Despite what P90x tells you, your muscles don’t need to be confused because they’re already pretty dumb. Muscles don’t know how much weight you’re actually lifting, they only understand tension whether that be acute or chronic. Ever wonder why your hamstrings feel "tight" despite the fact that you stretch them almost daily? Perhaps it's time to think critically about the issue rather than just defaulting to commonly suggested solutions.
Muscles will only contract and relax when they receive a stimulus from neurons originating in your nervous system. Muscular tension can be present due to a lack of stability within a joint, as a compensatory pattern for an inhibited muscle, or to protect against a perceived threat (whether imaginary or actual in nature). For example, think about when someone jokingly tries to punch you in the stomach, what's the first thing that happens? You tense your abs as a protective mechanism to ensure the safety of your vital organs. So, when a muscle becomes hypertonic - a state of low grade, constant contraction - it's important to look at why the muscle (your hamstrings in this case) is guarding movement within a specific range of motion. Stretching will indeed cause a decrease in the neural input being sent to a muscle and thus reduce the resting tone. However, if the muscle is weak or inhibited due to inactivity, poor breathing patterns, or improper joint positioning, then it will slowly regain that tension as your body fights for stability. Now, this may not be the case with all folks as some may have bony limitations (e.g. hip impingement) and structural deformities of the pelvis (femoral retro/ante version), but for the vast majority of people, they will notice quite a drastic improvement in range of motion (ROM) within their distal segments when proximal stability is prioritized. In other words, when your core is firing properly, the torso provides a stable platform which allows your muscles to produce force through your limbs.
Let’s take a look at another problem area as it relates to the concept of hamstring tonicity: the lumbar spine. Low back pathologies are one of the largest issues in the medical community today and sedentary lifestyles and desk jobs are making matters worse. We need to remember that certain joints within the body are designed to be mobile: hips, shoulders, ankles, and thoracic spine. However, others should remain primarily stable: feet (specifically the arch), knees, scapulae (technically requires both), elbows, and lumbar spine. When performing any sort of basic motor pattern - push, pull, squat, hinge, lunge, etc. - the spine should remain in a neutral position throughout the entire range of motion. This optimizes joint mechanics and reduces stress placed upon tendons and ligaments. We now know from spinal biomechanics researcher Dr. Stu McGill's work that spinal micromovements generate the highest risk for low back pathologies so learning to control segmental motion while keeping a stable torso is one of the best strategies to help reduce low back pain. If you’re not sure how to actually accomplish this then you can refer to my article here on the subject: Ground Based Core Training. But what happens when things go wrong? Some feel fine while they’re running but then can't get out of bed the next morning. Others have no issues when they're upright but then suffer the unfortunate fate of a tweaked back while picking their kids up off the ground.
As I mentioned earlier, when the body doesn't have a stable base to generate tension from, you "leak" energy throughout the system and other muscles have to compensate in order to "pick up the slack". When the glutes are compressed in a seated position, blood flow is reduced and they become inhibited. Dr. Stu McGill has coined the term “glute amnesia” in which folks actually lose the ability to contract their glutes. If your core and glutes aren't active and firing before your next run, your spinal erectors may end up working twice as hard and pull your hips anteriorly putting the hamstrings on stretch with every stride. If one side of your pelvis is weak (hamstrings in this case), then the body will try to “hunt” for stability by locking down that weak muscle group to prevent injury. To quote legendary strength and conditioning coach, Pete Bommarito:
"Tightness is secondary to weakness."Protective tension exists for a reason - it's not an issue with the sarcomeres, it's an issue with your central nervous system and muscular activation. Always look down and upstream from the problem; if your hamstrings feel tight or adaptively short, they’re likely not the main issue, just a symptom of a larger system malfunction. Think of your pelvis like a bucket of water, if it becomes anteriorly tilted (aka the bucket tips forward and the water spills out), then your hamstrings will be actively lengthened before you even try to flex or extend your hip.
It's no wonder they feel chronically tight, they’re constantly under stretch when in a standing position. However, if you try to stretch them even further to help facilitate relaxation you can actually cause more issues. For example, the head of the femur can be pulled forward in the acetabulum due a lack of glute recruitment, which ends up creating more instability within the hip joint. As another great strength coach Eric Cressey once put it:
"Stretching out of alignment causes instability, strengthening out of alignment reinforces dysfunction and leads to injury."
In order to get your hamstrings to “shut off”, you have to fix your pelvic positioning by learning how to engage your abdominals and down regulate neural input to your spinal erectors and hip flexors (think: foam rolling and breathing drills).
Within your warmup, ALWAYS emphasize an element of core and glute activation. Side/front planks and glute bridging variations are simple, easy, and effective. Also, make sure that you're not just doing one continuous plank - you're trying to get your nervous system fired up before you train or head out for a run but, often times muscular endurance wanes after the first few seconds of contraction. Shoot for sets of 3-4 with 10-15 second repetitions of MVC (maximal voluntary contraction). Meaning, you want to squeeze everything as hard as you can (glutes, fists, quads, anterior core, adductors, etc.) to make sure that it's active and firing properly before you step under the bar or head out on the trail. However, make sure you’re breathing throughout the duration of the repetition, holding your breath is counterproductive to your goal. A great cue is to think about "pulling your elbows towards your toes and make your body as stiff as a board." If you start shaking, don't worry, you're doing it right. Here's a good activation series you can try before your next workout routines or run:
Don't just assume tightness is simply a muscular length issue; it could be something entirely unrelated and the muscle is simply guarding that range of motion as a protective mechanism. Remember, your body is always talking to you; it’s just a question of whether or not you’re actually listening.
Mike Wines has trained a wide variety of athletes and clients and seeks to provide programming and movement based solutions to match each individual’s goals. He is also the content editor at Muscle & Strength.