Optimizing Muscle Protein Synthesis Through Training & Diet

A term that often goes hand in hand with protein supplementation is muscle protein synthesis, or MPS for short. In the simplest sense MPS is the process of building muscle proteins specifically as opposed to making other types of proteins throughout the body. MPS is arguably the most important physiological factor in existence as it pertains to muscle growth and recovery. This article will discuss what MPS is and how to optimize it through training and diet.

What exactly is muscle protein synthesis?

MPS is the process of repairing and rebuilding muscle tissue as a result of exercise-induced microtraumas (weight training) or others stresses placed on the body such as a muscle injury. MPS is stimulated instantly upon starting exercise and may last as long as 48 hours before complete repair of the damaged tissue occurs. During this process, satellite cells are activated and fuse to the damaged muscle fibers where they help create new muscle protein strands. These new strands, in turn, increase the thickness of the damaged strand and lead to muscle repair and hypertrophy. However, for muscle growth to occur, the rate of MPS must be greater than the rate of muscle protein breakdown (MPB). If MPS exceeds MPB, your muscles will grow. If MPB exceeds MPS, loss in muscle mass occurs. This is why it is important to consume adequate amounts of protein on a daily basis as it provides the body enough amino acids to optimize MPS and minimize MPB.

Maximizing muscle protein synthesis through training

By itself, resistance training can increase MPS based on different intensities and workloads. Research has demonstrated that increases in muscle protein synthesis are minimal when a 20-40% 1RM (1 repetition max) load is used but maximal when a 70-90% 1RM load is utilized. However, using low loads performed to failure can equalize this response. Below are four practical ways to maximize MPS through training:
  1. Use multiple sets (3-6) instead of single sets for each exercise you perform. Burd et al. discovered this increased MPS to a greater degree.
  2. Whatever rep scheme you use, make sure the last two is each set are tough. Different rep ranges are equally effective in stimulating MPS as long as each set is taken to near muscular failure.
  3. Rest longer between sets (2-5 minutes). Research confirms this increases post-exercise MPS response compared to shorter rest periods.
  4. Train each muscle group at least two times a week. Doing so will result in larger muscle mass gains compared to training a muscle group only once a week.

Optimizing muscle protein synthesis through nutrition

Certain nutritional strategies can also be used in conjunction with strength training to increase MPS. These are:
  1. Consume 20-35 grams of high-quality protein each meal/snack to maximize MPS. Eating up to 40 grams may increase MPS by an additional 10-20%.
  2. Choose the most anabolic protein source. Digestion rate and amino acid profile (leucine in particular) determine the extent to which MPS is stimulated. Whey has been found to elevate MPS the greatest compared to casein and plant-based proteins.
  3. If suboptimal amounts of protein are consumed (less than 20 grams) supplemental leucine can be added to improve MPS.
  4. Drink a whey protein shake 30-60 minutes before exercise and immediately after to maximize MPS.
  5. Eat at least 20 grams of protein every three hours. This stimulates MPS more than the same amount of protein consumed in less normal amounts (40 grams every 6 hours), or more normal amounts (10 grams every 1.5 hours).
  6. Drink 40 grams of casein before sleep. This will help increase MPS overnight.
  7. Maintain a positive energy (calorie) balance. A negative calorie balance can decrease MPS rates.

The Bottom Line on Muscle Protein Synthesis

MPS in the physiological process that leads to muscle growth and recovery. It is stimulated by protein consumption, exercise, and other stressors and can be optimized through specific training and nutritional strategies. Furthermore, proper recovery between training sessions is paramount for this muscle building process to be effective. References: Pennings, B., Boirie, Y., Senden, J. M., Gijsen, A. P., Kuipers, H., & van Loon, L. J. (2011). Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. The American journal of clinical nutrition, 93(5), 997-1005. Miller, B. F., Olesen, J. L., Hansen, M., Døssing, S., Crameri, R. M., Welling, R. J., ... & Smith, K. (2005). Coordinated collagen and muscle protein synthesis in human patella tendon and quadriceps muscle after exercise. The Journal of physiology, 567(3), 1021-1033. Burd, N. A., Holwerda, A. M., Selby, K. C., West, D. W., Staples, A. W., Cain, N. E., ... & Phillips, S. M. (2010). Resistance exercise volume affects myofibrillar protein synthesis and anabolic signalling molecule phosphorylation in young men. The Journal of physiology, 588(16), 3119-3130. 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. McKendry, J., Pérez‐López, A., McLeod, M., Luo, D., Dent, J. R., Smeuninx, B., ... & Breen, L. (2016). Short inter‐set rest blunts resistance exercise‐induced increases in myofibrillar protein synthesis and intracellular signalling in young males. Experimental physiology, 101(7), 866-882. 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. Mamerow, M. M., Mettler, J. A., English, K. L., Casperson, S. L., Arentson-Lantz, E., Sheffield-Moore, M., ... & Paddon-Jones, D. (2014). Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. The Journal of nutrition, 144(6), 876-880. Witard, O. C., Jackman, S. R., Breen, L., Smith, K., Selby, A., & Tipton, K. D. (2014). Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. The American journal of clinical nutrition, 99(1), 86-95. Areta, J. L., Burke, L. M., Ross, M. L., Camera, D. M., West, D. W., Broad, E. M., ... & Hawley, J. A. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. The Journal of physiology, 591(9), 2319-2331. van Vliet, S., Burd, N. A., & van Loon, L. J. (2015). The skeletal muscle anabolic response to plant-versus animal-based protein consumption. The Journal of nutrition, 145(9), 1981-1991. Levenhagen, D. K., Gresham, J. D., Carlson, M. G., Maron, D. J., Borel, M. J., & Flakoll, P. J. (2001). Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. American Journal of Physiology-Endocrinology And Metabolism, 280(6), E982-E993. Groen, B., Pennings, B. A. R. T., Beelen, M., Wallis, G. A., Gijsen, A. P., Senden, J. M., & Van Loon, L. J. (2012). Protein ingestion before sleep improves postexercise overnight recovery. Medicine and science in sports and exercise, 44(8), 1560-1569.