Intensity Endurance Training Research Articles

Long term (3 years) weight loss after low intensity endurance training targeted at the level of maximal muscular lipid oxidation

Among various strategies of exercise intensification proposed for the management of obesity and type 2 diabetes, endurance training remains a well recognized procedure. When targeted with exercise calorimetry at levels where lipid oxidation is maximal (LIPOXmax), it has been shown to improve mitochondrial respiration, blood glucose control and blood lipids, low grade inflammation and body composition, even at low weekly volume. We investigated in this study its long term effects over 3 years (3x45 min/week) compared to low fat diet without exercise (LFD) and a control group without any exercise or diet (C). 88 subjects that continued LIPOXmax training more than 1 year (23 men, 65 women, age=20-85 years, body mass index =23-48 kg/m2) were compared to two matched groups (C and LFD). While C gained weight over this period, LFD and LIPOXmax group lose weight. Weight loss at 1 year was the same in exercise and diet group, but at 2 years and even more at 3 years there was a gradual weight regain in LFD so that results were better (p<0.01) in the exercise group who maintained weight loss in 80% of subjects. Average weight loss was -2,95 ± 0,37 kg after 3 months, -4,56 ± 0,68 kg after 1 year, -5,31 ± 1,26 kg at 2 years and -8,49 ± 2,39 kg at 3 years. The level at which LIPOXmax occurs is a predictor of weight loss at 1 year (r=-0,346 p<0,001) but not at 2 and 3 years. Weight loss at 3 months is a predictor of weight loss at 1 year (r=0,523 p<0,001) but not at 2 and 3 years. At 1 year subjects with LIPOX max in the lower quartile (<35% VO2max n=23) lose less weight than the others (-2.3 ± 0.98 vs -5.4 ± 0.83 p=0,05) but this difference vanishes over time. This study shows that this low intensity exercise training maintains its weight-reducing effect 3 years while diet is no longer efficient, and that this effect is initially related to muscular ability to oxidize lipids but that metabolic and behavioral adaptations have been further developed and contribute to a long lasting effect.

PERSONALIZED EXERCISE TRAINING PROGRAM AS A COUNTERMEASURE TO ORTHOSTATIC INTOLERANCE AFTER SPACE FLIGHTS.

PERSONALIZED EXERCISE TRAINING PROGRAM AS A COUNTERMEASURE TO ORTHOSTATIC INTOLERANCE AFTER SPACE FLIGHTS.

Effect of 12 Weeks of Intense Endurance Training and Bee Pollen Consumption on ABCA1 Gene Expression in Small Intestine, Liver and Gastrocnemius Muscle of Male Rats

Effect of 12 Weeks of Intense Endurance Training and Bee Pollen Consumption on ABCA1 Gene Expression in Small Intestine, Liver and Gastrocnemius Muscle of Male Rats

Effects of eight weeks of physical training on physical performance and heart rate variability in children

Summary Study aim: Physically active adults have been shown to have higher heart rate variability (HRV) than less active adults, but less is known about children in this regard. In adults, training-induced changes in physical performance have been shown to be related to increase in HRV, especially in its high frequency component (HF), which is a marker of parasympathetic activity. The purpose of this study was to examine whether 8 weeks of instructed physical training would improve physical performance and cardiac autonomic function (HRV) in secondary school pupils and to examine the relationship between changes in physical performance and the function of the autonomic nervous system. Material and methods: The test group included 12 girls and 12 boys and the control group 7 girls and 7 boys. All the sub­jects were 13-15 years old. Physical training included warm up, circuit training, endurance training, stretching and relaxation 3 times a week for eight weeks. Endurance training intensity was 70-75% of maximal heart rate. Endurance, flexibility, speed and power were measured before and after training. The low frequency (LF) and high frequency (HF) components of HRV were recorded in supine rest and in standing conditions before and after the eight-week period. Results: Time to exhaustion in the endurance test increased in the test group (p &lt; 0.001), flexibility and ball throwing improved in the test group (p &lt; 0.05), while no changes were observed in the control group. No significant changes were observed in HRV in either group. Conclusions: In conclusion, eight weeks of physical training improves physical performance in children, but it might not affect autonomic cardiac function.

Effect of Intensified Endurance Training on Pacing and Performance in 4000-m Cycling Time Trials.

Studies examining pacing strategies during 4000-m cycling time trials (TTs) typically ensure that participants are not prefatigued; however, competitive cyclists often undertake TTs when already fatigued. This study aimed to determine how TT pacing strategies and sprint characteristics of cyclists change during an intensified training period (mesocycle). Thirteen cyclists regularly competing in A- and B-grade cycling races and consistently training (>10h/wk for 4 [1]y) completed a 6-wk training mesocycle. Participants undertook individually prescribed training, using training stress scores (TrainingPeaks, Boulder, CO), partitioned into a baseline week, a build week, 2 loading weeks (designed to elicit an overreached state), and 2 recovery weeks. Laboratory-based tests (15-s sprint and TT) and Recovery-Stress Questionnaire (RESTQ-52) responses were repeatedly undertaken over the mesocycle. TT power output increased during recovery compared with baseline and loading weeks (P = .001) with >6-W increases in mean power output (MPO) detected for 400-m sections (10% bins) from 1200 to 4000m in recovery weeks. Decreases in peak heart rate (P < .001) during loading weeks and postexercise blood lactate (P = .005) during loading week 2 and recovery week 1 were detected. Compared with baseline, 15-s sprint MPO declined during loading and recovery weeks (P < .001). An interaction was observed between RESTQ-52 total stress score with a 15-s sprint (P = .003) and with a TT MPO (P = .04), indicating that participants who experienced greater stress during loading weeks exhibited reduced performance. To conclude, intensified endurance training diminished sprint performance but improved 4000-m TT performance, with a subtle change in MPO evident over the last 70% of TTs.

Nil Whey Protein Effect on Glycemic Control after Intense Mixed-Mode Training in Type 2 Diabetes.

This study aimed to determine if peritraining whey protein supplementation combined with MMIT can improve glycemic control. In a double-blind, randomized, placebo-controlled trial, 24 men (55.7 ± 5.6 yr) with T2D performed MMIT with whey (20 g) or placebo control for 10 wk. Glycemic control was assessed via glucose disposal rate during a euglycemic insulin clamp, fasting blood glucose concentration, and homeostatic model assessment of insulin resistance. Changes in peak oxygen consumption, 1-repetition maximum strength, vastus lateralis muscle, and subcutaneous adipose thicknesses, and waist circumference were also assessed. Ten weeks of MMIT substantially improved glucose disposal rate by 27.5% (90% confidence interval, 1.2%-60.7%) and 24.8% (-5.4% to 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in fasting blood glucose by -17.4% (-30.6% to -1.6%) and homeostatic model assessment of insulin resistance by -14.1% (-25.3% to 1.08%) in the whey group; however, whey effects were not clearly beneficial to glycemic outcomes relative to the control. MMIT also clearly substantially improved 1-repetition maximum by 20.6% (16.3%-24.9%) and 22.7% (18.4%-27.2%), peak oxygen consumption by 22.6% (12.0%-26.2%) and 18.5% (10.5%-27.4%), and vastus lateralis muscle thickness by 18.9% (12.0%-26.2%) and 18.6% (10.5%-27.4%) and possibly reduced waist circumference by -2.1% (-3.1% to -1.0%) and -1.9% (-3.7% to -0.1%) in the control and whey groups, respectively, but the whey-control outcome was trivial or unclear. A clinically meaningful enhancement in glycemic control after 10 wk of MMIT was not clearly advanced with peritraining whey protein supplementation in middle-age men with T2D.

The protective effects of Haematococcus pluvialis on the exercise-induced myocardial injury in rat

To study the protective effects of Haematococcus pluvialis (H. pluvialis) on myocardial injury of rats induced by endurance and intensive exercise. The model was based on intensive endurance training. Sixty-five male aged 42 days Wistar rats were randomly divided into 5 groups:control group (C group), general training group (M group), low dose H. pluvialis + training group (HM I group), middle dose H. Pluvialis + training group (HM Ⅱ group), high dose H. pluvialis + training group (HM Ⅲ group). Each group included 12 rats, and the rats were assigned to go on a 42-day swimming training regime. Professional gavage were taken daily. The rats in HM I, HM Ⅱ and HM Ⅲ group were treated with H. pluvialis at the doses of 0.067,0.133 and 0.4 g/kg by ig at 5 ml/kg and the normal saline were given to other groups. After a 42-day swimming training regime, myocardial injury markers such as serum alanine aminotransferase (ALT), myocardial superoxide dismutase(SOD) and malondialdehyde (MDA) were detected, the biochemical indexes such as serum and myocardial endothelin (ET) and calcitonin gene related peptide (CGRP)were detected. Serum ALT, lactate dehydrogenase(LDH), creatine kinase(CK), a-hydroxybutyrate dehydrogenase(a-HBDH), ET, myocardial MDA and ET in M group were significantly higher than those in C group (P<0.05 or P<0.01). The myocardial SOD activity and the myocardial and serum CGRP in M group were significantly lower than those in C group(P<0.05 or P<0.01). The contents of serum ALT, LDH and CK in HM groups were lower than those in the M group but there was no significant difference between the two groups. Compared with M group, H. pluvialis could decrease the levels of serum a-HBDH, ET and myocardial ET in a dose-dependent manner (P<0.05 or P<0.01). The above mentioned three parameters in HM Ⅲ group were lower than those in HM I group (P<0.05). H. pluvialis could decrease the levels of myocardial MDA and increase the levels of myocardial SOD activity and serum or myocardial CGRP in a dose-dependent manner (P<0.05 or P<0.01). The different doses of H.pluvialis can effectively reduce the free radicals caused by endurance and intensive training and enhance the immune function. Meanwhile H.pluvialis is able to guarantee the relative balance in ET an CGRP`s concentration. Therefore, the myocardial lipid peroxidation and myocardial injury are encumbered. Additionaly, high dose of H. pluvialis is proven to be the most effective.

Comparing sprint and endurance training on anxiety, depression and its relation with brain-derived neurotrophic factor in rats

Although the response of brain-derived neurotrophic factor (BDNF) has been shown to low intensity exercise training, but the effect of intensive exercise training is not clear. Also, there is insufficient information about relationship between BDNF and depression and anxiety following intensive exercise. This study aimed to investigate the effects of 6 weeks of intensive endurance training (ET) and sprint interval training (SIT) on brain BDNF and its relationship with anxiety and depression in Albino Wistar rats. Anxiety and depression of rats were measured by elevated plus maze (EPM) and tail suspension test (TST), respectively. All data were analyzed using one-way ANOVA and Pearson’s correlation coefficient at P<0.05 level. Both SIT and ET regimens increased BDNF content in the brain, and the alterations made were greater following SIT than ET. Also, both SIT and ET regimens increased number of entries and the time spent in the open arm significantly in EPM, with a higher elevation following SIT than ET. In addition, both SIT and ET regimens decreased number and duration of immobility significantly in TST, with a higher reduction following SIT than ET. Furthermore, BDNF content correlated positively with number of entries and the time spent in the open arm in EPM and negatively with number and duration of immobility in TST. Collectively, sprint interval training regimen, rather than intensive endurance training regimen, is highly potential to improve anxiety and depression through a greater increase in BDNF contents in brain.

The effects of different exercise training modalities on plasma proenkephalin Peptide F in women

Due to the important interactions of proenkephalin fragments (e.g., proenkephalin [107–140] Peptide F) to enhance activation of immune cells and potentially combat pain associated with exercise-induced muscle tissue damage, we examined the differential plasma responses of Peptide F to different exercise training programs. Participants were tested pre-training (T1), and after 8 weeks (T2) of training. Fifty-nine healthy women were matched and then randomly assigned to one of four groups: heavy resistance strength training (STR, n=18), high intensity endurance training (END, n=14), combined strength and endurance training (CMB, n=17), or control (CON, n=10). Blood was collected using a cannula inserted into a superficial vein in the antecubital fossa with samples collected at rest and immediately after an acute bout of 6 X 10 RM in a squat resistance exercise before training and after training. Prior to any training, no significant differences were observed for any of the groups before or after acute exercise. With training, significant (P≤0.95) elevations were observed with acute exercise in each of the exercise training groups and this effect was significantly greater in the CMB group. These data indicate that in untrained women exercise training will not change resting of plasma Peptide F concentrations unless both forms of exercise are performed but will result in significant increases in the immediate post-exercise responses. Such findings appear to indicate adrenal medullary adaptations opioid production significantly altered with exercise training.

Isolated Subepicardial Right Ventricular Outflow Tract Scar in Athletes With Ventricular Tachycardia

BackgroundHigh-level endurance training has been associated with right ventricular pathological remodeling and ventricular tachycardia (VT). Although overlap with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been suggested, the arrhythmogenic substrate for VTs in athletes is unknown. ObjectivesThe goal of this study was to evaluate whether electroanatomic scar patterns related to sustained VT can distinguish exercise-induced arrhythmogenic remodeling from ARVC and post-inflammatory cardiomyopathies. MethodsIn 57 consecutive patients (mean age 48 ± 16 years; 83% male) undergoing catheter ablation for scar-related right ventricular VT, 2 distinct scar distributions were identified: 1) scars involving the subtricuspid right ventricle in 46 patients (group A); and 2) scars restricted to the anterior subepicardial right ventricular outflow tract in 11 patients (group B). ResultsDefinite ARVC or post-inflammatory cardiomyopathy was diagnosed in 40 (87%) of 46 group A patients but was not diagnosed in any patients in group B. All group B patients underwent intensive endurance training for a median of 15 h/week (interquartile range [IQR]: 10 to 20 h/week) for a median of 13 years (IQR: 10 to 18 years). The cycle lengths of scar-related VTs were significantly faster in group B patients (257 ± 34 ms vs. 328 ± 72 ms in group A; p = 0.003). Catheter ablation resulted in complete procedural success in 10 (91%) of 11 group B patients compared with 26 (57%) of 46 group A patients (p = 0.034). During a median follow-up of 27 months (IQR: 6 to 62 months), 50% of group A patients but none of the group B patients had a VT recurrence. ConclusionsThis study describes a novel clinical entity of an isolated subepicardial right ventricular outflow tract scar serving as a substrate for fast VT in high-level endurance athletes that can be successfully treated by ablation. This scar pattern may allow distinguishing exercise-induced arrhythmogenic remodeling from ARVC and post-inflammatory cardiomyopathy.

Cornu cervi pantotrichum supplementation improves physiological adaptions during intensive endurance training.

Cornu cervi pantotrichum (CCP), used in traditional Chinese medicine, is a well-known yang-invigorating agent with multifunctional bioactivities. We previously showed, through an acute exercise challenge, that short-term CCP supplementation improved physical activities and fatigue-associated biochemical indices. Questions about the long-term effects of CCP treatment on exercise performance and physical fatigue, as well as safety, with intensive exercise training need further research. ICR-strain mice were randomly assigned to three groups: (1) sedentary control and vehicle treatment (SC); (2) exercise training with vehicle treatment (ET); and (3) ET with CCP treatment at 4,108 mg/kg/day (ET+CCP). We assessed the physical performance, body compositions, and serum levels of lactate, ammonia, glucose and creatine kinase (CK) after an acute exercise challenge. The ET and ET+CCP groups had significantly increased grip strength and endurance swimming time, and decreased serum lactate and ammonia levels after the acute exercise challenge than the SC group. Moreover, serum ammonia and CK levels in the ET+CCP group were significantly decreased when compared to that of the ET only group. In regard to the body composition, the ET+CCP group inhibits the decrease in fat tissue, and related biochemical changes induced by the high intensity endurance training CCP supplementation combined with high-intensity endurance exercise could significantly improve the physiological adaptions related to fatigue or energy consumption and maintain the fat composition when compared to treatment with training only. Therefore, CCP may potentially improve the physiological adaptions in intensive exercise training.

A Combined and Intensive Exercise Model Improves Physical Capacity in Cardiac Patients

Objective: We have measured the effect of combined strength and high intensity endurance training on physical capacity and lipid profile in patients with heart and coronary diseases. We wanted to see whether cardiac patients were able to increase training intensity to improve strength without losing endurance capacity. Methods: Thirty heart-operated subjects participated in an intervention period of 10 weeks. The age of the participants was between 52-72 years. The Resistance-Interval group (RE-INT) practiced four times a week with two intensive endurance (spinning) sessions and two strength training sessions. The endurance training consisted of intervals where the heart rate reached>90% of maximum heart rate. Strength training was performed in three series with a load of 8-12 repetition maximum (RM). The subjects in the control group (CON) performed two to three sessions per week according to a national program specialized for coronary patients (called “Ullevaal model”). We had a randomized controlled trial. Results: Maximal leg strength increased in both groups during the intervention, but the increase was higher in the RE-INT group (from 107.9 ± 8.1 kg to 162.0 ± 8.4 kg) compared to the CON group (from 110.8 ± 8.9 to 125.4 ± 9.5 ) (p<0.001). Strength in chest press, the maximal oxygen uptake and the concentration of high densitylipoprotein (HDL) protein increased in both groups during the test period. However, no differences were observed between the RE-INT and CON group. Low density-lipoprotein (LDL), blood pressure and body weight did not change during the intervention period in any of the groups. Conclusion: cardiac patients were able to increase training intensity, strength and maximal oxygen uptake during a period of 10 weeks. We found that combined training has an effective impact on the increase in leg strength. The increase in muscle strength can be vital for the everyday quality of life in cardiac patients.

Short-term intense exercise training reduces stress markers and alters the transcriptional response to exercise in skeletal muscle.

The purpose of this investigation was to examine the influence of short-term intense endurance training on cycling performance, along with the acute and chronic signaling responses of skeletal muscle stress and stability markers. Ten recreationally active subjects (25 ± 2 yr, 79 ± 3 kg, 47 ± 2 ml·kg-1·min-1) were studied before and after a 12-day cycling protocol to examine the effects of short-term intense (70-100% V̇o2max) exercise training on resting and exercise-induced regulation of molecular factors related to skeletal muscle cellular stress and protein stability. Skeletal muscle biopsies were taken at rest and 3 h following a 20-km cycle time trial on days 1 and 12 to measure mRNA expression and protein content. Training improved (P < 0.05) cycling performance by 5 ± 1%. Protein oxidation was unaltered on day 12, while resting SAPK/JNK phosphorylation was reduced (P < 0.05), suggesting a reduction in cellular stress. The maintenance in the myocellular environment may be due to synthesis of cytoprotective markers, along with enhanced degradation of damage proteins, as training tended (P < 0.10) to increase resting protein content of manganese superoxide dismutase and heat shock protein 70 (HSP70), while mRNA expression of MuRF-1 was elevated (P < 0.05). Following training (day 12), the acute exercise-induced transcriptional response of TNF-α, NF-κB, MuRF-1, and PGC1α was attenuated (P < 0.05) compared with day 1 Collectively, these data suggest that short-term intense training enhances protein stability, creating a cellular environment capable of resistance to exercise-induced stress, which may be favorable for adaptation.

Endurance Training Intensity Does Not Mediate Interference to Maximal Lower-Body Strength Gain during Short-Term Concurrent Training.

We determined the effect of concurrent training incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT) on maximal strength, counter-movement jump (CMJ) performance, and body composition adaptations, compared with single-mode resistance training (RT). Twenty-three recreationally-active males (mean ± SD: age, 29.6 ± 5.5 y; , 44 ± 11 mL kg−1·min−1) underwent 8 weeks (3 sessions·wk−1) of either: (1) HIT combined with RT (HIT+RT group, n = 8), (2) work-matched MICT combined with RT (MICT+RT group, n = 7), or (3) RT performed alone (RT group, n = 8). Measures of aerobic capacity, maximal (1-RM) strength, CMJ performance and body composition (DXA) were obtained before (PRE), mid-way (MID), and after (POST) training. Maximal (one-repetition maximum [1-RM]) leg press strength was improved from PRE to POST for RT (mean change ± 90% confidence interval; 38.5 ± 8.5%; effect size [ES] ± 90% confidence interval; 1.26 ± 0.24; P < 0.001), HIT+RT (28.7 ± 5.3%; ES, 1.17 ± 0.19; P < 0.001), and MICT+RT (27.5 ± 4.6%, ES, 0.81 ± 0.12; P < 0.001); however, the magnitude of this change was greater for RT vs. both HIT+RT (7.4 ± 8.7%; ES, 0.40 ± 0.40) and MICT+RT (8.2 ± 9.9%; ES, 0.60 ± 0.45). There were no substantial between-group differences in 1-RM bench press strength gain. RT induced greater changes in peak CMJ force vs. HIT+RT (6.8 ± 4.5%; ES, 0.41 ± 0.28) and MICT+RT (9.9 ± 11.2%; ES, 0.54 ± 0.65), and greater improvements in maximal CMJ rate of force development (RFD) vs. HIT+RT (24.1 ± 26.1%; ES, 0.72 ± 0.88). Lower-body lean mass was similarly increased for RT (4.1 ± 2.0%; ES; 0.33 ± 0.16; P = 0.023) and MICT+RT (3.6 ± 2.4%; ES; 0.45 ± 0.30; P = 0.052); however, this change was attenuated for HIT+RT (1.8 ± 1.6%; ES; 0.13 ± 0.12; P = 0.069). We conclude that concurrent training incorporating either HIT or work-matched MICT similarly attenuates improvements in maximal lower-body strength and indices of CMJ performance compared with RT performed alone. This suggests endurance training intensity is not a critical mediator of interference to maximal strength gain during short-term concurrent training.

The Benefits of High-Intensity Functional Training Fitness Programs for Military Personnel.

High intensity functional training (HIFT) programs are designed to address multiple fitness domains, potentially providing improved physical and mental readiness in a changing operational environment. Programs consistent with HIFT principals such as CrossFit, SEALFIT and the US Marine Corps' High Intensity Tactical Training (HITT) are increasingly popular among military personnel. The goal of HIFT programs is to produce high levels of cardiorespiratory fitness, endurance and strength that exceed those achieved by following current physical activity recommendations. Given the investment in and popularity of HIFT in the military, it is important to consider the potential impact of this approach to fitness training for the health of military personnel and their risk of training injury. In a previous report in this journal, we addressed the question of whether HIFT was associated with higher injury rates compared to other exercise programs. We argued that concerns about the injury potential of HIFT exercise programs were not supported by the scientific literature to date, although additional research was needed to directly compare injury rates in approaches such as CrossFit to traditional military fitness programs. In this article we will review the scientific data on the practical, health and fitness benefits of HIFT exercise programs for military populations. Practical benefits to HIFT exercise programs include shorter training times and volumes, exercises which simulate combat tasks, lower equipment costs, reduced potential for boredom and adaptation as a result of constant variation, less injury potential compared to high volume endurance training, and scalability to all fitness levels and rehabilitation needs. For instance, HIFT training volumes are typically between 25% to nearly 80% less than traditional military fitness programs without reductions in fitness outcomes. HIFT program also provide an impressive range of health benefits such as the promotion of metabolic conditioning and muscular strength, less systemic inflammation or oxidative damage compared to sustained aerobic activity, and promoting general physical preparedness (GPP) for the unpredictable physical demands of combat. Given the unique benefits of HIFT, we recommend that these programs become the standard for military physical training. Despite the promise of HIFT fitness programs, questions remain about implementing these programs in the military context. For instance, no large scale randomized trials comparing traditional military physical training with HIFT programs on both health and injury outcomes have been conducted. Such a trial could identify key elements from both types of programs which should be incorporated in future approaches to military fitness training. Also, research regarding the optimal ways of implementing HIFT to maximize both GPP and combat oriented physical skills is lacking. It is likely that an approach to HIFT training which promotes GPP for all personnel along with specialized elements selected on the basis of individual occupation demands would be maximally disseminable in the military.

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373).

How Do World-Class Nordic Combined Athletes Differ From Specialized Cross-Country Skiers and Ski Jumpers in Sport-Specific Capacity and Training Characteristics?

To compare sport-specific laboratory capacities and the annual training of world-class Nordic combined (NC) athletes with specialized ski jumpers (SJ) and cross-country (XC) skiers. Five world-class athletes from each sports discipline were compared. Ski jump imitations were performed on a 3-dimensional force plate in NC athletes and SJ, whereas XC skiing characteristics were obtained from submaximal and maximal roller ski skating on a treadmill in NC athletes and XC skiers. In addition, anthropometrics and annual training characteristics were determined. NC athletes demonstrated 9% higher body mass and showed 17% lower vertical speed in the ski jump imitation than SJ (all P < .05). NC athletes had 12% lower body mass and showed 10% lower peak treadmill speed and 12% lower body-mass-normalized peak oxygen uptake than XC skiers (all P < .05). NC athletes performed half the number of ski-jumping-specific sessions and outdoor ski jumps compared with SJ. NC athletes performed 31% less endurance training, mainly caused by lower amounts of low- and moderate-intensity training in the classical technique, whereas high-intensity strength and speed training and endurance training in the skating technique did not differ substantially from XC skiers. To simultaneously optimize endurance, explosive, and technical capacities in 2 different disciplines, world-class NC athletes train approximately two-thirds of the XC skier's endurance training volume and perform one-half of the ski-jump-specific training compared with SJ. Still, the various laboratory capacities differed only 10-17% compared with SJ and XC skiers.

Psychological and behavioral manifestations in alzheimer’ disease and mild cognitive impairment. Artemisa province

The synchronous activation of the muscles involved in force production is crucial for the neuromuscular performance, but the underlying mechanisms remain to be fully elucidated. Our aim was thus to contribute to understand the mechanisms involved in the synergistic activation of agonist muscles. Through wavelet-based time–frequency analysis, this study investigated the modulation of ‘beta’ intermuscular interactions (IM) during maximum isometric knee extensions performed before and after repetitive submaximal fatiguing contractions. Three groups of participants were included: 9 untrained subjects (control group, CO), 10 elite rugby league players (strength-trained group, ST) and 7 trail runners (endurance-trained group, ED), engaged for 5+ years in intense strength and endurance training, respectively. Before fatigue, CO showed higher IM when compared to ED, and a trend to higher IM when compared to ST. Following fatiguing contractions, all groups showed a decline in neuromuscular performance concomitant with a change (decline) in IM values for CO only. No differences were found between ST and ED regarding to IM either before or after fatiguing contractions. These findings suggested both a form of optimization of intermuscular coupling in trained individuals and the functional importance of intermuscular coupling as a mechanism responsible for the maintenance of the neuromuscular performance.

Effects of endurance and high intensity training on ICAM-1 and VCAM-1 levels and arterial pressure in obese and normal weight adolescents

ABSTRACTObjectives: Obesity prevalence has increased in Iranian adolescents in recent years. However, few studies have examined the impact of intervention programs on this health issue. The main objective of this study was to evaluate the effects of 8-week endurance training (ET) and high intensity interval training (HIIT) on intercellular adhesion molecule-1(ICAM-1) and vascular adhesion molecule-1(VCAM-1) levels among obese and normal-weight male adolescents.Methods: Thirty obese and 30 normal-weight subjects were assigned to the ET, HIIT, or control group for eight weeks. Before and after the intervention, ICAM-1, VCAM-1, body weight, BMI, VO2max, and blood pressures were measured. SPSS (Version 21) was used for data analysis, and the significance level was set at p < 0.05.Results: Mixed design ANOVAs indicated that the obese participants had significantly (p < 0.05) lower ICAM-1 levels in the ET (from 509 ± 61 ng/ml to 387 ± 43 ng/ml) and HIIT (from 517 ± 72 ng/ml to 374 ± 50 ng/ml), but their VCAM-1 level was significantly (p < 0.05) reduced only after the HIIT (from 1689 ± 119 ng/ml to 1282 ± 63 ng/ml). Similarly, normal weight participants significantly (p < 0.05) lowered their ICAM-1 levels in the ET (from 296 ± 18 ng/ml to 216 ± 14 ng/ml) and HIIT (from 289 ± 22 ng/ml to 202 ± 12 ng/ml), but their VCAM-1 level was significantly (p < 0.05) reduced only after the HIIT (from 895 ± 50 ng/ml to 673 ± 142 ng/ml). Systolic blood pressure and diastolic blood pressures of all the participants were significantly (p < 0.01) decreased at the conclusion of the ET and HIIT.Conclusion: While both the ET and HIIT were useful in lowering the SBP and DBP of the participants, HIIT was more effective than ET in reducing ICAM-1 and VCAM-1 content in normal and obese adolescents.

Electroinduced release of recombinant proteins from Escherichia coli

Satellite cells (SCs) are the resident stem cells of skeletal muscle tissue which play a major role in muscle adaptation, e.g. as a response to physical training. The aim of this study was to examine the effects of an intermittent lactate (La) treatment on the proliferation and differentiation of C2C12 myoblasts, simulating a microcycle of high intensity endurance training. Furthermore, the involvement of reactive oxygen species (ROS) in this context was examined. C2C12 myoblasts were therefore repeatedly incubated for 2 h each day with 10 mM or 20 mM La differentiation medium (DM) and in some cases 20 mM La DM plus different antioxidative substances for up to 5 days. La free (0 mM) DM served as a control. Immunocytochemical staining, Western blot analysis and colorimetric assays were used to assess oxidative stress, proliferation, and differentiation. Results show that La induces oxidative stress, enhances cell-cycle withdrawal, and initiates early differentiation but delays late differentiation in a timely and dose-dependent manner. These effects can be reversed by the addition of antioxidants to the La DM. We therefore conclude that La has a regulatory role in C2C12 myogenesis via a ROS-sensitive mechanism which elicits implications for reassessing some aspects of training and the use of nutritional supplements.