health literature-summary

Maximizing Muscle Growth

The red advice is based on meta-analyses or literature reviews.

TODO: The Complete Strength Training Guide

Can We Predict Muscle Growth?

At The Gym

  • Untrained people should work out 3 or more days per week. Trained people can get away with 2. dose response for strength development. Training twice per week is better than training once per week, and this probably remains true even after controlling for weekly volume Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis.Training 2 or 3 days per week is better than training once per week, but this result stops being significant after controlling for volume Grgic - still the sign in this study is in the right direction, so both studies show the balance of the evidence suggests working out multiple times per week is better than working out once per week.
  • You should perform about 4 sets for each exercise dose response for strength development. Multiple sets causes 40% more growth than a single set, and this gain seems almost entirely concentrated in the second and third sets Single vs. multiple sets. Multiple sets yield greater gains than a single set Bågenhammar Durall.
  • Resting 3 minutes between sets promotes more growth than shorter durations rest periods. Other research says the rest interval doesn't matter de Souza Jr.
  • Repetitions lasting 0.5 - 8 seconds have similar effects; reps lasting more than 10 seconds might be less effective repetition duration.
  • There's no reason to train to failure repetition failure.
  • Novices should lift as many reps as they can while lifting 60% of their max, while trained lifters should lift 80% dose response for strength development. According to the Brzycki formula, this corresponds to about 23 and 8 reps, respectively.
  • Trained lifters should lift as many reps as they can while lifting 85% of their max Maximizing strength development in athletes. According to the Brzycki formula, this corresponds to about 5 reps.
  • The free-weight bench press activates more muscles than the machine bench press, weakly suggesting that free-weights might prove better at stimulating muscle growth than machine exercises McCaw.
  • Full-body workouts appear better than Ratamess Calder, or at least no worse than Benton split-body workouts. However, its plausible split workouts can allow for higher volume given the same amount of effort, which could plausibly make split workouts more effective. More research is needed Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis.
  • Working out once per week may be enough to maintain muscle mass Trappe. A third the original volume is enough to maintain strength Bickel
  • When comparing dumbbells, barbells, and machines, it's complicated... Farias.
  • Exercising while losing weight helps maintain muscle mass A meta-analysis couldn't even confirm that resistance training helps retain muscle mass, but the evidence is weaker that it helps lose additional fat mass Sardeli (large-ish trials: Nicklas Hernández-Reyes).
  • todo Benito

In the Kitchen

  • Protein up to 1.6 grams per kg of body weight per day improve muscle gains protein supplementation - that's about double the 0.8 recommended for the general population. A literature review recommends higher levels for people simultaneously losing weight: between 2.3 and 3.1 dietary protein during caloric restriction g/kg/d. Finally, even in sedentary populations eating a caloric surplus, extra protein intake causes less of the gained weight to be fat Leaf.
  • Protein supplements work Protein supplementation, especially whey advantage whey,
  • Three studies have found that there is a limit to how much protein you can consume in one meal before its effect on muscle growth goes away. The estimates for this threshold generally fall between 20g and 30g of protein moderate serving of high-quality protein Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. However, a study in older adults did not reproduce this result, suggesting that benefits exist far past this 30g limit for that demographic Quantity of dietary protein intake, but not pattern of intake, affects net protein balance primarily through differences in protein synthesis in older adults.
  • Consuming protein around the time of your workout has no effect on muscle growth except insofar as it may boost your total protein consumption protein timing Wirth.
  • You should definitely take creatine supplements, which have been found to increase muscle mass by something like a sixth of a pound per week among older adults. The only side-effects found were minor gastrointestinal issues Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis.
  • Caffeine doesn't increase strength Astorino.
  • Recent meta-analyses and literature reviews are generally positive or neutral on the effect of chromium picolinate on muscle mass Lukaski Tsang Heffernan Willoughby..
  • todo Miller

Though I haven't found convincing evidence on muscle mass or strength, some other supplements do boost athletic performance:

  • Exercise lasting more than 60 seconds is improved with β-alanine consumption Hobson. These improvements were later confirmed Elliott-Sale. It is generally safe Painelli.
  • "Citrulline supplementation confers a significant performance benefit for high-intensity strength and power tasks in comparison to placebo, with a pooled SMD of 0.20 [0.01, 0.39]" Trexler.
  • Nitrate supplementation improves exercise tolerance but not performance Van De Walle.

I haven't really looked into steroid use, but The Science of Steroids: The Physiology and Psychology of How Steroids Make You Stronger seems like a good starting point.

Best Isolation Exercises

I couldn't find many exercises comparing actual strength or muscle mass gain, so we're going to have to rely on muscle activation. The best isolation exercises for each muscle group are:

  • Abs: Bicycle maneuver, Captain's chair American Council on Exercise (ACE)-sponsored Study Reveals Best and Worst Abdominal Exercises (see also Stenger).
  • Biceps: Concentration Curl, Cable curl, Chin-up ACE Study Reveals Best Biceps Exercises.
  • Chest: Barbell bench press, pec deck machine, bent-forward cable crossovers ACE-Sponsored Research: Top 3 Most Effective Chest Exercises.
  • Shoulders: dumbbell shoulder press, dumbbell front raise Dynamite Delts: ACE Research Identifies Top Shoulder Exercises, but see also Sweeney.
  • Back ACE-SPONSORED RESEARCH: What Is the Best Back Exercise?.

Literature Reviews

[TODO: Integrate this section into the "At The Gym" section]

From Oranchuk:

Isometric training at longer muscle lengths (0.86%‐1.69%/week, ES = 0.03‐0.09/week) produced greater muscular hypertrophy when compared to equal volumes of shorter muscle length training (0.08%‐0.83%/week, ES = −0.003 to 0.07/week). Ballistic intent resulted in greater neuromuscular activation (1.04%‐10.5%/week, ES = 0.02‐0.31/week vs 1.64%‐5.53%/week, ES = 0.03‐0.20/week) and rapid force production (1.2%‐13.4%/week, ES = 0.05‐0.61/week vs 1.01%‐8.13%/week, ES = 0.06‐0.22/week). Substantial improvements in muscular hypertrophy and maximal force production were reported regardless of training intensity. High‐intensity (≥70%) contractions are required for improving tendon structure and function. Additionally, long muscle length training results in greater transference to dynamic performance.

One literature review Manipulating resistance training program variables to optimize maximum strength in men: a review found

In general, maximum strength is best developed with 1–6 repetition maximum loads, a combination of concentric and eccentric muscle actions, 3–6 maximal sets per session, training to failure for limited periods, long interset recovery time, 3–5 days of training per week, and dividing the day’s training into 2 sessions. Variation of the volume and intensity in the course of a training cycle will further enhance strength gains.

Another literature review Bird says:

  • Load should be increased 2-10% when you ca perform one or two reps over the desired number.
  • You should target 3-4 sets of 6-15 reps.
  • Both single- and multiple-joint exercises should be incorporated into the resistance training program.
  • Some evidence suggests doing larger multi-joint exercises before smaller single-joint exercises in a workout.
  • The optimal rest period between sets ranges from 0.5 to 8 minutes depending on one's goals.
  • They recommend a slow repetition velocity for novice and intermediate trainers, and a combination of slow and fast velocities for advanced trainers.
  • Untrained trainers should perform complete-body workouts 2-3 days per week. This recommendation changes to split-body workouts 4-6 days per week for advanced trainers.
  • "early increases in strength are associated mainly with neural adaptations, while hypertrophic responses begin to occur at the latter stages of training."
  • Although men are typically stronger than women, both sexes respond to training similarly in percentage terms.

A third literature review (TODO) Wernbom concludes

This review demonstrates that several modes of training and all three types of muscle actions can induce hypertrophy at impressive rates and that, at present, there is insufficient evidence for the superiority of any mode and/or type of muscle action over other modes and types of training. That said, it appears that exercise with a maximal-eccentric component can induce increases in muscle mass with shorter durations of work than other modes. Some evidence suggests that the training frequency has a large impact on the rate of gain in muscle volume for shorter training periods. Because longer studies using relatively high frequencies are lacking, it cannot be excluded that stagnation or even overtraining would occur in the long term. Regarding intensity, moderately heavy loads seem to elicit the greatest gains for most categories of training, although examples of very high rates were noted at both very low and very high intensities when the sets were performed with maximum effort or taken to muscular failure. Thus, achieving recruitment of the greatest numble of muscle fibres possible and exposing them to the exercise stimulus may be as important as the training load per se. For the total volume or duration of activity, the results suggest a dose-response curve characterized by an increase in the rate of growth in the initial part of the curve, which is followed by the region of peak rate of increase, which in turn is followed by a plateau or even a decline.

General Health Recommendations

From Prescription of resistance training for health and disease:

The current research indicates that, for healthy persons of all ages and many patients with chronic diseases, single set programs of up to 15 repetitions performed a minimum of 2 d·wk−1 are recommended. Each workout session should consist of 8-10 different exercises that train the major muscle groups. Single set programs are less time consuming and more cost efficient, which generally translates into improved program compliance. Further, single set programs are recommended for the above-mentioned populations because they produce most of the health and fitness benefits of multiple set programs. The goal of this type of program is to develop and maintain a significant amount of muscle mass, endurance, and strength to contribute to overall fitness and health. Patients with chronic diseases (e.g., arthritis) may have to limit range of motion for some exercises and use lighter weights with more repetitions.

From Prescription of Resistance Training for Healthy Populations:

A minimum of 1 set of 8 to 10 exercises (multi-joint and single joint) that involve the major muscle groups should be performed 2 to 3 times a week for healthy participants of all ages. More technical and advanced training including periodised multiple set regimens and/or advanced exercises may be more appropriate for individuals whose goals include maximum gains in strength and lean body mass.

Creatine Dosage

I couldn't find any meta-analyses on the optimal creatine dosage so I decided to take a look at the data on my own. I looked at the creatine meta-analysis and assumed the average American weight of ~180 lb to convert between studies using creatine in g vs. g/kg.

I looked at the three metrics included in the study (lean body mass, chest press, leg press) and analyzed how the effect size (d) changed as dosage changed. I found no statistically significant difference between low- and high-dosage creatine usage and found point estimates with both negative and positive signs depending on the metric and whether I used regression or a difference-in-means test. In other words, I found no real evidence that dose mattered. Note: this analysis was low-powered because (a) the effect estimates had significant variance (b) I only had ~27 estimates and (c) the doses fell in a relatively narrow range (3.4 g/d - 9 g/d).

Next I looked at the actual changes in those three measures (rather than effect sizes). I repeated my analysis of dosage with these measures and found similarly weak and mixed results.

I feel its worth noting that creatine is naturally created from two amino acids Creatine. In Wikipedia. Recommended amino acids consumption ranges from about 0.2g per day to about 4g per day Essential amino acid. In Wikipedia, which suggests single-digit grams of creatine per day is reasonable. Moreover, when subjects were given 30 g of creatine per day, roughly 20 g were excreted out of the body Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation; likewise subjects given 20 g per day excreted about 10 g Rawson (see introduction). These findings suggest ingesting more than 10 g per day is superfluous.

If you're interested in looking at the data yourself, you can either see the meta-analysis Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis or this convenient spreadsheet I put together.

Suspicious Studies

Now I want to move on to the controversial part of this page where I disagree with the academics with decades of experience. I think several of these meta-analyses suffer from significant problems.

Take dose response for strength development, for example. The authors found that trained athletes saw smaller returns from exercising 3 times per week rather than 2.

However, I'm suspicious of this study. It didn't look at a bunch of studies that investigated this question. Instead, it looked at a bunch of studies that investigated weight-lifting generally and compared how much strength increased relative to the group's standard deviation.

This choice of analysis doesn't make much sense to me. Suppose the meta-analysis had two studies:

  1. A set of 90-year-old apathetic women do 2 sets of bench press 3 times per week. Each lift is 3 inches. Another similar group is the control group.
  2. A set of driven 20-year-old men do 1 sets of bench press 2 times per week and are given 90g of protein as supplements. Each lift is 2 feet. Another similar groups is the control group.

It's all but certain the second study would find a larger effect size due to the demographic and procedural differences. The analysis in dose response for strength development would then conclude that 1 set is better than 2, and 2-days-per-week is better than 3. This is absurd reasoning.

They mention that they also did an analysis based on gender and age, but (1) they don't present this analysis and (2) this still ignores other factors such as protein intake.

The analyses Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis, Maximizing strength development in athletes, and Grgic also suffer from the same problems.

Instead, I think we're better off finding studies that keep the same sets and reps and just change the number of days worked per week.

I should note that some of the studies don't fall victim to these issues. For instance, Single vs. multiple sets and Bågenhammar both look at studies with groups that differ only in one variable and look at the differences in muscle growth between the groups.

At some point I should come back to this and re-examine the other meta-analyses (TODO).

These short-comings are a big problem since these were the studies we were relying on for optimal reps and optimal days-per-week estimates. For this reason, I think it's worth diving into these two topics a bit more.

Optimal Number of Reps (Bench Press)

This table lists studies where participants performed 3 sets of the bench press 3 times per week. "X > Y" means that performing X reps led to greater gains than Y reps. Some of the results are not statistically significant.

6 reps > 2 reps ~ 10 reps Effect of varied weight training programs
6-8 reps > 30-40 reps > 100-150 reps Anderson
8 > 16 Bemben
6 > 10 Comparative effects of three weight training programs
8-12 > 25-35 Effects of low-vs. high-load resistance training on muscle strength and hypertrophy in well-trained men

It looks like 3-9 reps is probably around optimal.

Optimal Number of Reps (Biceps Curl)

16 reps > 8 reps Bemben

Optimal Number of Reps (Legs)

30% 1RM (14 reps) > 90% 1RM (5 reps) Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men
80% 1RM > 30% Resistance exercise load does not determine training-mediated hypertrophic gains in young men

It looks like ~9 reps is around optimal.

Rhea, M. R., Alvar, B. A., Burkett, L. N., & Ball, S. D. (2003). A meta-analysis to determine the dose response for strength development. https://doi.org/10.1249/01.MSS.0000053727.63505.D4. Krieger, J. W. (2010). Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. The Journal of Strength & Conditioning Research, 24(4), 1150-1159. https://doi.org/10.1519/JSC.0b013e3181d4d436. Schoenfeld, B. J., Ogborn, D. I., & Krieger, J. W. (2015). Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine, 45(4), 577-585. https://doi.org/10.1007/s40279-015-0304-0. Davies, T., Orr, R., Halaki, M., & Hackett, D. (2016). Effect of training leading to repetition failure on muscular strength: a systematic review and meta-analysis. Sports medicine, 46(4), 487-502. https://doi.org/10.1007/s40279-015-0451-3. Schoenfeld, B. J., Pope, Z. K., Benik, F. M., Hester, G. M., Sellers, J., Nooner, J. L., ... & Just, B. L. (2016). Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. Journal of strength and conditioning research, 30(7), 1805-1812. https://doi.org/10.1519/JSC.0000000000001272. Morton, R. W., Murphy, K. T., McKellar, S. R., Schoenfeld, B. J., Henselmans, M., Helms, E., ... & Phillips, S. M. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med, 52(6), 376-384. https://doi.org/10.1136/bjsports-2017-097608. Symons, T. B., Sheffield-Moore, M., Wolfe, R. R., & Paddon-Jones, D. (2009). A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects. Journal of the American Dietetic Association, 109(9), 1582-1586. https://doi.org/10.1016/j.jada.2009.06.369. Chilibeck, P. D., Kaviani, M., Candow, D. G., & Zello, G. A. (2017). Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis. Open access journal of sports medicine, 8, 213. https://doi.org/10.2147/OAJSM.S123529. Peterson, M. D., Rhea, M. R., & Alvar, B. A. (2004). Maximizing strength development in athletes: a meta-analysis to determine the dose-response relationship. The Journal of Strength & Conditioning Research, 18(2), 377-382. https://doi.org/10.1519/R-12842.1. Helms, E. R., Zinn, C., Rowlands, D. S., & Brown, S. R. (2014). A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. https://doi.org/10.1123/ijsnem.2013-0054. Schoenfeld, B. J., Aragon, A. A., & Krieger, J. W. (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. Journal of the International Society of Sports Nutrition, 10(1), 53. https://doi.org/10.1186/1550-2783-10-53. Cermak, N. M., de Groot, L. C., Saris, W. H., & van Loon, L. J. (2012). Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. The American journal of clinical nutrition, 96(6), 1454-1464. https://doi.org/10.3945/ajcn.112.037556. Devries, M. C., & Phillips, S. M. (2015). Supplemental protein in support of muscle mass and health: advantage whey. Journal of food science, 80(S1), A8-A15. https://doi.org/10.1111/1750-3841.12802. Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2016). Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine, 46(11), 1689-1697. https://doi.org/10.1007/s40279-016-0543-8. Feigenbaum, M. S., & Pollock, M. L. (1999). Prescription of resistance training for health and disease. Medicine & Science in Sports & Exercise, 31(1), 38-45. Hass, C. J., Feigenbaum, M. S., & Franklin, B. A. (2001). Prescription of Resistance Training for Healthy Populations. Sports medicine, 31(14), 953-964. https://doi.org/10.2165/00007256-200131140-00001. Astorino, T. A., Rohmann, R. L., & Firth, K. (2008). Effect of caffeine ingestion on one-repetition maximum muscular strength. European journal of applied physiology, 102(2), 127-132. https://doi.org/10.1007/s00421-007-0557-x. McCaw, S. T., & Friday, J. J. (1994). A comparison of muscle activity between a free weight and machine bench press. J Strength Cond Res, 8(4), 259-264. Bågenhammar, S., & Ekvall Hansson, E. (2007). Repeated sets or single set of resistance training–A systematic review. Advances in Physiotherapy, 9(4), 154-160. https://doi.org/10.1080/14038190701554277. Durall, C. J., Hermsen, D., & Demuth, C. (2006). Systematic review of single-set versus multiple-set resistance-training randomized controlled trials: implications for rehabilitation. Critical Reviews™ in Physical and Rehabilitation Medicine, 18(2). https://doi.org/10.1615/CritRevPhysRehabilMed.v18.i2.20. Berger, R. (1962). Effect of varied weight training programs on strength. Research Quarterly. American Association for Health, Physical Education and Recreation, 33(2), 168-181. https://doi.org/10.1080/10671188.1962.10613188. Anderson, T., & Kearney, J. T. (1982). Effects of three resistance training programs on muscular strength and absolute and relative endurance. Research Quarterly for Exercise and Sport, 53(1), 1-7. https://doi.org/10.1080/02701367.1982.10605218. Bemben, D. A., Fetters, N. L., BEMBEN, M. G., Nabavi, N., & Koh, E. T. (2000). Musculoskeletal responses to high-and low-intensity resistance training in early postmenopausal women. Medicine & Science in Sports & Exercise, 32(11), 1949-1957. http://www.luzimarteixeira.com.br/wp-content/uploads/2009/09/high-and-low-intensity-resistance-training-and-bmd.pdf Berger, R. A. (1963). Comparative effects of three weight training programs. Research Quarterly. American Association for Health, Physical Education and Recreation, 34(3), 396-398. https://doi.org/10.1080/10671188.1963.10613249. Schoenfeld, B. J., Peterson, M. D., Ogborn, D., Contreras, B., & Sonmez, G. T. (2015). Effects of low-vs. high-load resistance training on muscle strength and hypertrophy in well-trained men. The Journal of Strength & Conditioning Research, 29(10), 2954-2963. https://doi.org/10.1519/JSC.0000000000000958. Schoenfeld, B. J., Ratamess, N. A., Peterson, M. D., Contreras, B., & Tiryaki-Sonmez, G. (2015). Influence of resistance training frequency on muscular adaptations in well-trained men. The Journal of Strength & Conditioning Research, 29(7), 1821-1829. https://doi.org/10.1519/JSC.0000000000000970. Benton, M. J., Kasper, M. J., Raab, S. A., Waggener, G. T., & Swan, P. D. (2011). Short-term effects of resistance training frequency on body composition and strength in middle-aged women. The Journal of Strength & Conditioning Research, 25(11), 3142-3149. https://doi.org/10.1519/JSC.0b013e31820f505f. Schoenfeld, B. J., Grgic, J., & Krieger, J. (2019). 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. Journal of sports sciences, 37(11), 1286-1295. https://doi.org/10.1080/02640414.2018.1555906. Trappe, S., Williamson, D., & Godard, M. (2002). Maintenance of whole muscle strength and size following resistance training in older men. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 57(4), B138-B143. https://doi.org/10.1093/gerona/57.4.B138. Tan, B. (1999). Manipulating resistance training program variables to optimize maximum strength in men: a review. The Journal of Strength & Conditioning Research, 13(3), 289-304. https://pdfs.semanticscholar.org/930a/b121b1b46776ffde3858979c747bd8f8ae93.pdf Bird, S. P., Tarpenning, K. M., & Marino, F. E. (2005). Designing resistance training programmes to enhance muscular fitness. Sports medicine, 35(10), 841-851. http://doi.org/10.2165/00007256-200535100-00002. Bickel, C. S., Cross, J. M., & Bamman, M. M. (2011). Exercise dosing to retain resistance training adaptations in young and older adults. Medicine & Science in Sports & Exercise, 43(7), 1177-1187. https://doi.org/10.1249/MSS.0b013e318207c15d Wernbom, M., Augustsson, J., & Thomeé, R. (2007). The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans. Sports medicine, 37(3), 225-264. https://doi.org/10.2165/00007256-200737030-00004. de Araújo Farias, D., Willardson, J. M., Paz, G. A., Bezerra, E. D. S., & Miranda, H. (2017). Maximal strength performance and muscle activation for the bench press and triceps extension exercises adopting dumbbell, barbell, and machine modalities over multiple sets. The Journal of Strength & Conditioning Research, 31(7), 1879-1887. https://doi.org/10.1519/JSC.0000000000001651. Moore, D. R., Robinson, M. J., Fry, J. L., Tang, J. E., Glover, E. I., Wilkinson, S. B., ... & Phillips, S. M. (2009). Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. The American journal of clinical nutrition, 89(1), 161-168. https://doi.org/10.3945/ajcn.2008.26401 Moore, D. R., Churchward-Venne, T. A., Witard, O., Breen, L., Burd, N. A., Tipton, K. D., & Phillips, S. M. (2015). Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences, 70(1), 57-62. https://doi.org/10.1093/gerona/glu103 Kim, I. Y., Schutzler, S., Schrader, A., Spencer, H., Kortebein, P., Deutz, N. E., ... & Ferrando, A. A. (2015). Quantity of dietary protein intake, but not pattern of intake, affects net protein balance primarily through differences in protein synthesis in older adults. American Journal of Physiology-Endocrinology and Metabolism, 308(1), E21-E28. https://doi.org/10.1152/ajpendo.00382.2014 Hobson, R. M., Saunders, B., Ball, G., Harris, R. C., & Sale, C. (2012). Effects of β-alanine supplementation on exercise performance: a meta-analysis. Amino acids, 43(1), 25-37. https://doi.org/10.1007/s00726-011-1200-z Saunders, B., Elliott-Sale, K., Artioli, G. G., Swinton, P. A., Dolan, E., Roschel, H., ... & Gualano, B. (2017). β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. British Journal of Sports Medicine, 51(8), 658-669. http://dx.doi.org/10.1136/bjsports-2016-096396 Dolan, E., Swinton, P. A., Painelli, V. D. S., Stephens Hemingway, B., Mazzolani, B., Infante Smaira, F., ... & Gualano, B. (2019). A systematic risk assessment and meta-analysis on the use of oral β-alanine supplementation. Advances in Nutrition, 10(3), 452-463. https://doi.org/10.1093/advances/nmy115 Trexler, E. T., Persky, A. M., Ryan, E. D., Schwartz, T. A., Stoner, L., & Smith-Ryan, A. E. (2019). Acute effects of citrulline supplementation on high-intensity strength and power performance: A systematic review and meta-analysis. Sports Medicine, 49(5), 707-718. https://doi.org/10.1007/s40279-019-01091-z Van De Walle, G. P., & Vukovich, M. D. (2018). The effect of nitrate supplementation on exercise tolerance and performance: A systematic review and meta-analysis. The Journal of Strength & Conditioning Research, 32(6), 1796-1808. https://doi.org/10.1519/JSC.0000000000002046 Burd, N. A., West, D. W., Staples, A. W., Atherton, P. J., Baker, J. M., Moore, D. R., ... & Phillips, S. M. (2010). Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men. PloS one, 5(8), e12033. Mitchell, C. J., Churchward-Venne, T. A., West, D. W., Burd, N. A., Breen, L., Baker, S. K., & Phillips, S. M. (2012). Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Journal of applied physiology, 113(1), 71-77. de Souza Jr, T. P., Fleck, S. J., Simão, R., Dubas, J. P., Pereira, B., de Brito Pacheco, E. M., ... & de Oliveira, P. R. (2010). Comparison between constant and decreasing rest intervals: influence on maximal strength and hypertrophy. The Journal of Strength & Conditioning Research, 24(7), 1843-1850. American Council on Exercise. (2001). American Council on Exercise (ACE)-sponsored Study Reveals Best and Worst Abdominal Exercises. https://www.acefitness.org/about-ace/press-room/press-releases/246/american-council-on-exercise-ace-sponsored-study-reveals-best-and-worst-abdominal-exercises/ American Council on Exercise. ACE Study Reveals Best Biceps Exercises. https://www.acefitness.org/education-and-resources/professional/prosource/august-2014/4933/ace-study-reveals-best-biceps-exercises/ American Council on Exercise. ACE-Sponsored Research: Top 3 Most Effective Chest Exercises. https://www.acefitness.org/certifiednewsarticle/2884/ace-sponsored-research-top-3-most-effective-chest-exercises/ American Council on Exercise. Dynamite Delts: ACE Research Identifies Top Shoulder Exercises. https://www.acefitness.org/education-and-resources/professional/prosource/september-2014/4972/dynamite-delts-ace-research-identifies-top-shoulder-exercises/ American Council on Exercise. ACE-SPONSORED RESEARCH: What Is the Best Back Exercise?. https://www.acefitness.org/education-and-resources/professional/certified/april-2018/6959/ace-sponsored-research-what-is-the-best-back-exercise/ Sweeney, S. Porcari, P. J., Camic, C. Kovacs, A., Foster, C. (2014). Shoulders above the rest?. https://acewebcontent.azureedge.net/certifiednews/images/article/pdfs/ACEShoulderStudy.pdf Oranchuk, D. J., Storey, A. G., Nelson, A. R., & Cronin, J. B. (2019). Isometric training and long‐term adaptations: Effects of muscle length, intensity, and intent: A systematic review. Scandinavian journal of medicine & science in sports, 29(4), 484-503. https://doi.org/10.1111/sms.13375 Stenger, E., Porcari, J. P., Camic, C., Kovacs, A., Foster, C. (2014). Abs! Abs! Abs!. https://www.acefitness.org/education-and-resources/professional/prosource/april-2014/3764/abs-abs-abs/ Wikipedia contributors. (2021, January 15). Creatine. In Wikipedia, The Free Encyclopedia. Retrieved 17:22, January 20, 2021, from https://en.wikipedia.org/w/index.php?title=Creatine&oldid=1000518137 Wikipedia contributors. (2021, January 10). Essential amino acid. In Wikipedia, The Free Encyclopedia. Retrieved 17:23, January 20, 2021, from https://en.wikipedia.org/w/index.php?title=Essential_amino_acid&oldid=999456328 Nuckols, G. (2014). The Science of Steroids: The Physiology and Psychology of How Steroids Make You Stronger. Stronger by Science. N https://www.strongerbyscience.com/the-science-of-steroids/ Calder, A. W., Chilibeck, P. D., Webber, C. E., & Sale, D. G. (1994). Comparison of whole and split weight training routines in young women. Canadian Journal of Applied Physiology, 19(2), 185-199.https://doi.org/10.1139/h94-014 Sardeli, A. V., Komatsu, T. R., Mori, M. A., Gáspari, A. F., & Chacon-Mikahil, M. P. T. (2018). Resistance training prevents muscle loss induced by caloric restriction in obese elderly individuals: a systematic review and meta-analysis. Nutrients, 10(4), 423. https://doi.org/10.3390/nu10040423 Harris, R. C., Söderlund, K., & Hultman, E. (1992). Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clinical science, 83(3), 367-374. Rawson, E. S., Stec, M. J., Frederickson, S. J., & Miles, M. P. (2011). Low-dose creatine supplementation enhances fatigue resistance in the absence of weight gain. Nutrition, 27(4), 451-455. https://doi.org/10.1016/j.nut.2010.04.001 Leaf, A., & Antonio, J. (2017). The effects of overfeeding on body composition: the role of macronutrient composition–a narrative review. International journal of exercise science, 10(8), 1275. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786199/ Miller, P. E., Alexander, D. D., & Perez, V. (2014). Effects of whey protein and resistance exercise on body composition: a meta-analysis of randomized controlled trials. Journal of the American College of Nutrition, 33(2), 163-175. Benito, P. J., Cupeiro, R., Ramos-Campo, D. J., Alcaraz, P. E., & Rubio-Arias, J. Á. (2020). A systematic review with meta-analysis of the effect of resistance training on whole-body muscle growth in healthy adult males. International journal of environmental research and public health, 17(4), 1285. Hernández-Reyes, A., Cámara-Martos, F., Molina-Luque, R., Romero-Saldaña, M., Molina-Recio, G., & Moreno-Rojas, R. (2019). Changes in body composition with a hypocaloric diet combined with sedentary, moderate and high-intense physical activity: A randomized controlled trial. BMC women's health, 19(1), 1-12. https://doi.org/10.1186/s12905-019-0864-5 Nicklas, B. J., Chmelo, E., Delbono, O., Carr, J. J., Lyles, M. F., & Marsh, A. P. (2015). Effects of resistance training with and without caloric restriction on physical function and mobility in overweight and obese older adults: a randomized controlled trial. The American journal of clinical nutrition, 101(5), 991-999. https://doi.org/10.3945/ajcn.114.105270 Willoughby, D., Hewlings, S., & Kalman, D. (2018). Body composition changes in weight loss: strategies and supplementation for maintaining lean body mass, a brief review. Nutrients, 10(12), 1876. https://doi.org/10.3390/nu10121876 Lukaski, H. C. (2019). Effects of chromium (III) as a nutritional supplement. In The Nutritional Biochemistry of Chromium (III) (pp. 61-77). Elsevier. https://doi.org/10.1016/B978-0-444-64121-2.00002-7 Tsang, C., Taghizadeh, M., Aghabagheri, E., Asemi, Z., & Jafarnejad, S. (2019). A meta‐analysis of the effect of chromium supplementation on anthropometric indices of subjects with overweight or obesity. Clinical obesity, 9(4), e12313. Heffernan, S. M., Horner, K., De Vito, G., & Conway, G. E. (2019). The role of mineral and trace element supplementation in exercise and athletic performance: a systematic review. Nutrients, 11(3), 696. https://doi.org/10.3390/nu11030696 Wirth, J., Hillesheim, E., & Brennan, L. (2020). The role of protein intake and its timing on body composition and muscle function in healthy adults: a systematic review and meta-analysis of randomized controlled trials. The Journal of nutrition, 150(6), 1443-1460. https://doi.org/10.1093/jn/nxaa049 Nuckols, G. (2022). The Complete Strength Training Guide. Stronger By Science. https://www.strongerbyscience.com/complete-strength-training-guide/ Nuckols, G. (2016, February 22). Can We Predict Muscle Growth? Retrieved June 24, 2019, from https://www.strongerbyscience.com/can-we-predict-muscle-growth/