Ergogenic Effects of Sodium Bicarbonate on Resistance Exercise: A Randomized, Double-Blind, Placebo-Controlled Study.

ABSTRACT: Varovic, D, Grgic, J, Schoenfeld, BJ, and Vuk, S. Ergogenic effects of sodium bicarbonate on resistance exercise: a randomized, double-blind, placebo-controlled study. J Strength Cond Res 37(8): 1600-1608, 2023-This study explored the effects of sodium bicarbonate ingestion on muscular endurance, power, and velocity in resistance exercise. Nineteen resistance-trained men ingested either 0.3 g·kg -1 of sodium bicarbonate or 0.21 g·kg -1 of placebo (sodium chloride) 180-60 minutes before exercise. The exercise protocol involved performing 3 sets with 70% of 1 repetition maximum to muscular failure in the bench press and biceps curl exercises. Analyzed outcomes included the number of repetitions performed in every set and throughout all 3 sets. In addition, power and velocity of the repetitions were explored by matching the number of repetitions between the sodium bicarbonate and placebo trials. In the bench press exercise, sodium bicarbonate increased the following: (a) the number of repetitions performed in the third set ( g : 0.30; p = 0.046), (b) the total number of repetitions performed throughout all 3 sets ( g : 0.23; p = 0.04), (c) peak power in the second set ( g : 0.19; p = 0.03), and (d) mean power ( g : 0.23; p = 0.03) and mean velocity ( g : 0.30; p = 0.02) in the third set. We did not find a significant difference between the conditions for any of the analyzed outcomes in the biceps curl exercise. Results indicate that sodium bicarbonate ingestion elicits an ergogenic effect on muscular endurance, power, and velocity in the bench press exercise. Given that ergogenic effects were observed only in the second and third sets, these data suggest that sodium bicarbonate acts by attenuating the suppressive effects of acidosis on muscle contractility.

Volume Load Rather Than Resting Interval Influences Muscle Hypertrophy During High-Intensity Resistance Training.

ABSTRACT: Longo, AR, Silva-Batista, C, Pedroso, K, de Salles Painelli, V, Lasevicius, T, Schoenfeld, BJ, Aihara, AY, de Almeida Peres, B, Tricoli, V, and Teixeira, EL. Volume load rather than resting interval influences muscle hypertrophy during high-intensity resistance training. J Strength Cond Res 36(6): 1554-1559, 2022-Interset rest interval has been proposed as an important variable for inducing muscle mass and strength increases during resistance training. However, its influence remains unclear, especially when protocols with differing intervals have equalized volume. We aimed to compare the effects of long (LI) vs. short rest interval (SI) on muscle strength (one repetition maximum [1RM]) and quadriceps cross-sectional area (QCSA), with or without equalized volume load (VL). Twenty-eight subjects trained twice a week for 10 weeks. Each subject's leg was allocated to 1 of 4 unilateral knee extension protocols: LI, SI, SI with VL -matched by LI (VLI-SI), and LI with VL-matched by SI (VSI-LI). A 3-minute rest interval was afforded in LI and VSI-LI protocols, while SI and VLI-SI employed a 1-minute interval. All subjects trained with a load corresponding to 80% 1RM. One repetition maximum and QCSA were measured before and after training. All protocols significantly increased 1RM values in post-training (p < 0.0001; LI: 27.6%, effect size [ES] = 0.90; VLI-SI: 31.1%, ES = 1.00; SI: 26.5%, ES = 1.11; and VSI-LI: 31.2%, ES = 1.28), with no significant differences between protocols. Quadriceps cross-sectional area increased significantly for all protocols in post-training (p < 0.0001). However, absolute changes in QCSA were significantly greater in LI and VLI-SI (13.1%, ES: 0.66 and 12.9%, ES: 0.63) than SI and VSI-LI (6.8%, ES: 0.38 and 6.6%, ES: 0.37) (both comparisons, p < 0.05). These data suggest that maintenance of high loads is more important for strength increases, while a greater VL plays a primary role for hypertrophy, regardless of interset rest interval.

Perceptual and Neuromuscular Responses Adapt Similarly Between High-Load Resistance Training and Low-Load Resistance Training With Blood Flow Restriction.

ABSTRACT: Teixeira, EL, Painelli, VdS, Schoenfeld, BJ, Silva-Batista, C, Longo, AR, Aihara, AY, Cardoso, FN, Peres, BdA, and Tricoli, V. Perceptual and neuromuscular responses adapt similarly between high-load resistance training and low-load resistance training with blood flow restriction. J Strength Cond Res 36(9): 2410-2416, 2022-This study compared the effects of 8 weeks of low-load resistance training with blood flow restriction (LL-BFR) and high-load resistance training (HL-RT) on perceptual responses (rating of perceived exertion [RPE] and pain), quadriceps cross-sectional area (QCSA), and muscle strength (1 repetition maximum [RM]). Sixteen physically active men trained twice per week, for 8 weeks. One leg performed LL-BFR (3 sets of 15 repetitions, 20% 1RM), whereas the contralateral leg performed HL-RT (3 sets of 8 repetitions, 70% 1RM). Rating of perceived exertion and pain were evaluated immediately after the first and last training sessions, whereas QCSA and 1RM were assessed at baseline and after training. Rating of perceived exertion was significantly lower (6.8 ± 1.1 vs. 8.1 ± 0.8, p = 0.001) and pain significantly higher (7.1 ± 1.2 vs. 5.8 ± 1.8, p = 0.02) for LL-BFR than that for HL-RT before training. Significant reductions in RPE and pain were shown for both protocols after training (both p < 0.0001), although no between-protocol differences were shown in absolute changes ( p = 0.10 and p = 0.48, respectively). Both LL-BFR and HL-RT were similarly effective in increasing QCSA (7.0 ± 3.8% and 6.3 ± 4.1%, respectively; both p < 0.0001) and 1RM (6.9 ± 4.1% and 13.7 ± 5.9%, respectively; both P < 0.0001), although absolute changes for 1RM in HL-RT were greater than LL-BFR ( p = 0.001). In conclusion, LL-BFR produces lower RPE values and a higher pain perception than HL-RT. However, consistent application of these approaches result in chronic adaptations so that there are no differences in perceptual responses over the course of time. In addition, muscle strength is optimized with HL-RT despite similar increases in muscle hypertrophy between conditions.

Varying the Order of Combinations of Single- and Multi-Joint Exercises Differentially Affects Resistance Training Adaptations.

Brandão, L, de Salles Painelli, V, Lasevicius, T, Silva-Batista, C, Brendon, H, Schoenfeld, BJ, Aihara, AY, Cardoso, FN, de Almeida Peres, B, and Teixeira, EL. Varying the order of combinations of single- and multi-joint exercises differentially affects resistance training adaptations. J Strength Cond Res 34(5): 1254-1263, 2020-Our study aimed to compare the effects of multi-joint (MJ) and single-joint (SJ) exercises, either isolated or in combination, and in different orders, on cross-sectional area (CSA) of the pectoralis major (PM) and different heads of the triceps brachii (TB), as well as on the one-repetition maximum (1-RM) in the bench press and lying barbell triceps press. Forty-three young men were randomly assigned to one of 4 possible RT protocols: barbell bench press plus lying barbell triceps press (MJ + SJ, n = 12); lying barbell triceps press plus barbell bench press (SJ + MJ, n = 10); barbell bench press (MJ, n = 10); or lying barbell triceps press (SJ, n = 11). Results showed significant within-group increases in 1-RM bench press for MJ, MJ + SJ, and SJ + MJ but not for SJ. Conversely, significantly greater within-group increases in elbow extension 1-RM were noted for SJ, MJ + SJ, and SJ + MJ but not for MJ. Significantly greater increases in PM CSA were observed for MJ, MJ + SJ, and SJ + MJ compared with SJ. Significant increases in TB CSA were noted for SJ, MJ + SJ, and SJ + MJ, but not for MJ, without observed between-group differences. Individual analysis of TB heads showed significantly greater CSA increases in the lateral head for MJ, MJ + SJ, and SJ + MJ compared with SJ. Alternatively, significantly greater increases in the long head were observed for SJ, MJ + SJ, and SJ + MJ compared with MJ. CSA increases for the medial head were statistically similar between conditions. Our findings indicate that muscular adaptations are differentially affected by performance of MJ and SJ exercises.

How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency.

Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.

Metabolic and hormonal responses to different resistance training systems in elderly men.

OBJECTIVE: To compare acute and sub-acute responses in hormonal profile and metabolic parameters in elderly people who participated in two methods of strength training (ST) with equalized loads. METHODS AND MATERIALS: A total of 12 elder individuals (65 ± 3 years) were randomly assigned to two training methods: constant intensity (CI, 3 sets of 10 repetitions with 75% of 1RM) and variable intensity (VI, 1st set: 12 repetitions at 67% of 1RM > 2nd set: 10 repetitions at 75% of 1RM and 3rd set: 8 repetitions at 80% of 1RM). Both methods included the following exercises: leg press, knee extension, and squat with 1 min rest intervals between sets. Free speed of execution and maximum range of movement were encouraged throughout each set for both protocols. Blood samples were analyzed included glucose, testosterone (T), cortisol (C), T/C rate, growth hormone (GH), and lactate at 2 and 24 h post intervention. RESULTS: There were no observed differences in glucose, testosterone, GH, and lactate concentrations both at 2 and 24 h after the execution of the two training methods. However, significant increases in the levels of T/C rate and decrease on cortisol were observed immediately post exercise for both protocols. CONCLUSIONS: Although no significant differences were observed between the two interventions in relation to the hormonal and metabolic parameters analyzed, both training methods promoted a favorable response, with a slight superiority noted for the CI method relative to the hormonal profile.

Resistance Training Combined With Diet Decreases Body Fat While Preserving Lean Mass Independent of Resting Metabolic Rate: A Randomized Trial.

The purpose of this study was to determine the effects of resistance training only (RT; n = 10), dietary intervention only (DIET; n = 10), resistance training plus diet (RT+DIET; n = 10), and control (CON; n = 10) on body composition and resting metabolic rate (RMR) in a cohort of 40 premenopausal female volunteers. Subjects in DIET and RT+DIET were provided with daily macronutrient and calorie goals based on DXA and RMR tests, with protein maintained at 3.1 g/kg/day. Subjects in the RT and RT+DIET groups performed a supervised progressive RT program consisting of exercises for all the major muscle groups of the body. Results showed a significant month-by-group interaction for change in fat mass with no significant linear trend for control. The three treatment groups all showed significant linear decreases in fat mass, but the slope of the decrease became progressively steeper from the RT, to DIET, to RT+DIET. A significant linear increase for lean mass was seen for resistance training only. There was a nonsignificant increase in RMR in all groups from Month 0 to Month 4 but no significant month by group interaction. In conclusion, significant reductions in fat mass were achieved by all experimental groups, but results were maximized by RT+DIET. Only the RT group showed significant increases in lean mass.

Effects of High Versus Low Protein Intake on Body Composition and Maximal Strength in Aspiring Female Physique Athletes Engaging in an 8-Week Resistance Training Program.

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 versus lower protein intakes in this population. This study examined the influence of a high versus low-protein diet in conjunction with an 8-week resistance training program in this population. A total of 17 females (21.2 ± 2.1 years; 165.1 ± 5.1 cm; 61 ± 6.1 kg) were randomly assigned to a high-protein diet (HP: 2.5 g·kg-1·day-1; n = 8) or a low-protein diet (LP: 0.9 g·kg-1·day-1, 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 increased significantly more in the HP group as compared with the LP group (p = .009), going from 47.1 ± 4.5 to 49.2 ± 5.4 kg (+2.1 kg) and from 48.1 ± 2.7 to 48.7 ± 2 kg (+0.6 kg) in the HP and LP groups, respectively. Fat mass significantly decreased over time in the HP group (14.1 ± 3.6 to 13.0 ± 3.3 kg; p < .01), but no change was observed in the LP group (13.2 ± 3.7 to 12.5 ± 3.0 kg). Although 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 fat-free mass in conjunction with a resistance training program.

The Effects of Muscle Strength Responsiveness to Periodized Resistance Training on Resistin, Leptin, and Cytokine in Elderly Postmenopausal Women.

Prestes, J, Nascimento, DdC, Neto, IVS, Tibana, RA, Shiguemoto, GE, Perez, SEA, Botero, JP, Schoenfeld, BJ, and Pereira, GB. The effects of muscle strength responsiveness to periodized resistance training on resistin, leptin, and cytokine in elderly postmenopausal women. J Strength Cond Res 32(1): 113-120, 2018-The aim of this study was to evaluate muscle strength responsiveness and to determine whether interleukin 4 (IL-4), leptin, and resistin would be affected by the individual pattern of response to a resistance training (RT) periodization program. Twenty-six elderly postmenopausal women participated in the present study (mean age = 62.57 ± 6.69 years and body mass index = 28.09 ± 4.83 kg·m). Four-month longitudinal training program was performed consisting of 2 whole-body sessions per week with increasing intensity and decreasing volume by using 6-14 repetitions maximum (RM). Two acute whole-body RT sessions (before and after chronic training) were also performed comprising 3 sets of 12-14RM. The responsiveness was determined based on their relative muscle strength gains in 45° leg press. High responders were defined as relative muscle strength gains ≥32% and low responders <32% (n = 13 in each group). Muscle strength increased by a higher amount in the high-responsive group as compared with the low-responsive group in the 45° leg press and bench press, whereas muscle strength increased for both groups when compared with pretraining evaluation (p = 0.001). Low responders displayed higher plasma leptin levels when compared with high responders at baseline (p = 0.001), and after 16 weeks of training, leptin levels were significantly lower when compared with baseline (pretraining period). Both groups displayed a decrease in baseline resistin values after 16 weeks of RT, but only a statistically simple main effect was observed for low responders. In addition, there were no effect of time and no significant interaction between the responsiveness and time on IL-4 concentration. In conclusion, RT is effective in improving upper and lower limb muscle strength in elderly women, with higher magnitudes of increase seen for those classified as high responders. Resistin and leptin displayed a decrease over time, regardless of responsiveness classification.

Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training.

We investigated the effects of low-load resistance training to failure performed with different rest intervals on acute hormonal responses and long-term muscle and strength gains. In the acute study, 14 participants were assigned to either a short rest (S, 30 s) or long rest (L, 150 s) protocol at 40% one-repetition maximum. Blood samples were taken before and after the workout. Both groups showed significant (p<0.05) increases in growth hormone and insulin-like growth factor 1 immediately post-workout. In the longitudinal study, the same protocol as in the acute study was performed 2 times per week for 8 weeks by 21 volunteers. Both groups showed significant increases in triceps (S: 9.8±8.8%, L: 10.6±9.6%, p<0.05) and thigh (S: 5.7±4.7%, L: 8.3±6.4%, p<0.05) cross-sectional area. One-repetition maximum also significantly increased for the bench press (S: 9.9±6.9%, L: 6.5±5.8%, p<0.05) and squat (S: 5.2±6.7%, L: 5.4±3.5%, p<0.05). In conclusion, our results suggest that acute hormonal responses, as well as chronic changes in muscle hypertrophy and strength in low-load training to failure are independent of the rest interval length.

Is there a relationship between back squat depth, ankle flexibility, and Achilles tendon stiffness?

This study investigated the relationship between back squat depth capacity, ankle dorsiflexion resistance to stretch and maximal range of motion (ROM), and Achilles tendon stiffness of healthy individuals (n = 20). Squat depth capacity was assessed with 2D kinematic analysis. Ankle dorsiflexion maximal ROM was assessed using a smartphone digital goniometry (lunge test) and isokinetic dynamometry (prone test). Ankle dorsiflexion resistance to stretch was assessed during the prone test. Achilles tendon stiffness was estimated at rest [using shear wave elastography (stiffness-SWE)] and during isometric contraction through tendon force-length relationship (using B-mode sonography). Squat depth was associated only with ankle dorsiflexion ROM in the lunge test (r = 0.69, p = 0.001). Ankle dorsiflexion ROM in the lunge test was associated with the ankle resistance to stretch (r = 0.46, p = 0.050) and Achilles tendon stiffness-SWE (r = 0.62, p = 0.005); and it was the only variable different between individuals with low and high squat depth capacity (p = 0.014). No other statistically significant associations were found. In conclusion, back squat depth is associated with ankle dorsiflexion ROM when the knee is flexed, without evident influence of global joint and Achilles tendon mechanical properties.

Split or full-body workout routine: which is best to increase muscle strength and hypertrophy?

OBJECTIVE: To compare the effects of different resistance training programs on measures of muscle strength and hypertrophy. METHODS: Sixty-seven untrained subjects were randomized to one of two groups: Split Workout Routine (n=35), in which muscle groups were trained twice per week in an A/B split consisting of eight sets per session, or Full-Body Workout Routine (n=32), in which muscle groups were trained four times per week with four and eight sets per session. Both groups performed eight to 12 repetition maximum per set, with 60 seconds of rest between sets. Maximal strength and muscle thickness were assessed at baseline and after eight weeks of training. RESULTS: A significant main effect of time (pre versus post) was observed for maximal strength in the bench press and squat exercises and thickness of the elbow extensor, elbow flexor and quadriceps femoris muscles. Selected variables did not differ significantly between groups. CONCLUSION: Resistance training twice or four times per week has similar effects on neuromuscular adaptation, provided weekly set volume is equal.

Mean Propulsive Velocity Is a Viable Method for Adjusting the Resistance-Training Load at Moderate Altitude.

We examined the viability of using mean propulsive velocity (MPV) to adjust the load in the countermovement jump (CMJ) at moderate altitude. Twenty-four volunteers were assigned to a 4-week power-oriented resistance training (RT) program in either normoxia (N, 690 m) or intermittent hypobaric hypoxia (IH, 2,320 m). The load was adjusted to maintain execution velocity of CMJ at 1m·s-1 of MPV. Relative peak power output (Prel), and percentage of velocity loss throughout the sets (VL) were determined for each session. The internal load was measured by the rating of perceived exertion (RPE). The absolute load lifted was higher in IH compared to N (75.6 ± 8.4 vs. 58.5 ± 12.3 kg P < 0.001). However, similar relative increases for both groups were found when comparing the final values (IH: 8.2%, P = 0.007; N: 9.8%, P = 0.03) with no changes in VL between groups (P = 0.36). Post-study Prel improved significantly only in IH (+7% W·kg-1, P = 0.002). Mean RPE was greater in IH vs. N (6.8 ± 1.5 vs. 5.6 ± 2, P < 0.001). The MPV seems to be a viable method for adjusting external load during RT at moderate altitude. However, given that RT at moderate altitude increases RPE, it is prudent to monitor internal load when using the MPV to best determine the actual physiological stress of the session.

Similar Muscular Adaptations in Resistance Training Performed Two Versus Three Days Per Week.

The purpose of the present study was to compare changes in muscle strength and hypertrophy between volume-equated resistance training (RT) performed 2 versus 3 times per week in trained men. Thirty-six resistance-trained men were randomly assigned to one of the two experimental groups: a split-body training routine (SPLIT) with muscle groups trained twice per week (n = 18) over four weekly sessions, or a total-body routine (TOTAL), with muscle groups being trained three times per week (n = 18) over three weekly sessions. The training intervention lasted 10 weeks. Testing was carried out pre- and post-study to assess maximal muscular strength in the back squat and bench press, and hypertrophic adaptations were assessed by measuring muscle thickness of the elbow flexors, elbow extensors, and quadriceps femoris. Twenty-eight subjects completed the study. Significant pre-to-post intervention increases in upper and lower-body muscular strength occurred in both groups with no significant between-group differences. Furthermore, significant pre-to-post intervention increases in muscle size of the elbow extensors and quadriceps femoris occurred in both groups with no significant between-group differences. No significant pre-to-post changes were observed for the muscle size of elbow flexors both in the SPLIT or TOTAL group. In conclusion, a training frequency of 2 versus 3 days per week produces similar increases in muscular adaptations in trained men over a 10-week training period. Nonetheless, effect size differences favored SPLIT for all hypertrophy measures, indicating a potential benefit for training two versus three days a week when the goal is to maximize gains in muscle mass.

Anabolic-androgenic steroids: procurement and administration practices of doping athletes.

Performance enhancing substances are becoming increasingly popular amongst bodybuilders and people who want to enhance their physiques. However, due to the rise of the Internet and laws prohibiting sales of these substances without prescription, the route of procurement and administration practices have become more and more dangerous. Prior to the mid-1970's, anabolic steroids were not regulated and easily available from physicians and pharmacies in several countries. In 1990, the United States enacted the Anabolic Steroid Control Act, leading to the proliferation of black markets and underground laboratories. The shift from pharmacy to underground online sites for the procurement of anabolic steroids led to an increase of fake products with low purity and the ability to potentially endanger the health of anabolic steroid users. Underground laboratories emerged both locally and in countries with lax legal regulations. 'Anabolic steroid tourism' and large networks of online resellers emerged, leading to the banalisation of the illegal procurement of anabolic steroids. Furthermore, the increase of anecdotal information spreading on the internet among anabolic steroid user forums nourishes the rampant misinformation and dangerous practices that currently exist. The dosages and ways of administration recommended on these forums can be false and misleading to those who lack a medical background and cannot go to their physician to seek advice because of the fear of repercussions. This review aims to elucidate and describe current practices of the anabolic-androgenic steroids black market and draw attention to potential dangers for users.

Effects of order of resistance training exercises on muscle hypertrophy in young adult men.

The purpose of the present study was to analyze the effects of the order of resistance training (RT) exercises on hypertrophy in young adult men. Thirty-six young adult men (age, 21.9 ± 2.5 years; body mass, 72.6 ± 12.1 kg, height, 176.9 ± 7.4 cm; body mass index, 23.1 ± 3.3 kg/m2) were randomly assigned to 1 of 2 training groups that performed a 6-week RT program in either (i) a traditional approach starting with multi-joint (MJ) exercises followed by single-joint exercises (SJ) (MJ-SJ, n = 19) or (ii) in reverse order (SJ-MJ, n = 17). Muscle thickness of the biceps brachii and mid-thigh were assessed by ultrasound. Lean soft tissue (LST) was assessed by dual-energy X-ray absorptiometry. Both groups similarly increased (P < 0.05) biceps brachii thickness (MJ-SJ = +14.2%, SJ-MJ = +13.8%). Alternatively, only the MJ-SJ group presented an increase in mid-thigh thickness from pre- to post-training (MJ-SJ = +7.2%, SJ-MJ = +3.9%). Upper limb LSTs (MJ-SJ = +5.2%, SJ-MJ = +7.5%) were statistically similar between conditions, and a trend for significance (P = 0.07) was found for trunk LST (MJ-SJ = +7.2%, SJ-MJ = +1.7%). Nonsignificant pre- to post-training changes were observed for lower limb LSTs (MJ-SJ = +0.7%, SJ-MJ = +1.8%). Our data suggest that both sequences are effective for increasing muscle hypertrophy over a short-term RT period; there may be a potentially beneficial hypertrophic effect for the mid-thigh by performing exercises in a manner that progresses from MJ to SJ exercises.

Is There a Postworkout Anabolic Window of Opportunity for Nutrient Consumption? Clearing up Controversies.

Nutrient timing is a popular strategy for enhancing muscular adaptations and athletic performance. From the standpoint of muscle hypertrophy, the concept of a "postworkout anabolic window of opportunity" has been proposed, whereby a limited time exists after training to optimize accretion of muscle proteins. Some researchers have gone so far as to claim that the timing of nutritional consumption is even more critical to muscle development than the absolute daily consumption of nutrients. Thus, the purpose of this paper is to review the current literature as to the relevance of the anabolic window of opportunity, and draw evidence-based conclusions for application into practice. J Orthop Sports Phys Ther 2018;48(12):911-914. doi:10.2519/jospt.2018.0615.

How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution.

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.

The role of hormones in muscle hypertrophy.

Anabolic-androgenic steroids (AAS) and other hormones such as growth hormone (GH) and insulin-like growth factor-1 (IGF-1) have been shown to increase muscle mass in patients suffering from various diseases related to muscle atrophy. Despite known side-effects associated with supraphysiologic doses of such drugs, their anabolic effects have led to their widespread use and abuse by bodybuilders and athletes such as strength athletes seeking to improve performance and muscle mass. On the other hand, resistance training (RT) has also been shown to induce significant endogenous hormonal (testosterone (T), GH, IGF-1) elevations. Therefore, some bodybuilders employ RT protocols designed to elevate hormonal levels in order to maximize anabolic responses. In this article, we reviewed current RT protocol outcomes with and without performance enhancing drug usage. Acute RT-induced hormonal elevations seem not to be directly correlated with muscle growth. On the other hand, supplementation with AAS and other hormones might lead to supraphysiological muscle hypertrophy, especially when different compounds are combined.

Differential effects of attentional focus strategies during long-term resistance training.

The purpose of this study was to investigate the effects of using an internal versus external focus of attention during resistance training on muscular adaptations. Thirty untrained college-aged men were randomly assigned to an internal focus group (INTERNAL) that focused on contracting the target muscle during training (n = 15) or an external focus group (EXTERNAL) that focused on the outcome of the lift (n = 15). Training for both routines consisted of 3 weekly sessions performed on non-consecutive days for 8 weeks. Subjects performed 4 sets of 8-12 repetitions per exercise. Changes in strength were assessed by six repetition maximum in the biceps curl and isometric maximal voluntary contraction in knee extension and elbow flexion. Changes in muscle thickness for the elbow flexors and quadriceps were assessed by ultrasound. Results show significantly greater increases in elbow flexor thickness in INTERNAL versus EXTERNAL (12.4% vs. 6.9%, respectively); similar changes were noted in quadriceps thickness. Isometric elbow flexion strength was greater for INTERNAL while isometric knee extension strength was greater for EXTERNAL, although neither reached statistical significance. The findings lend support to the use of a mind-muscle connection to enhance muscle hypertrophy.