Knowing how to pick the right weight and how heavy you should lift in your workout is difficult, especially if you're just starting with strength training for beginners or dipping a toe into weightlifting or resistance training for the first time. It's the next big decision after you've decided which kind of weight to go for (kettlebells, dumbbells, barbells and medicine balls, to name a few), and getting it right could be the difference between an epic and 'meh' gym workout.
Plump for too heavy a weight and you run the risk of injuring yourself. Go too light and your muscles won't be properly fatigued, grow muscle or build new tissue. Even seasoned lifters need to assess their choice of weight depending on what they're trying to achieve in their workout, but don't worry if you haven't got a scooby where to start - we're here to help...
How to choose the right weight by your goal
Choosing the right weight for a workout is important because it'll have a direct impact on a) your workout and b) whether you achieve the goals you set for yourself.
'Strength training [exercising with weights] is a method of training that helps you increase your muscular strength and build muscle mass and can use many different types of training,' explains Yumi Nutrition's Kate Whapples, a strength and conditioning coach. 'The goal of strength training is to provide a stimulus to the body that requires an adaption response.'
Generally speaking, there are three adaptations that can be achieved:
- Improved endurance (how long your muscles can work for until they reach fatigue)
- Increased strength (how much load you can lift)
- Muscle tissue breakdown and subsequent growth – this is known as hypertrophy
If you're choosing between one of these as your goal, there are handy formulas to use, incorporating both specific weights and the number of reps/sets you do. Here's a general guide:
How heavy your weight should be: Light (so that you can feasibly do more reps without compromising on form)
Reps/sets: 10-14 reps per set, 2-3 sets
How heavy your weight should be: Moderately heavy (a challenging weight that allows you to do more sets but fewer reps per set)
Reps/sets: 6-10 reps, 3-6 sets
How heavy your weight should be: Heavy (your max weight that allows you to do more sets but fewer reps per set)
Reps/sets: 4-6 reps, 2 or fewer sets
We know the 'lighter' and 'heavier' weight recommendations are very vague, but it really does depend on the individual, their experience, and their build, so it wouldn't be wise of us (or useful for you) if we were to specify weight ranges. That said, most workout plans will include a specific weight range or, at least, give you an indication of the right weight with how many reps you're being asked to complete.
How to check you've picked the right weight
An easy way to test is to try a couple of reps using a weight you think is appropriate. If it feels too light or too heavy, adjust accordingly. Saying that, you should be able to maintain good form for all reps – e.g. don't opt for an 8kg dumbbell because you can curl it for three decent reps but everything after that is a bit skewiff.
'By the last rep in any set you should really be struggling, this ensures 'that you fatigue the muscle fully, resulting in your body adapting and becoming stronger to be able to perform the task you ask of it,' says Kate Maxey, strength and conditioning Master Trainer at Third Space, London.
Pick a weight that makes the last couple reps of a set challenging but not impossible. We're trying to fatigue your muscles, not inflate your ego.
How to choose the right weight by exercise
When to use lighter weights
Core exercises require a lighter weight, especially when you're starting out. If you try to jackknife or leg raise with a weight that's too heavy, you'll end up recruiting muscles in your back and neck, instead. Not good. (If you're doing core exercises for beginners, think about ditching the weight altogether and getting the technique down pat, first.)
Equally, exercises that ask you to raise your arms above your shoulders like most tricep exercises, shoulder presses, and straight-arm pulses will need to be light enough that you can keep your core aligned throughout.
When to use a medium weight
Full-body workouts and exercises will likely split the difference and call for a medium weight. This is because you can call on your core stabiliser muscles to keep you strong whilst working the lower and upper body together. (Think weighted lunges or squats.)
When to use a heavier weight
Moves that are less explosive and recruit your biggest muscle groups require heavier weights to be effective. You want to feel the work from the very first rep. This is because the muscles in your lower body are some of the strongest and largest in your body. To properly fatigue them (and stimulate changes in endurance, strength or muscle growth) requires heavier loads. Think deadlifts and squat variations.
How to know if you're using the right weight for your workout
One of the simplest ways to be sure you have the right weight for a workout is by asking yourself the following questions:
- Can I feel the weight?
- Can I move through this exercise with good form?
- Will I be able to keep good form in every rep?
- Will I be able to complete all the sets?
- Do I feel like I’m being challenged?
For different exercises in your training plan, you will be given a weight suggestion of light, moderate or heavy. Now, how light or how heavy you go changes from person to person because of existing strength levels and exercise experience.
That said, here is a guideline for each of these weight categories, depending on where you gauge your ability.
If you're new to workouts and the weights area
- Barbell: 12kg – light, 16kg – medium, 18kg – heavy
- Dumbbells: between 2 and 10kg
- Medicine ball: between 4 and 6kg
- Kettlebell: between 4 and 12kg
If you have base strength thanks to regular cardio and bodyweight training
- Barbell: 14kg – light, 18kg – medium, 20kg – heavy
- Dumbbells: between 4 and 10kg (7kg dumbbells are a great place to challenge without discomfort)
- Medicine ball: between 6 and 8kg
- Kettlebell: between 6 and 14kg
If you can already squat your own bodyweight (or close)
- Barbell: 20kg – light, 30kg – medium, 50kg – heavy
- Dumbbells: between 6 and 10kg
- Medicine ball: between 6 and 10kg
- Kettlebell: between 8 and 18kg