Injury Risk in Strength Training: 5 Myths Put to the Test

Squats wreck your knees. Deadlifts wreck your back. Free weights are dangerous. And training heavy is something you should give up as you get older.

Statements like that sound cautious. The problem: they turn possible risks under particular conditions into general prohibitions.

The data paints a different picture. Strength training can cause injuries — as any sport can. But many of the best-known safety rules are either too blanket, or they confuse loading with damage.

The following sections examine five myths more closely.

How safe is strength training in the first place?

There is no single injury rate for “strength training”. Bodybuilding, powerlifting, weightlifting, strongman and ordinary gym training differ in their exercises, loads, training environments and even in how an injury is defined.

Which is exactly why spectacularly precise comparisons such as “strength training has 0.2 injuries per 1,000 hours, football 6.2” are problematic.

A large review of strength sports found, for instance:

• Bodybuilding: around 0.24–1 injury per 1,000 training hours
• Powerlifting: roughly 1.0–4.4 per 1,000 hours in newer reviews
• Olympic weightlifting: roughly 2.4–3.3 per 1,000 hours

Those are low to moderate rates overall — but not a universal number for every person who picks up a barbell.

More important than the exact comparison with other sports is the classification: strength training is fundamentally safe for healthy adults when the loading and the execution suit their training level. After reviewing 137 systematic reviews, the 2026 ACSM position stand likewise concludes that resistance training can be used safely and effectively in healthy adults of all ages.

Myth 1: deep squats wreck your knees

Deep squats increase the forces at the knee. That is correct.

It does not automatically follow that they damage the knee.

Loading is first of all the signal that tissue can adapt to. It becomes problematic mainly when capacity, training dose and the individual situation do not fit together.

A 2024 scoping review examined 15 papers on knee health in deep squats. In 14 of them, no negative effect on osteoarticular knee health was found. The authors assess deep squats, at appropriate load and technique, as a fundamentally safe exercise for people without relevant knee pathology.

That is a considerably better statement than “deep squats are always good for your knees”.

Because even a fundamentally safe movement can be inappropriate with an acute injury, a painful irritation or too rapid an increase in loading.

So for practical technique: use a depth you can control and that fits your goals and your individual anatomy. → Squat technique: individual, not dogmatic

Myth 2: the knees must not go past the toes

This rule is far too simple biomechanically.

If you want to squat deep, your centre of mass has to stay over your base of support. How far the knees, hips and torso move in doing so depends on your segment lengths, your foot position, the squat variation and your ankle mobility, among other things.

For many people that means: the knees move past the toes entirely naturally.

A small biomechanical study by Fry et al. compared squats with free knee movement against squats with a barrier keeping the knees behind the toes. The restriction did reduce the knee torque, but it raised the calculated hip torque very sharply — from around 28 to around 303 Nm.

That is not proof that restricted knee travel “injures your back”. It shows something more important: forces do not disappear just because you limit movement at one joint. They get distributed differently.

A comprehensive review from 2023 therefore concludes that a blanket restriction of knee travel is not sensible in healthy lifters.

→ Knees over toes: the science

Myth 3: deadlifting harms your back

Deadlifting puts high forces on the trunk and spine. That is no surprising finding either — it is exactly why the exercise can train the musculature involved effectively.

The traditional safety rule often runs:

Keep the back exactly neutral, avoid all flexion.

The evidence is not that clear-cut.

A 2026 narrative review summarises the newer literature like this: moderate spinal flexion under load is not automatically equivalent to injury in trained people. A modern risk model additionally accounts for load management, fatigue, movement control, individual anatomy, previous symptoms and the ability to tolerate changing positions under load.

That does not mean technique is irrelevant.

It means “not perfectly neutral” and “dangerous” are not the same thing.

What makes sense in practice:

• use a load you can control
• perform the movement reproducibly
• take large changes in technique under mounting fatigue seriously
• do not treat pain as a necessary training signal
• increase loading gradually rather than forcing jumps

If you do not want to drive heavy compounds to the point where technique falls apart, leaving a reserve in the set helps. How big that reserve should be depends on the exercise and the goal. → Training to failure — how close should you go?

Myth 4: free weights are fundamentally more dangerous than machines

Here the frequently quoted statistic is worth a closer look.

A US analysis of injuries treated in emergency departments between 1990 and 2007 found:

• 90.4% of the recorded cases involved free weights
• in 65.5%, the mechanism was a weight falling on the person
• strains and sprains were the most common diagnosis at 46.1%

At first glance that sounds like a clear win for machines.

But the study had no exposure denominator: it does not say how many hours people trained with free weights and machines in total. So you cannot conclude from that 90.4% that a rep with a barbell is any particular multiple riskier.

What you can very much learn from it: a relevant share of injuries arises from accidents with the equipment.

Which makes safety precautions sensible:

• set the safeties on bench press and squats appropriately
• structure heavy solo sets so that failing stays controllable
• secure plates and equipment properly where the situation calls for it
• keep the training area clear
• on very fatiguing sets, pick a variation you can bail out of safely

Machines can be practical for that — particularly when you train alone or want to take a movement deliberately close to failure. But they are not automatically “safe”, and free weights are not automatically “dangerous”.

Myth 5: heavy strength training is only for the young

Age changes training — but not overnight on your 40th birthday.

In 2026 the ACSM pooled data from more than 30,000 people and reached a clear result: resistance training improves strength, muscle mass and physical function across adulthood. For older adults, NSCA position statements likewise show that progressive strength training can be safe and effective when it is individually adapted.

So the key adjustment is not:

“Past a certain age, train light only.”

But:

Adapt training dose, exercise selection and progression to the person.

Someone who is healthy at 55, has trained for years and tolerates heavy squats well does not automatically need a reduced program. Someone starting at 25 after a long break, in pain, or without movement experience, may well need a more conservative entry.

Range of motion should not hang on your year of birth alone either. → Full ROM vs. partial reps

More on this: → Strength training after 40

What actually influences injury risk in practice

Research on specific risk factors in strength training is less clear-cut than social media rules suggest. A few principles make sense all the same.

Loading has to match your current capacity

More weight, more sets and more proximity to failure are all forms of additional loading.

None of them is dangerous in itself. It gets problematic when several variables rise sharply at once and the body gets no time to adapt.

So progression should be systematic, not frantic.

Technique is not a beauty contest

A rep does not have to look exactly like a textbook picture.

But your technique should stay controllable and repeatable under the load you have chosen. If a movement changes sharply as fatigue mounts, that is a useful signal — regardless of whether the rep formally still “counts”.

Fatigue changes decisions

The more tired you get, the harder it becomes to keep positions and speed stable. Which is a good reason not to drive every set of a complex compound to absolute failure.

→ Training to failure — how close should you go?

Exercise selection has to suit you

There is no compulsory exercise.

If a variation repeatedly causes complaints even though technique, load and progression are sensible, a different exercise can serve the same training purpose better. → Exercise selection and order

Warming up is preparation — not a shield

Specific warm-up sets can improve your performance on heavy sets and help you gauge the movement and how the day is going. Direct evidence that a particular strength training warm-up reliably prevents injuries is limited, though.

That is a good reason for a sensible warm-up — but no reason to attribute a guarantee to it.

→ Warming up in strength training

The short version

• Performed sensibly, strength training is a comparatively safe form of training — but there is no universal injury rate.
• Deep squats are not inherently harmful to healthy knees.
• Knees past the toes is a normal part of the squat for many body proportions.
• Deadlifting is not automatically bad for the back, and slight spinal flexion is not equivalent to injury.
• The high free-weight share in emergency department data is heavily shaped by accidents with falling weights and proves no intrinsic danger of the exercise type.
• Age alone is no reason to avoid heavy strength training.
• Sensible risk reduction comes above all from appropriate loading, controllable technique, reasonable safety precautions and a progression that matches your own capacity.

Further reading:

• Squat technique: individual, not dogmatic
• Knees over toes: the ATG science check
• Training to failure — how close should you go?
• Exercise selection and order
• Warming up in strength training

Sources

• Keogh JWL, Winwood PW (2017). The Epidemiology of Injuries Across the Weight-Training Sports. Sports Medicine, 47(3):479–501.
• Aasa U, Svartholm I, Andersson F, Berglund L (2017). Injuries among weightlifters and powerlifters: a systematic review. British Journal of Sports Medicine, 51(4):211–219.
• Tung MJY, Lantz GA, Lopes AD, Berglund L (2024). Injuries in weightlifting and powerlifting: an updated systematic review. BMJ Open Sport & Exercise Medicine, 10(4):e001884.
• Rojas-Jaramillo A et al. (2024). Impact of the deep squat on articular knee joint structures, friend or enemy? A scoping review. Frontiers in Sports and Active Living, 6:1477796.
• Fry AC, Smith JC, Schilling BK (2003). Effect of knee position on hip and knee torques during the barbell squat. Journal of Strength and Conditioning Research, 17(4):629–633.
• Illmeier G, Rechberger JS (2023). The Limitations of Anterior Knee Displacement during Different Barbell Squat Techniques: A Comprehensive Review. Journal of Clinical Medicine, 12(8):2955.
• Cherni B, Marzouki H, Selmi O et al. (2026). Beyond the Neutral Spine: A Narrative Review and Modern Framework for Low Back Injury Prevention in Deadlifting. Sports, 14(4):151.
• Kerr ZY, Collins CL, Comstock RD (2010). Epidemiology of Weight Training-Related Injuries Presenting to United States Emergency Departments, 1990 to 2007. American Journal of Sports Medicine, 38(4):765–771.
• Currier BS, D’Souza AC, Singh MAF et al. (2026). Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine & Science in Sports & Exercise, 58(4):851–872.