Interval Endurance Training Research Articles

A low-carbohydrate, high-fat diet leads to unfavorable changes in blood lipid profiles compared to carbohydrate-rich diets with different glycemic indices in recreationally active men.

In addition to recent discussions of low-carbohydrate, high-fat diets (LCHF) from a performance perspective, there is a paucity of knowledge regarding influence of the combined effect of an exercise and nutritional intervention, which varies in carbohydrate (CHO) intake and glycemic indices, on blood lipid levels in recreationally active men. A total of 65 male runners (VO2 peak = 55 ± 8 mL·min-1·kg-1) completed a 10-week ad libitum nutritional regimen (LOW-GI: ≥ 65% low GI CHO per day, n = 24; HIGH-GI: ≥ 65% high GI CHO per day, n = 20; LCHF: ≤ 50 g CHO daily, n = 21) with a concurrent prescribed endurance training intervention. Fasting total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined before and after the intervention. Additionally, 24-h dietary recalls were completed twice weekly. Following the intervention, TC was significantly higher in LCHF (196 ± 37 mg·dL-1) compared to both LOW-GI (171 ± 41 mg·dL-1) and HIGH-GI (152 ± 28 mg·dL-1, p < 0.001). Additionally, LDL-C levels increased in LCHF (+17 ± 21 mg·dL-1, p = 0.001), while they decreased in both CHO groups (p < 0.05, respectively). Only the HIGH-GI group demonstrated a significant reduction in HDL-C (-3 ± 9 mg·dL-1, p = 0.006), while a decrease in TG was only significant in LOW-GI (-18 ± 36 mg·dL-1, p = 0.008). Although mean blood lipid levels remained within the normal range, the data indicate that a low-carbohydrate, high-fat (LCHF) diet leads to unfavorable changes in individual blood lipid profiles compared to carbohydrate-rich diets. Therefore, it is recommended that the impact of a low-carbohydrate diet on blood lipids be considered when counseling active and healthy individuals.

Relationship Between HRV Stability And Fitness-related Outcomes Following Two-weeks Of Resistance Or Endurance Training Intervention

Relationship Between HRV Stability And Fitness-related Outcomes Following Two-weeks Of Resistance Or Endurance Training Intervention

Endurance training and essential amino acid intervention synergize to ameliorate fructose-induced metabolic dysfunction in mice

Purpose: Excessive fructose (FRU) consumption can rapidly produce multiple features of metabolic syndrome, including dysregulation of systemic metabolism, insulin resistance, and diabetes. Essential amino acids (EAAs) and endurance exercise training (ET) improve abnormal metabolism in various disease conditions, yet their combined effect and metabolic mechanism remain unclear. Thus, the current study aimed to investigate metabolic kinetic mechanism and the combined effect of EAA and ET on fructose-induced metabolic dysfunction. Materials and methods: Mice were randomly divided into 5 groups with an 8-week intervention: normal chow (CON), FRU, FRU+ET, FRU+EAA or FRU+ET+ EAA, followed by stable isotope tracer infusions ([U-13C16]palmitate, [D2]glucose, and [D5]glycerol) or D2O administration to determine substrate metabolic flux rates and their contribution to TCA cycle flux and protein synthesis rates of various organs, respectively. Summary of results: FRU-induced adverse changes in body weight and physical function were reversed by ET, EAA, or ET+EAA. In stable isotope tracing analysis, ET and ET+EAA alleviated hyperglycemia by suppressing hepatic glucose production rate, while EAA and ET+EAA normalized palmitate turnover and contribution to TCA cycle in various organs. Additionally, the altered protein synthesis measured using a D2O labeling method was normalized by ET and ET+EAA. Conclusion:These findings suggest that the combined treatment of dietary EAAs and ET more effectively mitigates fructose-induced metabolic dysfunction by normalizing hepatic glucose production rate, protein synthesis rates, and fatty acid metabolism. This research was supported by a grant of the Korea Health Technology R&amp;D Project through the Korea Health industry Development Institute (KHIDI), funded by the Ministry of Health &amp; Welfare, Republic of Korea (HI22C2208), and the National Research Foundation of Korea (NRF), funded by the Korea government (MSIT) (No. 2021R1A2C3005801), and partially funded by MYOCARE INC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effects of endurance training on muscle oxygen desaturation during incremental exercise tests: a systematic review and meta-analysis.

Minimum muscle oxygen saturation (SmO2min) measured via near-infrared spectroscopy (NIRS) is a common measure during incremental exercise testing (IET). Our objective was to determine the effects of pre-to-post endurance training on SmO2min (ΔSmO2min) during an IET, using a meta-analysis. MEDLINE, EMBASE, and SPORTDiscus. Studies including healthy individuals had to meet the following criteria: (1) endurance training intervention; (2) peripheral muscle NIRS; (3) incremental exercise test pre/post training; (4) SmO2 or analogous saturation parameter measured. A PEDro scale was used for risk of bias analysis. A random effect meta-analysis model was used to synthesize the effect of training on ΔSmO2min in individual studies. Statistical heterogeneity was quantified using I2 statistic. A meta-regression was used to estimate the effect of training on the relationship between peak cycling power output (Wpeak), peak pulmonary oxygen uptake (V˙O2peak), and ΔSmO2min. A mixed-effect model was used to estimate categorical variables. Five studies met the inclusion criteria. No difference in SmO2min was detected following training pre- and post-intervention IETs. A trend for an effect of training on the relationship between Wpeak and ΔSmO2min was observed (p = 0.06). This meta-analysis showed no effects of endurance training on SmO2min during an IET. Our results showed a trend for an effect of training on the relationship between Wpeak and ΔSmO2min, with no effect for V˙O2peak and ΔSmO2min. It is possible that SmO2min is not affected by endurance training, and may be used as a physiological marker for improvements in submaximal performance rather than at peak.

Sex differences in muscle protein expression and DNA methylation in response to exercise training

BackgroundExercise training elicits changes in muscle physiology, epigenomics, transcriptomics, and proteomics, with males and females exhibiting differing physiological responses to exercise training. However, the molecular mechanisms contributing to the differing adaptations between the sexes are poorly understood.MethodsWe performed a meta-analysis for sex differences in skeletal muscle DNA methylation following an endurance training intervention (Gene SMART cohort and E-MTAB-11282 cohort). We investigated for sex differences in the skeletal muscle proteome following an endurance training intervention (Gene SMART cohort). Lastly, we investigated whether the methylome and proteome are associated with baseline cardiorespiratory fitness (maximal oxygen consumption; VO2max) in a sex-specific manner.ResultsHere, we investigated for the first time, DNA methylome and proteome sex differences in response to exercise training in human skeletal muscle (n = 78; 50 males, 28 females). We identified 92 DNA methylation sites (CpGs) associated with exercise training; however, no CpGs changed in a sex-dependent manner. In contrast, we identified 189 proteins that are differentially expressed between the sexes following training, with 82 proteins differentially expressed between the sexes at baseline. Proteins showing the most robust sex-specific response to exercise include SIRT3, MRPL41, and MBP. Irrespective of sex, cardiorespiratory fitness was associated with robust methylome changes (19,257 CpGs) and no proteomic changes. We did not observe sex differences in the association between cardiorespiratory fitness and the DNA methylome. Integrative multi-omic analysis identified sex-specific mitochondrial metabolism pathways associated with exercise responses. Lastly, exercise training and cardiorespiratory fitness shifted the DNA methylomes to be more similar between the sexes.ConclusionsWe identified sex differences in protein expression changes, but not DNA methylation changes, following an endurance exercise training intervention; whereas we identified no sex differences in the DNA methylome or proteome response to lifelong training. Given the delicate interaction between sex and training as well as the limitations of the current study, more studies are required to elucidate whether there is a sex-specific training effect on the DNA methylome. We found that genes involved in mitochondrial metabolism pathways are differentially modulated between the sexes following endurance exercise training. These results shed light on sex differences in molecular adaptations to exercise training in skeletal muscle.

Comparison of an exergame and a moderate-intensity endurance training intervention on physiological parameters

Background&#x0D; Exergames are interactive video games that stimulate an active, whole-body gaming experience (Best, 2013). By combining electronic entertainment with physical exercise, exergames offer novel opportunities to expand physical activity in different age groups and settings. Even though studies have found a significant increase in energy expenditure when playing exergames compared to normal video games, most games only induce low to moderate-intensity activity which is too low to result in relevant physical adjustments (Biddiss &amp; Irwin, 2010). This study assessed the effects of an 8-week exergame-training (EXT) in an innovative exergame called the ExerCube and compared it with a typical moderate-intensity endurance training (ET) intervention.&#x0D; Methods&#x0D; In total, 19 individuals (10 female; age 26.9 ±8.7 years; body mass index (BMI) 23.6 ±3.1 kg/m2) participated and were block randomized into an EXT group (n = 9) and an ET group (n = 10). Throughout the 8-week intervention period, the EXT group attended 20-30-minutes of EXT three times a week while the ET group completed 15-45-minutes of ET (jogging/cycling at 65-75% of maximal heart rate) three times a week. Before and after the intervention BMI, systolic and diastolic blood pressure, and VO2max (spiroergometry; start: 50 or 75 W; increment: 25 W/min) were assessed and compared (paired-samples t-test, ANOVA).&#x0D; Results&#x0D; Significant time × group interaction effects were found for VO2max (F(1,17) = 11.345; p = .004, ηp2 = .400). The EXT group revealed significant within-group effects in VO2max from pre (43.2 ±10.6 ml/kg*min) to post (46.9 ±10.9 ml/kg*min; p = .004, d = 1.308) while the ET group revealed no significant changes (pre: 39.4 ±5.4 ml/kg*min; post: 39.7 ±4.9 ml/kg*min; p = .466, d = .241). No significant time × group interaction effects were detected in systolic blood pressure (F(1,17) = .050; p = .825, ηp2 = .003) or diastolic blood pressure (F(1,17) = .005; p = .943, ηp2 = .000). However, there was a significant decrease in the peripheral systolic blood pressure from pre (122 ±10 mmHg) to post (117 ±12 mmHg; p = .034, d = .792) in the ET group but not in the EXT group (pre: 118 ±8; post: 114 ±7; p = .156, d = .523). Concerning BMI, no significant interaction effects (F(1,17) = 2.818; p = .111, ηp2 = .142) were detected.&#x0D; Conclusions&#x0D; The EXT seems to be more effective as conventional ET exercise approach to improve endurance performance. This is promising as exergame may develop intrinsic motivation/enjoyment for physical activity. Further studies confirming these findings and extending to psychological variables are needed.&#x0D; References&#x0D; Best, J. R. (2013). Exergaming in youth: Effects on physical and cognitive health. Zeitschrift für Psychologie, 221(2), 72-78. https://doi.org/10.1027/2151-2604/a000137&#x0D; Biddiss, E., &amp; Irwin, J. (2010). Active video games to promote physical activity in children and youth: A systematic review. Archives of Pediatrics &amp; Adolescent Medicine, 164(7), 664-672. https://doi.org/10.1001/archpediatrics.2010.104

Effects of endurance exercise training on left ventricular structure in healthy adults: a systematic review and meta-analysis.

To determine the impact of endurance training (ET) interventions on left ventricular (LV) chamber size, wall thickness, and mass in healthy adults. Electronic databases including CINAHL, MEDLINE, PsycINFO, SPORTDiscus, Cochrane library, and EBM Reviews were searched up to 4 January 2022. Criteria for inclusion were healthy females and/or males (>18 years), ET intervention for ≥2 weeks, and studies reporting pre- and post-training LV structural parameters. A random-effects meta-analysis with heterogeneity, publication bias, and sensitivity analysis was used to determine the effects of ET on LV mass (LVM) and diastolic measures of interventricular septum thickness (IVSd), posterior wall thickness (PWTd), and LV diameter (LVDd). Meta-regression was performed on mediating factors (age, sex, training protocols) to assess their effects on LV structure. Eighty-two studies met inclusion criteria (n = 1908; 19-82 years, 33% female). There was a significant increase in LVM, PWTd, IVSd, and LVDd following ET [standardized mean difference (SMD) = 0.444, 95% confidence interval (CI): 0.361, 0.527; P < 0.001; SMD = 0.234, 95% CI: 0.159, 0.309; P < 0.001; SMD = 0.237, 95% CI: 0.159, 0.316; P < 0.001; SMD = 0.249, 95% CI:0.173, 0.324; P < 0.001, respectively]. Trained status, training type, and age were the only mediating factors for change in LVM, where previously trained, mixed-type training, young (18-35 years), and middle-aged (36-55 years) individuals had the greatest change compared with untrained, interval-type training, and older individuals (>55 years). A significant increase in wall thickness was observed in males, with a similar augmentation of LVDd in males and females. Trained individuals elicited an increase in all LV structures and ET involving mixed-type training and rowing and swimming modalities conferred the greatest increase in PWTd and LVDd. Left ventricular structure is significantly increased following ET. Males, young and trained individuals, and ET interventions involving mixed training regimes elicit the greatest changes in LV structure.

Prescribing and adjusting exercise training in chronic respiratory diseases – Expert-based practical recommendations

BackgroundInternational guidelines recommend endurance (ET) and strength training (ST) in patients with chronic respiratory diseases (CRDs), but only provide rough guidance on how to set the initial training load. This may unintentionally lead to practice variation and inadequate training load adjustments. This study aimed to develop practical recommendations on tailoring ET and ST based on practices from international experts from the field of exercise training in CRDs. Methods35 experts were invited to address a 64-item online survey about how they prescribe and adjust exercise training. ResultsCycling (97%) and walking (86%) were the most commonly implemented ET modalities. Continuous endurance training (CET, 83%) and interval endurance training (IET, 86%) were the frequently applied ET types. Criteria to prescribe IET instead of CET were: patients do not tolerate CET due to dyspnoea at the initial training session (79%), intense breathlessness during initial exercise assessment (76%), and/or profound exercise-induced oxygen desaturation (59%). For ST, most experts (68%) recommend 3 sets per exercise; 62% of experts set the intensity at a specific load that patients can tolerate for a range of 8 to 15 repetitions per set. Also, 56% of experts advise patients to approach local muscular exhaustion at the end of a single ST set. ConclusionsThe experts´ practices were summarized to develop practical recommendations in the form of flowcharts on how experts apply and adjust CET, IET, and ST in patients with CRDs. These recommendations may guide health care professionals to optimize exercise training programs in patients with CRDs.

Patterns and determinants of adherence to resistance and endurance training during cancer treatment in the Phys-Can RCT

BackgroundKnowledge regarding adherence is necessary to improve the specificity of exercise interventions during cancer treatment. We aimed to determine adherence to resistance and endurance training interventions in parallel; identify subgroups with similar adherence characteristics; and examine determinants of these subgroups.MethodsIn the Phys-Can randomised controlled trial, participants (n = 577, 81% women, mean(SD) age 59(12) years, and 50% with BMI ≥ 25 kg/m2) starting (neo-) adjuvant treatment for breast, colorectal or prostate cancer were randomized to 6-month of high (HI) or low-to-moderate intensity (LMI) supervised, group-based resistance training and individual home-based endurance training, with or without behavior change support. Adherence was calculated as performed exercise volume as a proportion of prescribed exercise volume (0–100%), overall (HI and LMI groups) and for frequency, intensity, type and time (FITT principles) (HI group). Adherence to resistance training was plotted against adherence to endurance training overall and for each FITT principle. K-means cluster analysis was used to identify subgroups with similar adherence characteristics. Potential determinants of subgroup membership were examined using multinomial logistic regression.ResultsWe found a positive curvilinear correlation between adherence to resistance and endurance training overall. A similar correlation was seen for adherence to frequency of resistance vs. endurance training in the HI group. In the HI group, adherence to resistance training intensity and time was > 80% for almost all participants. For endurance training adherence ranged from 0 to 100% for each of the FITT principles. Three clusters were identified, representing low, mixed, and high adherence to resistance and endurance training overall. Participants with higher age (Relative risk ratio [95% CI]; LMI: 0.86[0.77–0.96], HI: 0.83[0.74–0.93]), no behaviour change support (LMI: 0.11[0.02–0.56], HI: 0.20[0.05–0.85]), higher cardiorespiratory fitness (LMI: 0.81[0.69–0.94], HI: 0.80[0.69–0.92]), more fatigue (according to the reduced activity subscale of the MFI questionnaire) (LMI: 0.48[0.31–0.73], HI: 0.69[0.52–0.93]) or higher quality of life (LMI: 0.95[0.90–1.00], HI: 0.93[0.88–0.98]) were less likely to be in the low than the high adherence cluster whether randomised to LMI or HI training. Other determinants were specific to those randomised to LMI or HI training.ConclusionsIn an exercise intervention during cancer treatment, adherence to resistance and endurance training were positively correlated. Personalisation of interventions and additional support for some subgroups of participants may improve adherence.Trial registrationNCT02473003 (clinicaltrials.gov, Registered 16/06/2015).

Effect of different types of muscle activity on the gene and protein expression of ALDH family members in C57BL/6J mouse skeletal muscle.

Aldehyde dehydrogenase (ALDH) is an enzyme that detoxifies aldehydes and is primarily involved in alcohol metabolism. Recently, we have shown that ALDH also plays an important role in skeletal muscle homeostasis. To better understand the role of ALDH in skeletal muscle, it is necessary to clarify the adaptability of ALDH. In this study, we examined the effects of endurance training, compensatory hypertrophy by synergist ablation (SA), and denervation-induced atrophy on gene expression and protein levels of selected ALDH isoforms in skeletal muscle. Ten-week-old C57BL/6J mice were subjected to each intervention, and the plantaris muscle was collected. Gene expression levels of Aldh1a1 were decreased by SA and denervation, but ALDH1A1 protein levels were not affected. Protein levels of ALDH1B1 increased after chronic endurance training, SA, and denervation interventions. However, the increase in Aldh1b1 gene expression was observed only after SA. The gene expression of Aldh2 was decreased after SA, but ALDH2 protein levels remained unchanged. Denervation increased both the Aldh2 gene and ALDH2 protein levels. Taken together, each isoform of ALDH undergoes unique quantitative adaptations in skeletal muscle under different conditions.

TGF-β Induction of miR-143/145 Is Associated to Exercise Response by Influencing Differentiation and Insulin Signaling Molecules in Human Skeletal Muscle

Physical training improves insulin sensitivity and can prevent type 2 diabetes (T2D). However, approximately 20% of individuals lack a beneficial outcome in glycemic control. TGF-β, identified as a possible upstream regulator involved in this low response, is also a potent regulator of microRNAs (miRNAs). The aim of this study was to elucidate the potential impact of TGF-β-driven miRNAs on individual exercise response. Non-targeted long and sncRNA sequencing analyses of TGF-β1-treated human skeletal muscle cells corroborated the effects of TGF-β1 on muscle cell differentiation, the induction of extracellular matrix components, and identified several TGF-β1-regulated miRNAs. qPCR validated a potent upregulation of miR-143-3p/145-5p and miR-181a2-5p by TGF-β1 in both human myoblasts and differentiated myotubes. Healthy subjects who were overweight or obese participated in a supervised 8-week endurance training intervention (n = 40) and were categorized as responder or low responder in glycemic control based on fold change ISIMats (≥+1.1 or <+1.1, respectively). In skeletal muscle biopsies of low responders, TGF-β signaling and miR-143/145 cluster levels were induced by training at much higher rates than among responders. Target-mining revealed HDACs, MYHs, and insulin signaling components INSR and IRS1 as potential miR-143/145 cluster targets. All these targets were down-regulated in TGF-β1-treated myotubes. Transfection of miR-143-3p/145-5p mimics in differentiated myotubes validated MYH1, MYH4, and IRS1 as miR-143/145 cluster targets. Elevated TGF-β signaling and miR-143/145 cluster induction in skeletal muscle of low responders might obstruct improvements in insulin sensitivity by training in two ways: by a negative impact of miR-143-3p on muscle cell fusion and myofiber functionality and by directly impairing insulin signaling via a reduction in INSR by TGF-β and finetuned IRS1 suppression by miR-143-3p.

Physiological and Perceptual Responses in Spinal Cord Injury Handcyclists During an Endurance Interval Training: The Role of Critical Speed.

This study sought to determine the physiological (oxygen uptake, heart rate, and blood lactate concentration) and perceptual (rating of perceived exertion) responses during an endurance interval training at the critical speed in elite handcyclists with spinal cord injury. Eight handcyclists performed an incremental test, three tests to exhaustion at a constant speed to determine critical speed, and the endurance interval training. The endurance interval training consisted of 6 × 5 mins at the individualized critical speed, with passive recovery of 50 secs. All testing was performed using their own handcycles on an oversized motorized treadmill. Physiological and perceptual responses were assessed during the incremental and endurance interval training tests. There was no significant difference in average oxygen uptake from the first to the sixth repetition. The mean ∆[La-]10_last between the 10th to the 30th minute of the exercise was -0.36 mmol·l-1, and no difference was detected from the first to the sixth repetition. The heart rate also remained stable during endurance interval training, whereas rating of perceived exertion increased significantly throughout the session. Repetitions of 5 mins at the critical speed in elite handcyclists are associated with cardiorespiratory and lactate steady state, whereas the perceived exertion increased systematically.

Effects of Different Exercise Interventions on Cardiac Autonomic Control and Secondary Health Factors in Middle-Aged Adults: A Systematic Review.

This systematic review was conducted in accordance with the PRISMA guidelines to summarize the existing literature on the effects of different exercise interventions on cardiac autonomic control and secondary health factors. Resting heart rate variability (HRV) was used as indicator of cardiac autonomic control. Secondary factors were related to factors that contribute to cardiovascular health. Studies examining the effects of endurance, resistance, multimodal, or coordinative training interventions in healthy participants aged between 45 and 60 years old on average were considered. The methodological quality of the studies was examined using two assessment scales (TESTEX and STARDHRV). PROSPERO registration number: CRD42020206606. The literature review retrieved eight studies fulfilling all inclusion criteria. Cardiac autonomic control and cardiovascular health improved after endurance and multimodal interventions. Resistance training had no significant impact on HRV or any secondary health factor. Coordinative exercise interventions showed inconclusive results regarding HRV but showed significant improvements in secondary health factors. The quality assessment tools revealed some methodological and reporting deficits. Despite the small number of studies, we suggest endurance and multimodal interventions including aerobic exercises for the enhancement of cardiac autonomic control and the reduction of cardiovascular risk in middle-aged adults. Further studies need to be conducted to examine the long-term effects of exercise in the midlife period.

Two-year follow-up after a six-week high-intensity training intervention study with breast cancer patients: physiological, psychological and immunological differences

Purpose Previously we demonstrated the feasibility of a six-week-long combination of high-intensity interval endurance and strength training (HIT/HIRT) for women with nonmetastatic breast cancer leading to improvements in psychological well-being and performance. Now we report results of a 24-month follow-up. Methods Previous intervention (IG, n = 10; 58.7 ± 8.4yrs) and control group (CG, n = 9; 58.8 ± 6.6yrs) were asked for follow-up examinations 12 (T12) and 24 months (T24) after cessation of the supervised training (POST). Medical history, mental well-being, performance and immunological variables were analyzed with respect to intervention start (PRE). Results IG maximum oxygen consumption (⩒O2peak) 12%-improved POST (p = 0.05) and declined to baseline values T24, while CG ⩒O2peak increased 12% T24 (p = 0.01). IG strength (1RM) increased 31% POST (p < 0.001) and remained above baseline level T24 (p = 0.003), whereas CG 1RM slightly improved T24 (+19%, p = 0.034). IG Anxiety and Depression decreased POST and did not change until T24. IG C-reactive protein decreased POST and increased to pre-exercise levels T24. CG immunological/inflammatory/life quality markers did not change. Conclusions Six weeks of HIT/HIRT by breast cancer patients can induce similar beneficial effects like two years of convalescence, but outcomes were unstable and showed a fast backslide in aerobic capacity, activity level and in pro-inflammatory state within 12 months. IMPLICATIONS FOR REHABILITATION High-intensity interval endurance and strength training (HIT/HIRT) for female breast cancer patients was shown to improve psychological well-being and performance, but long-term effects/adherence are unknown. Significant backslides in aerobic capacity, activity level as well as in the pro-inflammatory response after one and two years are observed and should be monitored. Continuous supervision and/or support of breast cancer patients before, during, and after medical care due to poor training adherence when voluntarily executed is recommended.

The Effect of High- and Moderate-intensity Endurance Training on Some Anabolic/Catabolic Osteokines in Old Male Wistar Rats

Background: Bone-related osteokines are crucial for bone function and metabolic response to physical activity. The present study aimed to shed light on the effect of different intensities of continuous and interval endurance training on the serum levels of some osteokines that are associated with wingless-related integration site (WNT) signaling pathway and Receptor Activator of Nuclear Factor (NF)-κB Ligand (RANKL) in old male Wistar rats. Materials and Methods: A total of 24 old male Wistar rats (mean age: 23 months, mean weight: 437.93 g) were randomly assigned to three groups: interval endurance-training group (n=8), continuous endurance-training group (n=8), and control group (n=8). The continuous and interval training interventions comprised 8 weeks of treadmill exercise, 5 days a week. The continuous endurance-training group started to exercise at 60% of velocity at maximal oxygen uptake (vVO2max) for 16 min during the first week. It continued with 70% of vVO2max for 45 min from the fourth week onward. In contrast, the interval endurance-training group switched on exercise with 40%-80% of vVO2max from the first week and persisted with 30%-110% of vVO2max from the fourth week onward. As the exercise bout was completed, the enzyme-linked immunosorbent assay was applied to measure the study dependent variables. Statistical analysis was further performed using 1-way analysis of variance, considering the significance level of P≤0.05. Results: The study results demonstrated a significant difference in the levels of Oteoprotegerin (OPG) (P=0.036) and RANKL (P=0.001) in the experimental (namely, interval and continuous training) groups compared with the controls following the exercise bout. However, the level of sclerostin was not significantly changed (P=0.549). Conclusion: High-intensity endurance training in the RANKL/OPG and WNT pathways decreased sclerostin and RANKL levels, but this decrease was significant at the RANKL level. It was effective with regard to the intensities of different types of endurance exercise.

Home-based and personalized endurance training program for patients with mild to moderate hemophilia A: What can be expected?

Some studies suggest that an acute exercise bout can improve the hemostatic process in patients with hemophilia A (HA). No interventional studies have been carried out to assess the influence of endurance training on this effect. We aimed (1) to determine the acceptability of a 6-week personalized endurance training program that HA patients could implement in their daily life and (2) to determine the impact of this endurance training program on endurance capacity and various factors supporting the hemostatic process. Seventeen subjects with mild to moderate HA aged 18 to 45 years were engaged in a home-based and personalized endurance training program (eighteen training sessions, three sessions per week). For each subject, endurance capacity was assessed at inclusion during an exhaustive exercise test coupled with gas exchanges. From this endurance assessment, a personalized interval endurance training plan was drafted and standardized to provide moderate [at the first ventilatory threshold (VT)] to high (at the second VT) metabolic intensity training. At inclusion, the hemostatic process was assessed at rest and after the exhaustive exercise bout. These same tests were repeated after the endurance training program. All 17 patients completed the endurance training program. There were no bleeding-related incidents. Endurance power was increased after the training program (maximal aerobic power: +14%, +0% to +32% for median, minimum and maximum values respectively, P = 0.003; first ventilatory threshold power: +22%, 0% to +100%, P = 0.0006; second ventilatory threshold power: +25%, 0% to +53%, P = 0.0004). In patients with mild HA, endurance training slightly increased FVIII levels when assessed after the maximal exercise bout. Our results support the promotion of a personalized, standardized and home-based exercise prescription for hemophilia patients to improve their cardiorespiratory fitness without negatively influencing the coagulation process. Des études ont suggéré que la réalisation d’un exercice musculaire aigu peut améliorer l’efficacité du processus d’hémostase chez des patients porteurs d’une hémophilie A. Aucune étude interventionnelle n’a jamais été réalisée pour vérifier l’influence d’un entraînement régulier en endurance sur cet effet aigu. Notre étude de type interventionnelle, monocentrique, exploratoire et menée auprès d’un échantillon de patients hémophiles A avait pour objectifs (1) d’évaluer l’acceptabilité de la mise en place au domicile d’un programme d’entraînement en endurance prescrit et personnalisé et (2) de caractériser l’effet de cet entraînement sur les ressources fonctionnelles en endurance et sur le processus hémostatique. Un effectif de 17 patients hémophiles A de sévérité mineure à modérée et âgés de 18 à 45 ans a été recruté. Les ressources fonctionnelles en endurance ont été évaluées à l’inclusion par un test d’exercice musculaire sur bicyclette ergométrique couplé à la mesure des échanges gazeux respiratoires. Cette évaluation a permis de prescrire à chaque patient un programme d’entraînement personnalisé sur bicyclette ergométrique à domicile, à raison de 3 séances par semaine pendant 6 semaines, en créneaux, aux intensités des seuils ventilatoires et codifié via les contrôles de la fréquence cardiaque et de la puissance développée. Un accompagnement téléphonique par un éducateur médico-sportif était proposé au moins une fois par semaine. À l’inclusion, le processus d’hémostase était quantifié au repos et dans les suites immédiates du test d’exercice maximal. À l’issue du programme d’entraînement en endurance, toutes les mesures ont été contrôlées. Les 17 patients ont pu réaliser le programme d’entraînement prescrit. Aucun événement hémorragique n’a été signalé durant la période d’entraînement. À l’issue du programme d’entraînement et en comparaison avec les valeurs mesurées à l’inclusion, la puissance maximale aérobie a augmenté (+14 %, +0 % et +32 % pour respectivement la médiane, le minimum et le maximum ; p = 0,003) de même que les puissances mesurées aux seuils ventilatoires (1 er seuil ventilatoire : +22 %, 0 % et +100 %, p = 0,0006 ; 2 e seuil ventilatoire : +25 %, 0 % et +53 %, p = 0,004). À l’issue du programme d’entraînement, le processus d’hémostase n’a été dégradé chez aucun des patients. Dans le sous-groupe des patients porteurs d’une forme mineure de la maladie, l’entraînement en endurance a légèrement majoré la réponse sécrétoire en facteur VIII induite par la réalisation du test d’exercice d’intensité maximale. Notre étude a permis de vérifier que l’application d’une prescription d’entraînement en endurance à des patients porteurs d’une hémophilie A de sévérité mineure à modérée peut être envisagée au domicile des patients. Cette pratique induit une amélioration de la ressource fonctionnelle en endurance des patients hémophiles A sans modifier le processus d’hémostase.

Effect of 6 weeks of very low-volume high-intensity interval training on oral glucose-stimulated incretin hormone response

ABSTRACT Introduction: Decreased fasting and oral glucose-stimulated incretin hormone concentrations following moderate-intensity continuous endurance training interventions have been reported in glucose-tolerant people, however results are conflicting. The effect of more time-efficient, very low-volume, high-intensity interval training (HIT) on circulating incretin hormone levels has never been studied. Materials and methods: Ten sedentary and overweight-to-obese participants (4 women and 6 men; age 43 ± 6 years (mean ± SD); BMI 30.2 ± 3.2 kg∙m−2; HbA1c 35 ± 5.1 mmol∙mol−1 (5.3 ± 0.3%); VO2max 30 ± 5 ml∙min−1∙kg−1) from the Copenhagen cohort of the METAPREDICT trial underwent 6 weeks of supervised low-volume HIT (3 sessions per week: 7 × 1 min at ∼100% VO2max separated by 1 min of active recovery). We measured glucose, insulin, C-peptide, glucagon, GLP-1 and GIP concentrations during a frequently sampled 75 g oral glucose tolerance test as well as VO2max and body composition before and after the intervention. Results: Training compliance was 100%. Relative VO2max improved after the intervention (median 2.69 ml∙min−1∙kg−1, IQR [0.43; 3.14], p = 0.037) while there were no significant effects on body weight and composition. No significant effects on oral glucose-stimulated glucose and hormone responses or estimates of insulin sensitivity and β-cell function were observed. Conclusion: Low-volume HIT improved aerobic fitness, but neither affected glucose tolerance nor oral glucose-stimulated incretin hormone responses in sedentary and overweight-to-obese people. Highlights Ten sedentary, overweight-to-obese, glucose-tolerant participants underwent 6 weeks of supervised, very low-volume HIT. Aerobic fitness improved. Fasting and oral glucose-stimulated incretin hormone concentrations were not affected.

Using endurance training in nature as a resource in inpatient psychotherapy

Using endurance training in nature as a resource in inpatient psychotherapy Objectives: Although positive effects of nature on mental health are generally well-documented, clinical studies into the deliberate use of nature as a resource in in-patient psychotherapy are missing. The following study examined whether an endurance training intervention in psychosomatic rehabilitation showed differential effects on patients depending on its implementation in an indoor or outdoor nature setting. Methods: Endurance training indoors (ergometer) was compared to training outdoors in the nature (walking) in N = 88 in-patients of a psychosomatic rehabilitation clinic using a linear mixed effects model. Health effects were examined using a standardized questionnaire on somatic symptoms (Giessener Beschwerdebogen GBB-24) and a mood questionnaire (Aktuelle Stimmungsskala ASTS). Seasonal effects were assessed by testing half of the sample in summer and half in winter. Secondary analyses of the linear mixed effects model were run for depression as primary diagnosis which accounted for half of the sample. Results: A nature setting positively predicted improvements on the ASTS positive mood scale (B = 0.34; t(245) = 3.25; p = .001; pBonferroni = .052). No significant interaction was found between the effect of the training setting and depression as primary diagnosis (B = -0.05; t(245) = -0.30; p = .76) in secondary analyses. Conclusions: The results primarily point to an improvement in mood following endurance training in a nature setting. Improvements are independent of depression as the primary diagnosis.

Experiences of Older Adults Preparing for Their First Triathlon: “A Qualitative Study of the Participation in an Endurance Training Intervention.”

ABSTRACT Purpose: The overall aim of the present study was to explore the experiences of older adult exercisers participating in an individualized training program lasting 3 months preparing for completing a triathlon competition. Methods: Fourteen older Norwegian adults (median age (interquartile range, IQR) for males (N=10) and females (N=4) were 70.0 (65.0-75.5) and 57.5 (56.3-62.5) years, respectively) participated in 3-month individualized training program comprising three weekly sessions of running, cycling, and swimming. Both field- and laboratory-based testing were conducted. The participants attended two sports nutrition and competitive psychology seminars focusing on triathlon competition. The participants were interviewed in depth in three different focus groups. Thematic analysis was utilized to analyze the findings. Results: Participants improved their performance in all field-based tests. After completion of the thematic data analysis the main finding and overarching theme of well-being and being fit emerged. Additionally, three main themes were identified: 1) motivation; 2) progress and coping; and 3) breaking barriers. Conclusion: Psychological well-being and satisfaction of being fit seem to be vital to participate in a triathlon competition. Promoting specific age-appropriate participation in sports activities can be an effective strategy for promoting a healthy lifestyle among the elderly.

Effects of two endurance training protocols (High ­Intensity Interval Training = HIIT versus Polarized Training = POL) on endurance capacity, heart rate at rest and heart rate variability (HRV) in young sport students

The goal of the present study was the analysis of the effects of two endurance training interventions (HIIT versus POL) over a period of 5 weeks on 16/17 year old sport major students. The study was integrated in regular P.E. lessons. In addition to the training load, daily changes of easily measurable cardiologic parameters were monitored in order to assess their validity in predicting endurance performance. The students conducted 12 training sessions in two groups. With pre- and post-tests the endurance capacity was determined via Luc Léger’s shuttle run test. Heart rate parameters were measured within a time period of one week prior to and after the intervention. Running performance improved in the HIIT group significantly by 6.5% (p &lt; 0.05), but remained constant in the POL group (+2,4%). Those students who improved their endurance performance by at least 5% simultaneously had a significantly (p &lt; 0.05) increased HRV (rMSSD +11%). Participants who could not improve their persormance by 5% showed a significantly (p &lt; 0.05) decreased HRV (rMSSD –8%). The HIIT group improved their endurance capacity with only 47% of training time compared to the POL group. HRV was, in contrast to resting heart rate, a valid predictor of endurance capacity.