No matter your interest or level of involvement, the fact of the matter is that muscle endurance plays a huge role in just about aspects of the sports and fitness world.
Whether you're a powerlifter looking to lift as much as you can for a single repetition, or a soccer player performing repetitive sprints, the ability to perform at your best, largely depends on the endurance of your muscles.
Over the years, exercise scientists have developed a variety of different assessment techniques and have come up with several different methods and training programs specifically designed to improve muscular endurance.
However, before we get too far into how to go about make improvements, let's first discuss in more detail what muscle endurance actually is and why it's so important when it comes to sports and exercise performance.
What is Muscle Endurance and Why’s it Important?
Muscle endurance measures the ability of a muscle group to contract against resistance over a period of time. This can either be a single sustained contraction like in a core plank, or it may be the count of multiple contractions in a set of squats.
Muscular endurance is one of many vital components that contribute to athletic performance variables such as strength, speed, power, agility, aerobic, and anaerobic capacity. When concentrating on sports/exercise performance, all of these components must be appropriately trained for.
Different training strategies are used by athletes, coaches, and trainers to improve sports performance. Resistance training targets strength and power.
High-intensity interval training (HIIT) is used to improve aerobic and anaerobic capacity. This training technique improves the amount of energy available in the muscle to enable it to contract.
Muscle endurance training specifically is designed to allow the muscles to fire repetitively over a greater period of time before tiring.
How Do You Asses Muscle Endurance?
Assessment is important in any physical training program as it helps to identify weaknesses, gains, and progress. When it comes to assessing muscle endurance, testing should be evaluated initially and then retested at intervals several weeks apart -- most experts use 4-6 week interval testing.
Standard testing can be easily performed by just anyone with three basic exercises: the squat, the pushup, and the plank. For most individuals, the squat and pushup are completely unweighted exercises where the number of maximal reps before failure is counted. The plank is performed for the maximal amount of time before failure.
For more highly trained individuals, it may be necessary to add weight to the squat and convert the pushup into a bench press for a more reliable test.
Strand et al identified certain norms in plank testing both men and women, and athletes and non-athletes. Men typically lasted longer in the plank than did women, and athletes lasted longer than non-athletes. (1)
They also found that improving plank endurance required plank training at a minimum of at least three times a week. However, training 5X per week showed the most improvement.
How Can You Improve Your Muscle Endurance?
Over the years, numerous interventions have been attempted to further improve muscular endurance. They range the gamut from connecting electrodes to your brain to altering your dietary habits. Some methods have been shown to work, while others have not.
We have all been trained to do a light warmup, then stretch, and then begin your training. It seems to make sense: get the muscles warmed and the blood flowing, stretch the muscle to improve its flexibility, range of motion and prevent injury, and then train.
Mild, static stretching has been shown to have no effect on muscle endurance. In fact, stretching the muscle against contraction -- something called proprioceptive neuromuscular facilitation (PNF) -- has been shown to have a negative effect on muscular endurance. (2)(3)
This negative effect of PNF on muscle endurance may be due to the intensity and duration of the stretch.
So if static stretching has no effect and PNF has a negative effect, should stretching be performed? Exercise scientists are a little divided in their opinions. Some studies have shown benefits for injury prevention, and some have not. Part of the reason for this may be due to the individual sport.
Certain sports require a lot of bouncing and jumping (soccer, football, hockey) and seem to benefit from stretching. In other sports such as cycling and swimming, where the stretch-shortening cycles of the muscle are not significant, there does not seem to be a benefit. (4)
2. Hypoxia Training Running
Altitude training has become very popular as a means of improving exercise performance at sea level or to help the athlete better compete at higher altitudes.
True hypoxic training occurs when the athlete trains at an altitude where the partial pressure of oxygen in the air is reduced, or when a special mask fitted with a reduced partial pressure of oxygen supply is attached. It does not occur by wearing a mask that reduces your normal airflow.
“Live low train high” is a popular technique for training athletes. In regards to exercise performance, hypoxic training has not consistently been shown to improve performance at sea level. Further, it has not been shown to effectively improve muscle endurance at all. (5)(6)
The term dehydration refers to the process of losing body water. Hypohydration is the state of having less than the ideal amount of water in your system. Hypohydration can be mild, moderate, or severe. In both athletes and non-athletes, hypohydration has been shown to impair muscle endurance, power, and strength.
However, the effect is even more severe in older individuals. A 1% loss in body water -- the equivalent of about a glass of water -- results in significant impairment in muscle endurance and strength.
When combined with the normal diminished muscle performance seen with aging (called dynapenia), inadequate hydration can end have severe effects on muscle endurance in older folks. (7)
4. High-Intensity Functional Training (HIFT)
HIFT involves whole body, functional exercises with universal muscle recruitment patterns performed in intense, short, repeated sets. Yes, that's a mouth full, but what it basically means that these exercises typically involve multiple planes of movement and are designed to stress the different muscle systems in a balanced and integrated manner.
This may sound like High-Intensity Interval Training or (HIIT), but it's significantly different. HIFT uses multiple different exercise modalities such as Olympic or powerlifts, body-weight exercises, and aerobic training while HIIT typically only involves intervals of one training modality. (8)
Unlike some of the other techniques on this list, there is a sizeable body of evidence that HIFT can in fact help to improve your muscle endurance. For instance, one 2015 study ultimately found that participants saw significant improvements in both muscle endurance and athletic performance after following a 6-week HIFT program.(9) HIIT on the other hand has not been shown to have the same effects.
5. RMET - Respiratory Muscle Endurance Training
The advantage of HIFT is that it is designed to have a whole-body muscle endurance impact. Scientists have noted that when specific muscle groups are targeted for improving endurance, results in those muscle groups are seen. If a muscle group is not targeted with the exercise, however, its endurance will not be improved.
As such, trainers of endurance athletes such as long-distance runners, have developed RMET to specifically target the muscles of respiration. Similar to HIFT, Study findings also confirm that RMET can be effective for improving respiratory muscle endurance and aid in improving your overall endurance as well. (10)
6. tDCS - Transcranial Direct Current Stimulation
tDCS works by firing a weak electric current directly to the scalp and hence to the brain. Though it sounds like something out of the Matrix, it has been shown to elicit some increases in strength.
It does this by changing the membrane potential of the nerve cells of the brain cortex. This is where the motor neurons originate.
Sounds very cool: plugin, turn on, enter the terminator. However, the studies in tDCS have not shown any benefit in muscle endurance. (11)
7. Keto - Low Carb - High Fat Diet
Carbohydrates -- specifically glycogen stores and glucose -- are the immediate energy supplies of exercising muscle. Scientists have found that a low-carb, high-fat, keto-type diet used for 3-4 weeks will increase the burning of fat for energy purposes.
Retooling the muscle to utilize these fats and decrease the dependence on carbohydrates can also occur with aerobic exercise.
So then is keto a more beneficial dietary strategy for muscular endurance? The jury is out on this. Studies have shown tremendous variation in athletes and a single successful strategy, as well as the proper periodization for this strategy, has not yet been adequately determined. Currently, standard carbohydrate nutritional recommendations for athletes are still considered superior. (12)
Muscle Performance Optimizer (MPO)
Developed by Dr. Schneider while working with professional athletes, MPO is an all-natural performance enhancer that's been shown to improve muscle power and endurance. During intense training as is seen in training camps or pre-camp combine training, athletes typically see a decrease in their power and endurance over the course of several weeks. Protein supplementation, however, has been shown to partially mitigate some of this decline. (13)
However, instead of just mitigating decline, adding MPO into the mix can actually help you to increase your power and endurance. For example, one study we conducted in association with Justin Roethlingshoefer, M.S., C.S.C.S, and the Hockey Summit placed participants (all professional hockey players) into one of two groups.
Group one took only a whey protein supplement daily, while group 2 also supplemented with MPO on top of whey. Both groups participated in a 13-week preseason training program where multiple performance metrics were regularly tracked.
At the conclusion of the study, we found that those in the MPO group, on average, saw a significant increase (4.5%) in muscle endurance compared to the whey only group, who, on average, saw moderate (and in some cases even severe) declines in muscle endurance over the course of preseason training.
Caffeine is often used by athletes for focus and enhanced athletic performance. Studies evaluating the dosing of caffeine have shown two interesting findings. First, that caffeine does improve endurance in the muscles of the upper body, however, the same effects have not been observed in lower body muscles. (13)
Second, that a small dose (2mg/kg) or the equivalent of a single cup of coffee, has the exact same effect as double or even triple the smaller dose.
Muscle endurance, or the ability of a muscle group to contract against resistance over a period of time, plays an integral role in sports and exercise performance.
When it comes to improving the endurance of your muscles, numerous different methods have been developed, however, some have been shown to be effective, while others have not. Stretching for instance, may be common practice, but research suggests that it may not offer much practical benefit in terms of improving muscle endurance.
Similarly, while a high-fat, low-carb diet sounds good in theory, exercise scientists have yet to find convincing evidence that it can help to improve muscle endurance or exercise performance.
Other strategies like HIFT and RMET appear to be more promising, with multiple studies demonstrated that regular adherence to a specialized training program can help to significantly improve endurance and performance.
On top of that, some supplements may also help to improve muscle endurance. MPO is an all-natural performance enhancer that's been shown to significantly improve muscle endurance even in elite athletes. There is also some evidence that caffeine may also help to improve endurance, particularly in the muscles of the upper body as well.
- “Norms for an isometric muscle endurance test” Strand, S.L., et al. Journal of Human Kinetics. Apr. 2014.
- “Acute effects of different stretching exercises on muscular endurance” Franco, B.L, et al. Journal of Strength and Conditioning Research. Nov. 2008.
- “Acute effects of two different stretching methods on local muscular endurance performance” Gomes, T.M., et al. Journal of Strength and Conditioning Research. Mar. 2011.
- “Stretching and injury prevention: an obscure relationship” Witvrouw, E., et al. Sports Medicine. 2004.
- “Effects of Respiratory Muscle Endurance Training in Hypoxia on Running Performance” Katayama, K., et al. Medicine and Science in Sports and Exercise. Jul. 2019.
- “Is hypoxia training good for muscles and exercise performance?” Vogt, M., Hoppeler, H. Progressive Cardiovascular Disorders. Jun. 2010.
- “Impact of Mild Hypohydration on Muscle Endurance, Power, and Strength in Healthy, Active Older Men” Goulet, E.D.B, et al. Journal of Strength and Conditioning Research. Dec. 2018.
- “High-Intensity Functional Training (HIFT): Definition and Research Implications for Improved Fitness” Feito, Y., et al. Sports (Basel). Apr. 2018.
- “Multimodal high-intensity interval training increases muscle function and metabolic performance in females” Buckley, S., et al. Applied Physiology, Nutrition, and Metabolism. Jul. 2015.
- “Effects of Respiratory Muscle Endurance Training in Hypoxia on Running Performance” Katayama, K. et al. Medicine & Science in Sports & Exercise. Jul. 2019.
- “Is tDCS an Adjunct Ergogenic Resource for Improving Muscular Strength and Endurance Performance? A Systematic Review” Machado, S., et al. Frontiers in Psychology. May. 2019.
- “Ketogenic low‐CHO, high‐fat diet: the future of elite endurance sport?” Burke, J.M. The Journal of Physiology. May. 2020.
- “What Dose of Caffeine to Use: Acute Effects of 3 Doses of Caffeine on Muscle Endurance and Strength” Grgic, J., et al. International Journal of Sports Physiology and Performance. Sep. 2019.
- “Effect of whey vs. soy protein supplementation on recovery kinetics following speed endurance training in competitive male soccer players: a randomized controlled trial” Kritikos, S., et al. Journal of the International Society of Sports Nutrition. Mar. 2021.