Despite what you’ve heard, stretching before a workout won’t make you more flexible – and stretching afterwards won’t make your muscles less sore, experts have revealed.

According to Professor Kieran O’Sullivan, who studies musculoskeletal pain at the University of Limerick, the 10 minutes you might spend flexing those hamstrings are effectively useless – and could even cause harm.

For the average person doing moderate amounts of exercise, ‘the value of stretching relative to other workouts becomes much less’, according to Professor O’Sullivan.

This is because research has show that stretching has little impact on muscle fibers  beyond that of exercise alone. Even walking can be enough to reduce the risk of strain and injury.

Khloe Kardashian has become well known for her fitness journey, and even hosted a reality show about the process, called ‘Revenge Body’

Stretching works by temporarily reducing the amount of blood and oxygen flowing to your muscles, Professor Judy Delp, who teaches biomedical sciences at the Florida State University College of Medicine, told TIME. 

This deficiency is said to motivate the body’s cells to deliver an excess of blood and nutrients to the muscle fibers – making them better able to cope with the impact of movement. 

But the evidence for those benefits are somewhat limited, Professor Nicolas Babault, physiology of exercise at the University of Burgundy, told TIME. 

Also, stretching after a workout doesn’t seem to improve muscle soreness in the coming days, according to a 2011 review of 12 studies on the topic by researchers from the UK-based nonprofit Cochrane. 

This stands in direct contrast to what fitness influencers and celebrities, such as the likes of Khloe Kardashian, share about their routines. 

Some experts say that movements involving dynamic stretching – like squats and walking lunges – are useful, but traditional types should be ditched.

 Kardashian trainer Joel Bouraima recently revealed that Khloé’s workout routine always starts with at least thirty minutes of stretching to ‘warm up’. 

Folding over to touch your toes before or after a workout might make you feel like you’re getting more flexible, but what you’re actually feeling is your body relaxing Professor Kieran O’Sullivan said. 

These positions are called static stretches, and they involve holding poses for prolonged periods of time while breathing, Leigh-Ann Bramble Bramble physical therapist from the Hospital for Special Surgery’s Sports Rehabilitation and Performance Center, said.

But some studies have shown that holding these poses for prolonged periods of time might make it harder to gain speed – and might actually hurt.

‘Using static stretching in a warm-up prior to an athletic competition may actually negatively impact your performance. This is because static stretching may limit your body’s ability to react quickly,’ she said. 

Some trainers say if any movement is going to make a difference to muscle pain, it’s dynamic stretching. These stretches are repetitive movements that combine to activate muscles, joints and ligaments. 

This includes things like torso twists, walking lunges, squats and leg swings. These movements get blood flowing to your muscles, increasing temperature and decreasing stiffness. 

In order to actually get more flexible you have to lengthen your muscles, which involves dynamic stretching, Polly de Mille, an exercise physiologist at Hospital for Special Surgery, said.

Lengthening only happens when you do this consistently over months and years, in routines like dancers or gymnasts. You can also incorporate things like foam rolling into your routine, to help move it along, Ms. de Mille said. 

But if you’re just trying to make sure you stay within a healthy range of mobility, then getting a little bit of walking activity each day should do it, Professor Delp said. 

‘If you walk regularly and you’re taking your joints through that range of motion, you are [stretching] without realizing it,’ Delp said. 

This is more than enough for most people, said Professor Timothy Caulfield, who lectures on health law and science policy at the University of Alberta. Professor Caufield shared in a comment on X that though he hasn’t stretched in 15 years, he’s doing just fine. 

‘”…stretching either before or after your workout does little to impact muscle soreness over the next few days…” Agreed. I haven’t stretched in 15 years! #Move,’ Caufield wrote.