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Isaac Callihan


December 7, 2023

Stop Stretching Your Hamstrings! - Do THIS Instead!

Hamstring stretching has been listed as a remedy for sciatica, back, hip, and leg pain. Fitness and yoga courses instruct people how to stretch their hamstrings by bending forward from standing or lying with the knees straight and ankles flexed creating a targeted stretch for the hamstring muscles.

Stretching the hamstring muscles will not make them longer because the tension or contraction of a muscle is under control of the nervous system. You simply cannot make a muscle longer by pulling on it. Hamstrings do not exist in isolation from the rest of the body; where the global reality is that all parts affect the whole. Many people injure their spine and lower backs, tear or inflame hamstring tendon attachments and even rupture discs doing stretches such as seated and standing forward bends in yoga.

Keeping the back muscles and hamstrings strong and tight is good for your body.

These muscles of the back body (extensor chain) keep the body upright for activities such as walking and running. The extensor chain includes the erector spinal muscles as well as the hamstrings, and gluteal muscles and even the plantar fascia and muscles in the arch of the foot.

Oddly enough, people with strong functional back and gluteal muscles may have trouble bending over with straight knees because their extensor chain works efficiently.

This is not a problem unless one believes the flexibility myth that being able to touch the toes without bending the knees is a good indication of health and agility. Those who are unable to do this pose are labeled inflexible and it is the hamstring muscles that become the ‘fall guy’ for the so-called “inflexibility”.

There are dubious benefits in stretching the hamstrings as it does not contribute to strength in the butt or the back and in fact, the flat lumbar/sacral position created in forward folds may give you a C shape to your spine and a flat lower back and butt. This is because the ligaments that hold our natural lumbar curve and sacral nutation become lax from forward bends that target the hamstrings.

Hypermobile folks who do hamstring stretches with ease are blissfully unaware that in many cases, reversing the natural tilt of the sacrum and pulling on the hamstring area by using muscular forces to bend with both knees straight, is stretching out the ligament tension needed to keep the hip joint stable and the spine upright in its natural curves throughout a lifetime. Also the hip socket (acetabulum) is under tremendous compression loads when we do poses that push the belly into the thighs.

Ligaments do not have a lot of sensory nerves and so we cannot feel when they are being compromised. It takes years for pathology in the hip joints to show up, but a continuous tugging on the SI (sacral/hip/ hamstring) area that occurs in these poses undermines the curving forces needed for shock absorption and hip stability. When the hamstring ligaments that attach to the pelvis, get injured, it can take a year for the ligaments to recover.

Why do my hamstrings feel short and tight? Hamstrings are most likely not short and tight but long, tense and weak. Pulling on them will only give a few minutes of relief as the stretch reflex in the nervous system creates inhibitory signals to create length and keep tissues from tearing. When doing compartmentalized hamstring stretching like forward bends, the feeling of relief from the stretch reflex only lasts about 20 minutes and then the hamstrings feel tight again. For this reason, hamstring stretches never seem to work and must be repeated over and over. Hamstrings are ‘tight’ because the front body is short so shortening the front body to stretch the back is like digging a hole in the sand.

Why then do my hamstrings feel tense?

Most people sit a lot during the day and this weakens the back muscles and hamstrings. Breathing muscles are inhibited and the muscles of the back body are not working since the chair back works like a brace. In particular, the groin and hip flexor muscles shorten and when we stand up, they still retain a shortness that puts a strain on the extensor chain (muscles of the back body).

Hamstrings may have restricted blood flow and if the trunk muscles are weak or shortened, there may be poor pelvic alignment that leads to inflammation of the hamstring attachments. Weak back muscles mean more work for the hamstrings when standing and breathing can be shallow as these muscles support the spine and lift ribs to inflate the lung tissue.

So please stop stretching your poor hamstrings and remember that the nervous system controls tension in the hamstrings and stretching them to make them ‘longer’ is an antiquated myth, not grounded in any anatomical reality. Pulling on any muscle in a static stretch will not make a muscle longer but might damage the tendons and ligaments that keep joints stable during movement. Instead take long walks, lay on a big exercise ball to open the front of your body and try a standing desk.

The body is global; not made of parts.

The mindset in Western fitness and even yoga has been to stretch parts like the hamstrings, and strengthen pieces with the idea that the whole body will then come together in one big organized picture. It will not and over a period of time, yoga practitioners like any discipline that has positions or compartmentalized poses that over-ride natural anatomical function, will suffer from injuries in the long and short term. When posture is naturally aligned, the human body stays agile without the need to do intense stretches to relieve tension of the hamstrings.

Coach Isaac

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