Intensity Resistance Training Research Articles

Effects Of Equal-volume Resistance Training With Different Intensity On Muscle Quality In Prediabetes Elders.

Aging is accompanied by a progressive decline in skeletal muscle system. These problems could increase the risks of chronic diseases, falls, and mortality. Resistance training (RT) is an effective strategy to enhance muscle strength, mass, and quality in older populations. However, few studies have examined the influence of different resistance training intensity on skeletal muscle system in prediabetes elders. PURPOSE: The present study is to investigate the effects of high-intensity versus low-intensity RT on muscle strength, body composition, muscle quality, and functional capacity in older adults with prediabetes. METHODS: Twenty-five prediabetes elders (67 ± 4 yrs) were randomized into 1 of 2 groups: high intensity RT (HIGH, 3 × 8 × 80% of 1RM, n = 13) and low intensity RT (LOW, 3 × 16 × 40% of 1RM, n = 12). The 8-week RT program performed 3d·wk-1, using 8 exercises for the whole body. Anthropometric, muscle strength, body composition, muscle quality, and functional capacity were measured pre- and post-training. RESULTS: No significant difference was observed in body composition in both groups (p > 0.05). Both groups presented significant improvement for functional capacity (grip strength, time up and go test and 30-second chair stand; p < 0.05) with no difference between groups (p > 0.05). The HIGH showed significant improvements in muscle strength compared with the LOW (p < 0.05) for total 1RM (HIGH = 22.9%; LOW = 15%), seated row 1RM (HIGH = 24.2%; LOW = 9.9%), back extension 1RM (HIGH = 29%; LOW = 17.5%), leg curl 1RM (HIGH = 22.3%; LOW = 13.7%), leg press 1RM (HIGH = 20.4%; LOW = 11.6%), total muscle quality (HIGH = 21.3%; LOW = 11.8%), upper muscle quality (HIGH = 22.6%; LOW = 12.8%), and lower muscle quality (HIGH = 21.8%; LOW = 11.2%). CONCLUSION: These results suggest that both HIGH and LOW, characterized by the same training volume, improve functional capacity and maintain body composition, whereas HIGH is superior for enhancing muscle strength and muscle quality in older adults with prediabetes.

Targeted High-Intensity Exercise With And Without Osteoporosis Medications To Reduce Fracture Risk In Postmenopausal Women

PURPOSE: The goal of the MEDEX-OP trial was to compare the effectiveness of a high intensity resistance and impact training (HiRIT) program to a Pilates-based exercise program (Buff Bones®, BB), alone or in combination with antiresorptive bone medications, on indices of fracture risk (bone mineral density [BMD], body composition, muscle strength, functional performance). METHODS: Otherwise healthy postmenopausal women with low bone mass (T-score ≤ -1.0), screened for conditions known to influence bone and muscle health, who were on or off stable doses (≥ 12 months) of antiresorptive medication were recruited. One hundred and fifteen women (63.6 ± 0.7 years; BMI 25.5 kg/m2; FN T-score -1.8 ± 0.1) were randomly allocated to twice-weekly, 40-min, supervised HiRIT (5 sets of 5 repetitions at >80% 1 RM) or BB, stratified by medication intake, resulting in four groups: HiRIT (n = 42), BB (n = 44), HiRIT-med (n = 15), BB-med (n = 14). Analyses of covariance, adjusted for baseline age, were performed (data presented as mean ± SE). RESULTS: HiRIT but not BB improved lumbar spine BMD (1.9 ± 0.4% versus -0.6 ± 0.4%, p < 0.005), trochanteric BMD (2.9 ± 0.7 versus -0.6 ± 0.6, p = 0.002) and stature (0.2 ± 0.1 cm versus -0.0 ± 0.1 cm, p = 0.004). HiRIT-med improved BMD more than HiRIT alone at the femoral neck (4.9 ± 1.3% versus -0.0 ± 0.7%, p = 0.008) and total hip (2.2 ± 0.7% versus -0.5 ± 0.4%, p = 0.007). HiRIT and BB both improved muscle strength and functional performance but HiRIT effects were greater for isometric back muscle strength (31.8 ± 3.2% versus 14.4 ± 3.1%, p < 0.005) and five times sit-to-stand test (-11.8 ± 1.8% versus -3.8 ± 1.8%, p = 0.002). Both programs were well tolerated (7 adverse events: HiRIT, 3; BB, 4) and exercise compliance was good (82.4 ± 1.3%). CONCLUSION: High intensity resistance and impact training improved bone mass, muscle strength, functional performance and stature while Pilates-based exercise only improved functional performance. Combining osteoporosis medication with HiRIT may enhance effects on bone at the hip but more trials are needed to fully test the interaction.

Chronic Effect of a Cafeteria Diet and Intensity of Resistance Training on the Circulating Lysophospholipidome in Young Rats.

The daily practice of physical exercise and a balanced diet are recommended to prevent metabolic syndrome (MetS). As MetS is a multifactorial disorder associated with the development of serious diseases, the advancement of comprehensive biomarkers could aid in an accurate diagnosis. In this regard, it is known that gut microbiota is altered in MetS, and especially, lipid metabolites species are highly modified, thus emerging as potential biomarkers. In preliminary studies, we observed that alterations in serum lysoglycerophospholipids (Lyso-PLs) were shared between animals with diet-induced MetS and those performing resistance exercises assiduously. Therefore, our objective was the targeted determination of the lysophospholipidome in young rats fed a standard (ST) or a cafeteria diet (CAF) and submitted to different training intensities to evaluate its potential as a biomarker of a detrimental lifestyle. Targeted metabolomics focused on lysophosphatidylcholines (Lyso-PCs) and lysophosphatidylethanolamines (Lyso-PEs) and multivariate statistics were used to achieve an integral understanding. Chronic intake of CAF altered the serological levels of both lipid subclasses. Twenty-two Lyso-PLs were significantly altered by CAF, from which we selected Lyso-PCs (14:0), (17:1) and (20:2) and Lyso-PEs (18:2) and (18:3) as they were enough to achieve an optimal prediction. The main effect of physical training was decreased Lyso-PEs levels with disparities among training intensities for each diet. We concluded that an examination of the lysophospholipidome reveals the general state of the metabolome in young female rats, especially due to intake of an MetS-inducing diet, thus highlighting the importance of this family of compounds in lipid disorders.

Range of motion of resistance exercise affects the number of performed repetitions but not a time under tension

The resistance training volume along with the exercise range of motion has a significant impact on the training outcomes. Therefore, this study aimed to examine differences in training volume assessed by a number of performed repetitions, time under tension, and load–displacement as well as peak barbell velocity between the cambered and standard barbell bench press training session. The participants performed 3 sets to muscular failure of bench press exercise with the cambered or standard barbell at 50% of one-repetition maximum (1RM). Eighteen healthy men volunteered for the study (age = 25 ± 2 years; body mass = 92.1 ± 9.9 kg; experience in resistance training 7.3 ± 2.1 years; standard and cambered barbell bench press 1RM > 120% body mass). The t-test indicated a significantly higher mean range of motion for the cambered barbell in comparison to the standard (p < 0.0001; ES = −2.24). Moreover, there was a significantly greater number of performed repetitions during the standard barbell bench press than cambered barbell (p < 0.0001) in a whole training session, while no difference was found in total time under tension (p = 0.22) and total load–displacement (p = 0.913). The two-way repeated-measures ANOVA indicated a significant barbell × set interaction effect for peak velocity (p = 0.01) and a number of repetitions (p = 0.015). The post-hoc analysis showed a significantly higher number of repetitions for standard than cambered barbell bench press in set 1 (p < 0.0001), set 3 (p < 0.0001) but not in set 2 (p = 0.066). Moreover, there was a significantly higher peak velocity during the cambered than standard barbell bench press in set 1 (p < 0.0001), and set 2 (p = 0.049), but not in set 3 (p = 0.063). No significant differences between corresponding sets of the standard and cambered barbell bench press in time under tension and load–displacement were found. However, concentric time under tension was significantly higher during cambered barbell bench press in all sets (p < 0.05) when compared to the standard barbell bench press, while eccentric time under tension was significantly lower during the cambered than standard barbell bench presses only in the set 3 (p = 0.001). In summary, this study briefly showed that measuring training volume by the number of performed repetitions is not reliable when different exercise range of motion is used.

Effect of whole-body resistance training at different load intensities on circulating inflammatory biomarkers, body fat, muscular strength, and physical performance in postmenopausal women.

The primary purpose of this study was to identify the impact of whole-body resistance training (RT) at different load intensities on adipokines, adhesion molecules, and extracellular heat shock proteins in postmenopausal women. As secondary purpose, we analyzed the impact of RT at different load intensities on body fat, muscular strength, and physical performance. Forty participants were randomized into lower-load intensity RT (LIRT, n = 20, 30-35 repetition maximum in the first set of each exercise) or higher-load intensity RT (HIRT, n = 20, 8-12 repetition maximum in the first set of each exercise). Adipokines (adiponectin and leptin), adhesion molecules (MCP-1 and ICAM-1), extracellular heat shock proteins (HO-1 and eHSP60), body fat, muscular strength (1RM), and physical performance [400-meter walking test (400-M) and 6-minute walking test (6MWT)] were analyzed at baseline and after 12-weeks RT. There was a significant time-by-group interaction for eHSP60 (P = 0.049) and 400-M (P = 0.003), indicating superiority of HIRT (d = 0.47 and 0.55). However, both groups similarly improved adiponectin, ICAM-1, HO-1, body fat, 1RM, and 6MWT (P < 0.05). Our study suggests that load intensity does not seem to determine the RT effect on several obesity-related pro-inflammatory and chemotactic compounds, body fat, 1RM, and 6MWT in postmenopausal women, although a greater improvement has been revealed for eHSP60 and 400-M in HIRT. Novelty: Higher-load intensity resistance training improves eHSP60 and 400-M in postmenopausal women. Resistance training improves the inflammatory profile, body fat, muscle strength, and 6MWT, regardless of load intensity.

Volume Reduction: Which Dose is Sufficient to Retain Resistance Training Adaptations in Older Women?

We compared the effects of different resistance training (RT) volume reduction strategies on muscular strength and lean soft-tissue (LST) in older women. Fifty-seven physically independent women (>60 years) performed a 20-week pre-conditioning phase of a standardized whole-body RT program (eight exercises, three sets, 8-12 repetitions, three sessions a week), and were then randomly assigned to one of the following conditions: reduced volume for a single set (RV1, n=20) or two sets (RV2, n=19), or maintained volume of three sets (MV, n=18) for 8 weeks (specific training phase). Muscular strength in the chest press, leg extension, and preacher curl exercises was determined by one-repetition maximum tests. A dual-energy X-ray absorptiometry device was used to estimate LST. An increase in muscular strength (16.3-32.1%) and LST (3.2-7.9%) was observed after the pre-conditioning phase. There was an increase in chest press for all groups (9.4-16.7%) after the specific training phase. In contrast, only MV increased significantly in the leg extension (4.4%). No between-group differences were revealed for LST in the specific training phase. Our results suggest that reduced RT volume from three to one set per exercise for 8 weeks seems sufficient to retain neuromuscular adaptations in older women.

The Effects of Combined Same Session Aerobic and Resistance Training on Physical Performance in Coronary Artery Disease Patients: Protocol Comparison

Aerobic training is included to cardiac rehabilitation programs together with resistance training. The effects of combined aerobic and resistance training performed in a same session with different protocols on peak aerobic capacity (VO2peak) and maximal dynamic strength (1RM: one repetition maximum) are not well known. We compared the effectiveness of two different combined aerobic and resistance training programs for 12 weeks performed three times in a week in stable Coronary Artery Disease (CAD) patients (n=30) who had previously performed aerobic training only. The patients were randomized to High Volume- Low Intensity Group (HLG) or Low Volume-High Intensity Group (LHG). Both groups performed laboratory controlled aerobic exercise first (60min, 80% of lactate threshold) followed by six major muscle group resistance exercises (HLG: 30-35% of 1RM, 3 sets, 12 repetitions) or (LHG: 60-70% of 1RM, 3 sets, 6 repetitions). VO2peak remained at the baseline level for whole study group (23 ± 6 vs. 24 ± 7 ml·kg-1·min-1, p=0.380) and the responses did not differ between the HLG and LHG (p=0.891). Muscle strength increased when analyzed as one group for both upper (Push Up; 24 ± 8 vs. 30 ± 7 kg, p &lt;0.0001) and lower body (Leg Extension; 20 ± 6 vs. 27 ± 6 kg, p &lt;0.0001) with no difference between subgroups (p=0.240 and p=0.504, respectively). As conclusion, combined aerobic and resistance training in the same training session for 12 weeks improved maximal strength independently of the intensity of resistance training. These results highlight the importance of regular resistance training, even at moderate intensity, for CAD patients in terms of physical performance and independent living.

Training for Muscular Strength: Methods for Monitoring and Adjusting Training Intensity.

Linear loading, the two-for-two rule, percent of one repetition maximum (1RM), RM zones, rate of perceived exertion (RPE), repetitions in reserve, set-repetition best, autoregulatory progressive resistance exercise (APRE), and velocity-based training (VBT) are all methods of adjusting resistance training intensity. Each method has advantages and disadvantages that strength and conditioning practitioners should be aware of when measuring and monitoring strength characteristics. The linear loading and 2-for-2 methods may be beneficial for novice athletes; however, they may be limited in their capacity to provide athletes with variation and detrimental if used exclusively for long periods of time. The percent of 1RM and RM zone methods may provide athletes with more variation and greater potential for strength-power adaptations; however, they fail to account for daily changes in athlete's performance capabilities. An athlete's daily readiness can be addressed to various extents by both subjective (e.g., RPE, repetitions in reserve, set-repetition best, and APRE) and objective (e.g., VBT) load adjustment methods. Future resistance training monitoring may aim to include a combination of measures that quantify outcome (e.g., velocity, load, time, etc.) with process (e.g., variability, coordination, efficiency, etc.) relevant to the stage of learning or the task being performed. Load adjustment and monitoring methods should be used to supplement and guide the practitioner, quantify what the practitioner 'sees', and provide longitudinal data to assist in reviewing athlete development and providing baselines for the rate of expected development in resistance training when an athlete returns to sport from injury or large training load reductions.

Amyotrophic Lateral Sclerosis, Resistance Training, Endurance Exercise, Tolerance, and Compliance

Amyotrophic Lateral Sclerosis, Resistance Training, Endurance Exercise, Tolerance, and Compliance

500-P: Determinants of Exercise-Induced Increase in Insulin Sensitivity

Exercise training enhances insulin sensitivity (Si) in humans. However, it is to be determined which phenotypic and muscle molecular changes underwrite this change in Si. We sought to understand the mechanisms behind increased Si following 12 weeks of high intensity aerobicinterval (HIIT), resistance (RT), or combined (CT) exercise training in 30 young and 24 old humans. Measurements included Si estimated from a two-stage hyperinsulinemic-euglycemic clamp, and a host of independent variables including VO2 peak, muscle mitochondrial respiration, Liver FWF (Fat-Water-Fraction), visceral and subcutaneous fat, and gene expression from muscle biopsies. We performed a univariate and multivariate analysis of Si vs. phenotypic changes induced by training. After adjusting for age, sex and exercise group, VO2max was positively associated with an increase in Si from pre to post exercise (p=0.032). Interestingly, within the RT group alone, positive association between VO2max and Si (p=0.05) and negative association between liver FWF and Si (p=0.034) were observed. Within the HIIT group, there was a positive association between muscular strength and Si (p=0.04). Separate multivariate models assessed the effect of muscle gene expression changes on Si while adjusting for age, training type, response to training, VO2max, and mitochondrial function. Enrichment Analysis of genes associated with Si showed upregulation of genes in Branched-Chain Amino Acid (BCAA) and Lysine metabolism, although the latter was specifically upregulated with HIIT. Products of lysine metabolism, such as alpha-aminoadipic acid have been implicated in development of insulin resistance and BCAA are involved in signaling of insulin response. A strong positive association of Si with both BCAA (FDR 0) and lysine metabolism (FDR 0.008) following HIIT and a weaker correlation between Si and BCAA metabolism (FDR 0.002) following RT indicates the role of muscle AA metabolism as a common factor contributing to enhanced Si following exercise training. Disclosure A. Prabha kumar: None. S. Dasari: None. M. W. Pataky: None. J. Crook: None. C. T. Ball: None. K. Klaus: None. I. R. Lanza: None. M. M. Robinson: Stock/Shareholder; Self; GE Healthcare. K. Nair: None. Funding National Institutes of Health (R01AG09531)

Feasibility and efficacy of a multicomponent exercise medicine programme in patients with pancreatic cancer undergoing neoadjuvant therapy (the EXPAN trial): study protocol of a dual-centre, two-armed phase I randomised controlled trial

IntroductionExercise is emerging as a therapy in oncology for its physical and psychosocial benefits and potential effects on chemotherapy tolerability and efficacy. However, evidence from randomised controlled trials (RCTs) supporting...

The Effects of Low Volume Versus High Volume Sled-Push Training on Muscular Adaptation

PURPOSE: This study aimed to compare the effects of low-volume and high-volume sled-push resistance training on muscle strength, power, and body composition.METHODS: Twenty-four college students were recruited and matched based on baseline one-repetition maximum (1-RM) into one of the three groups: 1) low volume (LV) resistance training, 2) high volume (HV) resistance training, or 3) control (CON) (n=8 per group). The LV training consisted of five single repetitions of pushing a weighted sled for 9.1 m. The HV training consisted of three sets of five repetitions of pushing a weighted sled for 9.1 m. Training consisted of three weekly workouts performed on nonconsecutive days for 6 weeks. This study utilized a pre-test and post-test design consisting of 1-RM, Wingate power test, standing long jump, vertical jump, and body composition.RESULTS: After 6 weeks of training, there was a similar but significant increase in 1-RM in both training groups (pre-test: LV=226.8±14.8 kg vs. HV=217.7±19.5 kg; post-test: LV=298.5±15 kg vs. HV=286.9±16 kg, &lt;i&gt;p&lt;/i&gt;&lt;.001). However, no improvements were observed in the Wingate power test, standing long jump, vertical jump, or body composition in both training and CON groups (&lt;i&gt;p&lt;/i&gt;&gt;.05).CONCLUSIONS: The results suggested that low-volume resistance training was as effective as a high-volume protocol for improving muscle strength. However, the present study was unable to determine the effects on muscle power and body composition.

Comparing the reinforcing value of high intensity interval training versus moderate intensity aerobic exercise in sedentary adults

Exercise is a reinforcer for both animals and humans, as they will work progressively harder to gain access for the opportunity to exercise. Exercise activates brain reward pathways similar to drugs of abuse, and the magnitude of the reinforcing value of exercise is a predictor of exercise behavior. The majority of research on exercise reinforcement has studied moderate intensity aerobic exercise (MIAE) or resistance training. There is limited research on the relative reinforcing value (RRV) of high intensity interval training (HIIT), which is often reported to be a preferred form of exercise in comparison to MIAE. Experiment 1 was a pilot study of 20 sedentary females designed to compare the reliability of differences in RRVHIIT vs RRVMIAE over two sessions, assess protocols comparing different volumes of HIIT in comparison to MIAE, and estimate sample sizes needed for a fully powered study to assess which type of exercise protocol was a better substitute for a highly liked sedentary activity. Experiment 2 studied 44 participants to assess whether HIIT or MIAE would be better substitutes for highly liked sedentary activities. Experiment 1 showed that measures of RRVHIIT or RRVMIAE were reliable, and that volume of HIIT did not influence RRVHIIT, even if it was of equal amount or duration to MIAE. Experiment 2 showed that HIIT was a more preferred substitute for sedentary behaviors than MIAE. Predictors of RRVMIAE were liking of MIAE and pleasantness of affect post MIAE. These results suggest inactive people may find interval training to be more reinforcing than MIAE, and may be more likely to adopt and maintain an exercise program involving HIIT rather than MIAE. The next stage of research should be to understand how to sensitize the RRV of exercise to motivate sedentary people to be more active.

The effect of Progressive Resistance Training and High Intensity Interval Training on TRAF6 gene expression of the heart muscle and serum TNF-α levels in male diabetic rats

Background: The most common causes of mortality in diabetic patients are cardiovascular disorders, one of the reasons being inflammatory factors. Given that physical activity can reduce inflammation, the present study was to investigate the effects of two types of Progressive Resistance Training (RT) and High Intensity Interval (HIIT) on the expression of TRAF6 gene and serum levels of TNF-α in male diabetic rats. Methods: In this experimental study, 72 male rats were divided into 6 groups of 12 diabetic rats (n=12), control (n=12), diabetic High Intensity Interval Training (n=12), High Intensity Interval Training(n=12), diabetic Progressive Resistance Training(n=12) and Progressive Resistance Training(n=12). Progressive Resistance Training was performed in a 6-weekly 3-session, climbing the vertical ladder, with 50%, 75%, 90% and 100% the body weight of the animals. After successful completion, 30 gr were added to the weights, to the extent that the rats cannot carry the ladder. High Intensity Interval Training were also performed at 6-weekly 3-session, with an intensity of 50 to 110% of the VO2max. 24 hours after the completion of the training, the functional test was taken and the animals were autopsy 48 hours after the test. Finally, the expression of TRAF6 gene was evaluated using Real Time PCR and serum TNF-α level by ELISA method. Results: TRAF6 levels increased significantly after the two Training in the diabetic group, which was higher in the HIIT group and serum TNF-α levels decreased significantly after both types of training, which was more prominent in the HIIT group. Conclusion: HIIT and RT can play an important role in reducing the inflammatory factor of TNF-α in diabetic patient that HIIT is more effective in this regard. Increasing the gene expression of the mediating agent TRAF6 can be induced in inflammatory pathways, which may require a reduction in exercise intensity or in anti-inflammatory routes indicating a positive effect of training on diabetes.

The effect of two different intensities of resistance training with blood flow restriction on muscle strength, body fat percentage and serum level of Irisin in overweight women

مقدمه: شیوع اضافه‌وزن و چاقی و عوارض آن به­سرعت در جهان در حال افزایش است. بنابرین لازم است روش‎های نوینی برای پیشگیری و درمان آن ارائه گردد. مطالعه حاضر با هدف مقایسه اثر 6 هفته تمرین مقاومتی با محدودیت جریان خون (کاتسو) با دو شدت متغیر بر درصد چربی، قدرت عضلانی و سطح سرمی آیریزین در زنان دارای اضافه‎وزن انجام شد. روش­کار: این مطالعه نیمه تجربی در سال 1398 بر روی 42 زن دارای اضافه­وزن در شهر مشهد انجام شد. افراد به‌طور تصادفی در سه گروه تمرینات مقاومتی همراه با محدودیت جریان خون با شدت 30-20% از یک تکرار بیشینه، تمرینات مقاومتی همراه با محدودیت جریان خون با شدت 50-40% و گروه کنترل تقسیم شدند. گروه‌های تمرین به‌مدت 6 هفته، هفته­ای 3 جلسه و هر جلسه 60-50 دقیقه به تمرین پرداختند. قبل و بعد از مداخله تمرینی سطوح سرمی آیریزین، قدرت عضلانی و درصد چربی گرفته شد. تجزیه و تحلیل داده‌ها با استفاده از نرم‌افزار آماری SPSS (نسخه 23) و آزمون تحلیل کوواریانس (ANCOVA) انجام شد. میزان p کمتر از 05/0 معنی‌دار در نظر گرفته شد. یافته­ها: شش هفته تمرین مقاومتی همراه با کاتسو با دو شدت متفاوت منجر به افزایش معنی­دار قدرت در مرحله پس‌آزمون شد (001/0=p). تغییرات سطح سرمی آیریزین و درصد چربی معنی­دار بین دو گروه نبود (05/0p≥). نتیجه­گیری: تمرین مقاومتی همراه با کاتسو بدون تغییر در سطح سرمی آیریزین، در شدت 30-20% منجر به کاهش معنی­دار درصد چربی شد.

Long Term Concurrent Heat Stress does not Improve upon Performance Gains by Resistance Training

Natural performance enhancement, muscle hypertrophy and muscle rehabilitation on an expedited timeframe is highly coveted in sports and recreational fitness industries. Some studies have indicated that heat stress can improve upon muscle hypertrophy when used in combination with resistance training (RT), while some have shown no changes. Improvements in performance aspects such as strength, speed and agility in response to long term RT are well established, however the additive effects of heat stress on performance enhancements by RT has only been sparsely investigated. We therefore investigated the effects of full body heat stress applied concurrently during high intensity RT on muscle mass, strength, speed, agility and force in males. A cohort (n=18) of recreationally active, anthropometrically matched males were assigned in to two groups, HEAT (n=8, age= 23.3 ±.3.1, body mass (BM) = 75.6 ± 14.5kg, height = 175.6 ± 8.8 cm) and CON (n=10, age= 21.0 ± 2.7, BM = 76.0 ± 11.3kg, height = 177.2 ± 9.6 cm). Each group undertook an identical, 10 week, full body RT program three days a week with a rest day in between. The control group trained in thermoneutral conditions (23°C, RH 25%), while the HEAT group trained in a climate chamber at 40°C, RH 30%. Strength (1RM leg and bench press via maximal repetition test), speed (5 and 10 m sprint time), agility (T-test), force (peak force during squat jump and ballistic push up) as well as body composition (DXA scan) were assessed at pre intervention, at week five and post intervention. Core temperature, HEAT (average peak temperature =38.18 ± 0.27 °C) and CON (37.97 ± 0.32 °C), as well as muscle temperature (at a depth of 3.5 cm in the vastus lateralis), HEAT (36.79 ± 1.55 °C) and CON (35.94 ± 1.51 °C) were also measured. Leg press 1 RM increased from pre intervention to post in both CON (50.25 ± 13.99 kg, p<0.05) and HEAT (32.75 ± 5.89 kg, p<0.05) while bench press 1RM showed no improvement. However, the relative strength (1RM divided by total muscle mass) improved only in bench press in both groups from pre intervention to post with CON (0.12 ± 0.009 kg.kg MM-1, p<0.05) and HEAT (0.06 ± 0.008 kg.kg MM-1) with relative leg press strength showing no improvement. Agility improved in the HEAT group at five weeks (0.3 s ± 0.16 s, p<0.05), however it was not different from pre intervention at post intervention. Agility did not improve in the CON group. No improvements were observed in 5m or 10m sprint time, or peak force generated in squat jump or ballistic push up in either group. Total upper body muscle mass increased in each group at post intervention, CON (1507.0 g ± 293.1 g, p<0.05), HEAT (806.6 g ± 213.9 g p<0.05) along with total muscle mass, CON (1760.8 g ± 306.4 g p<0.05) and HEAT (971.0 g ± 335.1 g p<0.05). Lower body muscle mass did not increase in either group. Total fat mass did not alter in either group pre to post intervention. These results indicate that, overall, heat stress applied concurrently with long term RT does not improve upon performance gains.

نقش شدت تمرین مقاومتی بر تغییرات هورمونی درگیر در هایپرتروفی

Background: The aim of this study was to Investigating the role of resistance training intensity on hormonal changes involved in hypertrophy and performance of bodybuilding athletes. Methods: For this purpose, 30 professional athletes were randomly divided into three groups of intense periodic resistance training, traditional resistance training and controls were divided. After initial sampling, the intervention groups were active for 12 weeks. Blood samples were taken 48 hours after the last training session to remove the response to the last training session. All data were analyzed at the significant level P≤0.05. Results: The results showed that testosterone, weight, fat percentage and body mass index in the periodic resistance training group had a significant change compared to the control group and traditional resistance training (P 0.05). However, these incremental changes have been more pronounced in the periodic resistance group. However, no significant change was observed in insulin, insulin resistance, glucose and glucagon (P>0.05). Discussion and Conclusion: The intensity of training seems to be an important and influential factor in the rate of change in factors related to athletes' performance. But it did not change the hormonal status of the athletes. Of course, more research is needed in the future to reach a definitive conclusion.

Marine phytoplankton improves recovery and sustains immune function in humans and lowers proinflammatory immunoregulatory cytokines in a rat model.

[Purpose] This study investigated the effects of marine phytoplankton supplementation (Oceanix®, Tetraselmis chuii) on 1) maximal isometric strength and immune function in healthy humans following a oneweek high-intensity resistance-training program and 2) the proinflammatory cytokine response to exercise in a rat model.[Methods] In the human trial, 22 healthy male and female participants were randomly divided into marine phytoplankton and placebo groups. Following baseline testing, participants underwent a 14-day supplement loading phase before completing five consecutive days of intense resistance training. In the rat model, rats were randomly divided into four groups (n=7 per condition): (i) control, (ii) exercise, (iii) exercise + marine phytoplankton (2.55 mg/kg/day), or (iv) exercise + marine phytoplankton (5.1 mg/kg/day). Rats in the exercising groups performed treadmill exercise 5 days per week for 6 weeks.[Results] In the human model, marine phytoplankton prevented significant declines in the isometric peak rate of force development compared to placebo. Additionally, salivary immunoglobulin A concentration was significantly lower following the resistance training protocol in the placebo group but not in the marine phytoplankton group. Marine phytoplankton in exercising rats decreased intramuscular levels and serum concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) and intramuscular concentrations of malondialdehyde.[Conclusion] Marine phytoplankton prevented decrements in indices of functional exercise recovery and immune function. Mechanistically, these outcomes could be prompted by modulating the oxidative stress and proinflammatory cytokine response to exercise.

Upper Threshold for Resistance Training Volume in Trained Women-RETRACTION.

Medicine & Science in Sports & Exercise: June 2021 - Volume 53 - Issue 6 - p 1318 doi: 10.1249/MSS.0000000000002672

Differences between adjusted vs. non-adjusted loads in velocity-based training: consequences for strength training control and programming

Strength and conditioning specialists commonly deal with the quantification and selection the setting of protocols regarding resistance training intensities. Although the one repetition maximum (1RM) method has been widely used to prescribe exercise intensity, the velocity-based training (VBT) method may enable a more optimal tool for better monitoring and planning of resistance training (RT) programs. The aim of this study was to compare the effects of two RT programs only differing in the training load prescription strategy (adjusting or not daily via VBT) with loads from 50 to 80% 1RM on 1RM, countermovement (CMJ) and sprint. Twenty-four male students with previous experience in RT were randomly assigned to two groups: adjusted loads (AL) (n = 13) and non-adjusted loads (NAL) (n = 11) and carried out an 8-week (16 sessions) RT program. The performance assessment pre- and post-training program included estimated 1RM and full load-velocity profile in the squat exercise; countermovement jump (CMJ); and 20-m sprint (T20). Relative intensity (RI) and mean propulsive velocity attained during each training session (Vsession) was monitored. Subjects in the NAL group trained at a significantly faster Vsession than those in AL (p < 0.001) (0.88–0.91 vs. 0.67–0.68 m/s, with a ∼15% RM gap between groups for the last sessions), and did not achieve the maximum programmed intensity (80% RM). Significant differences were detected in sessions 3–4, showing differences between programmed and performed Vsession and lower RI and velocity loss (VL) for the NAL compared to the AL group (p < 0.05). Although both groups improved 1RM, CMJ and T20, NAL experienced greater and significant changes than AL (28.90 vs.12.70%, 16.10 vs. 7.90% and −1.99 vs. −0.95%, respectively). Load adjustment based on movement velocity is a useful way to control for highly individualised responses to training and improve the implementation of RT programs.