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Effects of high-calorie supplements on body composition and muscular strength following resistance training
Abstract
Seventy-three healthy, male subjects randomly divided into 3 groups participated in a study to determine the effects of 2 high-calorie nutritional supplements on body composition, body segment circumferences, and muscular strength following a resistance-training (RT) program.
In addition to their normal diets group 1 (CHO/PRO; n=26) consumed a 8.4 Mj x day(-1) (2010 kcal) high calorie, high protein supplement containing 356 g carbohydrate and 106 g protein. Group 2 (CHO; n=25) consumed a carbohydrate supplement that was isocaloric with CHO/PRO. Group 3 (CTRL; n=22) received no supplement and served as a control. All subjects were placed on a 4-day x week(-1) RT program for 8 weeks.
Dietary analysis revealed no significant differences in total energy consumption or nutrients at any time in the non-supplemented diets of the 3 groups. Significant (p= or <0.05) increases in body mass (BM) and fat-free mass (FFM) were observed in CHO/PRO and CHO compared to CTRL. Mean (+/- SD) increases in BM were 3.1+/-3.1 kg and 3.1+/-2.2 kg, respectively. Fat-free mass significantly (p= or <0.05) increased 2.9+/-3.4 kg in CHO/PRO and 3.4+/-2.5 kg in CHO. Muscular strength, as measured by a one-repetition maximum in the bench press, leg press, and lat-pull down increased significantly (p= or <0.05) in all groups. No significant differences in strength measures were observed among groups following training.
Results indicate that high-calorie supplements are effective in increasing BM and FFM when combined with RT. However, once individual protein requirements are met, energy content of the diet has the largest effect on body composition.
... In similarly designed studies, Rozenek et al. [19] and Spillane and Willoughby [20] evaluated the effect of carbohydrate or carbohydrate-protein supplements on weight gain in men who partook in prescribed RET. Rozenek et al. [19] randomly assigned 73 untrained men to a high-carbohydrate, a high-protein plus carbohydrate, or a no-supplement control group. ...
... In similarly designed studies, Rozenek et al. [19] and Spillane and Willoughby [20] evaluated the effect of carbohydrate or carbohydrate-protein supplements on weight gain in men who partook in prescribed RET. Rozenek et al. [19] randomly assigned 73 untrained men to a high-carbohydrate, a high-protein plus carbohydrate, or a no-supplement control group. Supplements were mixed into 720 ml of 2% milk, which provided ~ 2010 extra kcal per day. ...
... Unfortunately, only one of the aforementioned published interventions (Table 2) included a true control group, which is necessary to evaluate the contribution of both components of the weight gain regimen. In this study, RET alone resulted in an average 1.4 ± 1.7 kg gain in LBM over 8 weeks that was less than the 3.4 ± 2.5 and 2.9 ± 3.4 kg gains experienced by the energy surplus groups [19]. It is also less than the average (2.4 to 3.5 kg) gains observed over 8 to 9 weeks in other previous studies ( Table 2). ...
Purpose of Review
Sports nutrition guidelines typically state that athletes desiring weight gain follow a regimen that includes increasing energy intake by ~ 300–500 kcal/day with an emphasis on adequate protein and carbohydrate and judicious inclusion of energy-dense foods, in combination with rigorous resistance training. This regimen is thought to promote weekly gains of ~ 0.45 kg (1 lb), mostly as lean body mass (LBM). This review summarizes the evidence supporting these intentional weight gain regimens in athletes.
Recent Findings
Although some research has been conducted in the past 5 years, research on intentional weight gain is lacking.
Summary
Currently, available data suggests that weekly weight gain of 0.45 kg (1 lb), primarily as LBM, may be difficult for some athletes to achieve. Available evidence, however, suggests that commonly recommended strategies to promote calorie surplus, including consuming larger portions, incorporating energy-dense foods, and prioritizing liquid over solid foods, may prove helpful.
... Seventeen studies that examined the long-term effects of different carbohydrate intakes on resistance training performance met the inclusion criteria [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77], summarized in Table 6 and Figure 5. Study durations ranged from three weeks to three months (average and median: 8 weeks). Four studies were crossover trials with an average of 23 ± 7 participants (median: 11) [61,64,70,75]; 10 studies were RCTs [62,[65][66][67][68]71,73,74,76,77] and three controlled trials [63,69,72] with an average of 37 ± 56 participants (median: 21) in each study. ...
... Seventeen studies that examined the long-term effects of different carbohydrate intakes on resistance training performance met the inclusion criteria [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77], summarized in Table 6 and Figure 5. Study durations ranged from three weeks to three months (average and median: 8 weeks). Four studies were crossover trials with an average of 23 ± 7 participants (median: 11) [61,64,70,75]; 10 studies were RCTs [62,[65][66][67][68]71,73,74,76,77] and three controlled trials [63,69,72] with an average of 37 ± 56 participants (median: 21) in each study. Participants were young, with an average age of 29 ± 8, and the majority were men, but two studies consisted of only women [66,73] and six studies contained both sexes [61][62][63]69,72,75]. ...
... Participants were young, with an average age of 29 ± 8, and the majority were men, but two studies consisted of only women [66,73] and six studies contained both sexes [61][62][63]69,72,75]. Training status was categorized as untrained [66], active [74], military trained [71,72], strength-trained [63][64][65]73,77], bodybuilders [76], powerlifters or weightlifters [61,68], CrossFit athletes [62,69,75] or other athletes [67,70]. ...
High carbohydrate intakes are commonly recommended for athletes of various sports, including strength trainees, to optimize performance. However, the effect of carbohydrate intake on strength training performance has not been systematically analyzed. A systematic literature search was conducted for trials that manipulated carbohydrate intake, including supplements, and measured strength, resistance training or power either acutely or after a diet and strength training program. Studies were categorized as either (1) acute supplementation, (2) exercise-induced glycogen depletion with subsequent carbohydrate manipulation, (3) short-term (2–7 days) carbohydrate manipulation or (4) changes in performance after longer-term diet manipulation and strength training. Forty-nine studies were included: 19 acute, six glycogen depletion, seven short-term and 17 long-term studies. Participants were strength trainees or athletes (39 studies), recreationally active (six studies) or untrained (four studies). Acutely, higher carbohydrate intake did not improve performance in 13 studies and enhanced performance in six studies, primarily in those with fasted control groups and workouts with over 10 sets per muscle group. One study found that a carbohydrate meal improved performance compared to water but not in comparison to a sensory-matched placebo breakfast. There was no evidence of a dose-response effect. After glycogen depletion, carbohydrate supplementation improved performance in three studies compared to placebo, in particular during bi-daily workouts, but not in research with isocaloric controls. None of the seven short-term studies found beneficial effects of carbohydrate manipulation. Longer-term changes in performance were not influenced by carbohydrate intake in 15 studies; one study favored the higher- and one the lower-carbohydrate condition. Carbohydrate intake per se is unlikely to strength training performance in a fed state in workouts consisting of up to 10 sets per muscle group. Performance during higher volumes may benefit from carbohydrates, but more studies with isocaloric control groups, sensory-matched placebos and locally measured glycogen depletion are needed.
... Despite a great deal of interindividual variability, the authors' model predicted that a body mass gain of ~ 0.55%/week was indicative of all body mass gains being fat-free mass (R 2 = 0.36). In an even more stark contrast to both the present and aforementioned findings, Rozenek and colleagues [40] reported nearly exclusive lean mass gains in a group of untrained subjects following a relatively large energy surplus (~ 3-kg body mass increase in eight weeks) while RT. Ultimately, larger surpluses are likely to cause excess gains in body fat, but the degree to which relatively larger or smaller surpluses impact gains in muscle mass is variable between individuals, and possibly impacted by the quality of the training program, its appropriateness for a given study group, which may be at least in part based on their prior training experience and history, with less-trained participants more capable of benefitting from larger surpluses. ...
Background
Many perform resistance training (RT) to increase muscle mass and strength. Energy surpluses are advised to support such gains; however, if too large, could cause unnecessary fat gain. We randomized 21 trained lifters performing RT 3 d/wk for eight weeks into maintenance energy (MAIN), moderate (5% [MOD]), and high (15% [HIGH]) energy surplus groups to determine if skinfold thicknesses (ST), squat and bench one-repetition maximum (1-RM), or biceps brachii, triceps brachii, or quadriceps muscle thicknesses (MT) differed by group. COVID-19 reduced our sample, leaving 17 completers. Thus, in addition to Bayesian ANCOVA comparisons, we analyzed changes in body mass (BM) with ST, 1-RM, and MT changes via regression. We reported Bayes factors (BF10) indicating odds ratios of the relative likelihood of hypotheses (e.g., BF10 = 2 indicates the hypothesis is twice as likely as another) and coefficients of determination (R²) for regressions.
Results
ANCOVAs provided no evidence supporting the group model for MT or squat 1-RM. However, moderate (BF10 = 9.9) and strong evidence (BF10 = 14.5) indicated HIGH increased bench 1-RM more than MOD and MAIN, respectively. Further, there was moderate evidence (BF10 = 4.2) HIGH increased ST more than MAIN and weak evidence (BF10 = 2.4) MOD increased ST more than MAIN. Regression provided strong evidence that BM change predicts ST change (BF10 = 14.3, R² = 0.49) and weak evidence predicting biceps brachii MT change (BF10 = 1.4, R² = 0.24).
Conclusions
While some group-based differences were found, our larger N regression provides the most generalizable evidence. Therefore, we conclude faster rates of BM gain (and by proxy larger surpluses) primarily increase rates of fat gain rather than augmenting 1-RM or MT. However, biceps brachii, the muscle which received the greatest stimulus in this study, may have been positively impacted by greater BM gain, albeit slightly. Our findings are limited to the confines of this study, where a group of lifters with mixed training experience performed moderate volumes 3 d/wk for 8 weeks. Thus, future work is needed to evaluate the relationship between BM gains, increases in ST and RT adaptations in other contexts.
... g/kg/d saw a positive increase in lean body mass (LBM) when paired with resistance exercise, supporting the need for higher protein synthesis when protein turnover is higher 6 . Rozenek et al. (2002) 18 , reported increases in strength and fat-free mass in trained male subjects who consumed 1.3-1.8 g/kg of protein and engaged in a resistance training program. ...
Introduction: Whether it is the athletic population or the general population, it is essential to understand considerations regarding the amount of protein consumed daily. Protein, often referred to as the body's building blocks, is an integral part of the diet. This macronutrient plays a vital role in developing and maintaining skeletal muscle mass. This paper aims to discuss protein intake at low (<1.2 g/kg/day), medium (1.2-2.2 g/kg), and high (>2.2 g/kg/day) levels that should be consumed with consideration of physically active populations and potential benefits or detrimental effects on body composition and performance. Methods: Searches of electronic databases PubMed and Google Scholar were undertaken to identify peer-reviewed journal articles that reported on dietary protein intake on body composition, and performance/strength. Discussion: Low protein intakes may not meet the needs of all physically active individuals. Medium and high protein intakes positively influenced body composition. Medium protein intakes can benefit strength and performance; however, these effects are not consistently reported with higher intakes. Conclusions: The minimum protein requirement for active individuals is 1.2 g/kg, and higher intakes are safe and effective for healthy, physically active individuals.
... Second, the results related to the joint torque (which is produced by all the knee extensor muscles) are not mentioned in the current study because the purpose was to evaluate the changes in the electrical activity of each surface quadriceps femoris muscle separately following KT applications. Finally, although a validated dynamic fatigue protocol 38 was applied, we did not directly measure using questionnaires different factors related to fatigue rate between measurements sessions, e.g., sleep quality 52 , mental fatigue 53 and nutrition diet 54 . However, none of the subjects reported sleep deprivation, malnutrition, or mental problems before the measurement sessions. ...
This study aimed to investigate how facilitatory and inhibitory KT of the Vastus Medialis affected the activation and the fatigue indices of VM, Vastus Lateralis (VL) and Rectus Femoris (RF) throughout a dynamic fatigue protocol. Seventeen collegiate athletes (Ten males, seven females, age: 24.76 ± 3.99 years, height: 1.73 ± 0.10 m, mass: 68.11 ± 8.54 kg) voluntarily participated in four dynamic fatigue protocol sessions in which no-tape (control condition), inhibitory, facilitatory and sham KTs were applied to the Vastus Medialis in each session. The protocol included 100 dynamic maximum concentric knee extensions at 90°/s using an isokinetic dynamometry device. The knee extensor muscle activities were recorded using wireless surface electromyography. The average muscle activity (Root mean square) during the first three repetitions and the repetitions number of 51-100, respectively, were used to calculate the before and after exhaustion muscle activity. Furthermore, median frequency slope during all repetitions was reported as the fatigue rate of muscles during different KT conditions and for the control condition (no-tape). The results showed neither muscle activation (significance for the main effect of KT; VM = 0.82, VL = 0.72, RF = 0.19) nor fatigue rate (significance for the main effect of KT; VM = 0.11 VL = 0.71, RF = 0.53) of the superficial knee extensor muscles were affected in all four conditions. These findings suggest that the direction of KT cannot reduce, enhance muscle activity or cause changes in muscle exhaustion. Future studies should investigate the generalizability of current findings to other populations. Abbreviations KT Kinesiotaping VL Vastus Lateralis RF Rectus Femoris EMG Electromyography MDF Median frequency VM Vastus Medialis RMS Root mean square STFT Short-time Fourier transform ANOVA Analysis of variance MVC Maximum voluntary contraction MVIC Maximum voluntary isometric contraction OPEN
... Previous studies show that rDNA transcription is augmented by protein supplementation (Figueiredo et al., 2018), enhancing ribosome biogenesis. Furthermore, with adequate proteinintake, sufficient kilo-caloric intake becomes a central factor for increasing lean muscle mass (Rozenek et al., 2002). Furthermore, the small tissue samples (~ 10 mg: 2.9 -22.9 mg) achieved due to the use of micro-biopsies, were smaller than previous studies (Brook et al., 2015;Figueiredo et al., 2015;Hammarström et al., 2019;Reidy et al., 2017), and increase the possibility of affecting total-RNA measurements due to the risk of drying out the RNA-pellet during extraction. ...
Seven weeks of high volume and very-high volume resistance training leads to indistinguishable adaptations in m. Vastus Lateralis thickness, strength and total-RNA abundance in untrained young adults-using a multigroup contralateral crossover design. Abstract The manipulation of volume elicits differentiated physiological adaptations in response to resistance training (RT). Early accumulation of total-RNA har been suggested as a mediator of muscle accretion in response to varying RT-volumes. The purpose of this study was to investigate the effects of RT-volumes on muscle thickness, strength and total-RNA abundance. Thirty-nine untrained young adults (25 + 4.1 years, 11 males, 28 Females) performed 0, 3 or 6 sets (Control, high volume (HV) or very-high volume (VHV)) of differentiated unilateral leg press and leg extension, 3 times weekly for 7 weeks at 10 repetition maximum (RM) for each leg, after 3 weeks of habituation where two sets of 10 RM were performed on all limbs except control (0 sets). Muscle thickness, strength and total-RNA was assessed by ultrasound-, isometric maximum voluntary contractions (MVC) and biopsies sampled from m. vastus lateralis at weeks-3, 0, 4 and 7. After 7 weeks of RT both volume conditions led to increases in muscle thickness (HV: ~ 36 % CI: [20, 55], VHV: ~32% CI: [15, 52]) and strength (HV: ~10% CI: [3.5, 17], VHV: ~14% CI: [6.5, 22]), with no difference between HV and VHV. RT led to increased total-RNA concentrations in m. vastus lateralis at week 4 (HV: ~20% CI: [3.5, 38], VHV: ~29% CI: [9.5, 51]), with no difference at week 7. There was no benefit to VHV compared with HV conditions on any measures (muscle thickness HV-VHV: ~3.5 % CI: [-16, 11.5], strength HV-VHV: ~3.5% CI: [-3.5, 11.5] and total-RNA HV-VHV: ~1 % CI: [-12, 16]). RT at HV and VHV seems to elicit nearly identical adaptations in young untrained individuals during a 7-week intervention.
... ,94 Changes in strength data resulting from the additional protein intervention were extracted from 50 studies testing 2283 subjects for lower-body strength33,36-39,43,44,47-49,52-58,61-65,67-70, 72,74-78,82,84,86,88-92,94,96,100-104 and only three studies with intervention groups without RE.41,99,105 Thirty-four studies tested bench-press strength33,[36][37][38]43,[47][48][49][53][54][55][62][63][64][65]67,68,70,72,74,75,77,78,82,84,[86][87][88]90,91,93,95,96,99 with 1049 subjects. The duration of the studies was, on average, 12 weeks for both bench-press and lower body strength. ...
Objectives
This systematic review, meta-analysis, and meta-regression aimed to determine if increasing daily protein ingestion contributes to gaining lean mass (LM), muscle strength, and physical/functional test performance in healthy persons.
Methods
The present review was registered on PROSPERO - CRD42020159001. A systematic search in Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Randomized controlled trials (RCT) including healthy and non-obese adult participants increasing daily protein intake were selected. Subgroup analysis, splitting the studies by participation in resistance exercise training (RE), age (< 65 or ≥ 65 y), and daily protein ingestion were also performed.
Results
74 RCT fit our inclusion criteria. The age range of the participants was 19 to 85 y, and study protocols in the trials lasted from 6 to 108 wks (76% of the studies between 8 and 12 wks). In ∼80% of the studies, baseline protein ingestion was at least 1.2 g of protein/kg/d. Increasing daily protein ingestion may lead to small gains in LM in subjects enrolled in RE (SMD [standardized mean difference] = 0.22, CI95% [95% confidence interval] 0.14:0.30, P < 0.01, 62 studies, moderate level of evidence). Also, ≥ 65 y subjects ingesting 1.2–1.59 g of protein/kg/d and younger subjects (< 65 y) increasing their ingestion to ≥ 1.6 g of protein/kg/d during RE showed a higher LM gain. Lower-body strength gain was slightly higher at ≥ 1.6 g of protein/kg/d during RE (SMD = 0.40, CI95% 0.09:0.35, P < 0.01, 19 studies, low level of evidence). Bench press strength was slightly increased by ingesting more protein in < 65 y subjects during RE (SMD = 0.18, CI95% 0.03:0.33, P = 0.01, 32 studies, low level of evidence). Effects on handgrip strength are unclear and only marginal for performance in physical function tests.
Conclusions
The number of studies increasing daily protein ingestion alone was too low (n = 6) to conduct a meta-analysis. The current evidence shows that increasing protein ingestion by consuming supplements or food, resulted in small additional gain in LM, and lower body muscle strength in healthy adults enrolled in RE. Effects on bench press strength and performance in physical function tests are minimal. The effect on handgrip strength was unclear.
Funding Sources
This research received a grant from the International Life Science Institute (Europe) and CNPq.
... ,94 Changes in strength data resulting from the additional protein intervention were extracted from 50 studies testing 2283 subjects for lower-body strength33,36-39,43,44,47-49,52-58,61-65,67-70, 72,74-78,82,84,86,88-92,94,96,100-104 and only three studies with intervention groups without RE.41,99,105 Thirty-four studies tested bench-press strength33,[36][37][38]43,[47][48][49][53][54][55][62][63][64][65]67,68,70,72,74,75,77,78,82,84,[86][87][88]90,91,93,95,96,99 with 1049 subjects. The duration of the studies was, on average, 12 weeks for both bench-press and lower body strength. ...
Abstract We performed a systematic review, meta‐analysis, and meta‐regression to determine if increasing daily protein ingestion contributes to gaining lean body mass (LBM), muscle strength, and physical/functional test performance in healthy subjects. A protocol for the present study was registered (PROSPERO, CRD42020159001), and a systematic search of Medline, Embase, CINAHL, and Web of Sciences databases was undertaken. Only randomized controlled trials (RCT) where participants increased their daily protein intake and were healthy and non‐obese adults were included. Research questions focused on the main effects on the outcomes of interest and subgroup analysis, splitting the studies by participation in a resistance exercise (RE), age (
... Such hopes may have been extrapolated from the favorable modulation of IF on mitochondrial biogenesis and the importance of diet-induced thermogenesis (DIT), that is, the energy dissipated as heat after a meal (101). Nevertheless, the management of caloric intake is the cornerstone of any diet aiming at weight loss or muscular growth (102)(103)(104). For example, energy balance and body weight are not substantially influenced by isocaloric substitution of dietary fats for carbohydrates and vice versa (105). ...
Chronobiology plays a crucial role in modulating many physiological systems in which there is nutritional synergism with meal timing. Given that intermitting fasting (IF) has grown as a flexible dietary method consisting of delayed or early eating windows, this scoping review addresses the effects of IF protocols on metabolism as they relate to clinical nutrition and the circadian system. While nocturnal habits are associated with circadian misalignments and impaired cardiometabolic profile – and nutritional physiology is better orchestrated during the day – most findings are based on animal experiments or human studies with observational designs or acute meal tests. Well-controlled randomized clinical trials employing IF protocols of delayed or early eating windows have sometimes demonstrated clinical benefits, such as improved glycemic and lipid profiles, as well as weight loss. However, IF does not appear to be more effective than traditional diets at the group level, and its effects largely depend on energy restriction. Thus, efforts must be made to identify patient biological rhythms, preferences, routines, and medical conditions before individual dietary prescription in clinical practice.
... Bodybuilders should consume between 1.6 and 2.2 g of protein per every kilogram of the body mass (g/kg b.w.) [1]. Together with caloric surplus, it creates an anabolic environment for post-workout recovery and muscle protein synthesis (MPS) [2]. On the other hand, the pre-contest diet of bodybuilders is low in calories. ...
Bodybuilders tend to overeat their daily protein needs. The purpose of a high-protein diet is to support post-workout recovery and skeletal muscle growth; however, its exact impact on gut microbiota still remains under investigation. The aim of this study was to assess the differences in selected gut bacteria (Faecalibacterium prausnitzii, Akkermansia muciniphila, Bifidobacterium spp., and Bacteroides spp.) abundance and fecal pH between the group of amateur bodybuilders and more sedentary control group. In total, 26 young healthy men took part in the study, and their daily nutrients intake was measured using a dietary interview. Real-time PCR was used to assess the stool bacteria abundance. Both groups reported fiber intake within the recommended range, but bodybuilders consumed significantly more protein (33.6% ± 6.5% vs. 22% ± 6.3%) and less fat (27.6% ± 18.9% vs. 36.4% ± 10%) than controls. Study results showed no significant differences in terms of selected intestinal bacteria colony forming unit counts. Significantly higher fecal pH in the bodybuilders’ fecal samples was observed in comparison to the control group 6.9 ± 0.7 vs. 6.2 ± 0.7. Gut microbiota composition similarities could be a result of appropriate fiber intake in both groups.
For most of the current century, exercise/nutritional scientists have generally accepted the belief that exercise has little effect on protein/amino acid requirements. However, during the same time period many athletes (especially strength athletes) have routinely consumed diets high in protein. In recent years, the results of a number of investigations involving both strength and endurance athletes indicate that, in fact, exercise does increase protein/amino acid need. For endurance athletes, regular exercise may increase protein need by 50 to 100%. For strength athletes, the data are less clear; however, protein intakes in excess of sedentary needs may enhance muscle development. Despite these observations increased protein intake may not improve athletic performance because many athletes routinely consume 150 to 200% of sedentary protein requirements. Assuming total energy intake is sufficient to cover the high expenditures caused by daily training, a diet containing 12 to 15% of its energy from protein should be adequate for both types of athletes.
A general update review of the dynamic aspect of protein metabolism is presented. The effect of excess protein level on protein metabolism has been the object of a limited number of studies in man. From the information available, it appears that the primary regulatory pathway for body protein homeostasis is the process of amino acid (protein) oxidation.
Regular physical activity can improve cardiovascular fitness and may reduce the likelihood and debilitating effects of cardiovascular disease.
Weight-training has generally been believed to have limited value in modifying risks of cardiovascular disease. Effects shown of resistance training on parameters associated with cardiovascular fitness and disease include: heart rate decreases for maximal work and recovery from short term weight-training, increased ventricular mass, and increased ventricular wall and septum thickness. Studies suggest that myocardial hypertrophy resulting from resistive training can be accompanied by positive myocardial adaptations.
Blood pressure response considerations to resistive training include: similarity of resistive exercise peak response to other forms of high intensity exercise, highest blood pressures occur at or near exhaustion during maximum lifts, training appears to reduce the exercise blood pressure. Given the blood pressure responses caution is required for individuals with cardiovascular disease.
Studies of high-volume weight-training indicate that small to moderate increases in aerobic power can occur in relatively short periods of time. The mechanisms by which weight-training increases V̇O2max is unclear.
Resistive training may produce positive changes in serum lipids with the volume of training being the dependent factor.
Cross-sectional and longitudinal studies of bodybuilders suggest that weight-training may beneficially alter glucose tolerance and insulin sensitivity. It appears that weight-training can increase short term high intensity endurance without a concomitant loss in performance. Resistive training increases power output and performance.
Body composition has important relationships to cardiovascular fitness, strength and flexibility. It is likely that it can be affected and controlled by use of large body mass during exercise depending on training volume.
The use of anabolic-androgenic steroids is epidemic in the sporting world, and the recent recognition of their pervasive use by recreational and adolescent athletes has made the abuse of these drugs a public health concern. A critical review of the literature supports the doctrine that anabolic-androgenic steroids can improve muscular performance if certain criteria are met, but some of the health risks associated with their use may be irreversible, and life-threatening. Furthermore, polydrug abuse, restrictive diets, and dehydrating practices may potentiate the health risks associated with weight training and steroid use. Recent investigations of nutritional and training alternatives to anabolic-androgenic steroids are promising. To help lure athletes from drug abuse, the pursuit of new areas of research and education should be priorities in the campaign against the abuse of anabolic steroids.
1. Thirteen adult females and two males were overfed a total of 79–159 MJ (1900–38 000 kcal) during a 3-week period at the Clinical Research Center, Rochester. The average energy cost of the weight gain was 28 kJ (6.7 kcal)/g, and about half the gain consisted of lean body mass (LBM) as estimated by ⁴⁰ Kcounting.
2. A survey of the literature disclosed twenty-eight normal males and five females who had been overfed a total of 104–362 MJ (2500–87000 kcal) under controlled conditions: twenty-five of these had assays of body composition, and three had complete nitrogen balances.
3. When these values were combined with those from our subjects (total forty-eight), there was a significant correlation between weight gain and total excess energy consumed ( r 0.77, P < 0.01) and between LBM gain and excess energy ( r 0.49, P < 0.01). Based on means the energy cost was 33.7 kJ (8.05 kcal)/g gain and 43.6% of the gain was LBM; from regression analysis these values were 33.7 kJ (8.05 kcal)/g gain and 38.4% of gain as LBM.
4. Individual variations in the response could not be explained on the basis of sex, initial body-weight or fat content, duration of overfeeding, type of food eaten, amount of daily food consumption or, in a subset of subjects, on smoking behaviour.
5. The average energy cost of the weight gain was close to the theoretical value of 33.8 kJ (8.08 kcal)/g derived from the composition of the tissue gained.
This article deals with the effects of conventional strength training and circuit resistance training on changes in body composition parameters. Recent data are provided on the technique of arm radiography to quantify changes in arm muscle and fat following strength development with hydraulic resistance exercise equipment.
Most research confirms that the body's increased use of protein, as a "fuel" and for repair, increases with aerobic exercise, especially during high intensity and long duration activity. Protein intake higher than the United States Food and Drug Administration's Recommended Dietary Allowance (RDA), with additional energy and resistance training, results in optimal protein status for participants in strength training. Although many active individuals interpret this research to mean that they need to consume extra protein foods or supplements to perform optimally, most people in the United States already consume protein at a level well above the RDA. Physicians should be aware that low energy consuming individuals (e.g., women, those dieting for weight loss, the elderly) may be at risk for low protein intake, and thus protein status, if they are active.
Most athletes today tend to have a larger muscle mass than their predecessors. Better training and nutrition practices are responsible for much of this difference, but whatever the mechanism, the balance between muscle protein synthesis and breakdown must be in favor of increased muscle protein. Applying new techniques for measuring whole body and muscle protein synthesis to resistance exercise has led to some interesting results. In the recovery period following resistance exercise, both muscle protein synthesis and breakdown are accelerated in the fasted state. Ingestion of carbohydrate or carbohydrate and protein during recovery further increases muscle protein synthesis, due in part to an improved anabolic hormone environment. In addition, the anabolic effect of a resistance training bout may last well beyond 48 hours. Using information obtained from research studies, better training and dietary practices can optimize the benefits from resistance training.