Can Resistance Training Improve Flexibility? Research Review

By Grant Frost · Physiotherapist • Last clinically reviewed: 21 September 2026

Does lifting weights make you less flexible? It's a common idea, but recent research suggests the relationship is more complicated - and potentially much more positive.

A 2025 systematic review, meta-analysis and meta-regression examined whether resistance training can improve joint flexibility in healthy adults.

The findings are interesting for anyone who wants to become stronger without sacrificing mobility. They are also relevant clinically because they challenge the idea that flexibility and strength have to be trained separately.

What Did the Research Find About Resistance Training and Flexibility?

The researchers included 36 studies involving 1,469 healthy adults. Overall, resistance training was associated with a moderate-to-large improvement in measures of joint flexibility.

The review also found that training intensity was an important moderator. Higher-intensity resistance training produced a larger pooled flexibility effect than lower-intensity training. However, the authors cautioned that substantial differences between studies limit how confidently these findings can be generalised.

It adds to the evidence that strength training itself can produce meaningful changes in range of motion.

• Flexibility improved: Resistance training was associated with significant improvements in joint flexibility.
• Higher intensity showed a larger effect: The high-intensity group had a greater pooled effect than the low-intensity group.
• Age was not a significant moderator: The analysis did not find a statistically significant effect of age on the flexibility response.
• Activity level was not a significant moderator: The researchers did not find clear evidence that baseline activity level explained differences in the flexibility response.

Why Might Resistance Training Improve Flexibility?

It may seem counterintuitive. If lifting weights builds muscle, shouldn't it make you tighter?

Not necessarily. The researchers discuss several possible explanations, including changes in neuromuscular coordination and greater tolerance to the sensation of stretch. However, these mechanisms were not directly established by the review, so they should be viewed as possible explanations rather than proven reasons why flexibility improves.

From a physiotherapy perspective, there is also an important distinction between passive flexibility and the range of movement you can actively control.

1. Strength can improve control: Becoming stronger may help you control a greater available range of movement.
2. Exposure to range can matter: Resistance exercises performed through a comfortable, controlled range expose the body to movement while simultaneously developing strength.
3. Stretch tolerance may change: Like stretching, resistance training may influence how comfortable you are moving into a stretched position.

How Strong Is the Evidence?

This is where the study becomes particularly interesting. The overall result is encouraging, but the authors were clear about its limitations.

• Substantial heterogeneity: The studies differed considerably in their participants, resistance-training programs, flexibility tests and study designs.
• Risk of bias: None of the included studies was judged to be at low risk of bias. Among the randomised studies, some had concerns and others were judged to have a high risk of bias.
• Healthy adults only: The review specifically examined healthy adults, so the findings should not automatically be applied to people with acute injuries, significant pain, neurological conditions or complex rehabilitation needs.
• More research is needed: The authors concluded that resistance training could be used to improve flexibility, but that the heterogeneity and risk of bias limit definitive conclusions.

How Can You Use Resistance Training to Improve Flexibility?

You don't necessarily need to choose between strength training and flexibility work. In many programs, they can be combined.

Exercises such as squats, lunges, presses and other resistance movements can be useful when they are performed through available range. The key is not simply how deep you go, but whether you can control the movement and progressively develop that range.

What Does This Research Mean From a Physiotherapy Perspective?

This is where I think the research becomes particularly useful.

You can't improve your range of motion if you don't explore its boundaries. This is all well and good when just stretching tissue, but it needs more of your attention and focus when adding weight and resistance.

In clinical practice, I would encourage everyone to work to the depth of a range that allows you to feel in control and safe. As soon as you feel your technique or control wane, you've likely found your current depth.

As your brain, tissue and nervous system develop that new capacity, your depth will likely improve.

This research adds another piece to this picture. It suggests that you can potentially improve flexibility while getting stronger, but it should never be at the expense of good form and technique.

The Bottom Line

A 2025 systematic review found that resistance training can improve joint flexibility in healthy adults, with higher-intensity training associated with larger flexibility effects. However, substantial variation between studies and concerns about risk of bias mean the findings should be interpreted with some caution.

From my perspective as a physiotherapist, the most useful message is simple: strength and flexibility do not have to be opposing goals. With appropriate exercise selection, technique and progression, resistance training may help you develop both.

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