If you often find yourself tiring halfway through your workouts, it's probably time to look at your muscular endurance.
Muscular endurance is one of the parts of musculoskeletal fitness. The other two are muscular strength and flexibility. Muscular strength and muscular endurance are different measurements.
Muscular strength focuses on the amount of weight used while muscular endurance relates to the number of repetitions you can do for a certain exercise. For instance, a novice may be able to do 5-10 reps of push-ups while a seasoned athlete can finish off three sets of 30 push-ups without feeling fatigued.
As such, increasing your muscular endurance level is critical if you want better performance in the gym and/or during competitions. Below, we explain what muscular endurance is, why it matters, and how to improve it.
Muscular endurance refers to the ability of a muscle or group of muscles to repeatedly perform an exercise over an extended period.
Simply put, it means doing the same movement for a high number of repetitions before muscle fatigue sets in. Therefore, exercising for longer periods before feeling exhausted indicates greater muscular endurance.
The definition of muscular endurance may vary depending on the type of training program. In strength training, muscular endurance refers to performing an exercise for a number of repetitions without stopping or breaking form. Usually, this entails lifting relatively lighter weights for high repetitions.
In endurance training and cardiovascular exercises, the terms "cardiovascular endurance" or "cardiorespiratory endurance" are used instead. As a 2019 study in the International Journal of Environmental Research and Public Health puts it, cardiovascular endurance is "the ability of the heart and lungs to deliver oxygen to working muscles during continuous physical activity."
Ideally, you should work on both types of endurance. This can be done through a mix of endurance training exercises. We'll explain this in detail later.
To understand muscular endurance, we first need to look at fast-twitch and slow-twitch muscle fibers.
A 2004 study in the Journal of PLOS Biology explains slow-twitch (or type-1) muscle fibers contract slowly. These use aerobic metabolism for continuous muscle contractions that are sustainable over an extended period of time.
On the other hand, fast-twitch (or type-2) muscle fibers contract more forcefully but burn out quicker. They primarily rely on anaerobic metabolism and the phosphocreatine system, producing lactic acid that results in muscle fatigue more quickly.
But, what exactly does this mean in terms of muscular endurance?
According to a 2012 study in the Journal of Strength and Conditioning Research, endurance athletes have a higher number of slow-twitch muscle fibers. On the other hand, elite strength and power athletes have proportionally larger amounts of fast-twitch muscle fibers.
This suggests slow-twitch muscle fibers are linked to greater muscular endurance while fast-twitch muscle fibers take over during short-duration, explosive movements, like performing heavy weight training and sprinting.
While you may be naturally predisposed towards either slow-twitch or fast-twitch exercises, it's possible to convert slow-twitch muscle fibers into fast-twitch ones and vice versa. For instance, the same 2012 study contends that some endurance training exercises (ex., long-distance running) promote the conversion of fast-twitch muscle fibers into slow-twitch muscle fibers.
However, performing high-intensity exercises (ex., sprinting) caused slow-twitch muscle fibers to change into fast-twitch ones.
In that sense, when you're looking to improve muscular endurance, choose specific types of exercises that engage primarily slow-twitch muscle fibers rather than fast-twitch fibers.
The main benefit of increasing muscle endurance is enhancing physical performance. For example, you might be able to swim extra laps or do more bicep curls without getting tired.
Another important benefit of muscular endurance is it tends to minimize the risk of injuries, particularly in sports and exercise. A 2019 study published in the International Journal of Sports Physical Therapy found that soccer players with low core endurance were more likely to experience more sprains and strains in their lower body.
Moreover, greater muscular endurance also helps you in daily life, since many of our everyday movements involve a mix of muscular endurance and strength. Walking up flights of stairs, playing fetch with your dog, and biking around the neighborhood are just a few examples.
Besides that, boosting your muscular endurance levels also gives you a higher quality of life. It’s been known for decades that regular aerobic exercise reduces the risk of heart disease, improves mental health, and manages diabetes.
Those wanting to increase muscular endurance look to three types of exercise: strength training, cardiovascular training, and circuit training. Fitness experts recommend combining these exercise programs (i.e., concurrent training) for better gains in terms of endurance and strength.
To improve muscular endurance through strength training, the American College of Sports Medicine recommends using a light to moderate amount of weight at high repetitions (15 or more reps) with short rest periods in between. This will help develop slow-twitch muscle fibers, which leads to greater muscular endurance and strength.
Some common types of muscular endurance exercises are push-ups, planks, bodyweight squats, sit-ups, and lunges. Since these exercises use your body weight as resistance, they can be done anywhere and at any time.
Alternatively, weight training also offers the same benefits — for instance, a close-grip bench press works various muscle groups (chest, triceps, and shoulders), thereby enhancing upper-body endurance.
A 2009 study featured in the Journal of Strength and Conditioning Research suggests that it’s best to use weight loads below 40% of your one-rep maximum when training for muscle endurance.
That means if the maximum amount of weight you can lift for a single repetition of the bench press is 200 pounds, then the weight load you use for training muscular endurance should be 80 pounds or less.
Cardiovascular endurance training, or cardio, involves any aerobic exercises you do over an extended period of time. Running, cycling, walking, jogging, or swimming are popular choices.
If you're a novice at cardio fitness, start slow. Aim for 20-30 minutes of moderate-intensity cardio (e.g., swimming laps or jogging) at least twice a week. Use a pace you're comfortable with before increasing the intensity.
For those who are already doing cardio regularly, keep at it. To improve your cardiovascular endurance, make sure you exercise three times a week or more. You can also work out for longer periods or with higher intensity and speed.
Circuit training is a time-efficient endurance training program. According to the American College of Sports Medicine, alternating between upper- and lower-body exercises to work different muscle groups encourages greater levels of muscular endurance and body strength.
This type of exercise program usually combines strength training (ex., push-ups and kettlebell squats) and cardio training (ex., cycling) in a single session. As such, circuit training accelerates both muscular and cardiovascular endurance gains. Talk about a win-win situation.
To get the most out of your circuit training program, a 2019 study in the International Journal of Exercise Science suggests prioritizing exercises targeted towards weaker muscle groups.
Besides leveraging muscular endurance exercises, the nutrients you consume also have an impact on reducing fatigue during training. Read on to find out which science-backed ingredients to include in your supplement regimen.
Beta-alanine helps make carnosine, which fights fatigue by reducing muscle acidity during high-intensity exercises. As such, higher levels of beta-alanine translate into greater muscle carnosine content, which in turn helps increase performance.
This theory was supported by a 2017 study in the Journal of Sports Medicine and Physical Fitness in which beta-alanine consumption improved athletes’ and non-athletes’ perceptions of muscle fatigue.
More recent research has also shown that beta-alanine may enhance physical performance (e.g., 1RM and total sets completed) and increase time-to-exhaustion during exercise.
While beta-alanine is a non-essential amino acid synthesized in your liver, taking a dietary supplement that contains this amino acid will further boost the carnosine content in your muscles.
In fact, a 2006 study in the Journal of Amino Acids says taking 3.2-6.4 g of a beta-alanine supplement daily for four weeks increases muscle carnosine by upwards of 64.2%.
Transparent Labs RawSeries Beta-Alanine is the perfect supplement to boost your carnosine levels. It contains 3 grams of beta-alanine per scoop to reduce muscle fatigue and enhance athletic performance.
Alternatively, the PreSeries Bulk Pre-Workout contains 4 grams of beta-alanine and 4 grams of BCAA per serving, the latter of which also supports muscle recovery and reduces fatigue during prolonged exercise.
Creatine is naturally present in your muscles, mostly in the form of phosphocreatine. Since phosphocreatine replenishes adenosine triphosphate (ATP), the body's main form of cellular energy, higher muscle creatine content translates to greater muscle endurance.
As such, creatine monohydrate is a popular ergogenic aid for athletes, particularly in terms of high-intensity exercises and weightlifting.
Among the many studies on creatine monohydrate, a 2011 study in the Journal of Nutrition found that taking a low dose of creatine (0.03 g/kg body weight daily) for six weeks increases fatigue resistance.
Similarly, a 2013 study featured in the Journal of Sports Medicine and Physical Fitness explains creatine supplementation may lessen blood lactate accumulation after high-intensity physical activities like sprinting and speed swimming.
There are many “new-age” forms of creatine on the market, but the evidence to support their advantages over creatine monohydrate remains controversial and limited. This is why StrengthSeries Creatine HMB is formulated with 5 grams of Creapure® creatine monohydrate and 2 grams of hydroxymethylbutyrate (HMB) plus BioPerine® for even greater bioavailability and absorption.
Betaine (or trimethylglycine) is a derivative of the amino acid glycine. Since betaine is necessary for synthesizing creatine (by donating a methyl group), it's a popular supplement for athletes looking to boost muscular strength and reduce fatigue.
A 2009 study in the Journal of the International Society of Sports Nutrition showed that two weeks of betaine supplementation to "significantly improve muscle endurance in a lower body workout by increasing the number of repetitions performed."
The RawSeries Betaine Anhydrous is a pre-workout supplement that promotes muscle endurance, strength, power, and force. With 2.5 grams of betaine anhydrous, this supplement helps gym-goers increase the number of repetitions and volume load you can perform in compound exercises.
To reduce muscle fatigue and soreness after your workout, follow up with New CoreSeries Post Workout, which contains 2.5 grams of BetaPure™ betaine anhydrous, 2 grams of beta-alanine, and a range of other beneficial recovery ingredients.
Besides focusing on boosting muscular strength and muscle mass, it's important to train for muscular endurance. This allows you to perform better (and longer), while also helping you stay healthy and reducing the risk of injuries.
A mix of exercise programs targeted at endurance training should be a core aspect of your workout routine. Supplement that with science-based ingredients proven to lessen muscle fatigue, and you’ll have a solid plan to level up your endurance.