There are numerous benefits associated with heavy resistance training. Despite this fact, many people, including health practitioners, are apprehensive to encourage participation in strength training due to certain fears and misconceptions around the safety of lifting heavy weights. It is a commonly held belief that heavy strength training is bad for the joints; comes with a high risk of injury; makes people excessively muscular; and is damaging to the spine. There are many who believe that strength training is safe, as long as the weights are ‘not too heavy’. Avoiding heavy lifting is a commonly delivered piece of advice from many health practitioners. Conversely, some of the most substantial benefits from strength training are actually found when people lift heavy enough to reach 80-85% of their 1RM - which is almost certainly going to constitute as ‘too heavy’. With such conflicting messages, it can be hard to know what is the best advice when it comes to weight lifting.
Resistance training is training against any form of resistance, including body weight; bands; free weights; or weights machines. This is separate to the sports of weightlifting and powerlifting, which are relating to maximal effort in the clean and jerk and snatch (weightlifting) and maximal effort in the squat, bench, and deadlift (powerlifting). Movements from both of these sports are commonly incorporated into regular full body strength training programs (5). In this article, heavy resistance training refers to using loads equal to and more than 80% 1RM, including on machines, using free-weights, and incorporating weightlifting and powerlifting movements.
Benefits of heavy resistance training:
Myth 1: Lifting heavy weights is bad for your joints.
A commonly held belief is that exposing your joints to high loads through heavy weights or high intensity training is inherently bad for them. There is no evidence that lifting heavy weights non-competitively is damaging to joints in the long term. While there is some evidence of increased risk of developing arthritis later in life in competitive weightlifters, no such link has been found for recreational lifters (4). Bear in mind that increased rates of arthritis in competitive sports participation is often due to the higher number of injuries sustained in competitive sport in general. The most significant risk factors for osteoarthritis are genetics, age, and a history of previous injury. In contrast, heavy resistance training is often proposed as a helpful way to manage arthritic conditions. For example, a study testing the effect of heavy lifting (up to 80% 1RM) in rheumatoid arthritis patients was demonstrated to be safe and an effective way to increase lean body mass (6).
Myth 2: Lifting heavy weights is bad for your spine.
As with most exercise, it is plausible that if built up gradually, there is no reason this is any more dangerous than any other way to load soft tissues. It could be argued that heavy lifting is beneficial to the spine as it builds strength in the surrounding muscles which can be helpful in people with low back pain and to prevent future injuries. If care is taken to progress gradually, then the risk of injury can be minimised. There is also the concept that the intervertebral discs may be capable of adapting to load like other soft tissues in the body, though current research is yet to demonstrate this conclusively. Heavy resistance training including weightlifting and powerlifting movements works with gradual and controlled exercises, where there is no unpredictability that is a common feature in other sports.
Myth 3: Lifting heavy weights can give you a hernia.
Looking through the literature, there is no direct evidence that heavy weightlifting causes inguinal hernias. There has been a potential link in a couple of studies indicating repetitive lifting as part of occupation may potentially be linked, but not participating in weightlifting. Only one study reporting on injuries amongst powerlifters and weightlifters reported hernias as one of the sustained injuries, and this was 1% of all injuries (1). Again, the human body is adaptable, and as long as weights are progressed gradually and sensibly, it is likely that the body is able to adapt to the demands placed upon it.
Myth 4: Lifting heavy weights makes you excessively muscular.
It takes a lot of dedicated time and particular effort to gain a sizeable amount of muscle. Those who develop a substantial amount of muscle bulk often exercise with this as their goal, and use a combination of weight training and nutrition in order to achieve it. Muscle building is also more associated with higher repetition lifting. If one’s aim is to reap the benefits associated with heavy strength training, the training is likely to take place in the 5 repetition range, which is less likely to be associated with muscle building. Additionally, some studies have found that in endurance athletes, for example, a 9 month involvement in strength training did not result in any muscle hypertrophy, though did result in 25% gain in maximal strength. The proposed reason was that the high volume of endurance training had a preventative effect on building muscle.
Myth 5: Lifting heavy weights isn’t necessary.
Research has found that higher rep, lower weight resistance training has limited benefits. While it may have some benefit to muscle strength and size and body composition for people who have not done this type of exercise recently, there is limited ongoing benefit as the body gets used to it. Heavy lifting, close to 80-85% 1RM max is necessary in order to get the most significant benefits to strength, power, and bone density (3).
Myth 6: People who run/cycle/swim/walk don’t need to lift weights.
While these activities provide benefits to the cardiovascular system, they do not provide substantial benefit in terms of building bone density or muscle size (3). Bones tend to get used to more repetitive activities, such as running or walking. Unfortunately this means that these activities do not have as significant benefits to improve bone density and prevent sarcopenia in the ageing adult. There is also evidence to suggest again that heavy weightlifting can be beneficial in endurance sports such as running or cycling, not just for injury prevention, but for improved performance, via improved economy of movement (13,14).
Safe participation guidelines