Low Back Pain. Free Weights Good, Weight Machines and Stretching Bad — It’s Science.

Are flexibility and muscle-strengthening activities associated with a higher risk of developing low back pain? J Sci Med Sport. 2013 Aug 8

The researchers followed 4610 adults and compared their exercise program and incidence of low back pain over an average of 4.9 years.

Quotes from the study:
“CONCLUSIONS: In this sample, stretching or use of weight training machines is associated with increased risk of developing low back pain compared to use of free weights, calisthenics or exercise classes.”

“Our data show that participants, who report regular stretching were at a greater risk of developing low back pain than those who did not.”

“We found participants who regularly used weight training machines were at a higher risk of developing LBP, but this association was not found in people who used free weights”

“One argument often given in favor of free weights over machines is that it allows not only for the development of the main target muscle group, but also surrounding stabilizing muscles, such as those in the back and abdomen. However, when using machines, the ROM is defined by the machine, providing isolation of the movement in one plane, meaning the deep paraspinal stabilizing muscles may not be engaged as much as they are with free weights, and subsequently underdevelop.”

Chad’s comments:

For the most part this study agrees with my observations. I put it under the category of vindication that I was right, and a lot of others wrong, when I was a physical therapy student in the 90’s. The researchers cite muscle cytoskeleton damage as why they think the stretching leads to increased low back pain, but my feeling is that modern society puts people in repeated and prolonged spine flexion, which over time leads to degenerative disc disease. Most stretching programs either purposely or accidentally put people into further spine flexion, repeatedly, worsening the condition. So I don’t doubt that stretching programs increase the risk of low back pain, particularly if they are stretching the spine itself. I just don’t see many patients complaining of low back pain that I would diagnose with cytoskeletal muscle damage. The general theme of flexibility of the spine causing more harm is in accordance with lumbar spine researcher Stuart McGill’s recommendations, which I am also largely in agreement with.

As for their rationale as to why machine training led to increased incidence of low back pain while free weights did not, I think the researchers are pretty close to the mark. I would add that unlike most machines, free weights generally require you to coordinate many joints together using the body as a single unit, such as in a squat or deadlift. With good technique, this imparts not just strength and endurance, but better motor control of the spine, all of which are protective. Also, most abdominal weight machines require repeated spine flexion or twisting, both of which have been shown to be pathologic stresses to the spine. These muscles are better strengthened isometrically which happens both explicitly and implicitly with a lot of free weight exercises. Certain weight machines in my opinion are often very useful and can play a role in everyone’s fitness program but the advantages and disadvantages of their use should be kept in mind and they are probably best worked into a program combined with free weight exercises for optimal function.

Likewise I do think some stretching has it’s place, but it should not be a foundation of one’s exercise program. People fall and break hips because they are not strong enough to prevent the fall. Generally nothing bad happens if you can’t bend over and touch your toes; plus, the posterior direction of herniation in peoples’ discs indicates that they bend forward too much as is and don’t need any special stretches in the same direction. Unfortunately many physical therapy clinics base their lumbar rehabilitation programs on traditional wisdom and start their patients with supine knees to the chest stretches (which is only more spine flexion) and posterior pelvic tilts (which are also more spine flexion), which is probably not the best thing to do. As they say, traditional wisdom is often long on tradition and short on wisdom.

Thanks for reading my blog. If you have any questions or comments (even hostile ones) please don’t hesitate to ask/share. If you’re reading one of my older blogs, perhaps unrelated to neck or back pain, and it helps you, please remember Spinal Flow Yoga for you or someone you know in the future.


Chad Reilly is a Physical Therapist, obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed his Yoga Teacher Training at Sampoorna Yoga in Goa, India.

4 thoughts on “Low Back Pain. Free Weights Good, Weight Machines and Stretching Bad — It’s Science.”

  1. So then what are the best machines to use for low back pain to benefit an exercise program already consisting of some free weights & bike/elyptical?

    • Hi Kat,

      This program contains most of what I like for low back pain. I think single leg press is good if one leg is stronger than another. I think hip abduction/adduction machine hits hard muscles that free weights don’t get quite as well. Cable exercises like the standing row and press hit the core real hard and have a degree of instability like free weights. Lat pulls are a favorite and I think my stepmill is great cardio and is lesser impact than running. Also EMS with the right machine, program and electrodes is way better for abdominals and low back pain than you would think and I use it on pretty much all my back pain patients that don’t have pacemakers. I hope that helps.

  2. Hi Chad!!!!…..what stretches do u recommend and use for your back pain patients? I see a lot of doctors & physios recommend williams or Mackenzie stretches a lot. After reading your articles on William’s stretches and Mckenzie’s stretches(also going thru a lot of research publications), I now recommend them to my patients with caution… much kudos to you!

    • Hi Mary. I think the best spine stretches are NONE. I don’t give my patients any spine stretches. Paul Williams made people worse because flexion stretching is exactly what bulges and herniates discs. McKenzie made people better than Williams, but according to this research he didn’t make them any better than if he just left them alone. I go into it in depth in the comments of that blog, including debates with several McKenzie therapists who thought they would tell me what’s what. If I have a patient with tight hamstrings then I’ll stretch their hamstrings, but never the spine. Even the hamstring stretches won’t help if they aren’t trained to bend at the hips and use that range to spare their spines. Thus in Spinal Flow it’s more strengthening of the entire body, some stretching of the hamstrings and shoulders, and a lot of practice of proper motor control and coordination, with an intention of making the ability to maintain a neutral spine during ADLs more habitual.

      And thank you!

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