Machines don’t train functional strength
Machines are designed to lock you into a fixed range of motion, targeting one muscle or joint. At first glance, this seems logical, for instance ‘I want stronger legs, so I’ll use the leg press – I want bigger arms, I’ll use the bicep curl machine’.
But, your body hasn’t evolved to work in this way. Muscles don’t operate in isolation, in the real world they work together. If your goal is to build strength that applies to everyday life, then you should train in a way that allows your muscles to work together, not in isolation.
Strength is the ability to produce force against an external resistance, and this ability is applied to movement that incorporates the whole body.
What’s the science behind this?
It’s called neuromuscular specificity, which simply means that strength must be acquired in ways that correspond with normal human movement patterns. Machines force your body into unnatural, fixed movement patterns which don’t resemble anything like everyday movement patterns.
A good example to consider is the leg press. You can move heavy weights with your legs whilst laying down on a machine, but this doesn’t teach you how to apply force through your feet while balancing yourself. Compare this to the barbell squat, which develops your ability to lift heavy loads whilst needing to maintain balance, coordination and stability – exactly what you need to be stronger in your day-to-day life.
One size doesn’t fit all
Machines can force your body to move in ways that are restricted, due to the design and size of components, which could lead to injury due to poor form. They also force you into unnatural positions and ranges of motion which are not adapted to individual anthropometry. In stark contrast, barbells adapt to the user – you’re not locked into a fixed path of movement, and they allow your body to move according to your proportions.
When using a machine, the machine itself counter balances the weight for you. This removes the need for your body to be able to stabilise the weight in the movement. Stability is a fundamental part of strength.
For instance, in a barbell deadlift your entire body needs to work to help stabilise the barbell as you lift – including your grip strength, core, back, and leg muscles, all contributing to a controlled movement. This type of full-body engagement is essential for building real strength that’s applicable outside of the gym. Machines simply don’t require it, and therefore it’s never developed.
Failure to progress
Strength is built through progressive overload (a gradual increase in weight over time). Machines often have weight increments of 2.5kg-5kg, which is often too much of a jump for consistent progress. Barbells allow far more gradual progress with fractional plates (as small as 0.25kg) These small increments ensure you can achieve steady, measurable progress without hitting a wall.
