Muscular Endurance Training Approaches

Muscular endurance is the ability to keep contracting a muscle against resistance. Resistance could be in the form of body weight, or an external resistance such as weights. If a muscle has to contract in a similar pattern more than once, you are using muscular endurance. Muscular endurance plays a key role in most athletic endeavours particularly sports involving repetitive movements for extended periods of time, for example, rowing, middle/long distance running and swimming.

Muscular endurance holds great importance in endurance training activities such as running, swimming, rowing, and cycling. However, the main goal of this topic is to explore muscular endurance within the context of resistance training, rather than aerobic exercises.

Many sports require a combination of muscular strength, power and endurance, which means resistance training programmes should encompass all of these training modes at different points in the training calendar. Where strength can be thought of as the force put into a particular movement, muscular endurance (or stamina) is the ability to produce this force repeatedly, or for an extended duration.

Muscular endurance can be targeted in a number of different ways. For cardiovascular endurance activities this will involve doing the activity regularly and applying the FITT and training principles to improve endurance and efficiency of movement. From a resistance training perspective, most muscular endurance exercises are isotonic in nature (i.e. have a concentric and eccentric phase), however some muscles of the body (particularly postural muscles) require isometric training, so they can hold positions for extended periods of time. This is also a form of muscular endurance.

Click on the arrows beneath the image to view a few examples of muscular endurance exercises.

Types of muscular endurance

According to Sport Fitness Advisor (n.d.) there are three main muscular endurance approaches that will cover most client needs:

1. Power endurance

This type of muscular endurance is most important for athletes who need to produce short, powerful movements several times with little to no rest between efforts. The objective is to maintain the same amount of power output with each effort, so a certain amount of endurance is required. This approach is typically characterised by intense, repeated efforts over a relatively short period of time (less than 30 seconds). For example, a tennis player has to produce several powerful shots in quick succession during a rally that might last 10-20 seconds. Other athletes like cricket fast bowlers, martial artists and wrestlers would also benefit from this type of muscular endurance training. The general progression for these types of athletes would be to develop their strength and power first, then move into power endurance training to train the muscle fibres to resist fatigue, so that their explosive power can be maintained for longer. More on the application of FITT principles to this form of training soon.

2. Short-term muscular endurance

Helpful for activities that include bouts of exercise that last between 30 seconds and 2 minutes duration. These might include continuous efforts like an 800m race, or intermittent sports like football, rugby etc. This type of training uses moderate to light loads of resistance over set periods or for a number of repetitions (more on these details soon). This form of training helps athletes cope with fatigue-inducing efforts better and tolerate working with high levels of lactic acid.

3. Long-term muscular endurance

Helpful in activities and sports that last for extended periods of time. Marathoners, rowers, basketball players and other athletes with games or races that last more than a few minutes will benefit from long-term muscular endurance approaches. These include working with light loads for extended periods of time. Often the only rest an athlete is given in this training approach is the time it takes to move between equipment.

As with any mode of training, the types of contraction, exercise choices, duration and intensity of exercises chosen, should be closely aligned with the goal of the exercise programme. For example, if training for a particular sport, the contraction types and choice of exercise should replicate the movements required in the sport. However, if the exercise goal is more general, then a wide range of exercises and contraction types can be used, e.g. If weight loss is the goal, then the exercises should be multi-joint compound exercises that elicit greater calorie expenditure should be used.

Benefits of muscular endurance training

The benefits of muscular endurance are numerous. While it is important for improving the performance of athletes in their various pursuits, the benefits of muscular endurance have a much wider reach than that. Along with the common benefits of exercise like improving sleep, improving mental health, and reducing the risk for chronic disease, the specific benefits of muscular endurance training include:

• Accessibility and social connection: Muscular endurance training modes are often the easiest to access. Body weight exercises can be performed easily at home without the need for expensive equipment or gym membership. If you want social connection, there are many events and classes you can attend that focus on muscular endurance
• Improvements in heart health: All cardiovascular activities (e.g. running, cycling, swimming etc.) are classed as muscular endurance activities. These forms of exercise improve heart strength and function, improve the efficiency of blood flow through the body and reduce the risk of heart disease.
• Helps raise metabolism and maintain a healthy weight: Muscular endurance activities using large muscle groups over extended periods of time elicit the highest calorie expenditure of all types of exercise. This gives more bang for your buck during exercise sessions. Muscular endurance training programmes result in improved body composition and muscle tone.
• Improves balance, bone density and joint function: Great for everyone, but especially older clients. Loading of bones and joints helps to maintain bone density, ligament, muscle and tendon strength and can improve balance reducing fall risk.
• Improved performance of physical activities: This doesn’t only refer to sports performance. Increasing muscular endurance will make everyday chores and activities easier too. The more stamina you have, the more effectively you will be able to perform tasks without the need to stop. For many clients, this can be simple things like washing the car, gardening or playing with the kids.
• Improved efficiency of movement: Using lighter loads allows the neuromuscular system to make more efficient connections and hone technique. This is why the first step in most resistance programmes for new clients is a muscular endurance approach. It allows time for a client to learn the motion (through repetition) before moving onto heavier loads and improves their movement efficiency under fatigue which can reduce injury risk.
• Improved posture: Postural muscles need to be able to perform their duties for extended periods of time. A targeted muscular endurance approach is the best method for increasing postural muscle stamina.

Human potential for muscular endurance

Humans have an amazing capacity for muscular endurance. Check out some of these records Note: not all of these have been verified by the Guinness Book of Records.

• Most consecutive push-ups: According to Topend Sports the world record for the greatest number of non-stop push-ups is 10,507 by Minoru Yoshida of Japan, which was achieved in October 1980, breaking the record of 7,650 by Henry C. Marshal (USA) from 1977. A short time after this record was set, the Guinness Book of Records stopped recording non-stop push-up records (no rest periods allowed) and instead started recording most push-ups in 24 hours with as many rest periods as they wanted. The record for this stand at 46,001 push-ups in a 24-hour period (set by Charles Servizo from the USA in 1993).
• Most consecutive pull-ups: The Guinness Book of Records reports this as 651 pull-ups without stopping. This record was set by Kenta Adachi (Japan) in 2022.
• Longest plank hold: Set by Australian Daniel Scali in 2021, this record stands at 9 hours, 30 minutes and 1 second.

Watch the longest plank hold in the following video.

If you would like to know more about these amazing muscular endurance records, check out “11 of the most hardcore fitness records ever”.

The following exercise recommendations are from the American College of Sports Medicine (n.d.)

Muscular endurance training sessions adhere to a consistent framework. These sessions typically involve higher volumes and intensities while using lower resistance. As we know, there are various strategies available within the realm of muscular endurance training. Nonetheless, when crafting training routines for muscular endurance, trainers often follow general guidelines, including:

• Light to moderate loads (of no more than 40-60% of 1RM)
• High repetitions (>15)
• Short rest periods (<90 seconds).

Like any exercise program, muscular endurance programs can be localised, targeting specific muscle groups, or generalised, taking a total body approach. For overall conditioning, the ACSM recommends selecting multi-joint exercises that engage multiple muscle groups. It's advisable to introduce plenty of programming variety, ideally transitioning between muscle groups for each set, and maintaining brief rest periods.

See the following programme training guidelines that you should use for programming muscular endurance in a little more detail.

Frequency

In terms of frequency of muscular endurance sessions, the best results appear to support training 3-4 times a week with 24 hours between targeting the same muscle groups for recovery. Novices should look to train using a full body approach, while more advanced exercisers may benefit from up to four to six sessions a week with a split muscle group approach used.

Volume

If you are a novice or intermediate exerciser, you should aim to perform each exercise for between 10-15 repetitions with good form for one to two sets. For advanced exercisers, plan for 15-25 repetitions for two to three sets per exercise. ACSM suggest between two and four exercises per targeted muscle group is considered appropriate for one exercise session (lower end for novices, higher end for advanced exercisers)

Loading

Loading will be somewhat dependent on the type of muscular endurance you are programming for (e.g. power, short-term or long-term muscular endurance). However, ACSM suggests a load of between 40-60% of a 1RM effort in a given exercise is an appropriate range for most muscular endurance approaches. Sports Fitness Advisor (n.d.) suggests a load of between 50-70% of 1RM could be used for power endurance training, but keep in mind that this form of training is generally reserved for athletes at the higher end of the training spectrum. More specific training guidelines for different types of muscular endurance training approaches will follow these more general guidelines.

Rest

It is generally agreed that shorter rest periods should be used for muscular endurance training. Less than 90 seconds is recommended, but as with any training approach, rest periods should be manipulated depending on the training stimulus you are wanting to achieve. Quinn (2022) suggests rest for between one and two minutes for high-repetition sets of over 15 repetitions, with less than 1 minute of rest programmed for sets of less than 15 repetitions. From a sports perspective, rest periods should reflect the actual rest allowed in games. Because of the explosive nature of power endurance training, longer rest periods are warranted (more in line with power training principles).

Training velocity

This will depend on the programme approach used. Power endurance training will utilise fast velocities, while long-term muscular endurance training will use a more measured and controlled velocity for repetitions. Velocity and tempo are similar terms that we use to describe the speed at which we perform a movement.

You will learn more about tempo when we cover hypertrophy training. You may see the terms tempo and velocity used interchangeably throughout the module.

Specific guidelines

The following table describes different muscular endurance resistance training approaches.

Watch the following video that recaps the key programme guidelines for muscular endurance.

Applying progressive overload

Of course, the variables associated with muscular endurance training covered above will ultimately be chosen for a programme based on the individual needs of a client. In general, new clients will start with lower resistance and repetitions, with longer rest intervals. As they improve their condition, repetitions, load, and rest intervals will be systematically manipulated to apply progressive overload. As they progress, the volume will increase (repetitions and sets), the load will increase, and rest intervals will shorten. For sports athletes, the training sessions will begin to replicate the duration, intensity, and rest experienced on game day (determining these variables will take some research on the part of the trainer).

As you have seen from the information covered above, there are many and varied ways to train muscular endurance. This makes it one of the most adaptable programme approaches of all the exercise training modes!

Many group fitness classes and indeed whole franchises now operate exclusively in the muscular endurance space. Some common examples of these in New Zealand include F45, Orange Theory, BFT, Les Mills Group Fitness classes like Body Pump, and many more!

Click the arrows below the image to see these examples.

Let’s look at some common muscular endurance training approaches that can be used to produce a varied and enjoyable series of workouts for your clients.

This is by no means an exhaustive list of muscular endurance approaches, the options are endless, but it covers some of the most common approaches. If you want to have a full comprehension of muscular endurance training approaches and who they are appropriate for, it pays to try them out for yourself. Particularly those you have never experienced them.

Circuit training

A series of exercises done in a set order. Usually involves a combination of bodyweight and resistance exercises (depending on location). There are many ways to set up circuit training, which makes them a great way to add variety to a client’s workout. Here are some common examples of circuit approaches:

Work:Rest ratio circuits

Where a number of exercises are performed for a set time period before moving to the next exercise with only a short rest period between exercises and a longer rest at the end of one round of all exercises. Common examples of this are 30 sec:30 sec (work: rest ratio), 40:20, 45:15, and 60:60 variants. Exercises can be selected to target different muscle groups on rotation. Each exercise is not necessarily performed at maximal intensity as the goal is to work for the allocated time (rather than max out).

An example of a simple circuit work:rest ratio circuit is below:

3 rounds of the following exercises with a 60-second rest between rounds. Each exercise is performed for 45 seconds at a consistent pace with 15 seconds to get to the next exercise.

• Goblet squats
• Resistance band chest press
• Sit-ups
• Step-ups
• Barbell row
• Prone hold
• DB shoulder press
• Walking lunges

Guerrilla circuits

A series of exercises targeting different muscle groups with a repetition allocation given to each that would be typically more than a client could do in one effort. A mix of bodyweight, light to moderate resistance, isometric holds and cardio exercises work best. The objective of the circuit is to finish all of the exercises in the fastest time possible (or as many of the exercises as possible in the time available). Exercises can be completed in any order and repetitions do not have to be completed before starting another exercise. The trainer can keep a tally of repetitions completed. Rest is taken where needed, but smart exercise order selection can reduce the need for this. Time frames for guerrilla circuits are generally between 10 and 20 minutes and contain between 6 and 12 exercises.

Clear the board

Similar to the Guerrilla circuit above, this workout allows the client to attack a series of exercises in any order they wish. Exercises must also be completed in full before moving on to the next exercise. Exercises should be multi-joint in nature and chosen to cover the majority of muscle groups. They can include a mix of isotonic and isometric exercises and should cover the main muscle groups 3-4 times in the workout. Each exercise in the workout can be done once only (with higher repetitions allocated, eg. 15-25), or multiple times with lower repetitions allocated, e.g. 0-15). Simply indicate this by placing marks next each exercise to indicate how many times each should be done). You can do the workout as a timed continuous one (e.g. 25 minutes taking rest when you need it), or can be broken up into shorter time intervals, e.g. 3 x 8 minutes with 2 minutes rest before continuing. An example of a clear-the-board workout is below (note: repetitions and weight should be adjusted based on the client's level of condition).

Clear-the-board workout

25 minutes or a clear board – take rest when you need it.

• Each exercise is to be completed before starting the next exercise
• Exercises can be completed in any order

Tabata training

Similar to work:rest ration circuits, but usually performed as repeated sets of an exercise performed intensely for a short time with short recovery periods. A traditional approach is the 20:10 work to rest Tabata, where you work intensely for 20 seconds, then rest for 10 seconds and repeat a number of times (usually 8). Another version is the 10:5 work-to-rest ratio Tabata where an activity is performed for 10 seconds with a 5-second rest interval and repeated 8 times. There are a number of different approaches you can take with Tabata including:

• Working on the same exercise throughout an entire set – e.g. air squats
• Alternating between two exercises targeting different muscle groups – e.g. Step ups and push-ups
• Working through four exercises for two rounds each –e.g. 2 sets of KB swings, 2 sets of upright rows, 2 sets of goblet squats, 2 sets of overhead triceps extensions.

There is also a fantastic array of Tabata Song lists on Spotify which have the work:rest ratios pre-programmed and instruction given for when to start and stop exercise.

AMRAP

AMRAP refers to, “As Many Reps (Rounds) As Possible”. This can be programmed for singular exercises, done in a rotation (e.g. 1 minute of push-ups, 1 minute of squats etc.). Using this format, you do as many repetitions as you can in that timeframe – max out). AMRAPS can also be small groupings of exercises where the objective is to complete as many rounds of the exercises as possible in a timeframe (usually 1-3 minutes). The exercises in a “round” should target different muscle groups. For example, a round approach to AMRAPS could be:

• 5 x air squats
• 5 x push-ups
• 5 sit-ups.

Complete the exercises in order as many times as possible in a minute. The key is to keep exercise reps short as it is more motivating to complete multiple rounds than one round. After a minute’s rest, it would be usual to rotate to a different set of exercises with different muscle targets. Recording completed reps/rounds is a great way to encourage effort. Clients can be allocated into groups and contribute repetitions/rounds to an overall group score. When completing multiple exercises round AMRAP, you can also count partial rounds, e.g. if a client finishes 2 full rounds of the exercises listed above and also completes another 5 air squats before the time runs out, they would score 2.1 rounds. This method of scoring encourages clients to work for the whole minute, rather than stop when they think they won’t finish a complete round.

EMOM

EMOM refers to “Every Minute on The Minute”. Similar to AMRAP in terms of set-up, but a different approach that allows some choice in terms of how a client goes about completion. The client will need to perform a series of exercises within a 1-minute time frame, but a new round of the same exercises will start every minute on the minute. The choice the client has is to complete the exercises as fast as possible and rest the remaining time, or to take a more measured approach and sacrifice recovery time before the next round begins. EMOMs will typically involve around 4-6 rounds of 3-4 exercises in one block. The number of exercises, difficulty of exercises, and number of rounds to complete will depend on the client’s training age and condition level. If completed quickly, exercise rounds should last between 30 and 40 seconds and target at least three different muscle groups. An example of one round of an EMOM workout is as follows:

Every minute on the minute for 5 minutes, clients must perform:

• Burpee to box jump x 5
• Decline push-ups x 6
• Weighted lunge x 5 on each leg

Rest for 2 minutes at the end of the 5-minute round, then repeat with a different set of exercises.

Climb the ladder or pyramid sets

These approaches work on the basis of adding additional repetitions in a gradual fashion to tax the muscles and improve endurance. Climb the ladder circuits essentially add one or two repetitions to all exercises each round reaching the real endurance range in later sets while under fatigue. A pyramid circuit essentially climbs the ladder, then comes back down again (i.e. gradually decreasing repetitions once you have reached the peak). These are very fatiguing approaches, so care should be taken when selecting exercises (opt for less complex techniques) and loading should be kept low to moderate. Examples of these types of circuits are shown below.

Isometric training

Isometrics is another effective method to build both strength and endurance. It is also known as tension endurance. Isometric exercises involve holding a position (i.e. plank) for a set time without moving your joints. The benefits of isometric training for muscular endurance are wide-ranging. They tend to activate more available motor units than other forms of exercise, can reduce sticking points in heavier lifts (by pausing at the weakest point of the lift), and assist muscle hypertrophy. They are also useful for maintaining muscle condition when joints are injured and help clients establish a strong mind-muscle connection (MacPherson, 2021). Isometric exercises can either be incorporated into the circuit training approaches above (alongside isotonic exercises) or trained in isolation in a standalone session.

The time for which a client holds their isometric exercises will again depend on their training age and exercise goals, but the initial aim for most novices will be to hold for a minimum of 30 seconds during traditional isometric exercises like the plank or wall sit. Other isometric approaches will use much shorter holds of only 2-5 secs to elicit benefit. The primary consideration when programming isometric exercises for clients is their ability to recruit the correct musculature during the exercise. When form is lost, or you suspect musculature other than the targeted muscles are working, the exercise should be stopped.

Isometric exercises can be used to target a number of different results including:

Core activation/spine and pelvis control

Exercises like planks (standard and side), hollow holds, glute bridge holds, and variants of these exercises (single leg and alternate arm/leg versions) are used to activate the core and other muscles of the LPHC. These muscles require isometric training as they play a key role in posture and pelvic alignment.

Isolated isometric training

These exercises are used to target specific muscles (that may be weak or poorly recruiting), or to target the sticking point (weakest point of a lift). Examples of these exercises include:

• Isometric bench press: Perform a regular bench press, but with a much lighter weight than you would normally press. Pause and hold the bar 8-12cm above your chest and hold for 2 to 3 seconds before driving the weight up (repeat for 12+ reps).
• Isometric squat: Using a barbell or dumbbells (lighter than you would normally squat), perform a squat, and hold the bottom position (or a sticking point you have) for 2 to 3 seconds (repeat for 12+ reps).
• Isometric push-ups: Isometric push-ups are challenging for your whole body. Drop into the bottom of a push-up position without touching the floor and hold for 3 to 4 seconds before pushing back up. Use regressions if required (repeat for 12+ reps).
• Isometric lunge: Single-leg unilateral exercises are excellent for building muscular balance and stability. Performing a lunge but hold the bottom part of the lunge for 3-5 secs. Ensure you engage the core and keep the torso upright (repeat for 12+ reps).
• Isometric pull-ups: A great way to increase your ability to do pull-ups. Simply hold onto the bar and contract your muscles without moving. Try this at the bottom of the lift by engaging your back muscles and biceps. Then try it at the top of the pull-up with your chin over the bar (note: you can get yourself up there with assistance). Hold each repetition for as long as you can engage the musculature well, then rest and repeat (2:1 work-to-rest ratio).

Of course, these same approaches can be used for nearly any resistance exercise

Grip strength

Improving your grip by strengthening your forearms, shoulders, and hands will go a long way toward improving other lifts such as pull-ups and deadlifts. Try these out:

• Dead hangs: Use a pull-up station for this. Take a firm grip and let your body hang while engaging your core to stop your legs swinging. Continue for as long as you have a strong grip (if your grip shifts to your fingers only, end the lift). Repeat 5 times, with a 2:1 work-to-rest ratio).
• Isometric grip hold: Stand side on to a barbell racked a bit below arm's length. Pick it up in the centre with one hand. Hold for 30 seconds and repeat with the other arm. Add weight to the bar as you require to make it challenging.
• Loaded carries: Walking with a load in your hands promotes functional strength, muscle gains, and stability. There are many loaded carry variations such as farmer's walks, suitcase carry, waiter's carry, and more. Choose a weight that is challenging, but that you are able to maintain correct body alignment with. It is particularly important that thoracic spine and neck position, along with pelvic tilt are maintained. Initially, it is better to choose a lighter weight but travel further.

Complex training

This is a series of exercises, each done for a number of repetitions, one after the other, without resting (like a circuit). The difference is these exercises are all completed with one piece of equipment without putting the equipment down until the end of the sequence. Common examples of equipment used are barbells, kettlebells, medicine balls, weight plates and dumbbells. The following are a couple of examples of an exercise set using this approach:

Barbell complex set

Using a barbell with weight plates appropriate to the level of the client. 15 repetitions each of:

• Squats.
• Overhead shoulder press.
• Straight leg deadlift.
• Bent over row.

Kettlebell complex set

Using a kettlebell weight appropriate to the level of the client. 15 repetitions each of:

• KB swings.
• Upright row.
• Two-hand overhead KB press.
• Single arm KB row.

As you can see, there are a huge number of muscular endurance training approaches that you can choose to programme from. Exploring a little more online will uncover a whole lot more. There is never any excuse for taking the same approach with a client week after week! The key to ensuring variety is to broaden your list of exercises and not fall into the habit of using the same exercises on repeat. The exercises you will be able to use in sessions will ultimately depend on the equipment and space you have available to train clients in. One great tip is if buying your own equipment for training clients, choose implements that you can do 100 exercises with rather than those that only have a few uses.

Remember, a lot can also be done using body weight. Download this great bodyweight exercise guide to make sure you have a wide range of bodyweight exercises at your disposal.

Time to look at the physiological changes that occur in muscles when you do muscular endurance training. Remembering that common cardio approaches to exercise are also muscular endurance in nature, it is unsurprising that many of the muscular adaptations seen after aerobic exercise training approaches are also seen following muscular endurance training approaches.

Muscle adaptations from cardio/muscular endurance approaches

Muscular endurance training increases the aerobic (oxidative) capacity of type IIa and IIb (fast twitch fibres) resulting in more fibres with fast-contracting, fatigue-resistant properties — This enables you to work harder for longer (Scott, Stevens and Binder-Macleod, 2001).

• Muscular endurance training increases the number of capillaries per area of muscle, increasing the oxygen supply to the muscle. Increasing the oxygen supply to the muscles is a vital part of holding off muscular fatigue, thus enabling muscles to complete more work before tiring (Kamga, Krishnamurthy and Shiva, 2012).
• Endurance training enables your body to use proportionally more fat during a given exercise intensity, sparing muscle glycogen (your muscles' fuel source) and allowing you to exercise longer at higher intensities. (Knuiman, Hopman and Mensink, 2015). This effect is most evident in longer-duration bouts of exercise (e.g. continuous circuit training or those involving prolonged periods of running (or other cardio modes).
• Muscular endurance exercise training increases myoglobin content in muscles (a protein that carries and stores oxygen in muscle cells). This is thought to increase the oxygen reserve in the muscle allowing for increased work capacity (Kamga, Krishnamurthy and Shiva, 2012).
• Muscular endurance exercise increases mitochondria content (energy powerhouses of muscle cells) per area of muscle, increasing the amount of energy available to the muscle and thus enabling the muscle to keep up with the demands of muscle for longer periods (Kamga, Krishnamurthy and Shiva, 2012).
• Schoenfield et al (2014) conducted a meta-analysis on muscular adaptations in low-versus high-load resistance training and found that even though there was a trend towards greater strength and hypertrophy outcomes with high load (strength) approaches, resistance training with higher repetitions and loads less than or equal to 50% of 1RM still promoted substantial increases in muscle strength and hypertrophy in untrained individuals which supports the use of muscular endurance resistance training in the early stages of resistance training. The mechanisms behind strength and hypertrophy adaptations in muscle will be covered in the coming topics.

While it appears that muscular endurance training can lead to significant improvements in strength and hypertrophy in untrained individuals, it appears that resistance training with high loads, may not return the favour. A recent review of the literature by Schoenfield et al (2021) reported mixed results from studies across the last 20 years. Early research indicated that heavy resistance training did not come close to improving muscular endurance when compared with high repetition low-load training. The authors, however, thought the available research was a little weak and seemed to relate more closely to lower-body exercises than upper-body exercises (which seemed to elicit equal/more muscular endurance benefit from medium loads and hypertrophy repetition ranges than high or low loads). While the authors said the research trended towards low load, higher repetition training for muscular endurance improvement, they agreed that more quality research is needed in this area before current protocols for muscular endurance are adapted.

Another excellent point raised by Schoenfield et al (2021) was that there have been very limited studies carried out on females on this topic despite plenty of anecdotal evidence that females exhibit greater muscular endurance than males, particularly in the lower limbs. Let’s find out what the research suggests.

Sex disparities in muscular endurance

Have you ever noticed that some females have fantastic endurance in some exercises (particularly high repetition lower body exercises or isometric holds) compared to males? Males and females differ in anatomy and physiology, which results in marked sex differences in neuromuscular performance and fatigability.

In general, the skeletal muscles of males are larger and stronger than in females. Male muscles appear to possess a greater proportional area of metabolically and functionally faster muscle fibres (Type II) than females. But do female's muscles resist fatigue better than males when put through comparable levels and types of work? A review of research in this area conducted by Hunter (2014) suggested that sex differences related to muscle fatigue were “task-specific”.

The following are the key findings reported in their review:

Single limb isometric contractions

There can be large sex differences in muscle fatigue for isometric fatiguing contractions, especially for some muscle groups. In general, females are less fatigable than males for isometric sustained and intermittent contractions performed at the same relative intensity for several muscle groups (mainly muscles of the lower limbs, hands, elbows, and lower back).

Isotonic contractions

Females were less fatigable than males when performing repetitions of exercise at matched speeds and relative intensity. This was backed up by the findings that these differences were more obvious at lower loads (50% 1RM) and diminished as the load was increased through to 1RM loads. There were also no apparent differences between male and female time to fatigue when subjects were instructed to contract as quickly as possible.

Lengthening (eccentric contractions)

No apparent sex differences were noted, however, females exhibited greater losses in force production across eccentric trials. The authors couldn’t determine whether this was fatigue, or a difference in pain response and a difference in the way the sexes respond to muscular pain. Lower pain thresholds in individuals, however, may affect the brain’s willingness to engage the muscle in further efforts.

The research provides explanations for these differences. It seems that muscle contractile mechanisms primarily contribute to variations in fatigue rates. However, it's worth noting that other factors, including muscle perfusion and voluntary activation, may also play a role.

The following are the key findings of a study by Hunter (2016):

• Larger muscle mass and strength (males) can play a primary role in limiting blood supply faster in males than females during low to moderate-force sustained isometric contractions performed at the same intensity. This is thought to be due to greater intramuscular pressures exerted on the main arteries feeding the muscle blood, which leads to reduced blood flow and reductions in oxygen perfusion into muscle cells and an increase in waste build-up (CO2) leading to faster fatigue in males.
• During isotonic contractions muscle perfusion appears less affected in males, so other mechanisms are primarily responsible for sex differences in fatigue including differences in muscle metabolism and contractile function along with the ability to voluntarily activate motor units as contractions go on. For example, females exhibit less fatigability in lower limb isometric exercises due to males having greater loss of voluntary activation (i.e. they can’t voluntarily contract as many motor units in the muscle as the contractions continue). This lack of ability to voluntarily contract motor units is thought to be linked to a greater build-up of exercise waste within the muscle (explained in detail in the next point).
• There are differences in fuel use during endurance sessions between males and females. Females tend to burn more fat and less carbohydrate and amino acids than males during similar-intensity muscular endurance activity. This is thought to be due to sex differences within skeletal muscle. Males have greater storage capacity for glycogen (carbohydrate) within their muscles, whereas females have greater oxidative capacity within the whole muscle than males. While the percentage (number) of fibre types are not dramatically different between males and females, females have smaller fast twitch fibres, so have a greater relative area of slow twitch fibres (thus increased aerobic capacity across the muscle). Because slow twitch fibres have greater fatigue resistance this is thought to play a role. It may also explain why the difference in fatigue rates between sexes diminished when the speed of contraction was increased.
• Another interesting (but yet unexplained) finding from a study mentioned by Hunter (2016) was that the fatigue resistance of females worsened when another cognitive task was introduced during an isometric hold. The study found that when given a complex question to solve females exhibited a reduction in their ability to maintain the contraction, whereas it had a very limited effect on the fatigue rate of males.
• The female ability to outlast males in certain forms of exercise also isn’t dramatically altered across the menstrual cycle despite changes to fuel use, hormonal changes etc. Any differences noted were insignificant when compared to the larger differences in sex

Muscular endurance and age

Aging often results in a decline of most physiological systems of the body. We are an aging population, so it is critical that our aging population maintain some appropriate level of neuromuscular function into old age, so that they can maintain normal daily activities and a level of independence.

It is well-documented that muscular strength and fibre size diminish with age (sarcopenia). This is thought to be due to muscle loss (atrophy) and issues with neuromuscular connection.

See the following image that depicts how muscle can diminish with age.

Tieland, Trouwburst and Clark (2017) explored the effects of aging and skeletal muscle and made the following conclusions about the effect of age on muscular endurance:

• It is clear from the research that aerobic capacity or the ability to meet the needs of contracting muscle reduces with age by up to 20% per decade in our later years. About 10% of this decline is thought to be the result of age-related changes to skeletal muscle (the other 10% is due to getting oxygen into the body through the respiratory system).
• Muscles examined in older populations exhibit less mitochondrial volume and also reduced mitochondrial function (i.e. they produce less ATP). It was thought that the reduction in ATP production, along with reduced oxygen delivery and a reduction in muscle tissue (atrophy) all contribute to a reduction in muscular endurance in older clients. Siparsky et al (2014) backs up Tieland, Trouwburst and Clark (2017) in suggesting that muscular endurance capacity declines about 10% per decade in later years.
• It would appear that the smaller the muscle group, the more noticeable the reduction in muscular endurance. It also appears to be type 2 fibres that have the most dramatic reduction in muscle, which might explain that while there is a 27% reduction in muscle strength per decade after age 70, muscular endurance only drops by around 10% a decade as type 1 fibres degrade more slowly.
• Hunter (2016) also reports that the sex differences afforded to females in relation to muscular endurance diminish with age.

Fitness testing for muscular endurance is simple by definition. Essentially muscular endurance is a test of how many repetitions of a given exercise you can do before fatigue forces you to stop. Isometric muscular endurance is equally as simple. How long can you perform a given muscular contraction before fatigue forces you to stop? Another measure often used in muscular endurance testing is the number of repetitions you can do in a set timeframe (usually 1 minute). There are a wide variety of different muscular endurance tests for different areas of the body.

Regardless of the test chosen, the most important parts of any fitness test are standardisation and repeatability. Standardisation in this instance does not refer to how well a given test works, or whether it is a well-known test, but rather how well the test is conducted by the trainer. Repeatability requires recording specific elements relating to the test conditions and how (specifically) the test was conducted so that it can be repeated in the same way when it comes time to re-test. Unless you ensure a test is conducted in the proper manner, and it is conducted the same way each time, testing is ultimately pointless. Ensuring tests are standardised and repeatable ensures the validity of test results.

There are a number of considerations you must make before choosing any test.

Note: The following information applies to any fitness tests, not just that of muscular endurance.

Considerations when choosing fitness tests for clients

First and foremost, ensure the test is relevant to the client’s goals. If the goals are general in nature, then a selection of tests from the upper, core and lower body is best practice. In terms of standardising the test conditions there are key considerations you should make:

Scheduling of tests

Testing should be performed at particular times that correspond to the aims of the tests. For example, you may wish to test at the beginning of certain phases of training, and then at regular intervals to monitor progress. Wherever possible try to schedule re-testing at similar times of the day/week as the original tests.

Nutritional preparation

Ensure clients are well nourished on the day of testing. Where possible, instruct them to consume a high-carbohydrate meal in the hours leading up to the testing session (such as pasta, potatoes, cereals, toast, fruit, etc.). In the two hours before completing the tests tell them not to consume a heavy meal; however, they are strongly advised to have eaten some food in the four hours preceding testing.

Caffeine products (such as coffee, cola or tea) should be avoided on the day of testing as they can dehydrate. For optimal results alcoholic beverages and tobacco products should be avoided 24 hours prior to testing.

Ensure the client is fully hydrated, particularly in hot conditions. Instruct them to drink regularly in the days leading up to testing, particularly in the 12 hours prior to testing. Remind them to top up body fluids by drinking water regularly throughout the testing session. Continue to consume adequate fluids following exercise to replace any fluids lost during testing.

Physical preparation

When preparing for testing, it's essential to advise clients to take certain steps to ensure accurate results:

Exercise Timing: Recommend avoiding heavy strenuous exercise within the 24 hours leading up to the test. This period of rest can help ensure their bodies are in an optimal state for evaluation.

Testing Day: Emphasise the importance of refraining from any exercise on the actual day of testing. A complete day of rest can further ensure that clients are well-rested and physically ready for accurate assessments.

In addition, it's crucial to advise clients to wear suitable clothing considering the prevailing conditions. Furthermore, clients should not engage in testing if they have any injuries or illnesses that could potentially worsen due to their participation.

The warm-up

Prior to any fitness assessment, it is important to have the body prepared by following a warm-up procedure. The procedure should be standardized so that if the test is repeated, the same warm-up can be repeated to help maintain consistency with the results. The actual warm-up conducted will depend on the test being performed. Regardless of the test to come, a good warm-up should last between 5-10 minutes and contain the following components:

See the following example of a warm-up for a full-body muscular endurance workout:

Test sequencing (order)

If your testing session involves multiple tests targeting different goals, then the order in which the fitness tests are performed can affect performance in subsequent tests. Here are some guidelines when deciding on what order to conduct the test. Note: These guidelines are most relevant for a full barrage of tests on a testing day. It would be highly recommended to break up tests across multiple days if possible.

Pre-warm-up assessments

1. Health Checks:
   Begin with blood pressure and resting heart rate assessments. These tests should be conducted while the individual is fully rested, meaning before initiating the warm-up routine.
2. Anthropometry: Following the health checks, proceed to measure body composition. This assessment should always be the immediate next step after completing any health checks.
3. Flexibility: Schedule flexibility assessments early in the session, before engaging in any physical activity.

Post-warm-up assessments

1. Speed/Power Tests
   Initiate testing with power assessments, as they demand full muscle activation. Performing other fatiguing tests beforehand can limit the individual's ability to generate absolute power.
2. Muscle Strength: After power tests, proceed to muscle strength tests (1-10RM). These strength assessments should be completed before moving on to muscle endurance tests.
3. Muscular Endurance: Following muscle strength assessments, allow for a minimum break of five minutes before conducting muscle endurance tests. If multiple muscular strength and endurance tests are part of the session, ensure ample recovery time is provided between individual tests.
4. Aerobic/Anaerobic Fitness: Consider the heart rate response when scheduling submaximal aerobic tests, as they may be influenced by prior tests and the athlete's mental state. Reserve fatiguing maximal exercise tests, such as VO2max or beep tests, and repeat sprint tests for the end of the session to minimize their impact on subsequent assessments. If both a repeat sprint test and a maximal aerobic test are on the agenda, it's advisable to conduct them in separate sessions for optimal accuracy.

Test standardisation: Control the controllable

The more parts of the fitness testing process you are able to control, the more standardised the test will be and the more reliable the results. The worst-case scenario for a personal trainer is a client whose results get worse after a period of training with you! In reality, a period of sustained training will almost certainly produce results, but if you don’t standardise the test process, you may find a client doesn’t perform as well as they could, e.g. if a client has not eaten or hydrated well leading up to the test, this could have a marked effect on their test performance. Here are the things that are important to try and control:

• Day and time of day (controllable).
• Temperature and environment (uncontrollable in some cases).
• Location and equipment used (controllable).
• The order of the tests performed (controllable).
• The warm-up – activities and order and duration (controllable).
• Nutritional status of the client (hard for you to control if the client isn’t on board).

Using established tests for client comparison

You don't have to use a well-established test with normative data. Normative data is valuable primarily for clients interested in comparing themselves to others in their age and sex group. Fitness tests prioritise personal improvement, so the most significant gauge is how much the client progresses individually.

Muscular endurance tests can use any exercise and approach you like as long as they are performed to failure (or loss of form) and completed under the same conditions. By not using an established test with normative data, it gives you the freedom to tailor the test for different client abilities, for example, new clients may not be able to complete full push-ups but could manage a number of incline push-ups.

Common muscular endurance fitness tests

The only way to truly understand each of these tests and be proficient in their application is to practice them. Some of these you can try yourself, and others you should practice on a willing client.

Repetition tests

For these tests, it is important to establish what constitutes a full repetition and be consistent with this. For example, as people tire, they generally get sloppy with their form and perform some incomplete repetitions. Examples of these include but are not limited to:

• Not achieving correct depth in movement, e.g., a squat, lunge, or push-up.
• Not fully extending at the top of the movement, e.g., a squat, push-up, or shoulder press.
• Not leaving the ground in a movement involving jumping (e.g., a burpee).
• Not clearing the bar with your chin during a pull-up, chin-up, etc.

It is important that you establish and clearly explain the test protocol to the client and give a full and detailed explanation (including demonstration) of what constitutes a repetition. You must also decide when the test will be stopped. For example, will you simply not count partial repetitions but allow the client to keep trying until they completely give up, or do you allow one failed repetition and then end the test on the next incomplete repetition? Additionally, is a client allowed to pause (rest) and then continue, or does the test need to be completed in one continuous effort? These decisions are yours to make but must be noted for replication in the re-test.

Maximum repetition tests

These tests can be done using any exercise. They are often bodyweight tests but could also be used for any weighted exercise using a 50% 1RM load. For general fitness improvement, it is best to perform multi-joint exercises targeting different areas of the body. These tests are designed to be completed in one continuous effort. The most common maximal tests for muscular endurance include:

• Max push-ups: Helpful to use a tennis ball or similar under the chest to help achieve consistent depth. Can use regressions such as knee push-ups or elevated push-ups.
• Max Pull-ups: Chin must reach above the bar and full extension of arms at the bottom of the movement (can be regressed by using band assistance or an assisted pull-up machine – note colour of band used or weight used).
• Max sit-ups: Need a reference point for trunk verticality at the top of the movement. No holding of the client’s feet.  (e.g. the standard for a butterfly sit-up test is to touch the floor behind your head at the bottom of the movement and to touch the floor in front of your toes at the top of the movement).
• Max weighted exercises: This can be done for any exercise with a resistance level of approximately 50% of 1RM. These tests are best performed on a machine (or using a rack with spotters) as the idea is to fail. Common exercises to test endurance on include:
  • Bench press.
  • Leg press.
  • Seated barbell shoulder press.
  • Lat pull down.
  • Barbell squat.
  • Seated row.

Repetitions in one-minute tests

Essentially the same as those tests listed above, but the idea is to perform as many repetitions as possible in one minute. Great to use for general population clients as most novices will fatigue well inside a minute. With these tests, clients can take a short rest when they need to and then complete more repetitions.

Cadence tests

There are a number of muscular tests that involve using a set cadence. These tests set a particular rhythm for repetition phases (emitting a tone for up and down phases). Common cadence tests include:

• Cadence pull-up test.
• Bench press cadence test.
• Partial curl test or curl-up beep test (for abdominals).

For valid, accurate and consistent testing it is best to use a metronome for these tests. 60 beats per minute (BPM) is a standard cadence. There are many metronome apps (mostly free) and even a YouTube clip like the following can work well.

Isometric holds for time

These tests are all about maintaining a position for as long as you can. These tests also need clear parameters set for when a test ends. Usual approaches are to give a singular warning for lost form and then cancel the test at the next loss of form. Measurements can be used to standardise these tests further (i.e., a measure from the floor to wall squat depth, a measure from elbow to toes for prone hold, etc.). Common isometric hold tests include:

• Dead hang.
• Flexed arm hang (90 degrees at the elbow or hold the top of the full chin up).
• Prone hold.
• Side hold.
• Wall sit.
• Dish hold.

Session Plan Templates

Every session plan you write should look professional and include all of the relevant information required for another trainer (or client) to deliver the session in your absence. We encourage you to use the following session plan template.

This editable document can be downloaded and saved onto your computer. You are welcome to adapt this template any way you need to suit your session plan approach, or you are welcome to develop your own template (to the same standard).

See the following blank template you can use:
Session Plan Template

See the following completed template as an example you can refer to:
Session Plan Template- Completed Example

Muscular endurance training is obviously a physical pursuit and fatigue is certainly due to the muscular demands of the exercise, but just as much as exercise is physical, it is also mental (particularly when the purpose of the exercise is repeated effort over time). Improving muscular endurance is all about pushing your limits of endurance, establishing new thresholds for exercise, and striving for peak performance, but what role does your mental state play in your ability to do this?

Fatigue is the inability to maintain a given exercise intensity. Pushing through fatigue during a workout is where you grow mental toughness, but it also comes with risk (like injury). This is why trainers sometimes err on the side of caution when it comes to pushing their clients. Trainers need to be able to read their clients and tailor the intensity of the workout to suit them. While this obviously gets easier the longer you work with a client, this is not simply guesswork in the early stages of a client/trainer relationship!

Rating of perceived exertion vs scientific measures

Rating of Perceived Exertion (RPE) is essentially a client’s perceived effort. The effectiveness of new clients in achieving a balance tends to be limited. This situation can manifest in two ways: clients might either exert excessive effort too soon, leading to early fatigue and the need to cease exercise, or they might not exert themselves sufficiently to achieve their desired fitness gains. Best (2019) describes RPE as “the little voice inside your head that either tells you to give up or keep going” when the going gets tough. A client’s drive to continue is a direct result of their perception of the effort required to complete an exercise and the perceived value of the reward that the completion of the activity will bring them. This is difficult for new clients to understand as they have not yet seen any results from the exercise they have done. This is why clients new to exercise give up easily when it gets tough. This makes it hard for a trainer to distinguish between a lack of effort and real physical fatigue.

An essential tool in working out how hard a client is pushing themselves is their heart rate. Having your client hooked up to a heart rate monitor and asking some questions of them to ascertain their RPE will go a long way to knowing how good your client is at determining their effort level during exercise. I f the client believes they are too fatigued to continue, even when their heart rate indicates otherwise, it raises a significant consideration. The problem is fatigue is multi-dimensional. It is not simply the inability of the body to keep up with the demands of working muscles, but also the nervous system’s willingness to do so.

Mental fatigue

It’s not only your body that has limits, but your mind does too. Best (2019) describes mental fatigue as “a psychological perspective of perceived and actual performance during exercise”. It can be used for good by increasing perceived effort to complete a heavy lift, run or workout, whereas it can also be used against the client who perceives the effort (or discomfort) not to be worth the reward. Mental fatigue can inhibit a client’s actions during exercise, by increasing perceived exertion and activating inhibiting factors involved in muscle contraction. It can also facilitate a client’s actions by increasing exercise effort towards a reward and deactivating inhibiting factors involved in muscle contraction (Best, 2019).

Right, time to apply what you have learned. Head to your assessment for an assessment guide video and instructions on submitting your assessments.

The assessment guide video explains your assessment task, which requires you to use the information you have learned on this topic to help a case study client.

This assessment will require you to apply the knowledge you have learned and practised by completing the following tasks:

• Design a Muscular Endurance programme for an Athlete
• Justify your selection of programme variables (e.g. modality of training, exercise selection, sets, reps, rest etc.)
• Design a progressed programme for the end of the mesocycle
• Justify the changes you implement to the progressed programme
• Select a relevant fitness test to test this fitness component.