Muscle Building in Pregnancy Part 2: What to expect (Part 2 - Women who don't lift weights, and want to start)

If you have never lifted weights before, or have had a break of at least 18 months and would like to start lifting weights during your pregnancy, or want to know what you can expect from a new client starting resistance training during pregnancy, this Part 2 of the blog post is for you.

(If you already lift weights and want to continue in pregnancy, check out part 1 of this blog post)

Short answer: Yes, it is absolutely possible to build muscle during pregnancy.

More nuanced answer: While it is physiologically possible, you have to do a few key things right in order to build muscle during pregnancy. Beginners to strength training often make a few key mistakes, women in particular are overly cautious and don't lift as much weight as they need to for muscle growth, and for pregnant women that can be compounded by fears that it's not "safe".

In this article I'm going to tell you exactly

• what drives muscle growth

• how to achieve it (safely) during pregnancy

• as well as practical realities of pregnancy that may make this difficult to do in practice (even if it's possible in theory)

First of all, is it safe?

Yes, lifting weights during pregnancy is safe, and as with almost all exercise during pregnancy, the known benefits (for both you and your baby) far outweigh the potential risks.

It's worth noting that physical activity, including lifting heavy things does not decrease OR increase one's risk of miscarriage or birth defects. But it does have considerable benefits for both baby and mother.

What may be deemed unsafe is long periods of heavy physical labour, but that is different to short workouts 2-3 times a week with the appropriate weight for your strength levels.

Benefits of exercise during pregnancy

For baby:

• promotes health of placenta

• builds a stronger heart and better cardiovascular health

• promotes a healthier birth weight and prevents excessive fat accumulation

• reduces their long-term risk of obesity

• may improve their brain development, motor skills and strength

• (not to mention the benefits of having a mum who is has better mental and physical health)

For you:

• boosts your energy and mood (and prevents or reduces depression and anxiety)

• improves body image

• eases and prevents back pain and pelvic pain

• prevents pelvic floor dysfunction

• improves digestion and prevents constipation

• increases muscle mass

• increases bone density

• reduces risk of gestational diabetes

• prevents excessive weight gain

• improves recovery postpartum

Official recommendations

Recommendations for pregnancy exercise from every single governing body are exactly the same:

• 150 minutes of cardiovascular exercise a week

• 2 strength sessions a week.

Drivers of muscle growth

There are a few things that are necessary for building muscle:

1. Mechanical load - this means lifting sufficient weight. This means that if you're lifting a 4kg dumbell, but you could be lifting 20kg, you are not creating sufficient stimulus to the muscle to grow. This is why many classes and exercise modalities designed for women (who do not want to lift heavy things) don't usually work.

2. Progressive Overload - you have to actually increase training intensity (the weight you're lifting) and/or training volume (load, reps or sets or a combination of 2 or 3) over time in order to build muscle. This means that while you may START with a 4kg dumbbell (or even less) in your first training session, if you continue to do the same weight for the same number of reps and sets over a number of months, you will not be building muscle. You have to actually progress onto heavier weights to drive muscle growth (we'll talk about how to do that later) Again, this is why most female-centered approaches to exercise fail to reliably produce muscle growth.

3. Consistency - this may seem obvious, but your body can produce very little muscle mass from a single session. You need consistent and repeated exposure to the stimulus. If you have a great session, but then don't squat again for another month, you will not build muscle mass.

4. Adequate nutrition and recovery - you can only train as hard as you can recover, and you don't build muscle from lifting weights, you build muscle from recovering from lifting weights. This means you need adequate calories, adequate protein (as well as other nutrients), adequate sleep and rest and manageable levels of stress.

If you want to learn more about how to strength train to ACTUALLY get results, join my free email course. '

HOW TO STRENGTH TRAIN

This course isn't specific to pregnancy, but the same principles apply.

It is, in theory AND in practice possible to meet all of these criteria (and I'm going to explain how below), but pregnancy poses several very real obstacles to achieving this, including fear, as well as pregnancy symptoms like fatigue, nausea, low mood and aches and pain (which I'll talk about more at the end).

It's also important to note, that as a woman who is not currently lifting weights, you actually have MORE potential for muscle growth than a very strong woman lifting very heavy weights. That may sound counter-intuitive, but our bodies are subject to the Law of Diminishing Returns. Beginners see fast return on investment. The more muscle you have, the harder it is to gain even more muscle.

So what does it look like in practice? How should you lift weights? How much weight should you use?

This is going to be relative to the strength level of the individual. For any given movement, like a squat, some beginners will, for one reason or another, have higher starting strength levels that others. That's also why we can't define what "heavy" is, because it's relative. So when pregnancy fitness blogs or influencers (or your mum, friends or doctor) tell you "don't lift more than 10lbs" - this is riduculous. For one woman, 10lbs may genuinely be very heavy relative to her strength levels. For another, it may be incredibly light.

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Therefore, what I like to do as a trainer (whether working with pregnant women or not) is first of all define the rep range. This will often simply be 5-10 reps. You should choose a weight that you can complete the allotted number of reps for. Let's say you're squatting, you take 5kg, and you can reach the top of the rep range (so here, 10 reps) with correct technique and full range of motion, the weight is too light and you should go UP in weight.

If you can't do 5 reps (with correct technique and full range of motion) it is too heavy - and you should go down in weight.

If you can do somewhere between 5 and 10 reps - for example, 7 - it's the "right" weight and you should keep working with that weight, trying to get more reps, until you reach 10.

This is called "auto-regulation" and there are 3 reasons I like to teach it:

1. Whether pregnancy, postpartum, or neither - it helps you identify a safe weight - one that is not too heavy (and could potentially lead to injuries)

2. It also helps to identify weights that are too light (yes, there is such a thing!) and that will not therefore be sufficient to produce muscle growth.

3. It both helps identify an appropriate (not too heavy, not too light) starting weight for the individual and it provides a fool-proof way of knowing when it is time to go UP in weight (leading to progressive overload). It means that the individual never needs a coach again, nor needs to ask the annoying questions "how much weight should I use?" It also provides the coach with a guide for knowing what the appropriate weight is for the trainee.

How should you progress? Using the exact same framework of "auto-regulation" described above.

1. Start with a rep range like 5-10

2. Take a weight you feel you can complete the exercise with for that many reps (yes, this will be a guess in the beginning, or you may simply take the lightest weight you have).

3. If you can reach the top of the rep range with that weight (let's say 5kg x 10 reps), it is too light and you should go up in weight (by 1kg, or the smallest increment you have) THE NEXT SET - yes, the next set.

   1. Not the next workout,

   2. not when 10 reps feels "easy"

   3. not when you can do "10 reps for all 3 sets" - the next set.

4. If with the heavier weight (let's say 6kg) you can reach 10 reps (with correct technique and full range of motion) you should go up to 7kg, and so on and so forth for the rest of time (yes, you will get to a point where you can't keep adding weight, but you're several steps away from that point, so don't worry about what you're going to need at level 14 when you're at level 1)

5. If you cannot complete the full 10 reps, and are in the designated rep range (5-10), let's say you can do 6 or 7 reps, you should continue to use the same weight and try to increase the number of reps you can complete in the next set (whether in the same workout or a subsequent workout)

It really as as simple as that. In my experience, most beginners start with a weight that is actually far too light for them (2 or 3kg), but they think will be challenging - but that's ok! It's better to start with something too light than too heavy, and you can progress from there.

In the presence of an experienced coach, they can usually take big leaps and progress by several kilos in the first few workouts and are gobsmacked by how much they can lift. However, when training alone, they are far more conservative than they need to be - this varies massively from individual to individual and their existing training experience, strength and fitness levels, but also their coordination and confidence and understanding of the instructions. I have found that in practice, it is reasonable to expect most women to progress by 1kg a training session (even though this is actually a slow rate) but it allows the trainee to build confidence gradually at a pace that feels doable for her. Occasionally, some women genuinely are very weak and will be genuinely challenged by 1-3 kilo weights, and will progress much more slowly. In either case, it doesn't really matter. Direction is more important than speed, and muscle/strength building is a long-term project and a marathon not a sprint - so building confidence and making it enjoyable and not intimidating, and accumulating small wins in the beginning is far more important than progressing at an "optimal" pace.

Again, I go through all this, step by step in my free online course

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Muscle soreness.

Muscle soreness in the days after a workout is also a good indicator of how challenging a given weight really is, and if you are ready to progress or not, even though this form of feedback is less immediate.

Muscle soreness is not a sign of a good workout, nor is it a sign that muscle building has occurred (if I got you to run a marathon tomorrow without training, do 1000 burpees or run downhill for 20 minutes, you would be as sore AF, but absolutely zero muscle building will have occurred). Rather, muscle soreness is a sign of novelty. You get sore from doing movements you don't usually do, or use a weight you don't usually use. If you do the same movements week in and week out, you will get progressively less sore, even if you're using heavier weights (this is called "the repeated bout effect") - this does not mean that "it's no longer working" - to the contrary, recovery has improved and you've progressed, so you've likely built muscle. Soreness is not necessary for muscle building.

At the end of the day, you can only train as hard as you can recover - therefore, regardless of how much weight you lifted, how sore you are after your workout is a good indication of if you did too much, too little, or got it just right (remember Goldilocks and the 3 bears???)

If you are incredibly sore after your workout, even if it felt "easy" at the time, it's a sign that it was a big stimulus and lot for your body to recover from. It doesn't mean that you did "too much" but to avoid crazy soreness next time, you might not increase the weights next time (don't worry, you'll be less sore due to the repeated bout effect). You might do 2 sets instead of 3, or fewer reps at the same weight. If you were INCREDIBLY sore (like, can't get off the toilet or brush your teeth) you might even reduce the weights (don't worry, once you've adjusted, you will increase the weights again later on down the line).

If you are not at all sore, you likely trained well below your actual threshold and ability and were probably overly conservative. You should definitely aim to go heavier next time, perhaps considerably so.

If you are a bit sore, too sore to workout again, but not so sore that you can't get up from the toilet - you likely hit the sweet spot. You should continue to go up in weights next time.

Rest between sets

This is not a HIIT workout. You should be resting in between sets for at least 1 minute, sometimes 2 or 3, especially in pregnancy. The goal is to go up in weights (which will drive muscle growth) and NOT to get your heart rate high (which will NOT drive muscle growth - although it's good for your cardiovascular health).

Light weight, high reps

The idea that you should use "light weights for high reps" is an oversimplification. Studies have shown repeatedly that you can build muscle across many rep ranges - like 1 single rep per set or 30 reps per set.

However, at the extremes it becomes very impractical. If you are doing sets of 30, sets become very long, it often challenges your cardiovascular system long before it challenges the muscles, and weights have to be quite low, so it doesn't load the muscles sufficiently.

However, if you're doing sets of ONE, or even 3 or 5, the weight has to be very HIGH and risk of injury is higher (especially for beginners and pregnant women). You also usually have to do many sets to compensate for the low volume, and if you're scared of the heavier weights (perfectly reasonable during pregnancy), you just might not end up stimulating the muscles sufficiently.

Therefore it's best to stick to 6-15 reps (which is quite a large range) and 8-12 reps for most of the exercises. If you're scared of adding more weight, you can always increase the rep range FIRST (say by doing 15 reps instead of 12) - to help bridge the gap.

But if you pick up 2lb dumbbells and wave them around for an hour, you will likely never create enough stimulus to actually grow muscle.

Toning

"Toning" is a completely made up marketing term that doesn't actually mean anything. You can either build muscle, or not build muscle. You cannot "tone" a muscle.

A muscle can basically do 3 things:

1. grow (get bigger = hypertrophy)

2. stay the same (maintaining muscle mass)

3. get smaller (atrophy).

(It can technically get stronger, i.e. move heavier weights without changing size, but let's leave that out for the sake of simplicity) But it cannot "get toned".

If you want to build muscle, you have to follow the principles I laid out in this article:

• sufficient load,

• progressive overload,

• nutrition and recovery

You cannot "tone" a muscle. "Light weights, high reps to tone" is nonsense and is usually insufficient load to build muscle, especially if there is no progressive overload over time.

When people say that a person looks "toned" it actually means:

1. She has a decent amount of muscle (built through moderate-to-heavy weights and progressive overload) and

2. Low enough levels of body fat that you can actually see the muscle mass underneath (losing body fat is a separate process entirely and I will cover it in a separate blog post).

   
   

It does NOT mean that she did low weights, high reps to "tone" the muscle.

How many times per week?

Recommendations for pregnancy (and across the lifespan) are to train twice a week.

Most women ask "is that enough?!" and the answer is yes - it absolutely is.

You can happily build muscle as a beginner with 2 training sessions a week, in fact even ONE training session a week is sufficient, as long as you do the following things:

• use sufficient load

• progressively overload (move onto heavier weights each week), and

• recover properly from workouts

i.e. the things I have been talking about throughout this blog post! You should also do the following:

• train FULL BODY - you should do at least one exercise per muscle group (legs, pull, push) per workout. You don't want to do "legs" once a week and "arms" on the other workout - you should workout upper and lower body in each workout

• focus on compound (multi-joint) exercises, rather than isolation (single joint) exercises. I like to define this as

  • LEGS - squats, deadlifts, lunges, hip thrusts (rather than quad extensions or glute exercises)

  • PULL - pulldowns and rows (rather than bicep curls)

  • PUSH - chest and shoulder press, pushups (rather than chest flies or lateral raises)

This allows you to cover more muscles in fewer exercises and allows you to progress more.

I have a 4-day course that gives you a taster of these sorts of exercises

HOW TO TRAIN DURING PREGNANCY

But if you want a written strength programme (for at home or the gym) you should join my Strong Pregnancy programme that tells you what exercises to do, how to modify for each month of pregnancy and guidance on how to progress.

Even with once a week - as long as you are training full body, and progressing from week to week, you can actually make really good progress. What matters is that you are challenging the muscles sufficiently for them to go into what is called "supercompensation" - when they recover from a training stimulus and become stronger than they were before the stimulus (training session) occured - as depicted in the "General Adaption Curve" below:

This is normally between 2-7 days after a workout for beginners. If you leave it too long before the next workout (say, 2 weeks) strength levels will return to baseline, which means you never actually end up progressing, you just stay the same. Obviously, this has its limits. If you are a complete beginner, you may get strength and muscle gains from just one training session a week, but after a while (probably after several months), you will plateau - that is when you can add a second session and continue improving. When you plateau on 2 sessions a week, you can add a third. This is a more realistic and sustainable approach than STARTING with 3 or 4 or 5 sessions a week, which may not give you enough time to recover, and will feel like a big change to your lifestyle.

Obviously, if you train twice a week, you'll progress more quickly than if you train once a week.

Again, if you want to learn more about effective strength training, you should join my free email course that includes sample training plans

LEARN TO STRENGTH TRAIN

And if you just want a programme designed for pregnancy, join Strong Pregnancy, that has both written programmes and follow along programmes for each month that are more accessible for beginners.

CHECK OUT STRONG PREGNANCY

Practical limitations of Pregnancy

Everything we've talked about so far is IN THEORY - but there are very real practical limitations that get in the way in pregnancy - let's discuss them

Caution

The first thing that usually gets in the way of actually gaining muscle in pregnancy is a fear of doing something wrong, hurting yourself, or causing a miscarriage. In fact, I find that even outside of pregnancy, the main reason women who are new to strength training do not actually build muscle is because they are far too cautious or fearful, underestimate what they are able to do and so don't push themselves enough or progress onto heavier weights. In pregnancy, this is compounded by a fear of causing damage to the baby or the pregnancy.

As I have already outlined here, lifting weight IS safe AND recommended for all uncomplicated pregnancies, and I'm sure you will agree that the guidelines I have laid out are very sensible (i.e. finding a weight you find comfortable to lift and gradually increasing the load from session to session).

Nonetheless, lifting weights makes many women nervous and many still will hear concerns from mothers, friends and even husbands. It's not because there is something inherently dangerous in lifting weights that they know about that you (or I or government health organizations) don't - it's simply that they don't actually know ANYTHING about the topic.

I have always said to all my clients that at the end of the day, even if concerns are not actually based on anything, it still is very important that you feel comfortable with your training programme. Despite it being safe, if YOU feel nervous about training in a certain way, it may not be worth the stress.

Pregnancy Symptoms

Then there are symptoms like fatigue, nausea and low mood that can make training especially difficult. As the pregnancy progresses, you may experience aches and pains that also make training hard (although strength training is ironically the antidote to these issues). Then there's the belly - once you get into your final trimester, the belly physically gets in the way of many of the movements - this doesn't mean that you can't train, but it does mean you need modifications, and most people don't know enough to know how to adjust your training (there will be a future blog post/podcast on this topic too). My online programme includes modifications for every stage of pregnancy.

Conclusion

If you are starting a strength training programme in pregnancy, it is absolutely possible to gain strength and muscle mass with the right training programme and approach - however, lots of things, both imaginary and real, get in the way. The bottom line is that all exercise and movement during pregnancy is incredibly healthy for both mother and baby, and strength training is the best way to get both health and aesthetic results - and the best way to support you through pregnancy, postpartum and throughout the lifespan.

Further reading

I intend on writing more posts like this as well as podcast episodes about pregnancy and postpartum training and nutrition. I have online programmes, free email courses, a podcast, and a 1:1 online coaching programme.

HOW TO STRENGTH TRAIN - free email course

HOW TO EXERCISE IN PREGNANCY - free email course

STRONG PREGNANCY - online programme for every stage of pregnancy, including mobility, strength, core and conditioning workouts

EXERCISING IN EARLY PREGNANCY - blog post

BUILDING MUSCLE IN PREGNANCY for women already lifting weights - blog post