As resistance trained athletes, fatigue is no stranger to us. It's very common (and expected) for performance to decline as a given workout progresses. However, for some, this drop-off in performance occurs much sooner and is much more pronounced than it is with others.
For example, say you're performing 5 sets of bench presses with a 12RM load. On your first set, achieving 12 reps is hard, but not impossible; on your 5th set, achieving 6-7 reps reps is a struggle. Sound familiar? What is it that causes such a profound waning effect even when substantial rest periods (more than 90 seconds) are utilized?
Well, it's not just one thing; in fact, it could be any number of things. Great answer, huh? Don't worry, I'm not going to leave you hanging. In this article I'll enumerate the possibilities and also provide you with recommendations to counteract these contributing factors.
Even if you don't suffer from Extreme Performance Decline Syndrome (EPDS), you can still benefit from the info presented here as it'll help you to bang out a few extra reps every workout. And who doesn't want that?
1. You're out of shape!
This one is rather obvious, however, some individuals think the
fact that they can't even run a mile without stopping twelve times
isn't going to affect their muscle building efforts. Sorry, if
you're huffing and puffing between sets in an attempt to catch your
breath, your performance is going to suffer.
Solution: Work on improving your level of fitness by means of HIIT cardio (high intensity interval training). An example of a HIIT sprint workout is to sprint for 20 seconds and follow it up with 20 seconds of active recovery (i.e. walking). That's one interval. Now, repeat this as many times as you can.
Try working up to 15 total intervals. In time, both your aerobic and anaerobic conditioning will improve. Do this and a poor level of conditioning will no longer impede your progress!
2. You possess a high percentage of Type IIB muscle fibers.
Type IIB muscle fibers are explosive in nature and as such are great for black belt karate kicks and/or power cleaning 1000 pounds. However, they aren't so great when it comes to your traditional 8-12 rep hypertrophy program because they have a low mitochondrial content and fatigue rather quickly (2).
Individuals with a high percentage of Type IIB muscle fibers in
comparison to Type I and Type IIA fibers may experience difficulty
in maintaining a given exercise prescription when working in higher
Solution: Pick your parents more wisely in your next life. No, just kidding. This actually isn't a bad thing as Type IIB fibers have the greatest hypertrophy potential of all muscle fibers.
Having said that, if you feel you're a more "explosive" trainee and don't fair well with higher rep protocols, try experimenting with lower rep, but still high volume programs for hypertrophy purposes (i.e. 12x4; four waves of 3,2,1; 15x2; repeated singles with minimal rest, etc.)
3. Your nutrition is inadequate. More specifically, you're not consuming enough carbs.
Upwards of 80% of the ATP needed for muscle contraction in a typical bodybuilding workout is provided by means of anaerobic glycolysis (3,4). Three sets of 10-12 reps will yield ~24% local reduction in muscle glycogen content (assuming the subject's muscle glycogen stores are full at the start of the workout) and ~38% after six sets (5).
If starting muscle glycogen content is low (due to insufficient
carbohydrate intake), performance will indeed be negatively
affected. Similarly, studies have shown that high initial muscle
glycogen levels increase time to exhaustion during intermittent
Solution: Use a fork and/or spoon and put food in your mouth regularly. Carbohydrate intake in general should be around two grams per pound of LBM (lean body mass) to ensure muscle glycogen stores are topped off before your workout begins.
Also, consuming a carbohydrate beverage immediately before or during your training session significantly, positively affects the number of sets and reps you can perform before exhaustion (8,9,12).
4. Your body isn't efficient at clearing lactic acid.
Lactic acid accumulation yields a high H+ concentration which in turn contributes to fatigue by interfering with several crucial steps in the contraction process (mainly reducing the force generated at a given Ca++ concentration and inhibiting sarcoplasmic reticulum Ca++ release) (2).
If your body isn't efficient at clearing lactic acid (i.e. most
of the lactic acid isn't removed before the start of your next work
set), performance will drop off at an accelerated rate.
Solution: Shorten your rest periods and/or spend more time in the higher rep ranges. The only way your body will improve its ability to clear lactic acid is by teaching it to do so. In time, your body will become more efficient at removing lactate and this will no longer be a limiting factor in your training. It's also possible to buffer lactic acid through supplementation (more on this later).
5. Your CNS needs a jolt!
Several studies have suggested that alterations in central
nervous system arousal can facilitate motor unit recruitment to
increase strength and alter the state of fatigue (13,14,15). That
is, the greater the arousal or alertness, the greater the
performance (to a point).
Solution: Try a nootropic supplement like Power Drive and/or SPIKE. While one isn't technically a CNS stimulant (Power Drive), both will increase alertness and arousal in the brain to a high degree.
A more basic choice if on a budget is caffeine as it's a central nervous system stimulant that's been shown to increase both arousal and alertness as well (16). A dose of 2-4mg/lb of LBM one hour before your training session should suffice (17,18).
6. You're experiencing normal, physiological, neuromuscular fatigue.
Any time you perform repeated bouts of high intensity exercise, fatigue is going to set in. This is unavoidable. Now, that's not to say you can't do anything to improve the rate of fatigue caused by these unavoidable factors. Below is a list of the possible contributing factors to normal neuromuscular fatigue and what you can do about it.
A) Failure at the neuromuscular junction. At one time, a certain muscle physiologist theorized that the neuromuscular junction was a site of fatigue (2), but then someone actually performed a couple of studies and found out that the first guy was an idiot (19,20).
Solution: You don't have to worry about this one because the first guy was an idiot.
B) Inability of the sarcolemma to maintain Na+ and K+ concentrations. During repeated stimulation, K+ accumulates outside the cell membrane and decreases inside the cell. This results in a depolarization of the cell and a reduction in action potential amplitude (2).
Solution: Sorry, there isn't much you can do about this one. Having said that, consuming inadequate amounts of sodium daily can potentially make the situation worse, so strive to consume 2g for each liter of water you ingest.
C) Depleted creatine phosphate (CP) stores. CP is needed to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP) in order to support muscular contractions during short-duration high intensity exercise. When CP is depleted, ATP regeneration is slowed, which is a contributing factor to fatigue (2).
Solution: Supplement with creatine. If you choose to load creatine, aim to ingest 20-25g daily separated into 3-5g doses for six days. Doing so will increase muscle creatine concentration by upwards of 20% (21).
You can also choose not to load and still achieve the same levels by consuming 3-5g daily; however, it'll take significantly longer (28 days) to obtain the same levels as you would if you chose to load. Also, it's recommended to cycle creatine in a fashion of two months on and one month off in an attempt to prevent creatine transporter down-regulation (22,23).
D) Change in acid-base balance. Some lactic acid accumulation is inevitable even in trainees whose lactic acid clearance capabilities are above average. An increased lactate concentration shifts the body into an acidotic state, a probable cause of fatigue during high intensity intermittent exercise (24,25).
Solution: Supplement with sodium bicarbonate (baking soda). One of the body's natural buffering agents is bicarbonate, which helps offset the drop in pH that contributes to muscular fatigue. Supplementation with sodium bicarbonate has been shown to improve performance (particularly when an interval style training protocol is used) by shifting the body into an alkalotic state, thus increasing the body's ability to buffer lactic acid (26).
Try consuming 300mg/kg of LBM one to two hours prior to your exercise session with at least one liter of water (24,26). Be forewarned, side effects such as gastrointestinal discomfort, bloating, and diarrhea may occur, particularly if sufficient water isn't taken along with the baking soda.
With that said, recent research at the human performance laboratory of my alma mater, The College of New Jersey, has given merit to another lactic acid buffering compound which initially seems to be more effective than baking soda without the aforementioned side effects (27). The compound is known as beta-alanine and works by increasing intracellular carnosine, a natural H+ buffer.
7. You're suffering from heavy metal toxicity.
A prominent strength coach once noted that unsuspected toxicity
levels, such as elevated aluminum levels, can result in increased
Solution: Throw away your Metallica albums and drink bottled water as opposed to Diet Coke.
While fatigue can't be completely prevented or avoided, it can be significantly lessened by following the recommendations presented in this article. You know what they say: knowledge isn't power, applied knowledge is power. Go get 'em.
1. Okay, I just made that up to sound cool, but the rest are real, I swear.
2. Power, Scott K, and Howley, Edward T. Exercise Physiology: Theory and Application to Fitness and Performance. New York: McGraw-Hill, 2001.
3. MacDougall JD, Ray S, Sale DG, et al. Muscle substrate utilization and lactate production duringweightlifting. Can JAppl Physiol 1999; 24: 209-15
4. Medbo JI, Tabata I. Anaerobic energy release in working muscle during 30 s to 3 min of exhausting bicycling. J Appl Physiol 1993; 75: 1654-60
5. Robergs RA, Pearson DR, Costill DL, et al. Muscle glycogenolysis during differing intensities of weight-resistance exercise. J Appl Physiol 1991; 70: 1700-6
6. Balsom PD, Gaitanos GC, Soderlund K, et al. High-intensity exercise and muscle glycogen availability in humans. Acta Physiol Scand 1999; 165: 337-45
7. Davis JM, Jackson DA, Broadwell MS, et al. Carbohydrate drinks delay fatigue during intermittent, high-intensity cycling in active men and women. Int J Sport Nutr 1997; 7: 261-73
8. Lambert CP, Flynn MG, Boone JB, et al. Effects of carbohydrate feeding on multiple bout resistance exercise. J Appl Sport Sci Res 1991; 5: 192-
9. Nicholas C, Tsintzas K, Boobis L, et al. Carbohydrate-electrolyte ingestion during intermittent high-intensity running. Med Sci Sports Exerc 1999; 31: 1280-6
10. Haff GG, Koch AJ, Potteiger JA, et al. Carbohydrate supplementation attenuatesmuscle glycogen loss during acute bouts of resistance exercise. Int J Sports Nutr Exerc Metab 2000; 10: 326-39
11. Haff GG, Stone MH, Warren BJ, et al. The effect of carbohydrate supplementation on multiple sessions and bouts of resistance exercise. J Strength Cond Res 1999; 13: 111-7
12. Maganaris CN, Maughan RJ. Creatine supplementation enhances maximum voluntary isometric force and endurance capacity in resistance trained men. Acta Physiol Scand 1998; 163: 279-87
13. Ikai, M., and K. Yabe. Training effect of muscular endurance by means of voluntary and electrical stimulation. Euro J Appl Phys 28:55-60. 1969.
14. A central nervous system component in local muscle fatigue. Euro J Appl Phys 38: 9-15. 1978
15. Asmussen, E., and B. Mazin. Recuperation after muscular fatigue by "diverting activities" Euro J Appl Phys 38: 1-7. 1978.
16. Nehlig, A., and G. Debry. Caffeine and sports acitivity: a review. Int J Sport Nutr 5:94-101. 1995.
17. Clarkson, P.M. Nutritional ergogenic aids: Caffeine. Int J Sport Nutr 3:103-111. 1993
18. Graham, T.E., and L.L. Spriet. Caffeine and exercise performance. Gatorade Sports Science Exchange 9(1). 1996.
19. Bigland-Ritchie, B. EMG and fatigue of human voluntary and stimulated contractions. Human Muscle Fatigue: Physiological Mechanisms, 130-56. London: Pitman Medical. 1981.
20. Merton, P.A. Voluntary strength and fatigue. J Phys 123:553-64. 1954.
21. Greenhaff PL, Bodin K, Soderlund K, et al. Effect of oral creatinesupplementation on skeletal muscle phosphocreatine resynthesis. Am J Physiol 1994; 266 (5 Pt 1): E725-30
22. Hultman E, Soderlund K, Timmons JA, et al. Muscle creatine loading in men. J Appl Physiol 1996; 81: 232-7
23. Guerrero-Ontiveros ML,Walliman T.Creatine supplementation in health and disease. Effects of chronic creatine ingestion in vivo: down-regulation of the expression of the creatine transporter isoforms in skeletal muscle. Mol Cell Biochem 1998; 184: 427-37
24. Horswill, C.A. Effects of bicarbonate, citrate, and phosphate loading on performance. Int J Sport Nutr. 5:S111-S119. 1995.
25. Kanter, M.M., and M.H. Williams. Antioxidants, carnitine, and choline as putative ergogenic aids. Int J Sport Nutr 5:S120-S131. 1995.
26. Matson, L.G., and Z.V. Tran. Effects of sodium bicarbonate ingestion on anaerobic performance: A meta-analytic review. Int J Sport Nutr 3:2-28. 1993.
27. Hoffman J et al. Effect of creatine and beta-alanine supplementation on performance and endocrine responses in strength/power athletes. Int J Sport Nutr Exerc Metab. 2006 Aug;16(4):430-46.