Man lifting a barbell doing a strength and muscle workout

Build a big, strong and lean body by learning how the 7 key training variables combine to create the perfect muscle-building workout

Your gym weight training workouts are determined by a number of different elements, better known as training variables. We’ll go into each one in more detail shortly, but here are the seven key variables used in all (good) training programmes, all of which have an effect on the training stimulus you place upon your muscles: exercise selection; exercise order; sets; reps; tempo; rest period; and weight selection.

It’s progressive changes to these gym weight training variables each week, and in each of the four blocks of your plan, that makes each session that little bit harder so you keep making progress and get to the finish line looking and feeling better than ever!

The 7 gym weight training variables

1: Exercise selection The different lifts you perform in a workout, which determines which muscles you train in that session
2: Exercise order The order in which you perform the exercises in as workout
3: Sets The number of times you perform a group of reps
4: Reps The number of times you perform an exercise without stopping for rest
5: Tempo The speed at which you perform a rep
6: Rest The time you have to recover between sets and exercises
7: Weight The amount of resistance you lift for each rep of each set

Progressive overload

The most obvious variable that changes from workout to workout is exercise selection, because the moves you do is what determines which muscle groups get worked. Weight is another important variable to change – ideally you will use slightly heavier weights for the same move with each passing week – because the key to building your best-ever body is to keep pushing your muscles harder as you get fitter and stronger to elicit even better results.

However, all seven variables are important and have a big role to play in the success of your transformation because they are all inter-linked, and the setting for one variable has a direct impact on the others.

For example, the number of reps in a set will determine how heavy a weight you can lift: a very high-rep set of 12 or 15 reps means you’ll need to select a much lighter weight than if doing a set of 5 reps. Similarly, a tempo of 2011 means you’ll need to go lighter than when doing 1010, because slower reps take longer to do and place more tension on your muscles, which will fatigue them faster. And a short rest period between sets means you can’t lift as heavy, because your muscles don’t have enough time to fully recover. Here’s how these seven key variables work, and why each one is so important.

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1 Exercise selection

The exercises you perform determine the muscle group or groups that get worked in that session, and in your plan the first three sessions of each week use one of the following approaches.

The first is an exercise selection strategy that combines “complementary” exercises, which is when different muscle groups move in similar ways, such as in a chest and triceps workout, where the main movement pattern is a “pushing” action, because you’re pushing the weight away from you. Another classic example is a back and biceps combination, because the movement pattern is a “pulling” action, where you’re pulling the weight towards you.

A second exercise selection strategy combines “antagonistic” exercises that work opposing muscle groups, such as in a chest and back session, or unrelated muscles groups, such as in a legs and shoulders session. Both of these approaches are effective in working multiple muscle groups hard in a time-efficient fashion to force your body into making positive adaptations fast.

Another approach, which is utilised in the fourth and final session of each week during the New Body Plan eight-week training programme, is to focus  your training time on a single muscle group to help you achieve specific and personalised body-part goals.

2 Exercise Order

The order in which you perform the exercises is important because it has an impact on the training stimulus you place upon on your muscles, and your body. Exercises can be performed individually in straight sets, in pairs in a superset, or in a group of three in a triset (or in groups of four or four moves, which are called giant sets), with each set strategy having a different impact on your muscles, and therefore your results.

3 Sets

A set is the number of reps you do in succession without stopping, and three of the most common set strategies are straight sets, supersets and trisets.

Straight sets

With straight sets you do all the sets of the first exercise, numbered exercise 1, then move on to exercise 2, and follow this pattern until you’ve done all the sets of the final lift of the session, at which point the workout is finished. Straight sets allow you to lift the heaviest weights, because you can focus on one exercise at a time, and typically get more rest between sets.


In a superset you do a set of the first exercise, called the A move, then a set of the second exercise, called the B move. There may or may not be a rest period between the A and B moves, but there is almost always rest after the B move before you return to the A move and repeat the superset. Once you’ve done all the sets of both the A and B moves the superset is completed. You may have to lift lighter weights in supersets, especially for the B exercise, than when doing either the A or B move as a straight set, because there’s typically less recovery time between exercises and sets to fatigue your muscles faster.


In a triset you do a set of the first exercise, called the A move, then a set of the second exercise, the B move, then a set of the third exercise, the C move. There may or may not be a rest period between the A and B moves, or the B and C moves, but there is almost always rest after the C move before you return to the A move and repeat the triset. Once you’ve done all the sets of all the moves the triset is completed. You may have to lift lighter weights in trisets, especially for the B and C exercises, than when doing each move as a straight set, because trisets are designed to fatigue the working muscles thoroughly, so you typically don’t get much time to recover between exercises.

4 Reps

Short for repetition, a rep is the completion of a given exercise through its entire range of motion from the start (or top) position to the end (or bottom) position and back to the start again. Your target number of reps per set has a huge influence on your weight selection, because too heavy a weight means you won’t be able to do all the reps, or at the stated tempo.

As a general rule, lower rep-sets (under five) done with heavy weights build strength or power, while rep-counts in the eight to 12 range are geared towards building muscle, known as hypertrophy. Sets with more than 12 reps, or those that you perform “To failure”, which indicates you do as many reps as you can before your form breaks down, or your muscles reach complete fatigue – improve muscular endurance, but also have a role to play in hypertrophy because they fatigue a lot of muscle fibres.

1 to 5 reps
Training aim: Increasing muscle strength and power
Weight: 85-100% of your one-rep max for the lift
Muscle response: Low-rep sets of heavy weights build strength and power because they recruit and fatigue your fast-twitch muscles fibres, which are responsible for your muscles’ explosiveness. This rep range also improves the communication pathway between your brain and muscles, which helps them contract faster and with more force to make them stronger and more powerful.

6 to 7 reps
Training aim: Optimal compromise between increasing muscle strength and size
Weight: 75-85% of your one-rep max
Muscle response: Sets in this rep range will still work your fast-twitch muscle fibres and improve the mind-to-muscle communication connection, but performing more reps will also fatigue more muscle fibres more thoroughly to result in improvements in both size and strength.

8 to 12 reps
Training aim: Increasing muscle size and improved strength
Weight: 65-75% of your one-rep max
Muscle response: The most effective approach to build lean muscle is for each set to last between 40 and 70 seconds, and sets in this rep range – when done using a controlled tempo – will allow you to hit this time target with a weight that is heavy enough to fatigue the muscles thoroughly, but not so heavy that you can’t do all the reps, or maintain correct form.

13+ reps
Training aim: Increasing muscle endurance and improved size
Weight: 60-65% of your one-rep max
Muscle response: Using lighter weights combined with a high rep range recruits and fatigues your slow-twitch muscle fibres, which are primarily responsible for muscular endurance. Sets in this rep range also improve the ability of these fibres to deal with a build-up of lactic acid and other waste products that accumulate during lifting, which are responsible for that “muscle burn” feeling. These sets also drive a lot of blood into the muscle, making it swell up and cause a muscle “pump”, so also have a role in increasing muscular size.

5 Tempo

Tempo is the speed at which you lift and lower the weight for each rep. It is often the most neglected training variable, but it’s one you can’t afford to ignore if you’re determined to build a better body. The more time you take performing each rep the harder your muscles must work to manage and control the load. This period of muscle workload is called “time under tension”.

The longer the time under tension, the greater the damage done to your muscle fibres, which your body must then repair and rebuild, which creates bigger and stronger muscles. Another benefit of using tempo correctly is injury prevention: slow and controlled reps keep the tension on the working muscles, whereas fast, explosive or uncontrolled reps can shift the stress to your joints and connective tissues, such as ligaments and tendons, which can result in injury.

To know how quickly you should perform each rep, every exercise in your plan is given a four-digit number, which you’ll find listed in each session’s workout table, alongside sets, reps and rest. Here’s what that four-digit code means:

• The first number the time in seconds you lower the weight
• The second number the time in seconds you pause in the bottom position
• The third number the time in seconds you lift the weight back up
• The fourth number the time in seconds you pause in the top position

In the example of a dumbbell bench press with a tempo of 2010, you will lower the weights down to your chest (the bottom position) in two seconds with no pause at the bottom, then press it back up in one second (to the top position), with no pause at the top.

For a dumbbell biceps curl with a tempo of 2011, you will lower the weights down in two seconds, with no pause at the bottom, then lift it back up in one second, with a once second hold in the top position where you squeeze your biceps hard.

For exercises with a tempo of X, this simply means you perform the rep explosively, so as quickly as you can whilst maintaining correct form.

6 Rest Period

Rest is the amount of time in seconds you rest between sets and exercises. The duration of your rest periods influences the efficiency, safety and effectiveness of your workouts, because when you lift weights you push your muscles out of their comfort zone to stimulate your body to grow them back bigger and stronger. But there’s only so much work they can do before the muscles’ energy stores are depleted, hampering their ability to do additional reps with good form. Resting for a predetermined amount of time allows your body to refuel your muscles so they can start lifting again.

Not resting for long enough between sets and exercises means your muscles don’t have the time to recover enough to perform the next set or hit the rep target, whereas too much rest means you lose your training focus and fail to stay in “the zone”. You’ll therefore fail to place a sufficient stimulus on the muscles to force the growth response you want. In some supersets and trisets there is deliberately zero rest between exercises, because the aim is to fatigue as many muscle fibres as possible to shock your muscles into growing back bigger and stronger.

7 Weight Selection

The weight is the amount of resistance you use to perform an exercise, and it goes without saying that the weight you select for each move has a big impact on your results. As a general rule, the weight should be heavy enough to make you really work for those final few reps of each set, without compromising your form. Here’s everything you need to know about how to pick the perfect weight for each exercise.

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