Why we lift heavy: For CrossFit and for life

Richard Harris
4 days ago
3 min read

The science behind lifting heavy

Let’s start with the science. When we lift heavy, we’re tapping into some powerful physiological mechanisms:

The All-or-Nothing Law: Muscle fibres don’t partially contract. They either fire completely or not at all. Heavy lifting forces your body to recruit more muscle fibres, especially the fast-twitch ones responsible for power and strength.
Motor Unit Recruitment: A motor unit is a nerve and the muscle fibres it serves. Lifting heavy increases the number of motor units recruited, improving coordination and force production.
Neurological Adaptations: Strength isn’t just about muscle size. It’s about your brain and nervous system learning to send stronger, faster signals. That’s why beginners often get stronger before they increase the size of their muscles – their nervous system is adapting.
Muscle Fibre Types: Strength training primarily targets Type II fibres – the fast-twitch fibres. These are responsible for explosive movements and high-force output. They fatigue faster than Type I (slow-twitch) fibres, but they’re crucial for power, speed, and strength.
What Counts as Heavy? Generally, lifting at 80% or more of your one-rep max (1RM) is considered heavy. That’s typically in the range of 1 - 6 reps per set. This level of intensity is what drives maximal strength gains and neurological adaptation.

Strength for longevity and health span

Strength is a foundational component of longevity and independence:

Being able to stand up from a chair, climb stairs, or catch yourself from a fall – these are strength-dependent tasks.
Playing with your children or grandchildren, carrying shopping bags, or moving furniture – all require functional strength.
Studies show that muscle mass and strength are strong predictors of health span – how long you live well, not just how long you live.
Sarcopenia: the age-related loss of muscle mass and strength. It starts earlier than most people think – often in your 30s or 40s – and accelerates with age. Strength training is the most effective way to slow, stop, or even reverse sarcopenia.

Strength for endurance athletes and CrossFit

Strength training is vital for endurance athletes and absolutely essential in CrossFit:

Stronger muscles are more resilient to fatigue, meaning endurance athletes can maintain form and efficiency longer.
Strength improves running economy, cycling power, and injury prevention.
In CrossFit, where we blend strength, endurance, and skill, having a solid strength base allows athletes to move efficiently under fatigue, recover faster, and perform better across all domains.

The never-ending challenge

Strength training is a lifelong pursuit. There’s no finish line. You don’t just ‘get strong’ and stop. It’s a process that evolves with you:

Your goals change. Your body changes. But the challenge remains.
It takes years to build real strength. And that’s the beauty of it – it teaches patience, discipline, and humility.
There’s always another level. Whether it’s refining technique, increasing load, or improving recovery – strength training keeps you engaged and growing.

The risks and the responsibility

Lifting heavy isn’t without risk. The biggest mistake? Prioritising intensity over mechanics:

Poor form under load can lead to injury – especially in the spine and shoulders.
That’s why we preach: Mechanics, then consistency, then intensity.
A well-coached lift is a safe lift. If you’re unsure, ask for help, film your lifts, or scale appropriately.

Bonus benefits

Here are a few more reasons to lift heavy:

Mental toughness: There’s something transformative about pushing through a heavy set. It builds grit.
Hormonal health: Heavy lifting boosts testosterone and growth hormone, which support metabolism and recovery.
Bone density: Resistance training is one of the best ways to prevent osteoporosis.

Conclusion

So whether you’re chasing a new deadlift PB or just want to be strong enough to live well, lifting heavy has a place in your life. Train smart, lift with purpose, and remember – strength is never a weakness.

For a more detailed insight in to this topic, listen to or watch Episode 40 of our QuickCast.

👉 Listen or watch now

📩 Have questions or need help with your lifting technique? Drop us an SMS on 07588 286277 or send us a WhatsApp!

Until the next blog post 😊