- On maximal contraction, they excerpt around 100 kg of compressive force on the L5S1 disk. Submaximal forces increase anterior shear forces at the L5S1 angle (1).
- Tight hip flexors accentuate a lumbar lordosis (lower back arch, and often, low back pain).
3. Tightness will limit full hip extension, affecting walking and running stride length.
4. Tight hip flexors create upper back and neck adaptations/compensations often resulting in posture and pain.
5. Stretching them will give you a “high” as good as any drug, intoxicant, or other activity! (2).
6. Tight hip flexors make standing difficult, increasing your desire to sit. This perpetuates the problem. (see Neumann article below)
7. Tightness interferes with the hip joints ability to optimally dissipate loads because of the regions of the joint with thicker cartilage, no longer overlap. Over time, this creates wear on the joint surfaces (subchondral bone).
REFERENCES :
- Bogduk N.1997. Clinical Anatomy
- McGonigal: The Joy of movement
- Neumann; Kinesiology of the musculoskeletal system page 348 of the Lumbar Spin.
HIP FLEXOR CONTRACTURE AND ITS EFFECTS
Hips that remain flexed for a prolonged time often develop flexion contracture. This situation may be associated with spasticity of the hip flexors, gross weakness of the hip extensors, a painful or inflamed hip joint capsule, a chronically subluxed hip, or
confinement to the seated position. Over time, adaptive shortening occurs in the flexor muscles and capsular ligaments, thereby limiting full hip extension. One consequence of a hip flexion contracture is a disruption in the normal biomechanics
of standing. Normally, upright walking in humans is relatively efficient from a metabolic perspective. Upright standing in healthy persons can usually be maintained with relatively little muscular activation across the hips. The extended hip can be passively stabilized through an interaction of two opposing torques: body weight and passive tension from stretched capsular ligaments, especially the iliofemoral ligament. Standing with the hips near full extension typically directs the force of body weight slightly posterior to the medial-lateral axis of rotation at the hip. The force of body weight, therefore, is converted to a very small, but nevertheless useful, hip extension orque. The hip is prevented from further extension by a passive flexion torque created by the stretched capsular ligaments, such as the iliofemoral ligament. The normal upright posture tends to align the hip such that the thicker regions of articular cartilage overlap, producing maximal protection of the underlying subchondral bone.
The static equilibrium formed between the forces of gravity and stretched connective tissues minimizes the need for metabolically “expensive” muscle activation during quiet standing. Of course, the muscles of the hip can contract strongly to provide greater stability when needed, especially when the body is subjected to potentially destabilizing external forces. With a hip flexion contracture, the hip remains partially flexed while the person attempts to stand upright. This posture redirects the force of body weight anterior to the hip, creating a hip flexion torque. Whereas gravity normally extends the hip during standing, gravity now acts as a hip flexor. In order to prevent collapse into full hip and knee flexion, active forces are required from hip extensor muscles. In turn, the metabolic cost of standing increases and in some persons, over time, increases the desire to sit. Often, prolonged sitting perpetuates the circumstances that initiated the flexion contracture. Standing with a hip flexion contracture interferes with the joint’s ability to optimally dissipate compression loads across the hip. Hip joint forces increase in response to the greater muscular demand to support the flexed posture. Furthermore, standing with partially flexed hips realigns the joint surfaces such that the regions of thicker articular cartilage no longer optimally overlap. This arrangement theoretically increases the stress across the hip, which over time may increase the wear on the joint surfaces.
Therapeutic goals for most impairments of the hip should include, when appropriate, maximizing hip extension. In general, this is achieved through strengthening the hip extensor muscles and stretching the hip flexors muscles and the capsular ligaments— most important, the iliofemoral ligament. Activation of the abdominal muscles through posterior tilting of the pelvis may also encourage extension of the hip joint. The capsular ligaments of the hip may be further stretched when extension is combined with slight abduction and internal rotation—the close-packed position of the hip.
Stretching physiology made simple
When we stretch, as in the example above, receptors within joints, tendons and muscles detect movement and changes in muscle length and tension. These receptors alert the central nervous system (CNS) to this event for an appropriate response. If you stretch too fast, for example, your muscles will contract to prevent damage.
Aside from stretching, receptors alert your CNS to events such as jumping and landing, leaning, or touching something hot. Reflex signals travel to the spinal cord and back in what is called a reflex ‘arc’. This enables a speedy response. It takes a second or two for messages to reach the brain itself – too long in this instance. Often, it is only after the reflex has occurred and the message arrives in the brain that you become aware of it.
We have a complex array of receptors and reflex arcs linking our muscles to our central nervous system. Two stretch receptors are most relevant to us.The muscle spindle stretch receptor detects changes in length and the speed of those changes. Basically, when a muscle stretches, the spindle sends a signal to the spinal cord, which then signals back to the to the muscle to contract and resist the stretch. This is known as the ‘stretch reflex’. Bottom line: Stretching at speed, like ballistic stretching, is counterproductive. It will fire the muscle spindle stretch receptor and cause the muscles to contract. The Golgi tendon organ (GTO) is a different story altogether. This receptor organ, located where the muscle and tendon join, detects changes in muscle tension. When tension increases, particularly if there is no limb movement, it signals muscles to relax to prevent injury. The GTO is like a thermostat, flicking off the heater to prevent a meltdown. The GTO forms the basis of what is called the contract/relax (C/R) technique; just one of the many found in the body of work known as PNF or proprioceptive neuromuscular facilitation. We will use this C/R technique throughout this book to deepen and accelerate our flexibility progress.
Here’s how it works:
- Take yourself VERY SLOWLY into a mild stretch. We call this the POINT OF TENSION, or POT. Moving quickly will trigger the stretch reflex. On a scale of one to ten, one being not much of a stretch and ten being complete agony, we
suggest a score of five or six. Hold the position for five breaths and settle. - Contract the muscles that you are trying to stretch. We will give you cues, of course; although it may seem counterintuitive, contract the muscles we recommend for five seconds. Use around 30 % of your maximum effort, and start gently.
- Relax totally and restretch to the new position. Don’t expect miracles, but you can expect to be able to go further into the stretch, often between 1 to 10 centimetres further. Hold the new POT for fifteen breaths.
Contract/relax in the posterior stretch
- Press the carriage away to the POT. Hold for 5 breaths.
- Contract the muscles you are stretching. In this case, it is the hamstrings. Contract for 5 seconds by pressing your feet down into the carriage. Use 30% of maximum force. The GTO will signal increased tension via a sensory nerve to the spinal cord. A relaxation signal will travel to the muscle, facilitating a re-stretch.
3.Relax and re-stretch to the new POT. Hold for 15 deep breaths.
Kneeling Hip Flexors
HOW TO STRETCH: Photo A
– Kneel next to box, front foot in front of knee
– Keep spine vertical and tilt pelvis backwards
– Tighten abdominal muscles
– Lean hips forwards towards floor
HOW TO CONTRACT: Photo B
– Press back knee into floor as if trying to swing the leg forward
HOW TO RESTRETCH: Photo C
– Tuck pelvis further and tighten abdominal muscles
– Press arm down into opposite knee
– Lean hips forwards towards front foot
PARTNER VARIATION: Photo D
– Partner aligns pelvis horizontally
– Partner presses pelvis towards front foot
Major muscles stretched
- Iliopsoas
- Pectineus
- TFL
Lunge Pose
HOW TO STRETCH: Photo A – Kneel as pictured, keeping arms inside of front foot
– Keep spine straight
– Take rear leg back as far as possible
– Keep front knee open at about 100° angle
– Sink hips towards floor
HOW TO CONTRACT: Photo A – Press both feet down into floor (do not move)
HOW TO RESTRETCH: Photo B
– Lean hips closer to floor, OR for more effect lift rear knee from floor (do not allow hips to lift)
PARTNER ASSIST: Photo C
– Partner presses down onto sacrum and rear of hip joint
– Partner lifts leg by pulling thigh up into straight leg position
Major muscles stretched:
Rectus femoris
Iliopsoas
Adductors magnus
Gluteus maximus
Lunge Pose Variation
HOW TO STRETCH: Photo D
– Lower yourself onto elbows
– Keep spine straight as possible
HOW TO CONTRACT: Photo D
– Press rear foot into floor
HOW TO RESTRETCH: Photo E
– Keep rear leg straight
– Twist spine and pelvis away from rear leg, towards front leg
– Keep hips low to floor
Major muscles stretched
1.TFL
2.Anterior portion of gluteus minimus and medius
3.Iliopsoas
The Lunge is a strong stretch for the rectus femoris and adductor magnus seen below.
Psoas major can also be seen.
Keeping the back straight by lifting the chest will engage the latissimus dorsi. This will tension the thoracolumbar fascia and support the lower back region.
Rectus femoris attaches from two points just under the front tip of the pelvis known as the ASIS. The psoas major can be seen attaching to the front of the lumbar vertebra. It joins with the illiacus and then wraps around to insert onto the lessor trochantor of the femur.
A portion of gluteus maximus inserts onto the leg bone or femur. As a result, when the leg is strongly flexed like this it will stretch. The adductor magnus once crossed the knee joint. Over time, its tendon became the lateral knee ligament. A portion of it will also stretch in this position.
