abundance in the Ex-leg. Additionally, mitochondrial complex IV decreased in the Ex-leg when compared to the Rest-leg. In the Ex-leg, TEM and immunofluorescence images showed mitochondrial cristae abnormalities, a mitochondrial fission phenotype, and increased mitophagosome-like structures in both subsarcolemmal and intermyofibrillar mitochondria. We also observed increased mitophagosome-like structures on the subsarcolemmal cleft and mitochondria in the extracellular space of SkM in the Ex-leg. We stimulated human primary myotubes with CCCP, which mimics mitophagy induction in the Ex-leg, and found that BNIP3L/NIX protein abundance decreased independently of lysosomal degradation. Finally, in another human cohort, we found a negative association between BNIP3L/NIX protein abundance with both mitophagosome-like structures and mitochondrial cristae density in the SkM. Conclusion The findings suggest that a single bout of resistance exercise can initiate mitophagy, potentially involving mitochondrial ejection, in human skeletal muscle. BNIP3L/NIX is proposed as a sensitive marker for assessing mitophagy flux in SkM.
Adaptación transcultural del cuestionario para valoración del fitness cardiorrespiratorio: CLINIMEX Aerobic Fitness Questionnaire
(Sociedad Chilena de Medicina del Deporte, 2025) Cancino, Jorge; Barrera-Cifuentes, María Paz; Cruz-Alaniz, Nicolás; León-Carrasco, Bárbara
Objetivo: Adaptar transculturalmente al español chileno el CLINIMEX Aerobic Fitness Questionnaire para estimar el fitness cardiorrespiratorio. Métodos: Se realizó una traducción inicial por dos traductoras bilingües de lengua materna chilena y una retrotraducción por dos traductores bilingües de lengua materna portuguesa. Luego, un comité de expertos revisó el cuestionario antes de su aplicación a un primer grupo de 40 personas mayores de 18 años. Tras confirmar su comprensibilidad, se aplicó la versión final a un grupo de 20 personas. Resultados: En la primera fase, un 27,5% (n=11) tuvo dificultades con el término “hatha”, un 10% (n=4) con “spinning”, un 7,5% (n=3) con “hidrogimnasia” y un 2,5% (n=1) con “musculación”. En el segundo grupo, el fitness cardiorrespiratorio estimado fue de 10.8±2.8 METs (rango 5-16). Conclusión: Se logró la adaptación del cuestionario CLINIMEX al español chileno. Esta adaptación constituye un paso fundamental para avanzar en el proceso de validación del instrumento en nuestra población y entregar una herramienta sencilla para la valoración clínica del fitness respiratorio. Objective: To carry out the cross-cultural adaptation of the CLINIMEX Aerobic Fitness Questionnaire intoChilean Spanish for the estimation of cardiorespiratory fitness. Methods: An initial translation was performed by two bilingual translators whose native language is Chilean Spanish, followed by a back-translation by two bilingual translators whose native language is Portuguese. A committee of experts then reviewed the questionnaire before it was administered to a first group of 40 individuals aged 18 and older. After confirming its comprehensibility, the final version was administered to a second group of 20 participants. Results: In the first phase, 27.5% (n=11) had difficulties with the term “hatha,” 10% (n=4) with “spinning,” 7.5% (n=3) with “hydrogymnastics,” and 2.5% (n=1) with “strength training.” In the second group, the estimated cardiorespiratory fitness was 10.8±2.8 METs (range 5–16). Conclusion: The CLINIMEX questionnaire was successfully adapted into Chilean Spanish. This adaptation represents a key step toward the validation of the instrument in our population and provides a simple tool for the clinical assessment of cardiorespiratory fitness.
Association between adipose tissue characteristics and metabolic flexibility in humans: A systematic review
(Frontiers Media S.A., 2021-12-03) Glaves, Alice; Díaz-Castro, Francisco; Farías, Javiera; Ramírez-Romero, Rodrigo; Galgan, Jose E.; Fernández-Verdejo, Rodrigo
Adipose tissue total amount, distribution, and phenotype influence metabolic health. This may be partially mediated by the metabolic effects that these adipose tissue characteristics exert on the nearby and distant tissues. Thus, adipose tissue may influence the capacity of cells, tissues, and the organism to adapt fuel oxidation to fuel availability, i.e., their metabolic flexibility (MetF). Our aim was to systematically review the evidence for an association between adipose tissue characteristics and MetF in response to metabolic challenges in human adults. We searched in PubMed (last search on September 4, 2021) for reports that measured adipose tissue characteristics (total amount, distribution, and phenotype) and MetF in response to metabolic challenges (as a change in respiratory quotient) in humans aged 18 to <65 years. Any study design was considered, and the risk of bias was assessed with a checklist for randomized and non-randomized studies. From 880 records identified, 22 remained for the analysis, 10 of them measured MetF in response to glucose plus insulin stimulation, nine in response to dietary challenges, and four in response to other challenges. Our main findings were that: (a) MetF to glucose plus insulin stimulation seems inversely associated with adipose tissue total amount, waist circumference, and visceral adipose tissue; and (b) MetF to dietary challenges does not seem associated with adipose tissue total amount or distribution. In conclusion, evidence suggests that adipose tissue may directly or indirectly influence MetF to glucose plus insulin stimulation, an effect probably explained by skeletal muscle insulin sensitivity
Baseline body fat percentage is associated to weight and fat mass gain from high-fat overfeeding over 8 weeks
(Oxford University Press; Endocrine Society, 2025-04-21) Galgani, Jose E.; Fernández-Verdejo, Rodrigo; Bray, George A.; Smith, Steven R.; Ghosh, Sujoy; Javvadi, Pravalika; Ravussin, Eric
Background & aims: Epidemiological data suggest that participants with lower vs. higher body mass index (BMI) resist exposure to the obesogenic environment. To test this, we analyzed the relationship between overfeeding-induced weight and fat mass gains with baseline BMI and body fat percentage. Methods: In this controlled intervention study, 34 men (age: 26±5 y old; BMI: 25.5±2.4 kg/m2, body fat [DXA]: 19.3±5.1%) consumed for 8 weeks 40% more energy than needed at weight maintenance. The energy costs of weight and fat mass gain were calculated as the 8-week excess energy consumed divided by weight or fat mass gain. Energy expenditure (baseline and after overfeeding) was determined using a metabolic chamber and doubly labeled water. Transcriptomic analysis was conducted from abdominal subcutaneous adipose tissue samples. Results: Body weight increased 7.2±2.1 kg and fat mass 4.0±1.4 kg. There was no statistical association between baseline BMI and weight and fat mass gains. However, baseline body fat percentage was significantly associated with weight (r=0.57) and fat mass (r=0.59) gains. Body fat percentage was also statistically associated with energy cost of weight (r=-0.38) and fat mass (r=-0.40) gains. Metabolic adaptation in energy expenditure (adaptive thermogenesis) was unrelated to the energy cost of weight and fat mass gains. Transcriptomics analysis showed that high energy cost of weight gain was associated with up-regulation of inflammation-related pathways. Conclusion: Body fat percentage at baseline was inversely associated with overfeeding-induced weight and fat gain resistance. The underlying compensatory response appears unrelated to changes in energy expenditure.
Block strength training based on age-related functional consequences in older women
(PLOS One, 2025) Jofré-Saldía, Emilio; Festa, Raúl Ricardo; Villalobos-Gorigoitía, Álvaro; Jorquera-Aguilera, Carlos; Ojeda, Álvaro Huerta; Cancino, Jorge; Gea-García, Gemma María
Strength training is a form of healthy ageing in older women. Although recommendations currently exist, some are very broad or fail to cover the needs of aging. Therefore, the purpose of this study was to analyze the effects of blocks strength training based on age-related functional consequences on functional performance in older adult women. 82 community-dwelling older women (70.17 ± 6.04 y) were randomly assigned to either experimental (n = 40) or control (n = 42) group. Experimental group performed a Block Strength Training (BST) program based on strength, power, and muscular endurance, and different level of effort for 9 weeks, and control maintained daily routine with physical activity recommendations. Functional performance was assessed using absolute handgrip strength [AHS], timed up and go [TUG], two-minutes step test [2MST], five times stand-to-sit test [5-SST], 6-m walking speed test [6-WS] pre-post intervention. Statistical analyses were performed using two-way ANOVA (Time*Group) and effect size (partial eta-squared, ŋP2) with a significance level of p < 0.05. BST improved functional performance in the protocols of AHS (21.51 vs. 23.07-kg; + 7%), TUG (8.22 vs. 7.29-sec; + 11%), 2MST (78.76 vs. 97.18-steps; + 23%), 5-SST (12.68 vs. 9.43-sec; + 26%), and 6-WS (1.16 vs. 1.36- m·s-1; + 17%) compared to control (19.31 vs. 19.66-kg; 8.94 vs. 9.26-sec; 62.68 vs. 63.73-steps; 13.99 vs. 14.25-sec; 1.06 vs. 1.06-m·s-1, respectively) in a Time*Group interaction effect (p < 0.01; ŋP2 > 0.11). This BST is effective in improving overall functional performance and thus reducing the risk of physical frailty in community-dwelling older women. These findings strengthen the approach to exercise programming over recommendations, moving toward effective precision dosing for older adults.
BMAL1 and CLOCK proteins exhibit differential association with mitochondrial dynamics, protein synthesis pathways and muscle strength in human muscle
(The Physiological Society, 2024-06-26) Figueroa-Toledo, A. M.; Gutiérrez-Pino, J.; Carriel-Nesvara, A.; Marchese-Bittencourt, M.; Zbinden-Foncea, Hermann; Castro-Sepúlveda, Mauricio
Murine models lacking CLOCK/BMAL1 proteins in skeletal muscle (SkM) present muscle deterioration and mitochondria abnormalities. It is unclear whether humans with lower levels of these proteins in the SkM have similar alterations. Here we evaluated the association between BMAL1 and CLOCK protein mass with mitochondrial dynamics parameters and molecular and functional SkM quality markers in males. SkM biopsies were taken from the vastus lateralis of 16 male (non-athletes, non-obese and non-diabetic) subjects (8–9 a.m.). The morphology of mitochondria and their interaction with the sarcoplasmic reticulum (mitochondria-SR) were determined using transmission electron microscopy images. Additionally, protein abundance of the OXPHOS complex, mitochondria fusion/fission regulators, mitophagy and signalling proteins related to muscle protein synthesis were measured. To evaluate the quality of SkM, the cross-sectional area and maximal SkM strength were also measured. The results showed that BMAL1 protein mass was positively associated with mitochondria-SR distance, mitochondria size, mitochondria cristae density and mTOR protein mass. On the other hand, CLOCK protein mass was negatively associated with mitochondria-SR interaction, but positively associated with mitochondria complex III, OPA1 and DRP1 protein mass. Furthermore, CLOCK protein mass was positively associated with the protein synthesis signalling pathway (total mTOR, AKT and P70S6K protein mass) and SkM strength. These findings suggest that the BMAL1 and CLOCK proteins play different roles in regulating mitochondrial dynamics and SkM function in males, and that modulation of these proteins could be a potential therapeutic target for treating muscle diseases.
CCL5 Induces a Sarcopenic-like Phenotype via the CCR5 Receptor
(MDPI, 2025-01-13) Aguirre, Francisco; Tacchi, Franco; Valero-Breton, Mayalen; Orozco-Aguilar, Josué; Conejeros-Lillo, Sanabria; Bonicioli, Josefa; Iturriaga-Jofré, Renata; Cabrera, Daniel; Soto, Jorge A.; Castro-Sepúlveda, Mauricio; Portal-Rodríguez, Marianny; Elorza, ÁLvaro A.; Matamoros, Andrea; Simon, Felipe; Cabello-Verrugio, Claudio
Sarcopenia corresponds to a decrease in muscle mass and strength. CCL5 is a new myokine whose expression, along with the CCR5 receptor, is increased in sarcopenic muscle. Therefore, we evaluated whether CCL5 and CCR5 induce a sarcopenic-like effect on skeletal muscle tissue and cultured muscle cells. Electroporation in the tibialis anterior (TA) muscle of mice was used to overexpress CCL5. The TA muscles were analyzed by measuring the fiber diameter, the content of sarcomeric proteins, and the gene expression of E3-ligases. C2C12 myotubes and single-isolated flexor digitorum brevis (FDB) fibers were also treated with recombinant CCL5 (rCCL5). The participation of CCR5 was evaluated using the antagonist maraviroc (MVC). Protein and structural analyses were performed. The results showed that TA overexpression of CCL5 led to sarcopenia by reducing muscle strength and mass, muscle-fiber diameter, and sarcomeric protein content, and by upregulating E3-ligases. The same sarcopenic phenotype was observed in myotubes and FDB fibers. We showed increased reactive oxygen species (ROS) production and carbonylated proteins, denoting oxidative stress induced by CCL5. When the CCR5 was antagonized, the effects produced by rCCL5 were prevented. In conclusion, we report for the first time that CCL5 is a novel myokine that exerts a sarcopenic-like effect through the CCR5 receptor.
Cholic and deoxycholic acids induce mitochondrial dysfunction, impaired biogenesis and autophagic flux in skeletal muscle cells
(BMC, 2023-06-08) Abrigo, Johanna; Olguín, Hugo; Tacchi, Franco; Orozco-Aguilar, Josué; Valero, Mayalen; Soto, Jorge; Castro-Sepúlveda, Mauricio; Elorza, Alvaro A.; Simon, Felipe; Cabello-Verrugio, Claudio
Background Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia. Methods We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. Results DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. Conclusion Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.
Concurrent training and interindividual response in women with a high number of metabolic syndrome risk factors
(Frontiers Media S.A., 2022-09-22) Delgado-Floody, Pedro; Chirosa-Ríos, Luis; Caamaño-Navarrete, Felipe; Valdés-Badilla, Pablo; Herrera-Valenzuela, Tomás; Monsalves-Álvarez, Matías; Núñez-Espinosa, Cristian; Castro-Sepúlveda, Mauricio; Guzmán-Muñoz, Eduardo; Andrade, David C.; Álvarez, Cristian
The non-responders (NRs) after exercise training have been poorly studied in populations with morbid obesity. The purpose of this study was to determine the NR prevalence after 20 weeks of concurrent training of morbidly obese women with a high or low number of metabolic syndrome (MetS) risk factors. Twenty-eight women with morbid obesity participated in an exercise training intervention and were allocated into two groups distributed based on a high (≥3, n = 11) or low number (<3, n = 17) of MetS risk factors. The main outcomes were waist circumference (WC), fasting plasma glucose (FPG), high-density lipids (HDL-c), triglycerides (Tg), and systolic (SBP) and diastolic (DBP) blood pressure, and secondary outcomes were body composition, anthropometric and physical fitness, determined before and after 20 weeks of concurrent training. NRs were defined as previously used technical error cut-off points for the MetS outcomes. Significantly different (all p < 0.05) prevalences of NRs between the H-MetS vs. L-MetS groups (respectively) in WC (NRs 18.2 % vs. 41.1 %, p < 0.0001), SBP (NRs 72.7 % vs. 47.0 %, p = 0.022), DBP (NRs 54.5 % vs. 76.4 %, p < 0.0001), FPG (NRs 100% vs. 64.8 %, p < 0.0001), and HDL-c (NRs 90.9 % vs. 64.7 %, p = 0.012) were observed. In addition, the H-MetS group evidenced significant changes on ΔSBP (−10.2 ± 11.4 mmHg), ΔFPG (−5.8 ± 8.2 mg/dl), ΔHDL-c (+4.0 ± 5.9 mg/dl), and ΔTg (−8.8 ± 33.8 mg/dl), all p < 0.05. The L-MetS group only showed significant changes in ΔWC (−3.8 ± 5.0 cm, p = 0.009). Comparing H-MetS vs. L-MetS groups, significant differences were observed in ∆FPG (−5.8 ± 8.2 vs. +0.3 ± 3.2 mg/dl, p = 0.027), but not in other MetS outcomes. In conclusion, 20 weeks of concurrent training promotes greater beneficial effects in morbidly obese patients with a high number of MetS risk factors. However, the NR prevalence for improving MetS outcomes was significantly superior in these more-diseased groups in SBP, FPG, and HDL-c, independent of their major training-induced effects.
Creatine supplementation prior to strength exercise training is not superior in preventing muscle mass loss compared with standard nutritional recommendations in females after bariatric surgery: a pilot study
(Springer Nature, 2024) Díaz Pizarro, Marcelo; Pino Zúñiga, Johanna; Olivares Gálvez , Mariela; Rendón Vesga , Carolina; Luengas Tello, Rafael; Duque Seguro, Juan Camilo; Cancino, Jorge
Background: This study examines whether creatine supplementation combined with strength training mitigates muscle mass loss in women during early rehabilitation post-bariatric surgery, as its effectiveness remains untested in this context. Methods: Fifteen women (37.8 ± 9.6 years; BMI, 38.8 ± 5.6 kg/m2) completed the intervention (creatine group = 7; placebo group = 8). Both groups followed a strength training program three times a week for 8 weeks. The dosage for both the creatine and placebo was 8 g prior to each exercise session. Body weight, skeletal muscle mass, fat mass, handgrip strength, and physical activity levels were measured before and after the intervention. Results: The creatine group showed a reduction of 9.5 ± 1.5 kg in body weight, with a 0.72 ± 0.6 kg decrease in muscle mass and an 8.64 ± 1.2 kg reduction in fat mass. The placebo group had a reduction of 9.6 ± 3.5 kg in body weight, with a 0.6 ± 1.2 kg decrease in muscle mass and an 8.88 ± 3.2 kg reduction in fat mass, without significant differences between groups (p > 0.05). Conclusion: The pre-session strength exercise training creatine supplementation is not superior to placebo regarding body weight and fat mass losses and the attenuation of muscle mass loss during the first weeks of rehabilitation following bariatric surgery.
Current Periodization, Testing, and Monitoring Practices of Strength and Conditioning Coaches
(Human Kinetics, Inc., 2025) Washif, Jad Adrian; James, Carl; Pagaduan, Jeffrey; Lim, Julian; Lum, Danny; Raja Azidin, Raja Mohammed Firhad; Mujika, Iñigo; Beaven, Chistopher Martyn
This study investigated the periodization, testing, and monitoring practices of strength and conditioning practitioners across different levels of coaching experience and sports. Methods: An online survey was completed by 58 practitioners (25 sports/events) from 9 Southeast and East Asian countries. The survey focused on periodization models, programming frameworks, unloading strategies, fitness assessments, and pretraining readiness monitoring. Frequency analysis and chi-square tests were used to assess data distribution and differences. Results: Hybrid (multiple) periodization was favored over a single model for different training objectives (39%–45%), including very short-term training (≤4 wk). Emerging approaches, including flexible programming, were similarly adopted (43%). Program adjustment was primarily driven by athlete feedback (90%), self-observation (78%), and technical execution (74%). Major programming challenges identified were managing fatigue (72%), optimizing training stimuli (53%), specificity (50%), and adherence (47%). Deloading practices (95%) and tapering applications (91%) were common. Physical performance changes were primarily identified from testing (90%) but also athlete/coach feedback (76%), monitoring (71%), training data (67%), and performance data/statistics (62%). Strength assessments were conducted 2 to 4 times yearly (67%) using 1 to 4 exercises (76%). Pretraining readiness was monitored via conversations (71%), wellness tools (46%), and performance devices (31%). Practitioners also utilized monitoring technology, force plates (21%), and velocity-tracking devices (23%). Training load was commonly quantified using volume load (81%) and session RPE (72%). None of the comparisons differed across experience levels and sports types (P > .05). Conclusion: Practitioners adopted multiple periodization models, incorporating flexible approaches. Unloading strategies were commonly applied alongside various assessment methods. Technologies were used for monitoring, but conversational/subjective methods remained more widespread.
Detraining’s effects on cardiorespiratory fitness and maximal and explosive strength in army soldiers: does age matter?
(MDPI, 2024-07-01) Arce-Álvarez, Alexis; Zaio, Ángelo; Salazar-Ardiles, Camila; Álvarez, Cristian; Merino-Muñoz, Pablo; Vasquez-Muñoz, Manuel; Izquierdo, Mikel; Castro-Sepúlveda, Mauricio; Andrade, David C.
Purpose: This study investigated the impact of four weeks of age-dependent detraining on army soldiers’ cardiorespiratory fitness and maximal and explosive strength. Methods: Fourteen volunteer tactical athletes participated, divided into two age groups (20 to 29 and 30 to 40 years). Before and after the detraining period, we assessed their anthropometric measurements (weight, height, body mass index, fat mass, and fat-free mass), cardiorespiratory fitness (maximal oxygen uptake [VO2max] and ventilatory thresholds [VT1 and VT2]), and kinematic properties during a single-leg counter-moving jump (CMJ) test for both the dominant and non-dominant legs. Two-way ANOVA followed by the Holm–Sidak post hoc test was used. Results: The anthropometric and cardiovascular variables did not show significant differences between the groups. However, both groups exhibited a significantly reduced maximum time and speed at the VO2max. Furthermore, the flight time and maximum height during the CMJ significantly decreased in the non-dominant leg for both age groups. Notably, the dominant leg’s concentric impulse (CI) significantly reduced during the CMJ, but this effect was observed only in the 30–40 age group. There were significant differences between the two age groups. Conclusions: Our findings suggest that four weeks of detraining negatively impacts aerobic fitness and muscular strength, independently of age. However, the dominant leg may be more susceptible to detraining effects in army soldiers aged 30–40. Furthermore, as a perspective, our results strongly suggest that a detraining period could affect successful missions (aerobic performance deterioration), as well as promote a muscle imbalance between the legs, which could encourage muscle injuries and endanger combat missions.
Dog companionship and cortisol levels in youth. A systematic review and meta-analysis
(Elsevier, 2025) Peña-Jorquera, Humberto; Hernandez-Jaña, Sam; Sanchez-Martinez, Javier; Espinoza-Puelles, Juan Pablo; Martínez-Flores, Ricardo; Barreto-Schuch, Felipe; Yañez-Seplveda, Rodrigo; Delgado-Floody, Pedro; Ferrari, Gerson; Sadarangani, Kabir P.; Cancino, Jorge; Bento-Torres, Joao; Espinoza-Salinas, Alexis; Stamatakis, Emmanuel; Cristi-Montero, Carlos
Objective: Traditional and non-traditional strategies have been employed to improve youth health. Dog-assisted interventions have been proposed as a novel strategy to regulate stress and its consequences across all age groups. This systematic review and multilevel meta-analysis assessed the influence of dog-assisted interventions on cortisol levels in youth and explored potential moderators. Sources: We conducted a comprehensive systematic search across multiple databases, including PubMed, Scopus, Web of Science, Cochrane Library, and ScienceDirect, up to June 17, 2024, to evaluate the impact of dog-assisted interventions on youth cortisol levels. Two reviewers independently extracted and verified data from eligible randomized clinical trials, with a third reviewer ensuring accuracy. Cochrane's RoB 2.0 tool was used to assess the risk of bias. Heterogeneity was analyzed using Q and I2 statistics. A random-effects model was employed to calculate effect sizes (ES) using R software. Summary of the findings: Significant cortisol reductions were found for interventions lasting >15 min (ES: 0.65; p = .038), with a non-significant trend towards reduced cortisol in non-medical settings (ES: 0.46; p = .070). No significant effects were observed for shorter interventions, different control groups, or age-specific analyses. Meta-regression analysis revealed significant differences, showing better outcomes with longer intervention times and fewer female participants. Conclusion: Dog-assisted interventions lasting >15 min seem to be a promising and non-traditional strategy for regulating cortisol levels in children and adolescents in stressful situations. This study outlines gaps in the research and future directions.
Early Exercise Boosts Visceral Fat Loss Post‑Bariatric Surgery in the First Month
(Springer Nature, 2025) Cancino, Jorge; Lillo-Urzua, Paloma; Olivares-Galvez, Mariela; Palacio-Aguero, Ana; Duque, Juan Camilo; Luengas, Rafael; Pino-Zuñiga, Johanna
This letter to the editor addresses critiques of a clinical study evaluating the efficacy of an early, counseling-based physical exercise intervention in post-bariatric patients. The authors highlight the paucity of research regarding proactive modification of body composition within the initial postoperative month, focusing particularly on visceral adipose tissue mass. The implemented protocol consisted of a home-based, unsupervised resistance training regimen employing elastic bands, initiated between postoperative days 5 and 7, following individualized in-hospital familiarization and audiovisual instruction. The intervention demonstrated high feasibility, safety, and clinical applicability, especially for populations with limited access to direct supervision during the early postoperative period. No adverse events were reported. The significant reduction in visceral adiposity observed is underscored as a clinically relevant proxy for improved metabolic risk profile. The use of subjective scales of perceived exertion (such as the Borg Scale) is justified when objective monitoring devices are unavailable. The authors recommend that future research prioritize the identification of determinants influencing patient adherence to exercise prescription within post-bariatric rehabilitation frameworks, aiming to optimize therapeutic outcomes.
Early exercise through telerehabilitation after bariatric surgery: is it feasible?
(Springer, 2024) Pino Zúñiga, Johanna; Olivares, Mariela; Muñoz, Giselle; Boza, Camilo; Duque, Camilo; Cancino, Jorge
Purpose: The feasibility of early telerehabilitation after bariatric surgery is unknown. The objective of this study was to assess the feasibility and perception of engaging in the online exercise protocol in patients during the first month after bariatric surgery. Material and methods: A total of 67 patients, enrolled in a telerehabilitation program following bariatric surgery, completed a survey assessing their perception of the intensity, discomfort, and safety during exercise sessions. Results: Forty percent of participants began exercising between 5 and 10 days after surgery. Seventy-one percent of patients did not experience discomfort during the first month of exercise, and those who reported discomfort mainly mentioned dizziness and abdominal pain. No significant differences were found in the presence of discomfort among different types of surgeries performed. There was a significant difference in the presence of discomfort between patients who started exercising before and after 15 days of surgery, with less discomfort reported in the group that started after 15 days. Ninety-eight percent of patients felt safe during online exercise sessions. Most participants perceived the intensity of the sessions as moderate. The most frequently mentioned benefits of exercise were increased energy, mood, and feeling more active. Conclusion: Telerehabilitation conducted during the first month after bariatric surgery was feasible and well tolerated by patients, providing a safe alternative for those patients who face difficulties with in-person interventions.
Effect of supervised resistance training on arm volume, quality of life and physical perfomance among women at high risk for breast cancer-related Lymphedema: A study protocol for a randomized controlled Trial (STRONG-B)
(Frontiers Media S.A., 2022-03) Ramírez-Parada, Karol; Lopez-Garzon, Maria; Sanchez-Rojel, Cesar; Petric-Guajardo, Militza; Alfaro-Barra, Margarita; Fernández-Verdejo, Rodrigo; Reyes-Ponce, Alvaro; Merino-Pereira, Gina; Cantarero-Villanueva, Irene
Objectives: To determine the preventive effects of supervised resistance training on arms volume, quality of life, physical performance, and handgrip strength in Chilean women at high risk for breast cancer-related lymphedema (BCRL) undergoing chemotherapy. Design: Randomized control trial. Participants: One hundred and six women at high risk for breast cancer-related lymphedema aged 18 to 70 years. Interventions: Participants will be randomized into two groups: [a] intervention, who will receive 12 weeks of supervised resistance training (STRONG-B) during adjuvant chemotherapy; and [b] control, who will receive education to promote lymphatic and venous return, maintain range of motion, and promote physical activity. Main Outcome Measures: The primary outcome will be arms volume measured with an optoelectric device (perometer NT1000). Secondary outcomes will be quality of life, handgrip strength, and physical performance. Primary and secondary outcomes will be measured at baseline, just after the intervention, and 3 and 6 months after. Statistical analysis will be performed following intention-to-treat and per-protocol approaches. The treatment effect will be calculated using linear mixed models. Discussion: The STRONG-B will be a tailored supervised resistance training that attempts to prevent or mitigate BCRL in a population that, due to both intrinsic and extrinsic factors, will commonly suffer from BCRL.
Effects of an antioxidants cocktail on glucose metabolism at rest, during exercise, and during a glucose load in healthy young subjects
(Sociedad Chilena de Nutrición, Bromatología y Toxicología, 2023-12-15) Rodríguez, Ivan; Paez Espinosa, Enma Verónica; Zbinden-Foncea, Hermann; Echeverria, Francisca; Castro-Sepúlveda, Mauricio
Background: Reactive oxygen species (ROS) regulate glucose metabolism (GM) in skeletal muscle by improving the translocation of GLUT4. Antioxidant supplementation could block this physiological effect, altering glucose signaling during exercise. However, there is limited evidence in humans on whether antioxidant intake affects GM. Therefore, we aimed to determine the effect of an antioxidant cocktail (AOC) on GM at rest and during metabolic challenges. Methods: Ten healthy male subjects received AOC supplementation (1000 mg of Vitamin C, 600 IU of Vitamin E, and 600 mg of α-lipoic acid) or placebo (2.000 mg of talc) before two trials conducted 7 days apart. Trial 1: AOC 120 and 90 minutes before an endurance exercise (EEX) bout at 60 % of maximal oxygen uptake (VO2max); Trial 2: AOC 120 and 90 minutes before an oral glucose tolerance test (OGTT; 75 g glucose). Measurements of gas exchange and capillary blood samples were collected every 15 minutes during both trials. Results: AOC supplementation increased resting glucose levels (p<0.05). During Trial 1 (EEX), the AOC increased carbohydrate oxidation (CHOox) (p= 0.03), without effect in glucose blood levels. During Trial 2 (OGTT), the AOC supplementation had no significant effect on GM parameters. Conclusion: Acute supplementation with AOC increased resting glucose levels and CHOox during EEX in healthy subjects, with no effect on GM during the OGTT.
Effects of ketone bodies on energy expenditure, substrate utilization, and energy intake in humans
(American Society for Biochemistry and Molecular Biology, 2023-09-11) Fernández-Verdejo, Rodrigo; Mey, Jacob T.; Ravussin, Eric
Recientemente se ha prestado atención al potencial de los enfoques cetogénicos para regular el equilibrio energético, ya que las cetonas pueden influir tanto en el gasto como en la ingesta de energía. En esta revisión narrativa, resumimos la evidencia más relevante sobre el papel de la cetosis en el gasto de energía, la utilización de sustratos y la ingesta de energía en humanos. Consideramos diferentes estrategias para inducir la cetosis, como el ayuno, la manipulación dietética y las fuentes exógenas de cetonas. En general, la cetosis no tiene una influencia importante en el gasto energético, pero promueve un cambio en la utilización del sustrato hacia la oxidación de los cuerpos cetónicos. Las estrategias para inducir la cetosis mediante la reducción de la disponibilidad de carbohidratos en la dieta (p. ej., dietas cetogénicas) no influyen de forma independiente en la ingesta de energía, por lo que son igualmente efectivas para perder peso que las dietas con mayor contenido de carbohidratos. Por el contrario, la ingesta de triglicéridos de cadena media y ésteres de cetonas induce cetosis y parece aumentar el gasto energético y reducir la ingesta energética en el contexto de una alta disponibilidad de carbohidratos. Estas últimas estrategias conducen a una pérdida de peso ligeramente mayor. Desafortunadamente, distinguir los efectos de las diversas estrategias cetogénicasper se de los efectos de otras respuestas fisiológicas no es posible con los datos humanos disponibles. Se necesitan estudios hospitalarios altamente controlados que utilicen estrategias específicas para aislar los efectos independientes de las cetonas para abordar adecuadamente esta brecha de conocimiento.
Effects of Maca (Lepidium meyenii Walp.) on Physical Performance in Animals and Humans: A Systematic Review and Meta-Analysis
(MDPI, 2025) Huerta Ojeda, Álvaro; Rodríguez Rojas, Javiera; Cancino, Jorge; Barahona-Fuentes, Guillermo; Pavez, Leonardo; Yeomans-Cabrera, María-Mercedes; Jorquera-Aguilera, Carlos
Background: Lepidium meyenii Walp. (LmW), known as maca, has been shown to increase physical performance. However, the effect size (ES) of LmW on the different manifestations of physical performance has not yet been described. Objectives: To examine and qualitatively describe the studies published up to 2024 that employed LmW supplementation to increase physical performance in animal and human experimentation. In addition, the ES associated with the different interventions was calculated. Methods: The research followed PRISMA® guidelines for systematic reviews and meta-analyses, using Web of Science, Scopus, SPORTDiscus, PubMed, and MEDLINE databases until 2024. Randomized controlled studies with a pre- and post-test design, conducted both in vitro and in vivo in animals and humans, were included. Methodological quality assessment was performed using the CAMARADES tool for animal studies and the Newcastle Ottawa Scale for human studies. The main variables were the forced swimming test (FST), the rota-rod test (RRT), the grip strength test (GST), blood lactic acid (BLA), and lactic acid (LA). The analysis was conducted with a pooled standardized mean difference (SMD) through Hedges’ g test (95% CI). Results: Twenty-one studies were included in the systematic review and sixteen in the meta-analysis. They revealed a large effect for all outcomes (SMD: FST = 2.26, RRT = 6.26, GST = 5.23, LA = −1.01, and BLA = −1.70). Conclusions: The phytochemical compounds of LmW, mainly macamides, increase physical performance, showing a greater effect at higher doses (dose–response effect).
Effects of school closure on lifestyle behaviours and health outcomes in children during the COVID-19 pandemic in Chile: A time-matched analysis
(Wiley; World Obesity Federation, 2024-10-08) Suárez-Reyes, Mónica; Fernández-Verdejo, Rodrigo; Quintiliano, Daiana; Pinheiro, Anna Cristina; Pizarro, Tito
Background The COVID-19 pandemic led to school closures, potentially impairing children's behaviours and health. We aimed to explore the effects of school closure on lifestyle behaviours (dietary habits, physical activity) and health outcomes (adiposity, fitness, self-esteem, self-concept) in children. Methods We measured 247 children before school closure (October–November 2019) and after school reopening (October–November 2021) (COVID-19 group). To distinguish the changes due to school closure from changes due to growth, we included 655 age-matched children with cross-sectional measurements in October–November 2019 (control group). The response of this group (i.e., differences between children with 2 years of difference) was considered the expected response to growth. Two-way ANOVA was used to test age-by-group interactions, indicating an effect of school closure. Results In 7-to-9-year-old children, the COVID-19 group had larger-than-expected decreases in physical activity (by 0.4 points), resulting in higher physical inactivity prevalence (by 19 percent points) at 9 years. This was accompanied by larger-than-expected increases in fat percentage (by 6.1 percent point). In 8-to-10-year-old children, the COVID-19 group had higher physical inactivity prevalence at 10 years (by 20 percent points). This was accompanied by larger-than-expected increases in fat percentage (by 8.3 percent points), z-score BMI (by 0.90 units), and waist circumference (by 6.1 cm). In 9-to-11-year-old children, the COVID-19 group had larger-than-expected decreases in physical activity (by 0.3 points) and increases in self-concept (by 0.2 points). The response in dietary habits, fitness, or self-esteem was not different between groups. Conclusion Overall, school closure negatively impacted physical activity and adiposity, particularly in the youngest children.

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