We’ve all heard the argument in the weights room. The powerlifter who swears that anything over six reps is cardio, or the bodybuilder who is terrified of losing his gains if he ventures out of the ‘hypertrophy zone’.
These are just some of the misconceptions that abound when it comes to load selection and rep ranges. But, most of the time, the primary consideration should be finding what gives you the greatest enjoyment and allows you to perform consistently with minimal injury.
So, is heavier always better? Read on for everything you need to know to maximise your results, whatever your goal.
Do I need to lift specific weights for my goals?
Misconceptions about lifting different weights for different goals stem from the ‘strength-endurance continuum’ theory.
The idea is that rep ranges and load selection can be manipulated to achieve different outcomes, such as muscular strength, power, hypertrophy or endurance[1],[2].
The premise of this theory relies on the intensity of load and one-rep max testing, which measures the percentage of the maximum load you can use for good form for one repetition in an exercise. We can calculate recommended loads within different rep ranges based on this total.
The strength-endurance continuum presupposes that each loading zone creates a specific outcome and is incapable of producing results outside this scope[3],[4]. That is to say, if you want to get stronger, lifting anything over eight repetitions will be counterproductive to that goal. Likewise, if your goal is muscle growth, you should only train within the 9-12 rep range.
The strength-endurance continuum specifies that each loading zone corresponds to a percentage of your one-rep max for that exercise.
What does the science say?
1. If maximal strength is your goal, the weight you use is most important
If your goal is to become a champion powerlifter or improve the absolute maximum you can lift, the loading zone matters. One of the fundamental principles governing load selection is the principle of specificity, also known as the SAID principle (Specific Adaptations to Imposed Demands). This principle specifies that training adaptations are specific to the training stimulus [5]. In simple terms, if you want to improve your skill at lifting heavy things, you need to lift heavy things more often.
2. Training volume is most important for both functional strength and hypertrophy
If your goal is to improve your general strength levels or increase your muscle mass, the research shows that training volume is one of the most important factors. Training represents the total work you perform in and across sessions (reps x sets x load). Studies of strength and hypertrophy interventions show that both have a linear relationship with training volume [6],[7]. However, it’s worth noting that both goals have a point of diminishing returns, so more volume is not always better.
Adapted from Helms, E., (2015). The Muscle and Strength Pyramid, pg.32.
3. Muscle hypertrophy occurs through several mechanisms
Muscle hypertrophy occurs through varying markers, including post-exercise elevations in anabolic hormones, intracellular signalling, and acute muscle protein synthesis. In all instances, the intensity of effort is the most important factor [8],[9],[10],[11],[12],[13],[14]. Intensity of effort measures how close you are to failure during an exercise.
Most studies show that when volume and subjective intensity are matched, the results for strength and hypertrophy are broadly similar [15]. For example, low loads have been shown to be ineffective at driving anabolic responses if individuals do not train to failure [16],[17]. But when effort levels are equated, low loads are just as effective as moderate and heavy loads [18].
What are the pros and cons of lifting heavy?
Now, you might be thinking, ‘but I like lifting heavy stuff!’ and lifting heavy is certainly not something we would ever discourage. However, when it comes to training in low-rep ranges, there are a few important factors to consider:
1. Heavy loading zones are not suitable for beginners
Strength is a skill, and it takes time to develop recruitment patterns before you can get stronger [19]. It’s very unlikely you’d be able to perform high-intensity training safely as a complete beginner. Likewise, low rep zones don’t provide the ‘practice’ to become skilled in that movement [20].
2. There are multiple ways to improve strength
While heavy loads are necessary for increasing maximal strength, improving overall (functional) strength can be achieved with higher repetitions, even up to 20 reps. Research indicates that these findings occur primarily in beginner trainees [21],[22],[23]. As you become more experienced, light loads also increase strength levels, although heavy loads remain superior [24],[25].
3. Training for maximal strength has limited carryover
The strength advantages of heavy load training don’t have a huge carryover to other exercises. Most research uses a small selection of exercises throughout the intervention. This means that the results will always bias heavy lifting as the intervention provides ‘practice’ to the trainees and means their performance in that exercise improves. However, when researchers test trainees’ strength using isometric force-measuring devices, the benefits of heavy load training vary significantly. For instance, a recent meta-analysis found that this was not significant while there was a slight advantage of heavy loads over light loads [26]. Elsewhere, the results are mixed; some studies show heavy loads to be most beneficial, others indicate light loads are better, and yet others show no difference [27],[28],[29],[30],[31].
4. Strength zone training can be time consuming
You need more time to recover between sets when training with heavy loads. The body requires time to recuperate energy sources such as ATP (adenosine triphosphate) and phosphocreatine, clear fatigue-producing substances, and restore force production [32],[33]. The length of the rest you need to sustain your performance depends on the magnitude of the load you use [34]. Rest of at least three minutes appears optimal for sustaining strength in both loading zones of 50% and 80% of 1RM [35]. But if you only have an hour to train, you may struggle to fit in a lot of work, especially if you also include additional sets required to warm up to heavier loads.
5. Training with heavy loads is highly fatiguing
Higher intensities also result in higher cumulative fatigue and overtraining [36]. Studies comparing three-rep-max loads with ten-rep max loads have found that mental burnout, joint pain and injury increase with heavier loads when volume is equated [37]. Strength is also a skill that takes time to develop. If you struggle to maintain correct form at high loads, you could be ingraining poor motor patterns, further increasing the risk of injury [38].
What is the best way to build muscle and strength with weights?
1. Focus most of your work on moderate load training
Any rep range and load will induce hypertrophy if volume is equated and you train close to failure [44]. However, the key to this is sustainability and longevity. Studies comparing three-rep max rep and ten-rep max rep schemes have found that moderate repetition workouts were more time-effective and resulted in less mental burnout and joint pain [45]. As a result, loading zones between 8-12 reps are likely to be easiest to adhere consistently for long enough to achieve significant results.
2. Get stronger overall
Increasing your overall strength allows you to increase your total training volume more easily (progressive overload). So, if hypertrophy is your goal, it’s a good idea to include some lower rep training too[46]. Undulating heavy and moderate loads during higher volume training phases is an effective way to experience the benefits of heavier loading zones while minimising the risk of overtraining and injury [47].
3. Work within a variety of rep ranges
There’s nothing magical about any of the rep ranges, and while the 8-12 rep range is said to be ‘ideal’ for hypertrophy, this is because it is best suited to accumulating training volume. But in conjunction with this, it is still useful to incorporate some work at lighter loads. This allows us to stimulate muscles with a high level of endurance, helps to ensure connective tissue health and offers a break from heavy training while maintaining a training stimulus [48].
4. Focus on intensity of effort, not load
Intensity of effort is most important when it comes to maximising your gains. While going all out on every set is likely to leave you feeling overtrained and decrease your total training volume [49], your final set is an opportunity to go hard. As a general rule, aim to leave a couple of reps in the tank in your initial sets and then aim for failure in your final set.
5. Increase the load only when you can do so without sacrificing form
While it’s important to push hard, it’s equally crucial to know when to pull back. Training beyond technical failure, i.e., when your form breaks down, increases the risk of injury and takes away tension from the target muscles [50]. Likewise, it may not always be a good idea to perform ‘the big lifts’ to failure as it may limit the amount of work you can perform in the rest of the session [51].
6. Make use of intensity techniques to maximise muscle activation.
It’s an unfortunate fact that you won’t be able to increase the load week on week. However, you can incorporate intensity techniques such as a rest-pause or mechanical drop sets on single-joint exercises to get every last drop out of the target muscle.
The take-home
If your goal is to improve your maximal strength, practice makes perfect. But, if your goal is to improve your functional strength or increase muscle growth, the focus should be ensuring that you generate progressive overload through increases in training volume. And while there are important considerations for all loading zones, working within all rep ranges helps increase overall strength, minimise injury and maximise overall adherence.
