The hamstrings & low back pain

Are Tight Hamstrings Really Causing Your Low Back Pain?

Low back pain (LBP) is extremely common, affecting up to 80% of people at some point in their lifetime. One of the most frequently blamed contributors is hamstring tightness, often described as shortened muscles or reduced flexibility in the back of the thighs. But in people with low back pain, is hamstring “tightness” really just a flexibility problem? The short answer: not always.

How Hamstring Tightness Can Contribute to Low Back Pain

It’s true that reduced hamstring flexibility can play a role in low back pain.

When the hamstrings are tight, they:

• Pull downward on the pelvis

• Alter pelvic alignment

• Create muscle imbalances

• Restrict joint movement

• Contribute to postural asymmetries

Because the lumbar spine sits on the pelvis, any dysfunction in pelvic alignment or movement is often transferred directly to the low back resulting in pain, stiffness, or limited motion.

Tight hamstrings can also:

• Increase tension through the posterior fascial line

• Create trigger points in muscles and fascia

• Reduce hip and lumbar range of motion

• Increase strain on the low back during daily activities

Hamstring Anatomy: Why They Matter So Much

The hamstrings consist of three muscles located on the back of the thigh:

• Semimembranosus

• Semitendinosus

• Biceps femoris

These muscles attach at the ischial tuberosity (commonly called the “sit bone”) and cross the hip and knee joints. When excessive tension is present in the hamstrings:

• They pull downward on the sit bones

• The pelvis is positioned abnormally

• Pelvic joint motion becomes restricted

Since the lumbar spine relies on proper pelvic positioning for healthy movement, these changes frequently contribute to mechanical low back pain. But there’s more going on than muscle tightness. As Ulrik Sandström famously said, “Muscles are stupid and they do what they’re told.” In other words, the nervous system, not the muscle, is in control.

The Stretch Reflex Explained

Your body has a built-in protective mechanism called the stretch reflex. When a muscle is lengthened, sensory receptors signal the nervous system. If the stretch approaches what the brain perceives as an unsafe range, electrical activity increases and the muscle contracts to prevent injury. For example:

• When you bend forward to pick something up

• The hamstrings lengthen

• As you approach your perceived end range, the stretch reflex activates

• You feel “tightness” and are prevented from going further

This is normal and protective.

Why Hamstrings Feel Tighter in People With Low Back Pain

In people with low back pain, research shows that:

• The stretch reflex activates earlier

• Electrical activity in the hamstrings rises faster

• The nervous system has a lower tolerance to stretch

The result? Hamstrings feel tight, restricted, and inflexible—even when they may not be structurally shortened at all. In these cases, the muscle isn’t the problem. It’s simply responding to overprotective input from the nervous system.

Why Stretch Therapy and Soft Tissue Manipulation Work

Hamstring-related low back pain is often influenced by multiple factors, including:

• Myofascial trigger points

• Fascial adhesions

• Restricted hip joint mobility

• Overactivity of antagonist muscles (hip flexors and rotators)

• Nervous system hypersensitivity

Stretch Therapy (ST) combined with Soft Tissue Manipulation (STM) addresses both mechanical and neurological contributors.

What These Techniques Do

• Release restrictions in muscles and fascia

• Improve hip and pelvic joint mobility

• Reduce trigger points

• Improve neuromuscular coordination

• Restore balance between opposing muscle groups

How Stretch Therapy Reduces Low Back Pain

Repeated Stretch Therapy improves stretch tolerance which is the amount of length a muscle can reach without pain or threat perception.

As tolerance improves:

• The nervous system delays activation of the stretch reflex

• The brain recalibrates what it considers a “safe” range

• Muscles stop contracting prematurely

• Deeper, more effective stretching becomes possible

This allows for:

• Improved muscle extensibility

• Better joint motion

• Healthier fascial glide

• Reduced stress on the pelvis and lumbar spine

The result is less low back pain and improved movement confidence.

The Key Takeaway is:

Hamstring tightness in low back pain is not always a flexibility issue. Often, it’s a nervous system-driven protective response. Treating low back pain effectively requires addressing:

• Muscles

• Fascia

• Joints

• And the nervous system itself

That’s why a comprehensive approach rather than aggressive stretching alone leads to better, longer-lasting results.

Q & A:

Can tight hamstrings cause low back pain?
Yes, but not always due to muscle shortening. In many cases, the nervous system limits hamstring length through an overactive stretch reflex.

Why do my hamstrings feel tight even when I stretch them?
Your nervous system may be protecting the area due to low back pain, causing the muscles to contract earlier during stretching.

Does stretching help low back pain?
Yes—when combined with soft tissue work and neuromuscular techniques that improve stretch tolerance and reduce nervous system sensitivity.

What’s better than stretching alone for hamstring tightness?
A combination of Stretch Therapy, soft tissue manipulation, joint mobility work, and nervous system regulation.

Watch how to combine hamstring STRETCHING with fascial STRETCHING

Take-away: Hamstring muscle and facial restrictions as well as decreased stretch tolerance can contribute to LBP. ST and STM address these issues effectively decreasing LBP.

References

Halbertsma JPK, Goeken LN, Hof AL, et al. (2001). Extensibility and stiffness of the hamstrings in patients with nonspecific low back pain. Arch Phys Med Rehabilitation. 2001; 82: 232-8.

Kalyan B. Bhattacharyya. The stretch reflex and the contributions of C David Marsden. Annuals of Indian Academy of Neurology.2017.

Roberta Y W Law  1 , Lisa A Harvey, Michael K Nicholas, et al. Stretch exercises increase tolerance to stretch in patients with chronic musculoskeletal pain: a randomized controlled trial. Physical Therapy. 2009 Oct;89(10):1016-26

Halbertsma JPK , Goeken LNH. Stretching exercises: effect on passive extensibility and stiffness in short hamstrings of healthy subjects. Arch Phys Med Rehabil. 1994;75:976–981.

Magnusson SP , Simonsen EB, Aagaard P, et al. . A mechanism for altered flexibility in human skeletal muscle. J Appl Physiol. 1996;497:291–298.

Phil Page, PT, PhD, ATC, CSCS, FACSM. Current concepts in muscle stretching for exercise and rehabilitation. International Journal of Sports Physical Therapy. 2012 Feb; 7(1): 109–119.