Jason M. Cholewa

Basic Models Modeling Resistance Training: An Update for Basic Scientists Interested in Study Skeletal Muscle Hypertrophy

Human muscle hypertrophy brought about by voluntary exercise in laboratorial conditions is the most common way to study resistance exercise training, especially because of its reliability, stimulus control and easy application to resistance training exercise sessions at fitness centers. However, because of the complexity of blood factors and organs involved, invasive data is difficult to obtain in human exercise training studies due to the integration of several organs, including adipose tissue, liver, brain and skeletal muscle. In contrast, studying skeletal muscle remodeling in animal models are easier to perform as the organs can be easily obtained after euthanasia; however, not all models of resistance training in animals displays a robust capacity to hypertrophy the desired muscle. Moreover, some models of resistance training rely on voluntary effort, which complicates the results observed when animal models are employed since voluntary capacity is something theoretically impossible to measure in rodents. With this information in mind, we will review the modalities used to simulate resistance training in animals in order to present to investigators the benefits and risks of different animal models capable to provoke skeletal muscle hypertrophy. Our second objective is to help investigators analyze and select the experimental resistance training model that best promotes the research question and desired endpoints. J. Cell. Physiol. 229: 1148–1156, 2014.

Effects of betaine on body composition, performance, and homocysteine thiolactone

BackgroundThis study investigated the effects of long term betaine supplementation on body composition, performance, and homocysteine thiolactone (HCTL) in experienced strength trained men.MethodsTwenty-three subjects were matched for training experience (4.8 ± 2.3 years) and body fat percentage (BF%: 16.9 ± 8.0%), randomly assigned to either a placebo (PL; n = 12) or betaine group (BET; n = 11; 2.5 g/day), and completed a 6 week periodized training program consisting of 3 two-week micro-cycles. Bench press and back squat training volumes were recorded and changes in training volume were assessed at each micro-cycle. Fasting urine was collected at baseline (BL), weeks 2, 4 and 6, and assayed for HCTL. Subjects were tested prior to and following 6 weeks of treatment. Arm and thigh cross sectional area (CSA) was estimated via girth and skin fold measurements. Body density was estimated via skin fold calipers and used to estimate BF%, fat mass (FM), and lean body mass (LBM). Performance was assessed via vertical jump (VJ), bench press 1 RM (BP), and back squat 1 RM (BS).ResultsArm CSA increased significantly (p < .05) in BET but not PL. No differences existed between group and time for changes in thigh CSA. Back squat training volume increased significantly (p < .05) for both groups throughout training. Bench press training volume was significantly (p < .05) improved for BET compared to PL at microcycles one and three. Body composition (BF%, FM, LBM) improved significantly (p < .05) in BET but not PL. No differences were found in performance variables (BP, BS, VJ) between groups, except there was a trend (p = .07) for increased VJ power in BET versus PL. A significant interaction (p < .05) existed for HCTL, with increases from BL to week 2 in PL, but not BET. Additionally, HCTL remained elevated at week 4 in PL, but not BET.ConclusionSix-weeks of betaine supplementation improved body composition, arm size, bench press work capacity, attenuated the rise in urinary HCTL, and tended to improve power (p = .07) but not strength.

Synergistic effects of resistance training and protein intake: practical aspects.

Resistance training is a potent stimulus to increase skeletal muscle mass. The muscle protein accretion process depends on a robust synergistic action between protein intake and overload. The intake of protein after resistance training increases plasma amino acids, which results in the activation of signaling molecules leading to increased muscle protein synthesis (MPS) and muscle hypertrophy. Although both essential and non-essential amino acids are necessary for hypertrophy, the intake of free L-leucine or high-leucine whole proteins has been specifically shown to increase the initiation of translation that is essential for elevated MPS. The literature supports the use of protein intake following resistance-training sessions to enhance MPS; however, less understood are the effects of different protein sources and timing protocols on MPS. The sum of the adaptions from each individual training session is essential to muscle hypertrophy, and thus highlights the importance of an optimal supplementation protocol. The aim of this review is to present recent findings reported in the literature and to discuss the practical application of these results. In that light, new speculations and questions will arise that may direct future investigations. The information and recommendations generated in this review should be of benefit to clinical dietitians as well as those engaged in sports.

Targeting Inflammation and Downstream Protein Metabolism in Sarcopenia: A Brief Up-Dated Description of Concurrent Exercise and Leucine-Based Multimodal Intervention

Sarcopenia is defined as the progressive loss of muscle mass with age, and poses a serious threat to the physiological and psychological health of the elderly population with consequential economic and social burdens. Chronic low-grade inflammation plays a central role in the development of sarcopenia such that it alters cellular protein metabolism to favor proteolysis over synthesis, and thereby accelerates muscular atrophy. The purpose of this review is to highlight how exercise and nutrition intervention strategies can attenuate or treat sarcopenia. Resistance exercise increases not only muscle mass but also muscle strength, while aerobic exercise is able to ameliorate the age-related metabolic disorders. Concurrent exercise training integrates the advantages of both aerobic and resistance exercise, and may exert a significant synergistic effect in the aging organism. Higher protein intakes rich in the amino acid leucine appear to restore skeletal muscle protein metabolism balance by rescuing protein synthesis in older adults. There is good reason to believe that a multimodal treatment, a combination of exercise and increased leucine consumption in the diet, can combat some of the muscle loss associated with aging. Future research is needed to consolidate these findings to humans, and to further clarify to what extent and by which mechanisms protein metabolism might be directly involved in sarcopenia pathogenesis and the multimodal treatment responses.

Dietary proteins and amino acids in the control of the muscle mass during immobilization and aging: role of the MPS response

Dietary proteins/essential amino acids (EAAs) are nutrients with anabolic properties that may increase muscle mass or attenuate muscle loss during immobilization and aging via the stimulation of muscle protein synthesis (MPS). An EAA’s anabolic threshold, capable to maximize the stimulation of MPS has been hypothesized, but during certain conditions associated with muscle loss, this anabolic threshold seems to increase which reduces the efficacy of dietary EAAs to stimulate MPS. Preliminary studies have demonstrated that acute ingestion of dietary proteins/EAA (with a sufficient amount of leucine) was capable to restore the postprandial MPS during bed rest, immobilization or aging; however, whether these improvements translate into chronic increases (or attenuates loss) of muscle mass is equivocal. For example, although free leucine supplementation acutely increases MPS and muscle mass in some chronic studies, other studies have reported no increases in muscle mass following chronic leucine supplementation. In contrast, chronically increasing leucine intake via the consumption of an overall increase in dietary protein appears to be the most effective dietary intervention toward increasing or attenuating lean mass during aging; however, more research investigating the optimal dose and timing of protein ingestion is necessary. Several studies have demonstrated that decreases in postprandial MPS as a result of increased circulating oxidative and inflammatory are more responsible than muscle protein breakdown for the decreases in muscle mass during disuse and health aging. Therefore, nutritional interventions that reduce oxidation or inflammation in conjunction with higher protein intakes that overcome the anabolic resistance may enhance the MPS response to feeding and either increase muscle mass or attenuate loss. In preliminary studies, antioxidant vitamins and amino acids with antioxidant or anti-inflammatory properties show potential to restore the anabolic response associated with protein ingestion. More research, however, is required to investigate if these nutrients translate to increases in MPS and, ultimately, increased lean mass in aging humans. The purpose of the present review is to discuss the role of protein/EAA intake to enhance postprandial MPS during conditions associated with muscle loss, and bring new perspectives and challenges associated nutritional interventions aimed to optimize the anabolic effects of dietary protein/EAAs ingestion.

IMMUNOMETABOLIC RESPONSES TO CONCURRENT TRAINING: THE EFFECTS OF EXERCISE ORDER IN RECREATIONAL WEIGHTLIFTERS

Abstract Inoue, DS, Panissa, VLG, Monteiro, PA, Gerosa-Neto, J, Rossi, FE, Antunes, BMM, Franchini, E, Cholewa, JM, Gobbo, LA, and Lira, FS. Immunometabolic responses to concurrent training: the effects of exercise order in recreational weightlifters. J Strength Cond Res 30(7): 1960–1967, 2016—The relationship between immunometabolic response and performance is not well understood. This study evaluated the influence of concurrent strength and high-intensity aerobic sequence of exercise order between sessions on strength performance, metabolic, and inflammatory response. Eleven recreational weightlifters underwent the following 2 randomized sessions: (a) strength-aerobic exercise order (SA) and (b) aerobic-strength exercise order (AS). Blood samples were collected before (Pre) and immediately after the first exercise (Post-1) and the second exercise (Post-2) of each session. The SA condition presented a higher number of repetitions (SA: 54 ± 15 vs. AS: 43 ± 12) and total volume (SA: 7,265 ± 2,323 vs. AS: 5,794 ± 1846 kg) than the AS condition (both p = 0.001). Glucose was higher in Pre when compared with post-1 in both orders (p ⩽ 0.05); changes in lactate were time-dependent in the different orders (p ⩽ 0.05); however, AS post-2 lactate was lower when compared with SA post-2 (p ⩽ 0.05). Interleukin-6 levels showed time-dependent changes for both exercise orders (p ⩽ 0.05). Tumor necrosis factor alpha (TNF-&agr;) level was increased only in AS post-1 (AS: pre = 21.91 ± 35.47, post-1 = 26.99 ± 47.69 pg·ml−1 vs. SA: pre = 25.74 ± 43.64, post-1 = 29.74 ± 46.05 pg·ml−1, p ⩽ 0.05). These results suggest that concurrent training order exhibits different immunometabolic responses and, at least in part, can be associated with the acute decline in strength performance induced by concurrent exercise. Our results point to a possible role of TNF-&agr; (post-1 AS condition) as a trigger to restore the energy demand by providing substrates to help maintain contractile activity in skeletal muscle.

Hypertrophy-Promoting Effects of Leucine Supplementation and Moderate Intensity Aerobic Exercise in Pre-Senescent Mice

Several studies have indicated a positive influence of leucine supplementation and aerobic training on the aging skeletal muscle signaling pathways that control muscle protein balance and muscle remodeling. However, the effect of a combined intervention requires further clarification. Thirteen month old CD-1® mice were subjected to moderate aerobic exercise (45 min swimming per day with 3% body weight workload) and fed a chow diet with 5% leucine or 3.4% alanine for 8 weeks. Serum and plasma were prepared for glucose, urea nitrogen, insulin and amino acid profile analysis. The white gastrocnemius muscles were used for determination of muscle size and signaling proteins involved in protein synthesis and degradation. The results show that both 8 weeks of leucine supplementation and aerobic training elevated the activity of mTOR (mammalian target of rapamycin) and its downstream target p70S6K and 4E-BP1, inhibited the ubiquitin-proteasome system, and increased fiber cross-sectional area (CSA) in white gastrocnemius muscle. Moreover, leucine supplementation in combination with exercise demonstrated more significant effects, such as greater CSA, protein content and altered phosphorylation (suggestive of increased activity) of protein synthesis signaling proteins, in addition to lower expression of proteins involved in protein degradation compared to leucine or exercise alone. The current study shows moderate aerobic training combined with 5% leucine supplementation has the potential to increase muscle size in fast-twitch skeletal muscle during aging, potentially through increased protein synthesis and decreased protein breakdown.

Caffeine supplementation affects the immunometabolic response to concurrent training

The aim of the present study was to investigate the effects of caffeine (CAF) and carbohydrate (CHO) intake on strength performance and its metabolic and inflammatory responses during concurrent training. Seven active males ingested a double-placebo (P), CAF (capsule 5 mg/kg) or CHO (20% maltodextrin solution) supplementation before strength exercise. Participants performed three randomized sessions of 5,000-m high-intensity intermittent aerobic exercise at maximal intensity followed by strength exercise, performing after the P, CHO, and CAF intake. The blood samples were collected before (pre) and immediately after concurrent strength exercise (post). We found a similar number of repetitions and total volume in all supplementation groups. There was a main effect of time on glucose, lactate, and interleukin (IL)-6 (P<0.05). When compared the changes between groups (postvalues minus prevalues), there was lower glucose in CAF group when compared to CHO group (CAF= 5.0±10.4 vs. CHO=27.8±20 vs. P=15.1±14, P=0.031) and higher IL-6 levels (CAF=11.9±9.2 vs. CHO=−2.4±1.7 vs. P=4.3± 11.7, P=0.017). There was significant interaction for glucose and lactate (P<0.001). In conclusion, CAF and CHO intake did not improve strength performance during concurrent strength training in active males. However, CAF affected immunometabolic responses.

Acute capsaicin supplementation improves resistance training performance in trained men.

Abstract Conrado de Freitas, M, Cholewa, JM, Freire, RV, Carmo, BA, Bottan, J, Bratfich, M, Della Bandeira, MP, Gonçalves, DC, Caperuto, EC, Lira, FS, and Rossi, FE. Acute capsaicin supplementation improves resistance training performance in trained men. J Strength Cond Res 32(8): 2227–2232, 2018—The purpose of this study was to investigate the acute effect of capsaicin supplementation on performance, rate of perceived exertion (RPE), and blood lactate concentrations during resistance exercise in healthy trained young men. Ten resistance-trained men (age = 22.7 ± 4.0 years, mass = 82.3 ± 9.6 kg, and height = 175 ± 0.1 cm) completed 2 randomized, double-blind trials: capsaicin condition (12 mg) or a placebo condition. Forty-five minutes after supplement consumption, subjects performed 4 sets until movement failure in the squat exercise at 70% of 1 repetition maximum with 90 seconds of rest interval between sets. The total mass lifted (total repetitions × mass lifted) was calculated. The RPE was recorded after the last set. Blood lactate was analyzed after each set of exercise, immediately postexercise, and after 3, 5, and at 30 minutes during recovery. The number of repetitions in each set decreased significantly after all sets compared with set-1 and after set-3 and set-4 in relation to set-2 (p < 0.001); however, total mass lifted was higher in capsaicin compared with placebo (3,919.4 ± 1,227.4 kg vs. 3,179.6 ± 942.4 kg, p = 0.002). Blood lactate increased significantly after each set (p < 0.001); however, there were no differences between conditions. Rate of perceived exertion was significantly less for the capsaicin condition than placebo (17.2 ± 1.0 vs. 18.3 ± 1.7, p = 0.048). In summary, acute capsaicin supplementation improves lower-body resistance training performance in trained young men.

The effects of moderate- versus high-load resistance training on muscle growth, body composition, and performance in collegiate women.

Abstract Cholewa, JM, Rossi, FE, MacDonald, C, Hewins, A, Gallo, S, Micenski, A, Norton, L, and Campbell, BI. The effects of moderate- versus high-load resistance training on muscle growth, body composition, and performance in collegiate women. J Strength Cond Res 32(6): 1511–1524, 2018—Twenty young women (20.3 + 1.5 years, 164 + 6 cm, 68.7 + 13.8 kg) without prior structured resistance training experience were recruited for this study. Body composition (BodPod), compartmental water (Bioelectrical Impedance), 7-site skinfold, and arm and thigh cross-sectional area (CSA) were assessed before and after 8-week training. Performance testing consisted of vertical jump, 3-kg chest pass initial velocity, squat 1RM, and overhead press 1RM. After 2 weeks of familiarization training, subjects were matched for body composition and relative squat strength and randomly assigned to either a high-load (HL: n = 10; 4 sets of 5–7 repetitions) or moderate-load (ML: n = 10; 2 sets of 10–14 repetitions) group that completed 6–7 exercises per day performed to momentary muscular failure. Training was divided into 2 lower and one upper body training sessions per week performed on nonconsecutive days for 8 weeks. There were no statistically significant main effects for group or group × time interactions for any variable assessed. Both HL and ML resulted in similar significant increases in lean body mass (1.5 ± 0.83 kg), lean dry mass (1.32 ± 0.62 kg), thigh CSA (6.6 ± 5.6 cm2), vertical jump (2.9 ± 3.2 cm), chest pass velocity (0.334 ± 1.67 m·s−1), back squat one repetition maximum (1RM) (22.5 ± 8.1 kg), and overhead press (3.0 ± 0.8 kg). High-load group and ML group also both resulted in significant decreases in percent body fat (1.3 ± 1.3%), total body water (0.73 ± 0.70 L), and intracellular water (0.43 ± 0.38 L). The results of this study indicate that both moderate-load and high-load training are effective at improving muscle growth, body composition, strength and power in untrained young women.