Read time: 5 minutes

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The idea of lifting heavy things often goes hand-in-hand with resistance training.

But there’s a problem with this.

Because not everyone is a fan of big weights - nor busy gym environments either.

And these very factors prevent many from enjoying the benefits of resistance training.

Which is why you should know the amount of weight you lift matters far less than you might think.

In fact, some of the upsides of resistance training are comparable - and even superior - with lighter weights.

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Let’s talk about “load” in resistance training

By “load" we're talking about the weight lifted during an exercise.

This could be bodyweight alone, or added load with weights or resistance bands.

What’s most relevant is the relative load - or the weight lifted relative to the maximum possible (known as the one-repetition maximum or 1-RM).

The relative load can also be expressed as the maximum number of reps possible with a given weight (the repetition maximum or RM load).

So, what are “heavier” versus “lighter” loads in resistance training?

Here’s some common definitions based on RM and %1-RM:

• Low load (>15 RM or <60% of 1-RM)
• Moderate load (9-15 RM or 60%-79% of 1-RM)
• High load (≤8 RM or ≥80% of 1-RM)

So - why might ”load” be important in resistance training?

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Who cares about “load”, anyway?

Aside from those wanting to boast about lifting the heaviest, of course…

It’s no surprise the weight lifted impacts how many reps you can do - the higher the load, the less reps are possible.

But there’s more to it than that.

Lifting heavier means muscles need to produce more force.

We do this by sending stronger signals from the brain to the motor nerves latching onto muscle fibres.

The more force that’s needed, the greater the “drive” from the nervous system, and the more muscle fibres (including both smaller Type I and larger Type II fibres) get “recruited” to contribute.

This means with lighter loads, less muscle fibres are initially needed to produce the force required (unless there is maximal intent to move a light weight as fast as possible).

But as more reps are performed and muscle fibres become fatigued during a set, extra fibres are called into play.

So it’s possible to recruit a large proportion of your muscle fibres with heavy OR light weights.

The difference is, longer sets (more reps) may be needed to achieve this with lighter loads, and the signals from the nervous system may be lower than with higher-load training.

The question is: how does this all impact changes in strength or muscle mass?

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Does load matter for strength or power?

It’s commonly believed heavy weights are needed to maximise strength.

And to extent, this is true.

Heavier loads can lead to better strength gains, particularly when strength is measured in dynamic movements (like squats or bench press) included in a training program.

But here’s the thing:

When strength is tested using an unfamiliar movement (that wasn’t “practiced” during a training program), higher or lower loads promote similar strength gains.

This means some of the advantages of higher-load training may be due to its similarity to dynamic strength tests.

So lighter loads can improve strength - and the story is similar for muscle power, too.

Training with higher and lower loads promotes comparable muscle power gains (at least in older adults) - so long as there is intent to move the weight quickly.

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Do bigger weights equal bigger muscles?

The simple answer is no.

In fact there’s now ample evidence load matters little for building muscle.

This means lighter weights can be very effective for boosting your muscle mass.

But there is one caveat:

For lighter-load training, sets probably need to be taken closer to “failure” (where no more reps are possible) to build muscle.

This has its challenges - like higher levels of effort and discomfort - but shows heavy weights aren’t needed for muscle gains.

Here’s a summary of the advantages of high- and moderate-load training (versus lower-load training) for dynamic (1-RM) strength and muscle mass:

As you can see, higher-load training can further boost strength, but the same can’t be said for muscle growth.

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The case for lower-load resistance training

Given many are hesitant with big weights, it’s good to know lighter ones are enough to improve strength or power - and especially for building muscle.

But the benefits don’t stop there.

Lighter weights can also offset losses in muscle and strength during periods of reduced activity.

The metabolic health benefits of resistance training - like better glycaemic (blood glucose) control, and lower blood pressure and blood lipids - are similar with lighter and heavier weights, too.

Lighter-load training may also limit joint stresses that can be a issue for some, like those with osteoarthritis.

All-in-all, there’s a good case for including lower-load training as part of any well-rounded program.

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Lighter loads aren’t without their challenges

The lighter side of resistance training has many benefits.

But there’s a few caveats to consider, too.

Lifting lighter weights usually means longer sets (with more repetitions).

And lighter sets probably need to go closer to failure for similar muscle gains to higher-load training.

This means higher levels of effort and discomfort - things that could impede regular training for some.

But - it’s still possible to get decent benefits if lighter sets are stopped before failure.

Longer sets with lighter loads also comes with more fatigue, which means longer recovery times between sessions.

So a choice to lift lighter weights must consider these possible challenges too.

Maximising the benefits of lighter-load training

It’s clear decent gains in strength and muscle mass are possible with lighter load resistance training done:

• 2-3 times per week
• With 3-4 sets per exercise
• And using loads no less than 30% 1-RM

To maximise your muscle gains, taking some of your sets closer to failure may help, too.

And even if some benefits (like dynamic strength) are less with lighter-load training, that doesn’t mean the gains aren’t important, either.

It comes down to personal preference, too. Those who don’t like heavy weights or can tolerate more discomfort may favour lighter loads.

Plus, it’s not all-or-nothing either. There’s no reason you can’t use a variety of loads depending on what feels best to you.

The training program that makes you feel good is one you’ll probably stick to for longer.

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Heavy weights are NOT mandatory to benefit from resistance training

This is an important message for those who believe the contrary - or don’t like the idea of big weights.

Lighter weights have many benefits, which must be balanced with the potential downsides too.

Like many things - it really comes down to your preferences.

But knowing many paths lead to the same destination gives you freedom to choose the best one for you.

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As always, thanks for being here!

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Until next week,

Jackson

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IMPORTANT:

The information contained herein is of general nature only and does not constitute personal advice. You should not act on any information without considering your personal needs, circumstances, and objectives. Any exercise program may result in injury. We recommend you obtain advice specific to your circumstances from an appropriate health professional before starting any exercise program.