We often hear people say that lifting heavy is bad for your joints over time and increases the risk of injury. Some fitness enthusiasts are recommending higher reps and lower weights instead. So, is it really that simple, and is lifting heavy bad news for your joints? How do you settle on the right weight to still build strength and muscle while protecting your joints?
Researchers compared high repetitions and low weights with low repetitions and heavy weights in terms of pain, physical function, and muscle strength. Which is the more effective approach to add to a physical therapy program? Let’s check out the research.
The study

In a study published in the African Journal of Biological Sciences, the authors aimed to investigate the effects of muscular strength training on range of motion, functional capacity, and muscle strength in 48 individuals with mild-to-moderate knee osteoarthritis, aged between 50 and 60 years. All study participants had osteoarthritis in both knees, and the focus was on resistance training of the calf muscle.
The participants were placed in three groups and all groups trained three times every week for a total of four weeks:
- Group one took part in a standard physical therapy program.
- Group two underwent physical therapy in addition to a low-rep, heavy-weight calf training routine involving three sets of eight single-leg calf raises. Individuals progressively increased their weight over time.
- Group three did physical therapy in addition to a high-rep, low-resistance calf training routine involving the same exercise, but with 10 sets of 15 reps and a lighter weight.
The researchers evaluated pain levels, calf muscle strength, and physical functioning at the start and end of the study.
The results

The study authors revealed the following:
- When compared to the group that only did physical therapy, both of the additional training groups had improvements in function and pain.
- Group two, who performed low-rep, heavy-weight training, had the most significant gains overall, particularly in muscle strength and function. The strength gains were drastically higher in the low-rep heavy weight group.
- Both of the additional training groups had lower pain levels, and there was no notable difference in pain relief between those two groups.
The takeaway

Lifting heavy with control and the proper technique might be a good idea for your joint health, as long as you’re not pushing yourself beyond your capabilities. This study shows that using lower reps and higher resistance isn’t inherently bad for your joint health, even in those with osteoarthritis. This training style could be effective for enhancing muscle strength and joint function, as well as reducing pain.
Overall, both training styles are useful for lowering pain and enhancing function in those with knee osteoarthritis, as long as you maintain control and proper form. Additional research shows that doing strength training lowers the risk of getting knee osteoarthritis by 17-23%. The researchers found that strength training helps build supportive muscle strength in vulnerable joints.