Timing and Composition of Protein/Amino Acid Supplementation

 

Heavy resistance training changes the balance of muscle protein turnover leading to gains in skeletal muscle mass (6). The role of nutrition in affecting the adaptive response of skeletal muscle to heavy resistance training has been examined by several investigators. It has been posited that the provision of protein and amino acids is the key nutrient regulator of skeletal muscle protein turnover and subsequent skeletal muscle fiber hypertrophy. During exercise, muscle protein synthesis decreases together with a net increase in protein degradation and stimulation of branched-chain amino acid (BCAA) oxidation (the BCAAs are leucine, valine, and isoleucine). After exercise, recovery of muscle protein synthesis requires dietary protein or BCAAs. Thus, both insulin and leucine allow skeletal muscle to coordinate protein synthesis post-exercise upon the consumption of proper nutrients (4,5). However, in addition to the data showing that the acute response to combined heavy resistance exercise and nutrient ingestion (i.e., protein and amino acids) promotes skeletal muscle protein accretion (7–9), there are longitudinal studies that show improvements in body composition and exercise performance as a result of proper supplementation.

For instance, a recent study examined 10 weeks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20-g protein or 20-g dextrose placebo ingested 1 hour before and after exercise for a total of 40 g/d. The total pre- and post-serving of protein was as follows: 14-g whey protein concentrate, 6-g whey protein isolate, 4-g milk protein isolate, 4-g calcium caseinate, and 12-g free amino acids (0.22-g arginine, 0.22-g histidine, 0.14-g isoleucine, 6.0-g leucine, 0.44-g lysine, 0.44-g methionine, 0.20-g phenylalanine, 0.22-g valine, 0.12-g aspartate, 2.0-g glutamine, and 2.0-g tyrosine). Subjects exercised 4 times per week using 3 sets of 6–8 repetitions at 85–90% of the 1RM. Compared to carbohydrate supplementation, consuming the combination of protein and amino acids resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. In fact, the protein group experienced a mean increase of 5.6-kg of fat-free mass compared to the 2.7-kg gain in the carbohydrate group. More importantly, myofibrillar protein content was elevated by 45% in the protein-supplemented group versus 18% in the carbohydrate group. It is clear that within the parameters of this particular investigation, 10 weeks of resistance training combined with 20-g protein and amino acids ingested 1 hour before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance (10).

There are other investigations that support the findings by Willoughby et al. (10) that demonstrate that the consumption of carbohydrate alone does not promote optimal gains in muscle protein. Andersen et al. (1) compared the effects of 14 weeks of resistance training combined with timed ingestion of isoenergetic protein versus carbohydrate supplementation on muscle fiber hypertrophy and mechanical muscle performance. Supplementation was administered before and immediately after each training bout and, in addition, in the morning on nontraining days. After 14-weeks of resistance training, the protein group demonstrated statistically significant hypertrophy of type I (+18%) and type II (+26%) muscle fibers, whereas no change above baseline occurred in the carbohydrate group. Squat jump height increased only in the protein group, whereas countermovement jump height and peak torque during slow isokinetic muscle contraction increased similarly in both groups (1). Additionally, Bird et al. (2) examined 32 untrained young men who performed 12-weeks of resistance training twice weekly, consuming ∼675-mL of either a 6% carbohydrate (CHO) solution, 6-g essential amino acid (EAA) mixture, combined CHO + EAA supplement, or placebo (PLA). Muscle fiber cross-sectional area increased across groups for type I, IIa, and IIx fibers; however, the CHO + EAA had the greatest gains in muscle fiber cross-sectional area relative to PLA (P < 0.05). This study indicates that CHO + EAA ingestion enhances muscle anabolism following resistance training to a greater extent than either CHO or EAA consumed independently. It is posited that the synergistic effect of CHO + EAA ingestion maximizes the anabolic response presumably by attenuating the postexercise increase in protein degradation (2).

CONCLUSION AND PRACTICAL APPLICATIONS

Protein and amino acid supplementation before and after exercise have been shown to promote gains in skeletal muscle mass, muscle fiber cross-sectional area, or myofibrillar protein to a greater extent than carbohydrate alone. This supports the acute data that demonstrate that the ingestion of carbohydrates on net leg protein balance after resistance exercise is minor compared to the effect of EAA consumption (3). Consuming a combination of carbohydrate and protein/amino acid may be optimal for promoting skeletal muscle protein accretion. The mechanism for this may be related in part to the elevation of serum insulin and perhaps the up-regulation of IGF-1. However, Willoughby et al. (10) showed that the protein and amino acid supplement was shown to have a more pronounced effect on markers of skeletal muscle anabolism when compared to a carbohydrate PLA, despite a less pronounced serum insulin response. This may have been due to the added free amino acids, particularly leucine, where cooperatively with insulin and IGF-1 signaling may have further promoted skeletal muscle protein synthesis. The cellular mechanisms governing the role of nutrients in affecting skeletal muscle protein accretion are not entirely understood. From a practical standpoint, it is evident that in order to maximize gains in skeletal muscle mass and perhaps improve performance, the consumption and timing of a protein- or amino acid–based food or supplement may be warranted. Furthermore, the existing data suggest that carbohydrate alone is insufficient for promoting an anabolic response.▪

REFERENCES

1. Andersen, LL, Tufekovic, G, Zebis, MK, Crameri, RM, Verlaan, G, Kjaer, M, Suetta, C, Magnusson, P, and Aagaard, P. The effect of resistance training combined with timed ingestion of protein on muscle fiber size and muscle strength. Metabolism 54(2):151–156, 2005. Cited Here | PubMed | CrossRef

2. Bird, SP, Tarpenning, KM, and Marino, FE. Independent and combined effects of liquid carbohydrate/essential amino acid ingestion on hormonal and muscular adaptations following resistance training in untrained men. Eur J Appl Physiol 2006. Cited Here

3. Borsheim, E, Cree, MG, Tipton, KD, Elliott, TA, Aarsland, A, and Wolfe, RR. Effect of carbohydrate intake on net muscle protein synthesis during recovery from resistance exercise. J Appl Physiol 96: 674–678, 2004.Cited Here

4. Norton, LE and Layman, DK. Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr 136: 533S–537S, 2006. Cited Here | PubMed | CrossRef

5. Paddon-Jones, D, Sheffield-Moore, M, Katsanos, CS, Zhang, XJ, and Wolfe, RR. Differential stimulation of muscle protein synthesis in elderly humans following isocaloric ingestion of amino acids or whey protein. Exp Gerontol 41: 215–219, 2006. Cited Here | View Full Text | PubMed | CrossRef

6. Phillips, SM, Parise, G, Roy, BD, Tipton, KD, Wolfe, RR, and Tamopolsky, MA. Resistance-training-induced adaptations in skeletal muscle protein turnover in the fed state. Can J Physiol Pharmacol 80: 1045–1053, 2002. Cited Here | View Full Text | PubMed | CrossRef

7. Tipton, KD, Elliott, TA, Cree, MG, Aarsland, AA, Sanford, AP, and Wolfe, RR. Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab 292: E71–E76, 2006. Cited Here

8. Tipton, KD, Rasmussen, BB, Miller, SL, Wolf, SE, Owens-Stovall, SK, Petrini, BE, and Wolfe, RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab 281: E197–E206, 2001. Cited Here | PubMed | CrossRef

9. Tipton, KD, Ferrando, AA, Phillips, SM, Doyle, D, Jr, and Wolfe, RR. Postexercise net protein synthesis in human muscle from orally administered amino acids. Am J Physiol 276(4 Pt 1): E628–E634, 1999. Cited Here

10. Willoughby, DS, Stout, JR, and Wilborn, CD. Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength. Amino Acids 32: 467–477, 2006. Cited Here

Muscle Memory

Everything You Need to Know About Muscle Memory

You may have heard the term ‘muscle memory’ to describe the ability to remember movements, or maybe to describe the ability to quickly regain muscle mass that is lost after periods of inactivity.

When this term is thrown around casually as a marketing tool for an exercise program, it might cause you to wonder, “Is muscle memory a thing? Can my muscles remember my workout?”

Short answer: Yes, muscle memory is real, but it might not work as you think.

As a fitness trainer or enthusiast, this subject is an important one to consider.

What is Muscle Memory?

Muscle memory describes the ability to regain muscle mass in previously trained muscles. This means that once you’ve gained muscle mass through strength training if you lose it after taking time off from training, you can regain the muscle mass faster than the amount of time that it took to put it on in the first place.

This is good news!

How Does Muscle Memory Work?

Muscle memory doesn’t have to do with your muscle cells “remembering” exercise. As your muscles are trained, the number of muscle fiber nuclei, or myonuclei, can increase as muscle mass increases. There is still debate within the scientific community about the volume of strength training required for myonuclei to increase in number.

In a research review by Snijders et. al. (2020), data shows a linear relationship between muscle fiber size and the number of myonuclei in humans. This would suggest that hypertrophy training, and an increase in muscle size, would increase myonuclei.

The question that researchers are still debating is: What happens to the myonuclei during periods of inactivity? If you gain muscle mass, but then stop training, do you lose all the myonuclei that were gained during training?

Research performed on animals by Egner et al. (2013) shows that myonuclei that are gained during overload hypertrophy are not lost during 3 months of muscle atrophy when the muscle returns to its original size. Even though the muscle size decreased during this period of inactivity, the number of myonuclei did not. This research seemed very promising because it suggested that even though the muscle size decreased, the potential for faster muscle re-growth was there since the number of myonuclei was retained.

This is potentially good news for aging adults and those who may have had to take time off for training due to various reasons (like a pandemic, for example). There is some promising research in humans that suggests that myonuclei are retained after short-term physical inactivity and that rapid muscle re-gain is possible (Snijders et al., 2020). There is still a limited amount of research to fully support this view, however, so it is important to consider the current limitations of research.

Limitations of Muscle Memory

For some time, it was hypothesized that the increase in myonuclei in humans might be long-lasting or even permanent. At this time, the length of time that muscle memory lasts are uncertain. A review of research on muscle memory from Snijders, et al. (2020) found that “there is no consensus within the scientific community on the existence of muscle memory by myonuclear permanence in human skeletal muscle and more research is warranted using properly designed intervention studies.”

Further research is needed to form a more conclusive consensus on the lifespan of myonuclei that are gained through training and the implication of muscle re-growth.

It’s important to note that muscle memory is NOT the ability of the muscles to remember movements. The term muscle memory can be a bit of a misnomer because muscles don’t technically remember anything. In the brain, information is encoded, stored, and retrieved. What we perceive as the muscles “remembering” refers to motor learning that occurs in the central nervous system (CNS), not the muscles.

If you’ve ever taken years off from riding a bike, you may be surprised that after just a few wobbly moments, you’re riding as if you never took time off. Your brain remembers how to ride the bike, and you remain upright.

It is fair to say, however, that there is a neural component to muscle memory since someone who has performed an exercise before will do so more efficiently than someone who has not which may aid efforts to gain muscle mass.

How to Use the Concept of Muscle Memory for Hypertrophy

Muscle memory can be a game-changer for anyone who has had to take a break from training due to vacation, injury, or life events. Even though there is still some debate when it comes to muscle memory, we can still apply what we do know to take advantage.

There are two factors to consider when utilizing muscle memory:

1. Perform an adequate volume of training to induce muscle hypertrophy. To elicit the adaptation of muscle hypertrophy, one must strength train consistently (3-4 times per week) at a volume of 3-5 sets of 6-12 repetitions of exercises for 4-6 weeks. Someone who is just starting to train will need to work up to that intensity and volume by beginning with Stabilization Endurance Training and Strength Endurance training, which take 8 weeks to complete in total.

2. Minimize periods of inactivity, if possible. The longer you rest, the more muscle atrophy takes place. Additionally, the less activity you do during that rest, the higher the rate of atrophy. Taking a week off from your normal workout routine will hardly dent your progress but lying still in bed for 3 weeks can lead to significant atrophy. If possible, stay as active as possible while taking a break from strength training to minimize muscle mass loss.

How Long Does It Take to Get Back into Shape?
One of the first studies to see more rapid re-growth in resistance training was performed by Staron et al. in 1991. In this study, the female participants regained their muscle strength and fiber size during 6 weeks of retraining compared to the initial 20 weeks of strength training.

However, it seems that the rate at which muscle is re-gained can vary dependent on the level of inactivity that occurs during the lapse in training (Snijders et al., 2020). If you are bedridden for some time, it will likely take longer to get back into shape than if you simply stop resistance training but continue to do normal daily activities.

Consider this to be encouraging news if you, like many, took time off from training during the pandemic (or for any other reason!). There’s no time like the present to pick up those dumbbells again and remind those muscles how good it feels to lift. It might feel like you’re back at square one initially, but the gains will come back in no time.

References:

Egner, I. M., Bruusgaard, J. C., Eftestøl, E. and Gundersen, K. (2013). A cellular memory mechanism aids overload hypertrophy in muscle long after an episodic exposure to anabolic steroids. J. Physiol. 591, 6221-6230. https://doi.org/10.1113/jphysiol.2013.264457

Gundersen, K. (2016). Muscle memory and a new cellular model for muscle atrophy and hypertrophy. J Exp Biol, 219(2), 235-242. https://doi.org/10.1242/jeb.124495

Snijders, S. et al. (2020). The concept of skeletal muscle memory: Evidence from animal and human studies. Acta Physiol (Oxf), 229(3), e13465. https://doi.org/10.1111/apha.13465

Sarcopenia

How to Fight Sarcopenia (Muscle Loss Due to Aging)

Sarcopenia can occur naturally due to aging or other health conditions. But certain practices, including adjusting your diet and activity level, may help prevent or reverse it.

Sarcopenia, also known as muscle loss, is a common condition that affects 10% of adults who are over 50 years old.

While it can decrease life expectancy and quality of life, there are actions you can take to prevent and even reverse the condition.

Although some of the causes of sarcopenia are a natural consequence of aging, others are preventable. In fact, a healthy diet and regular exercise can reverse sarcopenia, increasing lifespan and quality of life.

This article explains what causes sarcopenia and lists many ways you can fight it.

What Is Sarcopenia?

Sarcopenia literally means “lack of flesh.” It’s a condition of age-associated muscle degeneration that becomes more common in people over the age of 50.

After middle age, adults lose 3% of their muscle strength every year, on average. This limits their ability to perform many routine activities (1, 2Trusted Source, 3Trusted Source).

Unfortunately, sarcopenia also shortens life expectancy in those it affects, compared to individuals with normal muscle strength (4Trusted Source, 5Trusted Source).

Sarcopenia is caused by an imbalance between signals for muscle cell growth and signals for teardown. Cell growth processes are called “anabolism,” and cell teardown processes are called “catabolism” (6Trusted Source).

For example, growth hormones act with protein-destroying enzymes to keep muscle steady through a cycle of growth, stress or injury, destruction and then healing.

This cycle is always occurring, and when things are in balance, muscle keeps its strength over time.

However, during aging, the body becomes resistant to the normal growth signals, tipping the balance toward catabolism and muscle loss (1, 7).

What to know about cardiorespiratory endurance

Cardiorespiratory Endurance

Cardiorespiratory endurance is an indication of overall physical health. Tests to measure this monitor how well the heart, lungs, and muscles perform during moderate to high intensity exercise.Increasing cardiorespiratory endurance improves oxygen uptake in the lungs and heart and can help a person sustain physical activity for longer.

Other names for cardiorespiratory endurance include cardiovascular fitness, cardiovascular endurance, and cardiorespiratory fitness.

In this article, we discuss what cardiorespiratory endurance is, how a person can measure it, and why it is important. We also look at how to improve cardiorespiratory endurance, including some examples of exercises.

Cardiorespiratory endurance measures how well the body performs during long periods of exercise. A person with high cardiorespiratory endurance can sustain high-intensity activities over an extended period without getting tired.

Measuring a person’s cardiorespiratory endurance involves examining how well their body takes in and utilizes oxygen.

When a person inhales, their lungs fill up with air and some of the oxygen it contains passes into the bloodstream. This oxygen-rich blood then travels to the heart, which circulates it around the body to the tissues and organs that need it.

The muscles require an adequate supply of oxygen and other nutrients to work properly during high-intensity or extended periods of exercise. If the muscles do not get enough nutrients, waste products begin to accumulate and cause fatigue.

A person’s level of cardiorespiratory endurance can directly affect their physical performance.

How is it measured?

Tests that measure cardiorespiratory endurance include:

Metabolic equivalents

Metabolic equivalents (METs) refers to the ratio between the energy expended during physical activity and the energy expended while at rest. Finding a person’s MET involves measuring how much oxygen their body uses at rest.

Maximum oxygen uptake

Maximum oxygen uptake (VO2 max) test determines the maximum amount of oxygen the body is capable of using during high-intensity activities, such as sprinting or biking.

The VO2 max test typically involves running on a treadmill or pedaling on a stationary bike as fast as possible. During the test, the person wears a chest strap or other body attachment that records their heart rate and a face mask that measures oxygen consumption.

Why is it important?

Cardiorespiratory endurance indicates a person’s level of aerobic health and physical fitness. This information can benefit everyone, not just professional athletes.

Having a high cardiorespiratory endurance generally means that a person can perform high-intensity exercise for longer.

People trying to lose weight may want to focus on increasing their cardiorespiratory endurance because doing higher-intensity aerobic activities can help a person burn more calories.

Scientific research also suggests some other potential health benefits from having an improved cardiorespiratory endurance. For example:

• A 2017 studyTrusted Source suggests that people with higher cardiorespiratory endurance are less likely to develop high blood pressure than those with a lower cardiorespiratory endurance.
• In a 2015 studyTrusted Source, researchers found a positive correlation between cardiorespiratory endurance levels and multitask performance among adults aged between 59 and 80 years.
• Improving cardiorespiratory endurance may decrease the risk of coronary heart disease and all-cause mortality, according to a 2015 studyTrusted Source.

How to improve it

People can improve their cardiorespiratory endurance through regular exercise.

The authors of a 2019 studyTrusted Source reported that resistance training, endurance training, and high-intensity interval training led to improvements in cardiorespiratory endurance and muscular strength among adults who were aged 40–65 years old and who were not previously physically active.

A 2017 study investigated the effectiveness of a 12-week cross-circuit training program in students who were overweight and had intellectual disabilities. The researchers found participants who followed the training program had an improved exercise endurance, muscle strength, and body mass index.

The following exercises can help improve cardiorespiratory endurance, build muscle, and burn calories. People can perform these physical activities at home or add them to their gym routine.

Try doing these exercises in sets of 10–15 repetitions, or as many repetitions as possible for 1 minute with a 20-second break in between sets.

Jumping jacks:

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1. Start by standing upright with legs together and arms at the sides of the body.
2. Jump up. While in the air, open the legs to spread the feet wide apart and raise the arms overhead.
3. While landing, bring the feet and arms back to the starting position.

Burpees:

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1. Begin standing with the feet shoulder-width apart.
2. Bend the knees and place the hands on the floor in front to come down into a squat position.
3. Jump the legs out behind to get into the push-up position, shifting the body’s weight onto the hands.
4. Jump the feet back into the squat position.
5. Jump up into the air with arms raised above the head.
6. Land back in the squat position.

Mountain climbers (running planks):

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1. Start in the plank position, aligning the shoulders over the wrists and keeping the legs straight. Keep the back flat and the head aligned with the spine.
2. Engage the core muscles.
3. Bring the right knee towards the chest.
4. Switch legs by returning the right leg to the starting position and bringing the left knee towards the chest. This completes one repetition.

Side-shuffle touches:

1. Start in a standing position with the feet shoulder-width apart and the arms down by the sides.
2. Bend the knees and squat down.
3. Shuffle a shoulder-width to the right and then touch the floor outside the right foot with the fingertips of the right hand.
4. Shuffle a shoulder-width to the left and then touch the floor outside the left foot with the fingertips of the left hand.
5. This is one repetition.

Other exercises that can help improve cardiorespiratory fitness include:

• running
• power walking
• swimming
• dancing
• jump rope
• high-intensity sports, such as basketball and soccer

Summary

Cardiorespiratory endurance is a measure of how well the heart, lungs, and muscles perform during moderate to high-intensity physical activity.

Getting regular physical activity, especially aerobic exercise, can improve cardiorespiratory endurance. Aerobic exercises can help promote heart and lung health and improve how well the body circulates and utilizes oxygen.

How to Improve Muscular Endurance

Muscular endurance refers to how long muscles can sustain exercise. Improving muscular endurance can help enhance overall health and fitness.

This article explores the benefits of muscular endurance, the best training routines to enhance it, and how people can adapt these techniques into common exercises.

We will also look at tips to prevent injury during training and how to design an exercise program that could lead to long-term performance and health benefits.

What is muscular endurance?

Muscular endurance is the ability to continue contracting a muscle, or group of muscles, against resistance, such as weights or body weight, over a period of time.

Increasing the performance of these muscles means they can continue to contract and work against these forces.

Greater muscular endurance allows a person to complete more repetitions of an exercise, for example, pushups or squats.

Benefits of muscular endurance training

According to the American Council on Exercise (ACE), the benefits of muscle endurance include:

1. helping maintain good posture and stability for longer periods
2. improving the aerobic capacity of muscles
3. improving the ability to carry out daily functional activities, such as lifting heavy items
4. increasing athletic performance in endurance-based sports

How to measure muscular endurance

Muscular endurance tests measure how many repetitions of a movement people can do before the muscles reach a state of fatigue and cannot continue the exercise.


Many tests focus on measuring upper and lower body muscle endurance by measuring how many pushups, squats, or situps people can achieve.


A person can work with fitness instructors to measure muscular endurance or record how many repetitions of a particular exercise they can perform before reaching the fatigue state.

How to improve endurance

To increase muscular endurance, ACE recommend a combination of lower and upper body exercises, with strengthening exercises to target the whole body.


Moderate resistance training, with short intervals in between for rest, creates short bursts of tension to build strength.


Circuit or high-intensity interval training (HIIT) can be a suitable way to combine cardio and strength training into one workout.


Unless a person’s fitness goals involve training for a particular endurance-based sport, training for muscular endurance alone may not be the most appropriate strategy.


The best exercise programs mix strength and muscular endurance training.


Some evidence also suggests that exercise programs that people find enjoyable may be more likely to generate long-term benefits, as they may be more likely to stick with them.


A 2015 studyTrusted Source comparing HIIT and steady-state training notes:


“Variety in the type of exercise is as important as the type of exercise. Particularly considering that the health benefits of exercise have to be viewed in the context of the likelihood that exercise is continued for several years, not just the weeks of a controlled study.”

Training for muscular endurance

When training to improve muscular endurance, what matters most is not the type of exercise, but how people design their workout.


People should take into consideration the following when tailoring a workout to boost muscular endurance:

1. the number of reps
2. the weight or resistant force on the muscles
3. the number of sets
4. length or rest periods

According to the National Strength and Conditioning Association, individuals training for muscular endurance should aim to complete three or more sets of 15 or more exercise reps with a load that is 50% or less of their one rep max (RM).


A person’s one rep max is the maximum load with which a person can complete one repetition of an exercise.


For example, a person may wish to use the leg press machine at the gym to build endurance in the legs.


If they have an RM of 300 pounds (lbs), they should aim to perform 2–4 sets of 15 or more reps with a load of 150lbs or less, with brief rest periods between sets.


As their muscular endurance for this exercise increases, they may wish to make the exercise more challenging by reducing rest times between sets, or increasing the reps per set, rather than increasing the load weight.


A person can apply the same principle of high rep and set volume, low–moderate load, and short rest periods to any exercise, such as bench presses, dumbbell curls, pushups, or squats.


People can choose exercises that suit their preferences and are challenging yet enjoyable enough to sustain training.

Example exercises


As we have already mentioned, there are no specific exercises that are better for training muscular endurance than others. The design of a training program makes it suitable for endurance training.


However, ACE recommend the following exercises for building muscle endurance, which a person can perform at home without equipment:

Pushup

A pushup works the triceps, chest, and shoulder muscles.

1. Start in a pushup position by lifting the body off the ground with the hands and toes, with the body in a straight line, horizontal to the floor.
2. Keep the hands flat on the floor shoulder-width apart and at roughly chest level.
3. Start with the arms straight, then bend the arms while keeping the body straight and engaging the core and glutes, to lower the body until the chest is close to the ground.
4. Straighten the arms to return to the starting position.
5. Repeat for 5–15 times, depending on difficulty, to perform one set

A person can also work the tricep muscles more by placing their hands close together and turn them inward, so the fingers and thumbs form a diamond shape.


To make the exercise easier, a person can place their hands on a bench or other stable, raised surface.


People can also modify a push up by placing the knees on the floor to make it easier or lift one leg off the floor to make it more difficult.

Squat

A squat works the glutes, calves, quads, and core muscles.

1. Stand with the feet just over shoulder-width apart with the toes pointing slightly outwards.
2. With the head facing forwards in a neutral position and back straight, extends the arms in front, so they are parallel with the ground.
3. Squat down by bending the knees, keeping the body weight centered over the arches of the feet and the thighs parallel to the floor.
4. Keep the back straight with the shoulders back and chest forwards.
5. Use the feet, legs, and hips to push back up to the starting position.
6. Beginners should aim for 5–10 reps, and they may perform the squat against a wall or end the movement in a seated position on a low surface to make it easier.

Abdominal crunch

An abdominal crunch works the abdominal muscles:

1. Lie on the back with knees bent and feet flat on the floor.
2. Place the hands lightly on the back of the head and chin tucked.
3. Slowly curl the upper body towards the knees, keeping the lower back on the mat.
4. Slowly lower back down to the starting position.
5. Perform 10–15 repetitions for one beginner set.

Pike crunch

Another example of an abdominal crunch is the pike crunch:

1. Lie with the back flat on the floor, with legs outstretched and arms above the head.
2. Lift the torso and legs off the floor to form a pike position.
3. Place the legs at right angles straight up in the air and reach with the arms toward the feet.
4. Slowly lower the legs and torso back to the floor.
5. Perform for 10–15 repetitions for one beginner set.

A person can also hold a stability ball between their ankles during this exercise.

Lunge

A lunge works the abs, buttocks, hips, and thighs:

1. Stand up straight with the feet together.
2. Bend one knee, lift the opposite leg, step forwards on to it, place the foot flat on the floor, and bend the supporting leg, so the knee reaches the bottom.
3. Use the front leg to push back up to the start position and repeat for the opposite leg.
4. Perform for 10–15 repetitions on each leg for one beginner set

Plank

A plank works the core and back muscles.

1. Start by lifting the body off the ground with the hands and toes, with the body in a straight line, horizontal to the floor
2. Keep the hands flat on the floor, with straight arms and wrists and the elbows directly underneath the shoulders.
3. Keep the chin tucked in, with the abs and thighs tight.
4. If the person is a beginner, hold for 30 seconds, rest for around 1 minute in between.
5. Repeat the plank at least three times.

A person can modify this exercise by resting on the forearms instead of the palms if they find it challenging to hold the plank position with straight arms.

Preventing injury

Tips to prevent injury during a workout include:

1. warming up with dynamic stretches before exercising, for at least 5 minutes
2. making sure to maintain proper posture and technique, and consulting with a fitness professional if unsure of these
3. exhaling during movements requiring more effort and inhaling on easier parts of the exercise
4. resting certain muscle groups at least 24 hours after working them out
5. cooling down and stretching after exercise
6. stopping physical activity if ill or injured

Summary

Muscular endurance is a muscle’s ability to continue contracting against resistance over a period of time.

People can improve their muscular endurance with strength and cardiovascular training.

Exercise adaptations: molecular mechanisms and potential targets for therapeutic benefit

 OVERVIEW: 

Exercise is fundamental for good health, whereas physical inactivity underpins many chronic diseases of modern society. It is well appreciated that regular exercise improves metabolism and the metabolic phenotype in a number of tissues. 

The phenotypic alterations observed in skeletal muscle are partly mediated by transcriptional responses that occur following each individual bout of exercise. This adaptive response increases oxidative capacity and influences the function of myokines and extracellular vesicles that signal to other tissues. 

Our understanding of the epigenetic and transcriptional mechanisms that mediate the skeletal muscle gene expression response to exercise as well as of their upstream signalling pathways has advanced substantially in the past 10 years. 

With this knowledge also comes the opportunity to design new therapeutic strategies based on the biology of exercise for a variety of chronic conditions where regular exercise might be a challenge. 

This Review provides an overview of the beneficial adaptive responses to exercise and details the molecular mechanisms involved. The possibility of designing therapeutic interventions based on these molecular mechanisms is addressed, using relevant examples that have exploited this approach.

Key points

• Exercise is effective in the primary prevention of 35 chronic diseases.

Heart disease

Stroke

High blood pressure

Type 2 diabetes

Obesity

Osteoporosis

Arthritis

Chronic obstructive pulmonary disease (COPD)

Asthma

Certain cancers (e.g., breast, colon)

Depression

Anxiety

Dementia

Alzheimer’s disease

Metabolic syndrome

High cholesterol

Gallbladder disease

Non-alcoholic fatty liver disease

Sleep apnea

Chronic back pain

Chronic neck pain

Fibromyalgia

Irritable bowel syndrome (IBS)

Chronic kidney disease

Peripheral artery disease

Varicose veins

Gout

Polycystic ovary syndrome (PCOS)

Erectile dysfunction

Chronic fatigue syndrome

Migraine

Psoriasis

Eczema

Multiple sclerosis

Inflammatory bowel disease (IBD)

• The adaptive response to exercise, which is mediated in part by transcriptional alterations in metabolic and other genes, is an important contributor to these health benefits.

• Identifying the mechanisms that mediate the exercise adaptive response could uncover molecular targets to guide the design of new medicines to better treat chronic diseases.

• A number of signalling, epigenetic and transcriptional molecules identified as contributing to the exercise adaptive response have been targeted pharmacologically to deliver health benefits in proof-of-concept studies.

• A further understanding of the complexities of the molecular responses to exercise will provide new opportunities to engage these mechanisms therapeutically.