Background: Fat loss mainly conveys the benefits of caloric restriction for people living with type 2 diabetes. The literature is equivocal regarding whether exercise facilitates fat loss during caloric restriction. This analysis aimed to assess the dose-response effects of exercise in combination with a caloric restriction on fat mass (FM) and FM percentage (FM %) in persons with diagnosed type 2 diabetes.
Methods: In this secondary analysis of a 4-armed randomized trial, 82 persons living with type 2 diabetes were randomly allocated to the control group (CON) (n = 21), diet control (DCON) (25 % caloric restriction; n = 20), diet control and exercise 3 times per wk (MED) (n = 20), or diet control and exercise 6 times per wk (HED) (n = 21) for 16 wk. The primary analysis was the change in FM% points. Secondary analyses included fat-free mass and visceral adipose tissue (VAT) volume (cm3).
Results: FM% decreased compared to CON by a mean difference of -3.5% (95% confidence interval (95%CI): -5.6% to -1.4%), -6.3% (95%CI: -8.4% to -4.1%), and -8.0% (95%CI: -10.2% to -5.8%) for DCON, MED, and HED, respectively. Compared to DCON, MED and HED decreased FM% by -2.8% (95%CI: -4.9% to -0.7%) and -4.5% (95%CI: -6.6% to -2.4%), respectively. The difference in FM% between HED and MED was -1.8% (95%CI: -3.9% to 0.4%). DCON and MED decreased fat-free mass compared to CON, whereas HED preserved fat-free mass (-0.2% (95%CI: -2.0% to 1.7%)). Compared to CON, VAT volume decreased by -666.0 cm3 (95%CI: -912.8 cm3 to -385.1 cm3), -1264.0 (95%CI: -1679.6 cm3 to -655.9 cm3), and -1786.4 cm3 (95%CI: -2264.6 cm3 to -1321.2 cm3) more for DCON, MED, and HED, respectively. HED decreased VAT volume more than DCON (-1120.4 cm3 (95%CI: -1746.6 cm3 to -639.4 cm3)) while the remaining comparisons did not reveal any differences.
Conclusion: All interventions were superior in reducing FM% compared to standard care. Adding exercise to a caloric restriction was superior in reducing FM% compared to a caloric restriction alone.
Background: Eccentric training, such as Nordic hamstring exercise (NHE) training, is commonly used as a preventive measure for hamstring strains. Eccentric training is believed to induce lengthening of muscle fascicles and to be associated with the addition of sarcomeres in series within muscle fibers. However, the difficulty in measuring sarcomere adaptation in human muscles has severely limited information about the precise mechanisms of adaptation. This study addressed this limitation by measuring the multiscale hamstring muscle adaptations in response to 9 weeks of NHE training and 3 weeks of detraining.
Methods: Twelve participants completed 9 weeks of supervised NHE training, followed by a 3-week detraining period. We assessed biceps femoris long-head (BFlh) muscle fascicle length, sarcomere length, and serial sarcomere number in the central and distal regions of the muscle. Additionally, we measured muscle volume and eccentric strength at baseline, post-training, and post-detraining.
Results: NHE training over 9 weeks induced significant architectural and strength adaptations in the BFlh muscle. Fascicle length increased by 19% in the central muscle region and 33% in the distal muscle region. NHE also induced increases in serial sarcomere number (25% in the central region and 49% in the distal region). BFlh muscle volume increased by 8%, and knee flexion strength increased by 40% with training. Following 3 weeks of detraining, fascicle length decreased by 12% in the central region and 16% in the distal region along with reductions in serial sarcomere number.
Conclusion: Nine weeks of NHE training produced substantial, region-specific increases in BFlh muscle fascicle length, muscle volume, and force generation. The direct measurement of sarcomere lengths revealed that the increased fascicle length was accompanied by the addition of sarcomeres in series within the muscle fascicles.
Exercise is a therapeutic approach in cancer treatment, providing several benefits. Moreover, exercise is associated with a reduced risk for developing a range of cancers and for their recurrence, as well as with improving survival, even though the underlying mechanisms remain unclear. Preclinical and clinical evidence shows that the acute effects of a single exercise session can suppress the growth of various cancer cell lines in vitro. This suppression is potentially due to altered concentrations of hormones (e.g., insulin) and cytokines (e.g., tumor necrosis factor alpha and interleukin 6) after exercise. These factors, known to be involved in tumorigenesis, may explain why exercise is associated with reduced cancer incidence, recurrence, and mortality. However, the effects of short- (<8 weeks) and long-term (≥8 weeks) exercise programs on cancer cells have been reported with mixed results. Although more research is needed, it appears that interventions incorporating both exercise and diet seem to have greater inhibitory effects on cancer cell growth in both apparently healthy subjects as well as in cancer patients. Although speculative, these suppressive effects on cancer cells may be driven by changes in body weight and composition as well as by a reduction in low-grade inflammation often associated with sedentary behavior, low muscle mass, and excess fat mass in cancer patients. Taken together, such interventions could alter the systemic levels of suppressive circulating factors, leading to a less favorable environment for tumorigenesis. While regular exercise and a healthy diet may establish a more cancer-suppressive environment, each acute bout of exercise provides a further "dose" of anticancer medicine. Therefore, integrating regular exercise could potentially play a significant role in cancer management, highlighting the need for future investigations in this promising area of research.
Purpose: This study aimed to assess the influence of older vs. younger age and previous anterior cruciate ligament (ACL) injury on resting serum cartilage oligomeric matrix protein (sCOMP[tpre]) concentration, on immediate load-induced sCOMP kinetics after a 30-min treadmill walking stress (∆_sCOMP[tpost]), and on the dose-response relationship between ambulatory load magnitude and ∆_sCOMP(tpost).
Methods: A total of 85 participants were recruited in 4 groups (20-30 years: 24 healthy, 23 ACL-injured; 40-60 years: 23 healthy, 15 ACL-injured). Blood samples were collected immediately before and after a walking stress at 80%, 100%, or 120% bodyweight (BW) on 3 test days and analyzed for sCOMP concentration. Linear models were used to estimate the effect of age, knee status (unilateral ACL injury, 2-10 years prior), and sex on sCOMP(tpre), ∆_sCOMP(tpost)), and the dose-response between ambulatory load magnitude and ∆_sCOMP(tpost).
Results: We found that sCOMP(tpre) was 21% higher in older than younger participants (p < 0.001) but did not differ between ACL-injured and healthy participants (p = 0.632). Also, ∆_sCOMP(tpost) was 19% lower in older than younger participants (p = 0.030) and increased with body mass index (p < 0.001), sCOMP(tpre) (p = 0.008), and with 120%BW (p < 0.001), independent of age, ACL injury, or sex.
Conclusion: Age but not prior ACL injury influences resting sCOMP and load-induced sCOMP. The dose-response relationship between ambulatory load magnitude and load-induced sCOMP changes is not affected by age, ACL injury, or sex. A better understanding of systemic sCOMP and the role of its mechanoresponse for the understanding of osteoarthritis pathophysiology and monitoring intervention efficacy may require knowledge of individual cartilage composition and tissue-level loading parameters.
Background: Physical activity can regulate and affect gene expression in multiple tissues and cells. Recently, with the development of next-generation sequencing, a large number of RNA-sequencing (RNA-seq)-based gene expression profiles about physical activity have been shared in public resources; however, they are poorly curated and underutilized. To tackle this problem, we developed a data atlas of such data through comprehensive data collection, curation, and organization.
Methods: The data atlas, termed gene expression profiles of RNA-seq-based exercise responses (GEPREP), was built on a comprehensive collection of high-quality RNA-seq data on exercise responses. The metadata of each sample were manually curated. Data were uniformly processed and batch effects corrected. All the information was well organized in an easy-to-use website for free search, visualization, and download.
Results: GEPREP now includes 69 RNA-seq datasets of pre- and post-exercise, comprising 26 human datasets (1120 samples) and 43 mouse datasets (1006 samples). Specifically, there were 977 (87.2 %) human samples of skeletal muscle and 143 (12.8 %) human samples of blood. There were also samples across 9 mice tissues with skeletal muscle (359, 35.7 %) and brain (280, 27.8 %) accounting for the main fractions. Metadata-including subject, exercise interventions, sampling sites, and post-processing methods-are also included. The metadata and gene expression profiles are freely accessible at http://www.geprep.org.cn/.
Conclusion: GEPREP is a comprehensive data atlas of RNA-seq-based gene expression profiles responding to exercise. With its reliable annotations and user-friendly interfaces, it has the potential to deepen our understanding of exercise physiology.