Hormonal responses and adaptations to resistance exercise and training

Effects of Menstrual Phase-Dependent Resistance Training Frequency on Muscular Hypertrophy and Strength

The present study investigated how different training frequencies during menstrual phases affect muscle hypertrophy and strength. Fourteen eumenorrheic women performed 3 sets of arm curls (8-15 repetitions) until failure for 12 weeks. Depending on the menstrual cycle phase, each subject trained each arm separately after either a 3- or a 1-d·wk training protocol during the follicular phase (FP-T) and a 3- or 1-d·wk training protocol during the luteal phase (LP-T). Cross-sectional area (CSA), 1 repetition maximum, and maximum voluntary contraction significantly increased 6.2 ± 4.4, 36.4 ± 11.9, and 16.7 ± 5.6%, respectively (p ≤ 0.05 vs. before training), in the FP-T group and 7.8 ± 4.2, 31.8 ± 14.1, and 14.9 ± 12.7%, respectively (p ≤ 0.05 vs. before training), in the LP-T group. Changes in CSA between the FP-T and the LP-T groups significantly and positively correlated (r = 0.54, p ≤ 0.05). There were no major differences among the different training protocols with regard to muscle hypertrophy and strength. Therefore, we suggest that variations in female hormones induced by the menstrual cycle phases do not significantly contribute to muscle hypertrophy and strength gains during 12 weeks of resistance training.

Association Between MCT1 A1470T Polymorphism and Fat-Free Mass in Well-Trained Young Soccer Players

The aim of this study was to investigate the association between the MCT1 A1470T polymorphism and fat-free mass in young Italian elite soccer players. Participants were 128 Italian male soccer players. Fat-free mass was estimated for each of the soccer player using age- and gender-specific formulas with plicometry. Genotyping for the MCT1 A1470T polymorphism was performed using polymerase chain reaction. The MCT1 A1470T genotypes were in agreement with the Hardy-Weinberg equilibrium distribution. The percentage of fat-free mass was significantly higher in soccer players with the TT genotype and in the T-allele-dominant model group (TT + AT) compared with the soccer players with the AA genotype. The MCT1 T allele is associated with the percentage of fat-free mass in young elite male soccer players. Elucidating the genetic basis of body composition in athletes could potentially be used as an additional tool for strength and conditioning professionals in planning and adjusting training. However, these results are preliminary and need to be replicated in more cohorts.

Short-Term Unilateral Resistance Training Results in Cross Education of Strength Without Changes in Muscle Size, Activation, or Endocrine Response

Short-term unilateral resistance training results in cross education of strength without changes in muscle size, activation, or endocrine response. J Strength Cond Res 30(5): 1213-1223, 2016-The purpose of this study was to assess the cross education of strength and changes in the underlying mechanisms (muscle size, activation, and hormonal response) after a 4-week unilateral resistance training (URT) program. A group of 9 untrained men completed a 4-week URT program on the dominant leg (DOM), whereas cross education was measured in the nondominant leg (NON); and were compared with a control group (n = 8, CON). Unilateral isometric force (PKF), leg press (LP) and leg extension (LE) strength, muscle size (by ultrasonography) and activation (by electromyography) of the rectus femoris and vastus lateralis, and the hormonal response (testosterone, growth hormone, insulin, and insulin-like growth factor-1) were tested pretraining and posttraining. Group × time interactions were present for PKF, LP, LE, and muscle size in DOM and for LP in NON. In all interactions, the URT group improved significantly better than CON. There was a significant acute hormonal response to URT, but no chronic adaptation after the 4-week training program. Four weeks of URT resulted in an increase in strength and size of the trained musculature, and cross education of strength in the untrained musculature, which may occur without detectable changes in muscle size, activation, or the acute hormonal response.

Effects of morning versus evening combined strength and endurance training on physical performance, muscle hypertrophy, and serum hormone concentrations

This study investigated the effects of 24 weeks of morning versus evening same-session combined strength (S) and endurance (E) training on physical performance, muscle hypertrophy, and resting serum testosterone and cortisol diurnal concentrations. Forty-two young men were matched and assigned to a morning (m) or evening (e) E + S or S + E group (mE + S, n = 9; mS + E, n = 9; eE + S, n = 12; and eS + E, n = 12). Participants were tested for dynamic leg press 1-repetition maximum (1RM) and time to exhaustion (Texh) during an incremental cycle ergometer test both in the morning and evening, cross-sectional area (CSA) of vastus lateralis and diurnal serum testosterone and cortisol concentrations (0730 h; 0930 h; 1630 h; 1830 h). All groups similarly increased 1RM in the morning (14%–19%; p < 0.001) and evening (18%–24%; p < 0.001). CSA increased in all groups by week 24 (12%–20%, p < 0.01); however, during the training weeks 13–24 the evening groups gained more muscle mass (time-of-day main effect; p < 0.05). Texh increased in all groups in the morning (16%–28%; p < 0.01) and evening (18%–27%; p < 0.001), however, a main effect for the exercise order, in favor of E + S, was observed on both testing times (p < 0.051). Diurnal rhythms in testosterone and cortisol remained statistically unaltered by the training order or time. The present results indicate that combined strength and endurance training in the evening may lead to larger gains in muscle mass, while the E + S training order might be more beneficial for endurance performance development. However, training order and time seem to influence the magnitude of adaptations only when the training period exceeded 12 weeks.

Paradoxical Sleep Deprivation Causes Cardiac Dysfunction and the Impairment Is Attenuated by Resistance Training

Background

Paradoxical sleep deprivation activates the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis, subsequently interfering with the cardiovascular system. The beneficial effects of resistance training are related to hemodynamic, metabolic and hormonal homeostasis. We hypothesized that resistance training can prevent the cardiac remodeling and dysfunction caused by paradoxical sleep deprivation.

Methods

Male Wistar rats were distributed into four groups: control (C), resistance training (RT), paradoxical sleep deprivation for 96 hours (PSD96) and both resistance training and sleep deprivation (RT/PSD96). Doppler echocardiograms, hemodynamics measurements, cardiac histomorphometry, hormonal profile and molecular analysis were evaluated.

Results

Compared to the C group, PSD96 group had a higher left ventricular systolic pressure, heart rate and left atrium index. In contrast, the left ventricle systolic area and the left ventricle cavity diameter were reduced in the PSD96 group. Hypertrophy and fibrosis were also observed. Along with these alterations, reduced levels of serum testosterone and insulin-like growth factor-1 (IGF-1), as well as increased corticosterone and angiotensin II, were observed in the PSD96 group. Prophylactic resistance training attenuated most of these changes, except angiotensin II, fibrosis, heart rate and concentric remodeling of left ventricle, confirmed by the increased of NFATc3 and GATA-4, proteins involved in the pathologic cardiac hypertrophy pathway.

Conclusions

Resistance training effectively attenuates cardiac dysfunction and hormonal imbalance induced by paradoxical sleep deprivation.

Immunometabolic Responses after Short and Moderate Rest Intervals to Strength Exercise with and without Similar Total Volume

This study investigated the influence of short and moderate intervals of recovery with and without equated volume during an acute bout exhaustive strength exercise on metabolic, hormonal and inflammatory responses in healthy adults. Eight physically active men (23.5 ± 3.1) performed three randomized sequences: Short (70% of 1 RM with 30 s of rest); Moderate (70% of 1 RM with 90 s of rest); and Volume-Equated Short (70% of 1 RM with 30 s of rest between sets with a repetition volume equal to that performed in Moderate). All sequences of exercises were performed until movement failure in the squat, bench press and T-bar row exercises, respectively. Glucose, lactate, testosterone, IL-6, IL-10, IL-1ra, and MCP-1 levels were assessed at rest, immediate post-exercise, and 1 h post. There was a main effect of time for testosterone (p < 0.001). The post hoc indicated differences between post-exercise and rest and post-1 h and post-exercise (p < 0.001). Lactate increased post-exercise when compared to pre and post-1 h (p < 0.001) and maintained higher post-1 h in relation to rest. IL-6 was greater post-exercise than rest (p = 0.045) and post-1 h and rest (p = 0.020). IL-10 was greater post-exercise (p = 0.007) and post-1 h (p = 0.002) than rest. IL-1ra increased post-exercise in relation to rest (p = 0.003) and MCP-1 was greater post-exercise than rest (p < 0.001) and post-1 h (p = 0.043). There were no significant differences between conditions or interaction. Thus, both short and moderate intervals of recovery induced greater metabolic, hormonal and inflammatory responses after acute bout of exhaustive strength exercise in healthy adult.

Neuroendocrine Responses and Body Composition Changes Following Resistance Training Under Normobaric Hypoxia

The aim of the present study was to evaluate the effects of a 6 week resistance training protocol under hypoxic conditions (FiO2 = 12.9%, 4000 m) on muscle hypertrophy. The project included 12 resistance trained male subjects, randomly divided into two experimental groups. Group 1 (n = 6; age 21 ± 2.4 years; body height [BH] 178.8 ± 7.3 cm; body mass [BM] 80.6 ± 12.3 kg) and group 2 (n = 6; age 22 ± 1.5 years; BH 177.8 ± 3.7cm; BM 81.1 ± 7.5 kg). Each group performed resistance exercises alternately under normoxic and hypoxic conditions (4000 m) for 6 weeks. All subjects followed a training protocol that comprised two training sessions per week at an exercise intensity of 70% of 1RM; each training session consisted of eight sets of 10 repetitions of the bench press and barbell squat, with 3 min rest periods. The results indicated that strength training in normobaric hypoxia caused a significant increase in BM (p < 0.01) and fat free mass (FFM) (p < 0.05) in both groups. Additionally, a significant increase (p < 0.05) was observed in IGF-1 concentrations at rest after 6 weeks of hypoxic resistance training in both groups. The results of this study allow to conclude that resistance training (6 weeks) under normobaric hypoxic conditions induces greater muscle hypertrophy compared to training in normoxic conditions.

Modified Daily Undulating Periodization Model Produces Greater Performance Than a Traditional Configuration in Powerlifters

The primary aim of this study was to compare 2 daily undulating periodization (DUP) models on one-repetition maximum (1RM) strength in the squat, bench press, deadlift, total volume (TV) lifted, and temporal hormone response. Eighteen male, college-aged (21.1 ± 1.9 years) powerlifters participated in this study and were assigned to one of 2 groups: (a) traditional DUP training with a weekly training order: hypertrophy-specific, strength-specific, and power-specific training (HSP, n = 9) or (b) modified DUP training with a weekly training order: hypertrophy-specific, power-specific, and strength-specific training (HPS, n = 9). Both groups trained 3 nonconsecutive days per week for 6 weeks and performed the squat, bench press, and deadlift exercises. During hypertrophy and power sessions, subjects performed a fixed number of sets and repetitions but performed repetitions until failure at a given percentage during strength sessions to compare TV. Testosterone and cortisol were measured at pretesting and posttesting and before each strength-specific day. Hypertrophy, power, and strength produced greater TV in squat and bench press (p ≤ 0.05) than HSP, but not for deadlift (p > 0.05). For squat and deadlift, there was no difference between groups for 1RM (p > 0.05); however, HPS exhibited greater increases in 1RM bench press than HSP (p ≤ 0.05). Effect sizes (ES) showed meaningful differences (ES > 0.50) in favor of HPS for squat and bench press 1RM. Testosterone decreased (p ≤ 0.05) at weeks 5 and 6 and cortisol decline at weeks 3 and 4. However, neither hormone was different at posttesting compared with pretesting (p > 0.05). Our findings suggest that an HPS configuration of DUP has enhanced performance benefits compared with HSP.

Physiological Effects of Nucleotide Supplementation on Resistance Exercise Stress in Men and Women

Nucleotide supplementation can reduce postexercise immunosuppression and hypothalamic-pituitary axis (HPA) axis activation in endurance exercise models. Nucleotide supplementation may aid recovery from other exercise modalities, such as heavy resistance exercise. Thus, the purpose of this investigation was to investigate the effects of nucleotide supplementation on the acute cortisol and immune responses to heavy resistance exercise and its effects on recovery. A double-blinded, crossover, mixed methods design with 10 men and 10 women was used. Each performed an acute heavy resistance exercise protocol (AHREP) after a loading period with a nucleotide or placebo supplement. Before and after the AHREP, and at 24, 48, and 72 hours post, blood samples were analyzed for cortisol, myeloperoxidase (MPO), and absolute neutrophil, lymphocyte, and monocyte counts. Creatine kinase (CK) was analyzed before and 24, 48, and 72 hours after the AHREP. Performance measures, including peak back squat isometric force and peak countermovement jump power were also analyzed. Nucleotide supplementation resulted in significant (p ≤ 0.05) decreases in cortisol and MPO immediately after the AHREP, and significantly lower CK values 24 hours later. The AHREP significantly affected leukocyte counts; however, no treatment effects were observed. Greater isometric force was observed immediately after AHREP and at 24 hours and 48 hours with nucleotide supplementation. Nucleotide supplementation seems to attenuate muscle damage, HPA axis and immune system activation, and performance decrements after heavy resistance exercise.

Exercise-induced skeletal muscle signaling pathways and human athletic performance

Skeletal muscle is a highly malleable tissue capable of altering its phenotype in response to external stimuli including exercise. This response is determined by the mode, (endurance- versus resistance-based), volume, intensity and frequency of exercise performed with the magnitude of this response-adaptation the basis for enhanced physical work capacity. However, training-induced adaptations in skeletal muscle are variable and unpredictable between individuals. With the recent application of molecular techniques to exercise biology, there has been a greater understanding of the multiplicity and complexity of cellular networks involved in exercise responses. This review summarizes the molecular and cellular events mediating adaptation processes in skeletal muscle in response to exercise. We discuss established and novel cell signaling proteins mediating key physiological responses associated with enhanced exercise performance and the capacity for reactive oxygen and nitrogen species to modulate training adaptation responses. We also examine the molecular bases underpinning heterogeneous responses to resistance and endurance exercise and the dissociation between molecular 'markers' of training adaptation and subsequent exercise performance.

Ultrasound evaluation of the subacromial space in healthy subjects performing three different positions of shoulder abduction in both loaded and unloaded conditions

BACKGROUND

Subacromial space (SS) narrowing may result in unsafe contact of rotator cuff tendons and bursa with the acromion, possibly promoting rotator cuff pathologies and pain. We measured SS in asymptomatic subjects after three movements employed for shoulder muscles' training.

PARTICIPANTS AND MAIN OUTCOME MEASURES

Twenty-five males (age 24±5years; stature 175±8 cm; body mass 74±12 kg) underwent SS ultrasound evaluation while executing with (WL) and without (NL) 4-kg load: 90° shoulder abduction (SA) without humerus rotation (90°_neutral); 90° SA maximal humeral external rotation (90°_er); maximum SA (above 90°) during upright row (UR). For inter-operator reliability analysis, a subset of 12 subjects was assessed by two operators.

RESULTS

Intra/inter-operator reliability coefficients were high (ICC>0.87; standard error of measurement range: 0.23-0.51 mm; minimum detectable change range: 0.61-1.79 mm). ANOVA revealed significant differences between loads (p = 0.003, η² = 0.37) and angles (p < 0.001, η² = 0.72), and interaction (p = 0.004, η² = 0.45). Normalized SS values WL were higher at 90°_er vs. 90°_neutral and UR (p < 0.001 for both). Differences in NL were found between 90°_neutral and both 90°_er (p = 0.002) and UR (p = 0.009).

CONCLUSIONS

When holding a 4-kg load, SS is larger at 90°_er than at 90°_neutral and UR shoulder abduction positions. In unloaded condition, SS at 90°_neutral is reduced compared to 90°_er and UR.

Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men

We reported, using a unilateral resistance training (RT) model, that training with high or low loads (mass per repetition) resulted in similar muscle hypertrophy and strength improvements in RT-naïve subjects. Here we aimed to determine whether the same was true in men with previous RT experience using a whole-body RT program and whether postexercise systemic hormone concentrations were related to changes in hypertrophy and strength. Forty-nine resistance-trained men (23 ± 1 yr, mean ± SE) performed 12 wk of whole-body RT. Subjects were randomly allocated into a higher-repetition (HR) group who lifted loads of ∼30-50% of their maximal strength (1RM) for 20-25 repetitions/set (n = 24) or a lower-repetition (LR) group (∼75-90% 1RM, 8-12 repetitions/set, n = 25), with all sets being performed to volitional failure. Skeletal muscle biopsies, strength testing, dual-energy X-ray absorptiometry scans, and acute changes in systemic hormone concentrations were examined pretraining and posttraining. In response to RT, 1RM strength increased for all exercises in both groups (P < 0.01), with only the change in bench press being significantly different between groups (HR, 9 ± 1, vs. LR, 14 ± 1 kg, P = 0.012). Fat- and bone-free (lean) body mass and type I and type II muscle fiber cross-sectional area increased following training (P < 0.01) with no significant differences between groups. No significant correlations between the acute postexercise rise in any purported anabolic hormone and the change in strength or hypertrophy were found. In congruence with our previous work, acute postexercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength. Our data show that in resistance-trained individuals, load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains.

Effects of endurance training only versus same-session combined endurance and strength training on physical performance and serum hormone concentrations in recreational endurance runners

This study investigated the effects of endurance training only (E, n = 14) and same-session combined training, when strength training is repeatedly preceded by endurance loading (endurance and strength training (E+S), n = 13) on endurance (1000-m running time during incremental field test) and strength performance (1-repetition maximum (1RM) in dynamic leg press), basal serum hormone concentrations, and endurance loading-induced force and hormone responses in recreationally endurance-trained men. E was identical in the 2 groups and consisted of steady-state and interval running, 4-6 times per week for 24 weeks. E+S performed additional mixed-maximal and explosive-strength training (2 times per week) immediately following an incremental running session (35-45 min, 65%-85% maximal heart rate). E and E+S decreased running time at week 12 (-8% ± 5%, p = 0.001 and -7% ± 3%, p < 0.001) and 24 (-13% ± 5%, p < 0.001 and -9% ± 5%, p = 0.001). Strength performance decreased in E at week 24 (-5% ± 5%, p = 0.014) but was maintained in E+S (between-groups at week 12 and 24, p = 0.014 and 0.011, respectively). Basal serum testosterone and cortisol concentrations remained unaltered in E and E+S but testosterone/sex hormone binding globulin ratio decreased in E+S at week 12 (-19% ± 26%, p = 0.006). At week 0 and 24, endurance loading-induced acute force (-5% to -9%, p = 0.032 to 0.001) and testosterone and cortisol responses (18%-47%, p = 0.013 to p < 0.001) were similar between E and E+S. This study showed no endurance performance benefits when strength training was performed repeatedly after endurance training compared with endurance training only. This was supported by similar acute responses in force and hormonal measures immediately post-endurance loading after the training with sustained 1RM strength in E+S.

The Effects of Different Warm-up Volumes on the 100-m Swimming Performance: A Randomized Crossover Study

The aim of this study was to compare the effect of 3 different warm-up (WU) volumes on 100-m swimming performance. Eleven male swimmers at the national level completed 3 time trials of 100-m freestyle on separate days and after a standard WU, a short WU (SWU), or a long WU (LWU) in a randomized sequence. All of them replicated some usual sets and drills, and the WU totaled 1,200 m, the SWU totaled 600 m, and the LWU totaled 1,800 m. The swimmers were faster after the WU (59.29 seconds; confidence interval [CI] 95%, 57.98-60.61) and after the SWU (59.38 seconds; CI 95%, 57.92-60.84) compared with the LWU (60.18 seconds; CI 95%, 58.53-61.83). The second 50-m lap after the WU was performed with a higher stroke length (effect size [ES] = 0.77), stroke index (ES = 1.26), and propelling efficiency (ES = 0.78) than that after the SWU. Both WU and SWU resulted in higher pretrial values of blood lactate concentrations [La] compared with LWU (ES = 1.58 and 0.74, respectively), and the testosterone:cortisol levels were increased in WU compared with LWU (ES = 0.86). In addition, the trial after WU caused higher [La] (ES ≥ 0.68) and testosterone:cortisol values compared with the LWU (ES = 0.93). These results suggest that an LWU could impair 100-m freestyle performance. The swimmers showed higher efficiency during the race after a 1200-m WU, suggesting a favorable situation. It highlighted the importance of the [La] and hormonal responses to each particular WU, possibly influencing performance and biomechanical responses during a 100-m race.

The effects of a roundtrip trans-American jet travel on physiological stress, neuromuscular performance, and recovery

The purpose was to examine the effects of a round trip trans-American jet travel on performance, hormonal alterations, and recovery. Ten matched pairs of recreationally trained men were randomized to either a compression group (COMP) (n = 10; age: 23.1 ± 2.4 yr; height: 174.8 ± 5.3 cm; body mass: 84.9 ± 10.16 kg; body fat: 15.3 ± 6.0%) or control group (CONT) (n = 9; age: 23.2 ± 2.3 yr; height: 177.5 ± 6.3 cm; weight: 84.3 ± 8.99 kg; body fat: 15.1 ± 6.4%). Subjects flew directly from Hartford, CT to Los Angeles, CA 1 day before a simulated sport competition (SSC) designed to create muscle damage and returned the next morning on an overnight flight back home. Both groups demonstrated jet lag symptoms and associated decreases in sleep quality at all time points. Melatonin significantly (P < 0.05) increased over the first 2 days and then remained constant until after the SSC. Epinephrine, testosterone, and cortisol values significantly increased above resting values before and after the SSC with norepinephrine increases only after the SSC. Physical performances significantly decreased from control values on each day for the CONT group with COMP group exhibiting no significant declines. Muscle damage markers were significantly elevated following the SSC with the COMP group having significantly lower values while maintaining neuromuscular performance measures that were not different from baseline testing. Trans-American jet travel has a significant impact on parameters related to jet lag, sleep quality, hormonal responses, muscle tissue damage markers, and physical performance with an attenuation observed with extended wear compression garments.

Strengthening the Gluteus Medius Using Various Bodyweight and Resistance Exercises

THE GLUTEUS MEDIUS (Gmed) IS AN IMPORTANT MUSCLE AND, IF WEAK, CAN CAUSE KNEE, HIP, OR LOWER-BACK PATHOLOGIES. THIS ARTICLE REVIEWS METHODS OF Gmed STRENGTH ASSESSMENT, PROVIDES EXERCISES THAT TARGET THE Gmed BASED ON ELECTROMYOGRAPHY, PRESENTS HOW TO IMPLEMENT Gmed STRENGTHENING IN HEAVY RESISTANCE TRAINING PROGRAMS, AND EXPLAINS THE IMPORTANCE OF INCLUDING THESE EXERCISES IN THESE PROGRAMS.

Short inter-set rest blunts resistance exercise-induced increases in myofibrillar protein synthesis and intracellular signalling in young males

What is the central question of this study? Does shorter rest between sets of resistance exercise promote a superior circulating hormonal and acute muscle anabolic response compared with longer rest periods? What is the main finding and its importance? We demonstrate that short rest (1 min) between sets of moderate-intensity, high-volume resistance exercise blunts the acute muscle anabolic response compared with a longer rest period (5 min), despite a superior circulating hormonal milieu. These data have important implications for the development of training regimens to maximize muscle hypertrophy. Manipulating the rest-recovery interval between sets of resistance exercise may influence training-induced muscle remodelling. The aim of this study was to determine the acute muscle anabolic response to resistance exercise performed with short or long inter-set rest intervals. In a study with a parallel-group design, 16 males completed four sets of bilateral leg-press and knee-extension exercise at 75% of one-repetition maximum to momentary muscular failure, followed by ingestion of 25 g of whey protein. Resistance exercise sets were interspersed by 1 min (n = 8) or 5 min of passive rest (n = 8). Muscle biopsies were obtained at rest, 0, 4, 24 and 28 h postexercise during a primed continuous infusion of l-[ring-(13) C6 ]phenylalanine to determine myofibrillar protein synthesis and intracellular signalling. We found that the rate of myofibrillar protein synthesis increased above resting values from 0 to 4 h postexercise with 1 (76%; P = 0.047) and 5 min inter-set rest (152%; P < 0.001) and was significantly greater in the 5 min inter-set rest group (P = 0.001). Myofibrillar protein synthesis rates at 24-28 h postexercise remained elevated above resting values (P < 0.05) and were indistinguishable between groups. Postexercise p70S6K(Thr389) and rpS6(Ser240/244) phosphorylation were reduced with 1 compared with 5 min inter-set rest, whereas phosphorylation of eEF2(Thr56) , TSC2(Thr1462) , AMPK(Thr172) and REDD1 protein were greater for 1 compared with 5 min inter-set rest. Serum testosterone was greater at 20-40 min postexercise and plasma lactate greater immediately postexercise for 1 versus 5 min inter-set rest. Resistance exercise with short (1 min) inter-set rest duration attenuated myofibrillar protein synthesis during the early postexercise recovery period compared with longer (5 min) rest duration, potentially through compromised activation of intracellular signalling.

Energetic interventions for healthspan and resiliency with aging

Several behavioral and pharmacological strategies improve longevity, which is indicative of delayed organismal aging, with the most effective interventions extending both life- and healthspan. In free living creatures, maintaining health and function into old age requires resilience against a multitude of stressors. Conversely, in experimental settings, conventional housing of rodents limits exposure to such challenges, thereby obscuring an accurate assessment of resilience. Caloric restriction (CR) and exercise, as well as pharmacologic strategies (resveratrol, rapamycin, metformin, senolytics), are well established to improve indices of health and aging, but some paradoxical effects have been observed on resilience. For instance, CR potently retards the onset of age-related diseases, and improves lifespan to a greater extent than exercise in a variety of models. However, exercise has proven more consistently beneficial to organismal resilience against a broad array of stressors, including infections, surgery, wound healing and frailty. CR can improve cellular stress defenses and protect from frailty, but also impairs the response to infections, bed rest and healing. How an intervention will impact not only longevity, health and function, but also resiliency, is critical to better understanding translational implications. Thus, organismal robustness represents a critical, albeit understudied aspect of aging, which needs more careful attention in order to better inform on how putative age-delaying strategies will impact preservation of health and function in response to stressors with aging in humans.

Salivary cortisol and testosterone responses to resistance and plyometric exercise in 12- to 14-year-old boys

This study examined changes in salivary testosterone and cortisol following resistance and plyometric exercise protocols in active boys. In a crossover experimental design, 26 peri-pubertal (12- to 14-year-old) soccer players performed 2 exercise trials in random order, on separate evenings, 1 week apart. Each trial included a 30 min control session followed by 30 min of either resistance or plyometric exercise. Saliva was collected at baseline, post-control (i.e., pre-exercise), and 5 and 30 min post-exercise. There were no significant differences in the baseline hormone concentrations between trials or between weeks (p > 0.05). A significant effect for time was found for testosterone (p = 0.02, [Formula: see text] = 0.14), which increased from pre-exercise to 5 min post-exercise in both the resistance (27% ± 5%) and plyometric (12% ± 6%) protocols. Cortisol decreased to a similar extent in both trials (p = 0.009, [Formula: see text] = 0.19) from baseline to post-control and then to 5 min post-exercise, following its typical circadian decrease in the evening hours. However, a significant protocol-by-time interaction was observed for cortisol, which increased 30 min after the plyometrics (+31% ± 12%) but continued to decrease following the resistance protocol (-21% ± 5%). Our results suggest that in young male athletes, multiple modes of exercise can lead to a transient anabolic state, thus maximizing the beneficial effects on growth and development, when exercise is performed in the evening hours.

Does Testosterone Modulate Mood States and Physical Performance in Young Basketball Players?

This study aimed to examine and compare mood states profile and physical performance during different training phases between 2 groups of adolescent basketball players that were differentiated according to baseline testosterone concentration (T). The basketball players were submitted to an intensified training period (OVL) followed by a tapering period (TP). Twenty-three young male basketball players initiated the study. Experimental criteria data were used to stratify 16 players into high-testosterone (HTC) or low-testosterone (LTC) concentration groups. All the 16 athletes undertook 5 weeks of OVL followed by a 3-week TP. Saliva sampling, Yo-Yo intermittent recovery level 1 (Yo-Yo IRL1) test and the T-test were conducted at the beginning (T1), after OVL (T2), and after TP (T3). A similar increase in internal training load was observed during OVL when compared with TP in both groups (p < 0.05). No difference in mood states was observed between groups (p > 0.05); however, LTC displayed a higher score for fatigue (p < 0.05) and a lower score for energy index (p < 0.05) in OVL, compared with TP. A significant improvement in the Yo-Yo IRL1 test and the T-test was observed (T1 to T3) (p < 0.05), with no difference between groups (p > 0.05). In conclusion, these results suggest that LTC athletes may be more susceptible to changes in mood states during intensified training periods. In addition, data indicate that a periodized training program successfully improved the physical performance (endurance and agility) of young basketball players; however, this improvement was not affected by testosterone level.

Effects of combined training vs aerobic training on cognitive functions in COPD: a randomized controlled trial

Aim

The aim of this study was to investigate the effects of high-intensity aerobic training (AT) and high-intensity aerobic training combined with resistance training (ie, combined training [CT]) on cognitive function in patients with COPD.

Methods

Twenty-eight Caucasian male patients (68.35±9.64 years; mean ± SD) with COPD were recruited and randomized into two groups, AT and CT. Both groups performed physical reconditioning for 4 weeks, with a frequency of five training sessions per week. The CT group completed two daily sessions of 30 minutes: one aerobic session and one strength session, respectively; The AT group performed two 30-minute aerobic endurance exercise sessions on treadmill. Physical and cognitive function tests were performed before and after the training intervention performances.

Results

Exercise training improved the following cognitive functions: long-term memory, verbal fluency, attentional capacity, apraxia, and reasoning skills (P<0.01). Moreover, the improvements in the CT group were significantly greater than those in the AT group in long-term memory, apraxia, and reasoning skills (P<0.05).

Conclusion

CT may be a possible strategy to prevent cognitive decline and associated comorbidities in male patients with COPD.

Neurotrophic growth factor responses to lower body resistance training in older adults

Resistance exercise is an efficacious stimulus for improving cognitive function in older adults, which may be mediated by the upregulation of blood-borne neurotrophic growth factors (NTFs) like brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1). However, the NTF response to resistance exercise and training in older adults is poorly understood. Therefore, the purpose of this study was to characterize the timing and magnitude of the NTF response following an acute bout of resistance exercise before and after 8 weeks of resistance training. Ten cognitively normal, older adults (ages 60–77 years, five men) were examined. The acute NTF response to resistance exercise was assessed via serum samples drawn at designated time points following exercise. This procedure was then repeated following 8 weeks of resistance training. BDNF increased immediately post-exercise (Δ9% pre-training, Δ11% post-training) then returned to resting levels while IGF-1 remained stable following resistance exercise before and after 8 weeks of resistance training. Basal levels of both NTFs were unaffected by the 8 week training period. We report a transient increase in serum BDNF following a bout of resistance exercise in older adults, which could have implications for the design of interventions seeking to maximize cognitive function in older adults.

Hormonal and Physiological Adaptations to High-Intensity Interval Training in Professional Male Canoe Polo Athletes

This study compared the effects of 2 different high-intensity interval training (HIIT) programs in professional male canoe polo athletes. Responses of peak oxygen uptake (VO2peak), ventilatory threshold (VT), peak and mean anaerobic power output (PPO and MPO), blood volume, and hormonal adaptations to HIIT were examined. Male athletes (n = 21, age: 24 ± 3 years; height: 181 ± 4 cm; mass: 85 ± 6 kg; and body fat: 12.9 ± 2.7%) were randomly assigned to one of 3 groups (N = 7): (a) (G1) interval paddling with variable volume (6, 7, 8, 9, 9, 9, 8, 7, 6 repetitions per session from first to ninth session, respectively) × 60 second at lowest velocity that elicited VO2peak (vVO2peak), 1:3 work to recovery ratio; (b) (G2) interval paddling with variable intensity (6 × 60 second at 100, 110, 120, 130, 130, 130, 120, 110, 100% vVO2peak from first to ninth session, respectively, 1:3 work to recovery); and (c) (GCON) the control group performed three 60 minutes paddling sessions (75% vVO2peak) per week for 3 weeks. High-intensity interval training resulted in significant (except as shown) increases compared with pretest, in VO2peak (G1 = +8.8% and G2 = +8.5%), heart rate at VT (b·min) (G1 = +9.7% and G2 = +5.9%) and (%maximum) (G1 = +6.9%; p = 0.29 and G2 = +6.5%), PPO (G1 = +9.7% and G2 = +12.2%), MPO (G1 = +11.1%; p = 0.29 and G2 = +16.2%), total testosterone (G1 = +29.4% and G2 = +16.7%), total testosterone/cortisol ratio (G1 = +40.9% and G2 = +28.1%), and mean corpuscular hemoglobin (G1 = +1.7% and G2 = +1.3%). No significant changes were found in GCON. High-intensity interval paddling may improve both aerobic and anaerobic performances in professional male canoe polo athletes under the conditions of this study.

Glucocorticoid Receptor (NR3C1) Variants Associate with the Muscle Strength and Size Response to Resistance Training

Glucocorticoid receptor (NR3C1) polymorphisms associate with obesity, muscle strength, and cortisol sensitivity. We examined associations among four NR3C1 polymorphisms and the muscle response to resistance training (RT). European-American adults (n = 602, 23.8±0.4yr) completed a 12 week unilateral arm RT program. Maximum voluntary contraction (MVC) assessed isometric strength (kg) and MRI assessed biceps size (cm2) pre- and post-resistance training. Subjects were genotyped for NR3C1 -2722G>A, -1887G>A, -1017T>C, and +363A>G. Men carrying the -2722G allele gained less relative MVC (17.3±1.2vs33.5±6.1%) (p = 0.010) than AA homozygotes; men with -1887GG gained greater relative MVC than A allele carriers (19.6±1.4vs13.2±2.3%) (p = 0.016). Women carrying the -1017T allele gained greater relative size (18.7±0.5vs16.1±0.9%) (p = 0.016) than CC homozygotes. We found sex-specific NR3C1 associations with the muscle strength and size response to RT. Future studies should investigate whether these associations are partially explained by cortisol's actions in muscle tissue as they interact with sex differences in cortisol production.

Exercise attenuates the major hallmarks of aging

Regular exercise has multi-system anti-aging effects. Here we summarize how exercise impacts the major hallmarks of aging. We propose that, besides searching for novel pharmaceutical targets of the aging process, more research efforts should be devoted to gaining insights into the molecular mediators of the benefits of exercise and to implement effective exercise interventions for elderly people.

Exercise-induced responses in salivary testosterone, cortisol, and their ratios in men: a meta-analysis

BACKGROUND

Testosterone, cortisol and their ratios may be indicators of anabolic status, but technical issues surrounding blood sampling has limited wider application. The advent of salivary testosterone (sal-T) analysis simplified sample acquisition, resulting in a subsequent rapid increase in the number of published research articles.

OBJECTIVE

The objective of this study was to undertake a meta-analysis to determine the effect of acute exercise bouts on post exercise sal-T and salivary cortisol (sal-C) concentrations and their ratio (sal-T:C).

DATA SOURCES

Relevant databases such as PubMed, Web of Science, Science Direct and SPORTDiscus were searched up to and including 31 December 2013 for the term 'saliva AND testosterone AND exercise'.

STUDY SELECTION

Studies (n = 21) selected from the 933 identified included randomised controlled trials (RCTs; n = 2), uncontrolled trials (UCTs; n = 18) and control trials (CTs; n = 1), all of which had an exercise component characterised as either aerobic, resistance or power training, each with acute sal-T and sal-C measurement obtained within 30 min of exercise bout completion.

STUDY APPRAISAL AND SYNTHESIS METHODS

A meta-analysis was conducted on change in sal-T, sal-C and the sal-T:C ratio following exercise using standard difference in means (SDM) and a random effects model.

RESULTS

For aerobic, resistance and power exercise, the overall SDMs for sal-T were 0.891, 1.061 and 0.509, respectively; for sal-C, the SDMs were 3.041, 0.773 and 1.200, respectively. For sal-T:C, the SDMs were -2.014, 0.027 and -0.968, respectively. RCTs, UCTs and CTs were separated by subgroup analysis. There were significant differences in overall weighted SDM values for sal-T between RCTs, UCTs and CTs within exercise modes. When examining aerobic exercise interventions, a quantitative interaction of study design was observed. RCTs resulted in a greater SDM than UCTs (1.337 vs. 0.446). Power interventions displayed a qualitative interaction with study design. UCTs where baseline measures were obtained 24 h before exercise had an SDM of -1.128, whereas UCTs where baseline was determined immediately prior to exercise had an SDM of 0.486. The single CT trial had an SDM of 2.260. Resistance exercise interventions were primarily UCTs; however, an observed influence of baseline sampling time whereby immediately pre- and 24 h pre-exercise resulted in differing SDMs. The sole resistance exercise RCTs resulted in the greatest SDM (2.500).

CONCLUSION

The current body of evidence regarding acute responses of sal-T to exercise is weak. This meta-analysis identifies varying exercise-dependent effect sizes. Each appear to be greatly influenced by study design and sample timing. There is a need for more RCTs and a standardised methodology for the measurement of salivary hormones in order to better determine the effect of exercise modality.

Short-Term High-Intensity Interval Training on Body Composition and Blood Glucose in Overweight and Obese Young Women

This study was to determine the effects of five-week high-intensity interval training (HIIT) on cardiorespiratory fitness, body composition, blood glucose, and relevant systemic hormones when compared to moderate-intensity continuous training (MICT) in overweight and obese young women. Methods. Eighteen subjects completed 20 sessions of HIIT or MICT for five weeks. HIIT involved 60 × 8 s cycling at ~90% of peak oxygen consumption ([Formula: see text]) interspersed with 12 s recovery, whereas MICT involved 40-minute continuous cycling at 65% of [Formula: see text]. [Formula: see text], body composition, blood glucose, and fasting serum hormones, including leptin, growth hormone, testosterone, cortisol, and fibroblast growth factor 21, were measured before and after training. Results. Both exercise groups achieved significant improvements in [Formula: see text] (+7.9% in HIIT versus +11.7% in MICT) and peak power output (+13.8% in HIIT versus +21.9% in MICT) despite no training effects on body composition or the relevant systemic hormones. Blood glucose tended to be decreased after the intervention (p = 0.062). The rating of perceived exertion in MICT was higher than that in HIIT (p = 0.042). Conclusion. Compared with MICT, short-term HIIT is more time-efficient and is perceived as being easier for improving cardiorespiratory fitness and fasting blood glucose for overweight and obese young women.

Effects of whole body vibration training on body composition, skeletal muscle strength, and cardiovascular health

Whole body vibration training (WBVT) has been used as a supplement to conventional exercise training such as resistance exercise training to improve skeletal muscle strength, specifically, in rehabilitation field. Recently, this exercise modality has been utilized by cardiovascular studies to examine whether WBVT can be a useful exercise modality to improve cardiovascular health. These studies reported that WBVT has not only beneficial effects on muscular strength but also cardiovascular health in elderly and disease population. However, its mechanism underlying the beneficial effects of WBVT in cardiovascular health has not been well documented. Therefore, this review highlighted the impacts of WBVT on cardiovascular health, and its mechanisms in conjunction with the improved muscular strength and body composition in various populations.

Effect of gender on the GH-IGF-I response to anaerobic exercise in young adults

Exercise-associated effects on the growth hormone-insulin-like growth factor-I (GH-IGF-I) axis were studied, mainly after aerobic exercise. We determined the gender effect on the GH-IGF-I axis response to a standard all-out Wingate anaerobic test (WAnT) in healthy active young adult men and women (men = 12 and women = 16; age range: 24-34 years). Blood samples for GH and IGF-I, key elements of the GH-IGF-I axis, were collected before and 20, 30, 40, and 60 minutes after the beginning of exercise. In addition, we collected postexercise blood lactate levels. Postexercise lactate levels were higher among men; however, this difference did not reach statistical significance (13.8 ± 1.3 vs. 11.1 ± 1.0 mmol·L, respectively; p = 0.1). The WAnT was associated with a significant increase in GH in both genders. However, GH peak was greater among women (10.8 ± 1.8 vs. 5.6 ± 1.4 ng·ml, in women and men, respectively; p < 0.01). In addition, postexercise GH peak occurred significantly earlier in female (20 minutes) compared with male participants (40 minutes). Exercise was associated with a significant increase in IGF only among men (from 166.8 ± 8.4 to 186.9 ± 9.3; p < 0.02); however, no significant between-gender effect was found. In summary, supramaximal anaerobic exercise was associated with a greater and earlier postexercise GH peak in women compared with men. All together, the results suggest anaerobic exercise-related anabolic-type hormonal response.

Cycling Exercise with Electrical Stimulation of Antagonist Muscles Increases Plasma Growth Hormone and IL-6

Performing aerobics and resistance exercise at exactly the same time has not been available although combining both types of exercise in one training program has been attempted. The hybrid training system (HTS) is a resistance exercise that combines voluntary concentric muscle contractions with electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on a cycle ergometer (HCE). Growth hormone (GH) and lactate are indicators of adequate training intensity. Interleukin-6 (IL-6) reflects enhancing lipid metabolism. The purpose of this study was to show that HCE provides sufficient exercise to stimulate the secretion of GH, lactate and IL-6. We compared an HCE test with cycle ergometer alone (CE). Ten healthy male subjects performed HCE and CE tests for 30 minutes each. The workload of both tests was set the same at 40% of each subject's peak oxygen uptake. For HCE, 2-minute HTS and 1-minute rest intervals were repeated. GH, lactate, and IL-6 were evaluated before and immediately after exercise, and at 15, 30 and 60 minutes. GH and lactate increased immediately after HCE. Moreover, the degree of the increases in GH after HCE (0 and 15 minutes) was higher than that after CE. IL-6 increased after HCE at 30 min, and the rate of change was higher than for CE. These results showed that HCE was more efficient in stimulating acute increases in GH, lactate and IL-6 than CE at the same workload. We may be able to combine electrically stimulated resistance exercise with aerobic exercise using HCE.

Acute responses of circulating microRNAs to low-volume sprint interval cycling

Low-volume high-intensity interval training is an efficient and practical method of inducing physiological responses in various tissues to develop physical fitness and may also change the expression of circulating microRNAs (miRNAs). The purpose of the present study was to examine whether miRNAs for muscle, heart, somatic tissue and metabolism were affected by 30-s intervals of intensive sprint cycling. We also examined the relationship of these miRNAs to conventional biochemical and performance indices. Eighteen healthy young males performed sprint interval cycling. Circulating miRNAs in plasma were detected using TaqMan-based quantitative PCR and normalized to Let-7d/g/i. In addition, we determined the levels of insulin-like growth factor-I, testosterone and cortisol, and anaerobic capacity. Compared to plasma levels before exercise muscle-specific miR-1 (0.12 ± 0.02 vs. 0.09 ± 0.02), miR-133a (0.46 ± 0.10 vs. 0.31 ± 0.06), and miR-133b (0.19 ± 0.02 vs. 0.10 ± 0.01) decreased (all P < 0.05), while miR-206 and miR-499 remained unchanged. The levels of metabolism related miR-122 (0.62 ± 0.07 vs. 0.34 ± 0.03) and somatic tissues related miR-16 (1.74 ± 0.27 vs. 0.94 ± 0.12) also decreased (both P < 0.05). The post-exercise IGF-1 and cortisol concentrations were significantly increased, while testosterone concentrations did not. Plasma levels of miR-133b correlated to peak power (r = 0.712, P = 0.001) and miR-122 correlated to peak power ratio (r = 0.665, P = 0.003). In conclusion sprint exercise provokes genetic changes for RNA related to specific muscle or metabolism related miRNAs suggesting that miR-133b and miR-122 may be potential useful biomarkers for actual physiological strain or anaerobic capacity. Together, our findings on the circulating miRNAs may provide new insight into the physiological responses that are being performed during exercise and delineate mechanisms by which exercise confers distinct phenotypes and improves performance.

Hormonal Responses to Active and Passive Recovery After Load Carriage

Military operations often induce fatigue resulting from load carriage. Recovery promotes military readiness. This study investigated the acute effects of AR vs. PR after load carriage on maximal isometric leg extension force (MVC) and serum hormonal concentrations. Male reservists (27 ± 3 years, 180 ± 7 cm, 74 ± 11 kg, V[Combining Dot Above]O2max 64 ± 9 ml·kg⁻¹·min⁻¹) completed PR (n = 8) or AR (n = 8) after 50 minutes of loaded (16 kg) uphill (gradient 4.0%) treadmill marching at individual anaerobic threshold. No differences were observed between groups in relative changes in MVC during the marching loading, after AR or PR or the next morning. Significant differences in relative responses to AR and PR postmarching loading were observed in serum testosterone (T), cortisol, and sex-hormone binding globulin immediately post AR and PR; however the next morning, all serum hormone concentrations had returned to normal. This study did not reveal any significant differences between the effects of AR and PR after an hour-long marching protocol at approximately anaerobic threshold on MVC or serum hormones the morning after the experimental marching protocol. Thus, based on the variable measured in this study, marching performed by physically fit army reservists at an intensity at or below anaerobic threshold may not necessitate specialized recovery protocols.

Effects of resistance exercise timing on sleep architecture and nocturnal blood pressure

Short sleep duration and poor quality of sleep have been associated with health risks including cardiovascular disease, diabetes, and obesity. Prior research has suggested that regular aerobic exercise improves the quality of sleep; however, less is known regarding resistance exercise (RE) and how RE may affect sleep architecture. The purpose of this study was to investigate the acute effects of timing of RE on sleep architecture and nocturnal blood pressure. College-aged subjects engaged in 5 laboratory visits. Visits 1 (C) and 2 provided a non-RE control day and established the 10-repetition maximum on each of 9 RE machines, respectively. During visits 3-5, the subjects reported at 0700 hours (7A), 1300 hours (1P), and 1900 hours (7P) in a randomized order to perform 30 minutes of RE. Ambulatory blood pressure and sleep-monitoring devices were worn during sleep after C, 7A, 1P, and 7P. Time to fall asleep was significantly different between RE conditions 7A and 1P and between 7A and 7P. All exercise conditions exhibited significantly fewer times woken than the non-RE control day, with 7P resulting in significantly less time awake after initially falling asleep as compared with C. Although timing of RE does not seem to statistically impact sleep stages or nocturnal blood pressure, these data indicate that engaging in RE at any time of the day may improve quality of sleep as compared with no RE. Resistance exercise may offer additional benefits regarding the ability to fall asleep and stay asleep to populations with osteoporosis, sarcopenia, anxiety, or depression.

Reduced susceptibility to eccentric exercise-induced muscle damage in resistance-trained men is not linked to resistance training-related neural adaptations

The purpose of this study was to examine the acute effects of maximal concentric vs. eccentric exercise on the isometric strength of the elbow flexor, as well as the biceps brachii muscle electromyographic (EMG) responses in resistance-trained (RT) vs. untrained (UT) men. Thirteen RT men (age: 24 ± 4 years; height: 180.2 ± 7.7 cm; body weight: 92.2 ± 16.9 kg) and twelve UT men (age: 23 ± 4 years; height: 179.2 ± 5.0 cm; body weight: 81.5 ± 8.6 kg) performed six sets of ten maximal concentric isokinetic (CON) or eccentric isokinetic (ECC) elbow flexion exercise in two separate visits. Before and after the exercise interventions, maximal voluntary contractions (MVCs) were performed for testing isometric strength. In addition, bipolar surface EMG signals were detected from the biceps brachii muscle during the strength testing. Both CON and ECC caused isometric strength to decrease, regardless of the training status. However, ECC caused greater isometric strength decline than CON did for the UT group (p = 0.006), but not for the RT group. Both EMG amplitude and mean frequency significantly decreased and increased, respectively, regardless of the training status and exercise intervention. Resistance-trained men are less susceptible to eccentric exercise-induced muscle damage, but this advantage is not likely linked to the chronic resistance training-induced neural adaptations.