This study investigated the impact of an isocaloric and isonitrogenous ketogenic diet (KD) versus a traditional western diet (WD) on changes in body composition, performance, blood lipids, and hormonal profiles in resistance-trained athletes.METHODS:Twenty-five college aged men were divided into a KD or traditional WD from weeks 1-10, with a reintroduction of carbohydrates from weeks 10-11, while participating in a resistance-training program. Body composition, strength, power, and blood lipid profiles were determined at week 0, 10 and 11. A comprehensive metabolic panel and testosterone levels were also measured at weeks 0 and 11.RESULTS:Lean body mass (LBM) increased in both KD and WD groups (2.4% and 4.4%, p<0.01) at week 10. However, only the KD group showed an increase in LBM between weeks 10-11 (4.8%, p<0.0001). Finally, fat mass decreased in both the KD group (-2.2 kg ± 1.2 kg) and WD groups (- 1.5 ± 1.6 kg). Strength and power increased to the same extent in the WD and KD conditions from weeks 1-11. No changes in any serum lipid measures occurred from weeks 1-10, however a rapid reintroduction of carbohydrate from weeks 10-11 raised plasma TG levels in the KD group. Total testosterone increased significantly from Weeks 0-11 in the KD diet (118 ng/dl) as compared to the WD (-36 ng/dl) from pre to post while insulin did not change.CONCLUSIONS:The KD can be used in combination with resistance training to cause favorable changes in body composition, performance and hormonal profiles in resistance-trained males.
The objective of the study was to investigate whether co-ingestion of carbohydrate and protein as compared with protein alone augments muscle protein synthesis (MPS) during early exercise recovery. Two months old rats performed 10 repetitions of ladder climbing with 75% of body weight attached to their tails. Placebo (PLA), whey protein (WP), or whey protein plus carbohydrate (CP) was then given to rats by gavage. An additional group of sedentary rats (SED) was used as controls. Blood samples were collected immediately and at either 1 or 2 h after exercise. The flexor hallucis longus muscle was excised at 1 or 2 h post exercise for analysis of MPS and related signaling proteins. MPS was significantly increased by CP compared with PLA (p<0.05), and approached significance compared with WP at 1 h post exercise (p = 0.08). CP yielded a greater phosphorylation of mTOR compared with SED and PLA at 1 h post exercise and SED and WP at 2 h post exercise. CP also increased phosphorylation of p70S6K compared with SED at 1 and 2 h post exercise. 4E-BP1 phosphorylation was inhibited by PLA at 1 h but elevated by WP and CP at 2 h post exercise relative to SED. The phosphorylation of AMPK was elevated by exercise at 1 h post exercise, and this elevated level was sustained only in the WP group at 2 h. The phosphorylation of Akt, GSK3, and eIF2Bε were unchanged by treatments. Plasma insulin was transiently increased by CP at 1 h post exercise. In conclusion, post-exercise CP supplementation increases MPS post exercise relative to PLA and possibly WP, which may have been mediated by greater activation of the mTOR signaling pathway
Lowery, RP, Joy, JM, Rathmacher, JA, Baier, SM, Fuller, JC Jr, Shelley, MC II, Jäger, R, Purpura, M, Wilson, SMC, and Wilson, JM. Interaction of beta-hydroxy-beta-methylbutyrate free acid and adenosine triphosphate on muscle mass, strength, and power in resistance trained individuals. J Strength Cond Res 30(7): 1843-1854, 2016-Adenosine-5'-triphosphate (ATP) supplementation helps maintain performance under high fatiguing contractions and with greater fatigue recovery demands also increase. Current evidence suggests that the free acid form of β-hydroxy-β-methylbutyrate (HMB-FA) acts by speeding regenerative capacity of skeletal muscle after high-intensity or prolonged exercise. Therefore, we investigated the effects of 12 weeks of HMB-FA (3 g) and ATP (400 mg) administration on lean body mass (LBM), strength, and power in trained individuals. A 3-phase double-blind, placebo-, and diet-controlled study was conducted. Phases consisted of an 8-week periodized resistance training program (phase 1), followed by a 2-week overreaching cycle (phase 2), and a 2-week taper (phase 3). Lean body mass was increased by a combination of HMB-FA/ATP by 12.7% (p < 0.001). In a similar fashion, strength gains after training were increased in HMB-FA/ATP-supplemented subjects by 23.5% (p < 0.001). Vertical jump and Wingate power were increased in the HMB-FA/ATP-supplemented group compared with the placebo-supplemented group, and the 12-week increases were 21.5 and 23.7%, respectively. During the overreaching cycle, strength and power declined in the placebo group (4.3-5.7%), whereas supplementation with HMB-FA/ATP resulted in continued strength gains (1.3%). In conclusion, HMB-FA and ATP in combination with resistance exercise training enhanced LBM, power, and strength. In addition, HMB-FA plus ATP blunted the typical response to overreaching, resulting in a further increase in strength during that period. It seems that the combination of HMB-FA/ATP could benefit those who continuously train at high levels such as elite athletes or military personnel.
Normally, skeletal muscle mass is unchanged, beyond periods of growth, but it begins to decline in the fourth or fifth decade of life. The mass of skeletal muscle is maintained by ingestion of protein-containing meals. With feeding, muscle protein synthesis (MPS) is stimulated and a small suppression of muscle protein breakdown (MPB) occurs, such that protein balance becomes positive (MPS>MPB). As the postprandial period subsides and a transition toward fasting occurs, the balance of muscle protein turnover becomes negative again (MPB>MPS). Thus, during maintenance of skeletal muscle mass, the long-term net result is that MPS is balanced by MPB. Acutely, however, it is of interest to determine what regulates feeding-induced increases in MPS, since it appears that, in a number of scenarios (for example aging, disuse, and wasting diseases), a suppression of MPS in response to feeding is a common finding. In fact, recent findings point to the fact that loss of skeletal muscle mass with disuse and aging is due not chronic changes in MPS or MPB, but to a blunted feeding-induced rise in MPS. Resistance exercise is a potent stimulator of MPS and appears to synergistically enhance the gains stimulated by feeding. As such, resistance exercise is an important countermeasure to disuse atrophy and to age-related declines in skeletal muscle mass. What is less well understood is how the intensity and volume of the resistance exercise stimulus is sufficient to result in rises in MPS. Recent advances in this area are discussed here, with a focus on human in vivo data.
PURPOSE:Acute bouts of resistance exercise and subsequent training alters protein turnover in skeletal muscle. The mechanisms responsible for the changes in basal post-absorptive protein turnover and its impact on muscle hypertrophy following resistance exercise training are unknown. Our goal was to determine whether post-absorptive muscle protein turnover following 12 weeks of resistance exercise training (RET) plays a role in muscle hypertrophy. In addition, we were interested in determining potential molecular mechanisms responsible for altering post-training muscle protein turnover.METHODS:Healthy young men (n = 31) participated in supervised whole body progressive RET at 60-80% 1 repetition maximum (1-RM), 3 days/week for 3 months. Pre- and post-training vastus lateralis muscle biopsies and blood samples taken during an infusion of 13C6 and 15N phenylalanine and were used to assess skeletal muscle protein turnover in the post-absorptive state. Lean body mass (LBM), muscle strength (determined by dynamometry), vastus lateralis muscle thickness (MT), myofiber type-specific cross-sectional area (CSA), and mRNA were assessed pre- and post-RET.RESULTS:RET increased strength (12-40%), LBM (~5%), MT (~15%) and myofiber CSA (~20%) (p < 0.05). Muscle protein synthesis (MPS) increased 24% while muscle protein breakdown (MPB) decreased 21%, respectively. These changes in protein turnover resulted in an improved net muscle protein balance in the basal state following RET. Further, the change in basal MPS is positively associated (r = 0.555, p = 0.003) with the change in muscle thickness.CONCLUSION:Post-absorptive muscle protein turnover is associated with muscle hypertrophy during resistance exercise training.
To achieve the criterion appearance prior to competing in a physique competition, athletes undergo preparatory regimens involving high-volume intense resistance and aerobic exercise with hypocaloric energy intake. As the popularity of "drug-free" competition increases, more athletes are facing this challenge without the recuperative advantage provided by performance-enhancing drugs. Consequently, the likelihood of loss of lean body and/or bone mass is increased. The purpose of this investigation was to monitor changes in body composition for a 29-year-old self-proclaimed drug-free female figure competitor during a 32-week preparatory regimen comprising high-volume resistance and aerobic exercise with hypocaloric energy intake. We used dual-energy x-ray absorptiometry (DXA) to evaluate regional fat and bone mineral density. During the initial 22 weeks, the subject reduced energy intake and engaged in resistance (4-5 sessions/week) and aerobic (3 sessions/week) training. During the final 10 weeks, the subject increased exercise frequency to 6 (resistance) and 4 (aerobic) sessions/week while ingesting 1130-1380 kcal/day. During this 10-week period, she consumed a high quantity of protein (~55% of energy intake) and nutritional supplements. During the 32 weeks, body mass and fat mass decreased by 12% and 55%, respectively. Conversely, lean body mass increased by 1.5%, an amount that exceeded the coefficient of variation associated with DXA-derived measurement. Total bone mineral density was unchanged throughout. In summary, in preparation for a figure competition, a self-proclaimed drug-free female achieved the low body-fat percentage required for success in competition without losing lean mass or bone density by following a 32-week preparatory exercise and nutritional regimen.
The primary aim of this study was to determine whether chronic mental stress moderates recovery of muscular function and somatic sensations: perceived energy, fatigue, and soreness, in a 4-day period after a bout of strenuous resistance exercise. Undergraduate resistance training students (n = 31; age, 20.26 ± 1.34 years) completed the Perceived Stress Scale and the Undergraduate Stress Questionnaire, a measure of life event stress. At a later visit, they performed an acute heavy-resistance exercise protocol (10 repetition maximum [RM] leg press test plus 6 sets: 80-100% of 10RM). Maximal isometric force (MIF), perceived energy, fatigue, and soreness were assessed in approximately 24-hour intervals after exercise. Recovery data were analyzed with hierarchical linear modeling growth curve analysis. Life event stress significantly moderated linear (p = 0.027) and squared (p = 0.031) recovery of MIF. This relationship held even when the model was adjusted for fitness, workload, and training experience. Perceived energy (p = 0.038), fatigue (p = 0.040), and soreness (p = 0.027) all were moderated by life stress. Mean perceived stress modulated linear and squared recovery of MIF (p < 0.001) and energy (p = 0.004) but not fatigue or soreness. In all analyses, higher stress was associated with worse recovery. Stress, whether assessed as life event stress or perceived stress, moderated the recovery trajectories of muscular function and somatic sensations in a 96-hour period after strenuous resistance exercise. Therefore, under conditions of inordinate stress, individuals may need to be more mindful about observing an appropriate length of recovery.
Previous data showed that the administration of high doses of melatonin improved the circadian system in athletes. Here, we investigated in the same experimental paradigm whether the antioxidant properties of melatonin has also beneficial effects against exercise-induced oxidative stress and muscle damage in athletes. Twenty-four athletes were treated with 100 mg.day-1 of melatonin or placebo 30 min before bedtime during four weeks in a randomized double-blind scheme. Exercise intensity was higher during the study that before starting it. Blood samples were collected before and after treatment, and plasma was used for oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), nitrite plus nitrate (NOx), and advanced oxidation protein products (AOPP) determinations. Glutathione (GSH), glutathione disulphide (GSSG) levels, and glutathione peroxidase (GPx) and reductase (GRd) activities, were measured in erythrocytes. Melatonin intake increased ORAC, reduced LPO and NOx levels, and prevented the increase of AOPP, compared to placebo group. Melatonin was also more efficient than placebo in reducing GSSG.GSH-1 and GPx.GRd-1 ratios. Melatonin, but not placebo, reduced creatine kinase, lactate dehydrogenase, creatinine, and total cholesterol levels. Overall, the data reflect a beneficial effect of melatonin treatment in resistance-training athletes, preventing extra- and intracellular oxidative stress induced by exercise, and yielding further skeletal muscle protection against exercise-induced oxidative damage.
Previous investigations of strength have only focused on biomechanical or psychological determinants, while ignoring the potential interplay and relative contributions of these variables. The purpose of this study was to investigate the relative contributions of biomechanical, anthropometric, and psychological variables to the prediction of maximum parallel barbell back squat strength. Twenty-one college-aged participants (male = 14; female = 7; age = 23 ± 3 years) reported to the laboratory for two visits. The first visit consisted of anthropometric, psychometric, and parallel barbell back squat one-repetition maximum (1RM) testing. On the second visit, participants performed isometric dynamometry testing for the knee, hip, and spinal extensors in a sticking point position-specific manner. Multiple linear regression and correlations were used to investigate the combined and individual relationships between biomechanical, anthropometric, and psychological variables and squat 1RM. Multiple regression revealed only one statistically predictive determinant: fat free mass normalized to height (standardized estimate ± SE = 0.6 ± 0.3; t(16) = 2.28; p = 0.037). Correlation coefficients for individual variables and squat 1RM ranged from r = -0.79-0.83, with biomechanical, anthropometric, experiential, and sex predictors showing the strongest relationships, and psychological variables displaying the weakest relationships. These data suggest that back squat strength in a heterogeneous population is multifactorial and more related to physical rather than psychological variables.
OBJECTIVE: Emerging research suggests that aerobic-based physical activity may help to promote survival among chronic obstructive pulmonary disease patients. However, the extent to which engagement in resistance training on survival among chronic obstructive pulmonary disease patients is relatively unknown. Therefore, the purpose of this study was to examine the independent associations of muscle strengthening activities on all-cause mortality among a national sample of U.S. adults with chronic obstructive pulmonary disease. We hypothesize that muscle strengthening activities will be inversely associated with all-cause mortality.
METHODS: Data from the 2003-2006 NHANES were employed, with follow-up through 2011. Aerobic-based physical activity was objectively measured via accelerometry, muscle strengthening activities engagement was assessed via self-report, and chronic obstructive pulmonary disease was assessed via physician-diagnosis.
RESULTS: Analysis included 385 adults (20 + yrs) with chronic obstructive pulmonary disease, who represent 13.3 million chronic obstructive pulmonary disease patients in the USA. The median follow-up period was 78 months (IQR=64-90), with 82 chronic obstructive pulmonary disease patients dying during this period. For a two muscle strengthening activity sessions/week increase (consistent with national guidelines), chronic obstructive pulmonary disease patients had a 29% reduced risk of all-cause mortality (HR=0.71; 95% CI: 0.51-0.99; P = 0.04).
CONCLUSION: Participation in muscle strengthening activities, independent of aerobic-based physical activity and other potential confounders, is associated with greater survival among chronic obstructive pulmonary disease patients.
Aspiring female physique athletes are often encouraged to ingest relatively high levels of dietary protein in conjunction with their resistance-training programs. However, there is little to no research investigating higher vs. lower protein intakes in this population. This study examined the influence of a high vs. low protein diet in conjunction with an 8-week resistance training program in this population. Seventeen females (21.2±2.1 years; 165.1±5.1 cm; 61±6.1 kg) were randomly assigned to a high protein diet (HP: 2.5g/kg/day; n=8) or a low protein diet (LP: 0.9g/kg/day, n=9) and were assessed for body composition and maximal strength prior to and after the 8-week protein intake and exercise intervention. Fat-free mass (FFM) increased significantly more in the HP group as compared to the LP group (p=0.009), going from 47.1 ± 4.5kg to 49.2 ± 5.4kg (+2.1kg) and from 48.1 ± 2.7kg to 48.7 ± 2 (+0.6kg) in the HP and LP groups, respectively. Fat mass significantly decreased over time in the HP group (14.1 ± 3.6kg to 13.0 ± 3.3kg; p<0.01) but no change was observed in the LP group (13.2 ± 3.7kg to 12.5 ± 3.0kg). While maximal strength significantly increased in both groups, there were no differences in strength improvements between the two groups. In aspiring female physique athletes, a higher protein diet is superior to a lower protein diet in terms of increasing FFM in conjunction with a resistance training program.
Resistance training (RT)-induced skeletal muscle hypertrophy is a highly intricate process. Despite substantial advances, we are far from understanding exactly how muscle hypertrophy develops during RT. The aim of the present review is to discuss new insights related to the role of skeletal muscle damage and muscle protein synthesis (MPS) in mediating RT-induced hypertrophy. Specifically, the thesis that in the early phase of RT (≤ 4 previous RT sessions) increases in muscle cross-sectional area are mostly attributable to muscle damage-induced muscle swelling; then (after ~ 10 sessions), a modest magnitude of muscle hypertrophy ensues; but only during a latter phase of RT (after ~ 18 sessions) is true muscle hypertrophy observed. We argue that the initial increases in MPS post-RT are likely directed to muscle repair and remodelling due to damage, and do not correlate with eventual muscle hypertrophy induced by several RT weeks. Increases in MPS post-RT session only contribute to muscle hypertrophy after a progressive attenuation of muscle damage, and even more significantly when damage is minimal. Furthermore, RT protocols that do not promote significant muscle damage still induce similar muscle hypertrophy and strength gains compared to conditions that do promote initial muscle damage. Thus, we conclude that muscle damage is not the process that mediates or potentiates RT-induced muscle hypertrophy.
There has been a proliferation in recent scholarly discussion regarding the scientific validity of single vs. multiple sets of resistance training (dose) to optimize muscular strength development (response). Recent meta-analytical research indicates that there exist distinct muscular adaptations, and dose-response relationships, that correspond to certain populations. It seems that training status influences the requisite doses as well as the potential magnitude of response. Specifically, for individuals seeking to experience muscular strength development beyond that of general health, an increase in resistance-training dosage must accompany increases in training experience. The purpose of this document is to analyze and apply the findings of 2 meta-analytical investigations that identified dose-response relationships for 3 populations: previously untrained, recreationally trained, and athlete; and thereby reveal distinct, quantified, dose-response trends for each population segment. Two meta-analytical investigations, consisting of 177 studies and 1,803 effect sizes (ES) were examined to extract the dose-response continuums for intensity, frequency, volume of training, and the resultant strength increases, specific to each population. ES data demonstrate unique dose-response relationships per population. For untrained individuals, maximal strength gains are elicited at a mean training intensity of 60% of 1 repetition maximum (1RM), 3 days per week, and with a mean training volume of 4 sets per muscle group. Recreationally trained nonathletes exhibit maximal strength gains with a mean training intensity of 80% of 1RM, 2 days per week, and a mean volume of 4 sets. For athlete populations, maximal strength gains are elicited at a mean training intensity of 85% of 1RM, 2 days per week, and with a mean training volume of 8 sets per muscle group. These meta-analyses demonstrate that the effort-to-benefit ratio is different for untrained, recreationally trained, and athlete populations; thus, emphasizing the necessity of appropriate exercise prescription to optimize training effect. Exercise professionals may apply these dose-response trends to prescribe appropriate, goal-oriented training programs.
It has been clearly established that maximal force and power is lower in the morning compared to noon or afternoon hours. This morning neuromuscular deficit can be diminished by regularly training in the morning hours. However, there is limited and contradictory information upon hypertrophic adaptations to time-of-day-specific resistance training. Moreover, no cellular or molecular mechanisms related to muscle hypertrophy adaptation have been studied with this respect. Therefore, the present study examined effects of the time-of-day-specific resistance training on muscle hypertrophy, phosphorylation of selected proteins, hormonal concentrations and neuromuscular performance. Twenty five previously untrained males were randomly divided into a morning group (n = 11, age 23 ± 2 yrs), afternoon group (n = 7, 24 ± 4 yrs) and control group (n = 7, 24 ± 3 yrs). Both the morning and afternoon group underwent hypertrophy-type of resistance training with 22 training sessions over an 11-week period performed between 07:30-08:30 h and 16:00-17:00 h, respectively. Isometric MVC was tested before and immediately after an acute loading exclusively during their training times before and after the training period. Before acute loadings, resting blood samples were drawn and analysed for plasma testosterone and cortisol. At each testing occasion, muscle biopsies from m. vastus lateralis were obtained before and 60 min after the acute loading. Muscle specimens were analysed for muscle fibre cross-sectional areas (CSA) and for phosphorylated p70S6K, rpS6, p38MAPK, Erk1/2, and eEF2. In addition, the right quadriceps femoris was scanned with MRI before and after the training period. The control group underwent the same testing, except for MRI, between 11:00 h and 13:00 h but did not train. Voluntary muscle strength increased significantly in both the morning and afternoon training group by 16.9% and 15.2 %, respectively. Also muscle hypertrophy occurred by 8.8% and 11.9% (MRI, p < 0.001) and at muscle fibre CSA level by 21% and 18% (p < 0.01) in the morning and afternoon group, respectively. No significant changes were found in controls within these parameters. Both pre- and post-training acute loadings induced a significant (p < 0.001) reduction in muscle strength in all groups, not affected by time of day or training. The post-loading phosphorylation of p70S6Thr421/Ser424 increased independent of the time of day in the pre-training condition, whereas it was significantly increased in the morning group only after the training period (p < 0.05). Phosphorylation of rpS6 and p38MAPK increased acutely both before and after training in a time-of-day independent manner (p < 0.05 at all occasions). Phosphorylation of p70S6Thr389, eEF2 and Erk1/2 did not change at any time point. No statistically significant correlations were found between changes in muscle fibre CSA, MRI and cell signalling data. Resting testosterone was not statistically different among groups at any time point. Resting cortisol declined significantly from pre- to post-training in all three groups (p < 0.05). In conclusion, similar levels of muscle strength and hypertrophy could be achieved regardless of time of the day in previously untrained men. However, at the level of skeletal muscle signalling, the extent of adaptation in some parameters may be time of day dependent.
Controversy exists about the maximum amount of protein that can be utilized for lean tissue-building purposes in a single meal for those involved in regimented resistance training. It has been proposed that muscle protein synthesis is maximized in young adults with an intake of ~ 20-25 g of a high-quality protein; anything above this amount is believed to be oxidized for energy or transaminated to form urea and other organic acids. However, these findings are specific to the provision of fast-digesting proteins without the addition of other macronutrients. Consumption of slower-acting protein sources, particularly when consumed in combination with other macronutrients, would delay absorption and thus conceivably enhance the utilization of the constituent amino acids. The purpose of this paper was twofold: 1) to objectively review the literature in an effort to determine an upper anabolic threshold for per-meal protein intake; 2) draw relevant conclusions based on the current data so as to elucidate guidelines for per-meal daily protein distribution to optimize lean tissue accretion. Both acute and long-term studies on the topic were evaluated and their findings placed into context with respect to per-meal utilization of protein and the associated implications to distribution of protein feedings across the course of a day. The preponderance of data indicate that while consumption of higher protein doses (> 20 g) results in greater AA oxidation, this is not the fate for all the additional ingested AAs as some are utilized for tissue-building purposes. Based on the current evidence, we conclude that to maximize anabolism one should consume protein at a target intake of 0.4 g/kg/meal across a minimum of four meals in order to reach a minimum of 1.6 g/kg/day. Using the upper daily intake of 2.2 g/kg/day reported in the literature spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal.
Inadequate sleep impairs maximal muscle strength in compound movements when performed without specific interventions designed to increase motivation. Strategies to assist groups facing inadequate sleep to effectively perform resistance training may include supplementing their motivation by training in groups or ingesting caffeine; or training prior to prolonged periods of wakefulness.
We conducted a systematic literature review and meta-analysis to assess the chronic effects of the sequence of concurrent strength and endurance training on selected important physiological and performance parameters, namely lower body 1 repetition maximum (1RM) and maximal aerobic capacity (VO2max/peak). Based on predetermined eligibility criteria, chronic effect trials, comparing strength-endurance (SE) with endurance-strength (ES) training sequence in the same session were included. Data on effect sizes, sample size and SD as well other related study characteristics were extracted. The effect sizes were pooled using, Fixed or Random effect models as per level of heterogeneity between studies and a further sensitivity analyses was carried out using Inverse Variance Heterogeneity (IVHet) models to adjust for potential bias due to heterogeneity. Lower body 1RM was significantly higher when strength training preceded endurance with a pooled mean change of 3.96 kg (95%CI: 0.81 to 7.10 kg). However, the training sequence had no impact on aerobic capacity with a pooled mean difference of 0.39 ml.kg.min-1 (95%CI: -1.03 to 1.81 ml.kg.min-1). Sequencing strength training prior to endurance in concurrent training appears to be beneficial for lower body strength adaptations, while the improvement of aerobic capacity is not affected by training order.
