Inhibited muscles & how to re-activate
What is are inhibited muscles?
And how can I re-activate my muscles?
In simple terms, muscle inhibition is like your nervous system putting a 'speed limiter' on a muscle. It occurs when your brain or spinal cord sends signals to prevent a muscle from contracting fully or effectively.
It’s rarely a problem with the muscle fibres themselves; rather, it's a communication glitch between the nerves and the tissue.
Why Does It Happen?
Your body usually inhibits muscles as a protective mechanism. Here are the most common triggers:
- Pain & injury: If a joint is injured or swollen, the brain shuts down the surrounding muscles to prevent further damage. This is known as Arthrogenic Muscle Inhibition (AMI).
- Overactive neighbours: If one muscle is extremely tight or overworked, its "partner" on the opposite side of the joint often gets signaled to relax. (e.g., tight hip flexors can inhibit the glutes).
- This is also a normal physiological response, the same one as is tested with a deep tendon reflex i.e. the patella reflex. It means that when you are using/contracting a muscle, the one on the opposite side of the joint relaxes to allow the movement - otherwise it would get torn.
- E.g. if you are straightening your knee (using the muscles on the front of your thigh, your quads), you need your hamstrings (the muscles on the back of your thigh) to relax or they could get torn - this is why hamstrings are vulnerable to tearing in high stress situations like on the football pitch!
- Restricted joints: Sacro-iliac dysfunction is just one area that often causes inhibition of the hip, pelvic and/or abdominals due to asymmetry and unstable movement patterns.
- Fatigue: When you push a muscle to its absolute limit, the nervous system reduces the power & speed signals to those fibers to prevent a tear.
- Post-surgery: After procedures like an ACL reconstruction, the quadriceps often 'go to sleep' and become very difficult to flex voluntarily.
How It Feels
You might notice muscle inhibition if you experience:
- 'Giving way': A feeling that a joint (like the knee) is unstable or might collapse.
- Muscle weakness: You try to squeeze the muscle hard, but it feels "mushy" or unresponsive.
- Compensations: Other muscles start hurting because they are doing the work for the inhibited one.
How to "Wake Up" the Muscle
Addressing inhibition usually requires more than just heavy lifting; you have to retrain the neural pathway.
- Isometrics (muscle energy techniques): Holding a contraction without moving the joint helps re-establish the nerve connection.
- Neuromuscular Stimulation: Using an e-stim device to artificially force the muscle to contract.
- Soft Tissue Work: Massaging the "overactive" opposing muscle to stop it from signaling the other to shut down.
- Mind-Muscle Drills: Slow, deliberate movements focusing entirely on the "feel" of the target muscle.
- Note:
Osteopathic techniques and
Neurological Integration are both extremely useful for helping your body re-align and 'releasing the handbrake' on your muscles.
Example 1: The abdominals = why can't I do a sit up?
It’s a common frustration! If you can do a 'crunch' but get stuck halfway up, (or can't even get your shoulders off the floor!) you're likely dealing with a tug-of-war between your core and your hips.
In a sit-up, the rectus abdominis (the 'six-pack' muscle) handles the first 30° of the movement. After that, the hip flexors are supposed to take over to pull your torso toward your thighs.
Here is the breakdown of what is likely happening:
1. The Underactive Muscles
These are the muscles that aren't providing enough "oomph" to complete the arc:
- Rectus Abdominis: If these are weak or inhibited, you can't get your shoulder blades off the floor to begin the move.
- Transverse Abdominis (TVA): This is your internal 'corset'. If it isn't bracing, your spine lacks the stable base needed to leverage yourself up.
- Obliques: These help stabilize the trunk as you move through the "sticky point."
- Gluteals: If your glutes/hip extensors aren't active, then the hip flexors/iliopsoas will be even more over-active.
2. The Overactive Muscles
When the core isn't firing correctly, other muscles try to 'cheat' to finish the rep:
- Hip flexors (Iliopsoas): If your feet fly off the floor when you try to sit up, your hip flexors are working too hard. Ironically, if they are too tight, they can actually pull on your lower back, making it harder for your abs to contract.
- Because the psoas attaches to your spine, it pulls your back into an arch. An arched back makes it mechanically impossible for the abs to shorten and pull you up.
- Neck flexors: If your neck hurts afterward, you’re likely pulling with your head to create momentum because the core isn't doing the lifting.
Why You Get Stuck
Most people get stuck at the transition point where the ribcage has to move over the pelvis. This is often due to lack of spinal articulation. If your back is stiff as a board, you’re trying to lift your entire torso like a heavy lever. If you can roll your spine one vertebra at a time, it requires significantly less raw strength.
Why are my abdominals inhibited in the morning?
Why can’t I do a sit up in the morning, but often can later in the day?
This is actually a very common problem, and it’s usually caused by a mix of spinal biomechanics and nervous system 'sleep inertia'.
1. Spinal Disc Hydration (The "Stiff Board" Effect)
While you sleep, your spinal discs (the "cushions" between your vertebrae) soak up fluid and expand. This is why you are actually slightly taller in the morning.
- Because your discs are plump and pressurised, your spine is naturally stiffer and more resistant to bending.
- Since a sit-up requires your spine to curl (flexion), your brain senses that extra pressure in your discs and inhibits the abdominals to prevent you from forcing a bend that might hurt your back. It’s your body's built-in safety brake.
2. The "Shortened" Hip Flexors
Most people sleep in a 'fetal' position or with knees slightly bent.
- After 7–8 hours in that position, your hip flexors (psoas) become physically tight and short.
- When you wake up and try a sit-up, those tight hip flexors immediately yank on your lower spine, pulling it into an arch. Once your back arches, your abdominals are mechanically 'turned off'.
3. Neural "Sleep Inertia"
Your nervous system operates at a lower voltage when you first wake up.
- Motor Unit Recruitment: It takes time for the brain to start efficiently recruiting high-threshold motor units (the ones needed for a 'fast-twitch' power move like an unassisted sit-up).
4. Body Temperature
Core body temperature is at its lowest right when you wake up. Cold muscles and tendons are less elastic. If the tissue doesn't want to stretch (like the muscles along your back), the opposing muscles (your abs) will be inhibited to avoid a 'tug-of-war' that could cause a strain.
Improving your sit-ups
To get your core "awake" and stop your hip flexors from taking over, we need to focus on sequencing. The goal is to ensure that the deep abdominals are ready to brace before the movement even starts.
Perform this circuit once, slowly, focusing on 'feeling' the muscles rather than rushing through the reps.
1. The 'Posterior Tilt' (the wake up)
Before you can sit up, you have to find your core.
- The Move: Lie on your back with knees bent. Try to flatten the small of your back against the floor so there is zero space between your spine and the ground.
- The Feel: You should feel your lower abs tighten.
- The Goal: Hold for 5 seconds, breathe out, and repeat 5 times. If you can't hold this tilt, a full sit-up will always be a struggle.
2. Dead Bugs (The Bracing Drill)
This teaches your core to stay engaged while your limbs move - essential for spinal stability.
- The Move: Lie on your back with arms reaching toward the ceiling and legs in 'tabletop' (knees bent at 90°).
- The Action: Slowly lower your right arm and left leg toward the floor simultaneously. Only go as low as you can without your lower back arching off the floor.
- The Reps: 5 per side, alternating.
3. Hollow Body 'Rock' (The Integration)
This mimics the mid-point of a sit-up where most people get stuck.
- The Move: Lie on your back, arms at your sides. Lift your head, shoulders, and feet about 2–3 inches off the floor.
- The Action: Shape your body like a banana. Press your lower back into the floor.
- The Reps: Hold for 15–20 seconds. If your back arches, tuck your knees in slightly to make it easier.
4. The "Roll Down" (going backwards to go forwards!)
Instead of going up, we go down. This uses gravity to help your brain learn the movement pattern.
- The Move: Start in a seated position with knees bent.
- The Action: Hug your knees to your chest to round your back. Slowly let go and try to roll down to the floor one vertebra at a time.
- The Challenge: Try to take a full 10 seconds to reach the floor. If there is a part where you 'drop' that is the exact spot where your muscle inhibition is occurring and you are losing control - really try to recognise when your low back starts to try to arch (hip flexors/iliopsoas are taking over) and stop before that point.
- The Reps: 5 slow descents (only as far as you can absolutely control it).
5. The 'Frog-legs' Sit Up
If you want to try a full sit-up after this routine, try the Frog-legs Sit-up:
- Sit with the soles of your feet together and knees dropped out to the sides (like a tailor stretch).
- This position mechanically relaxes the hip flexors, forcing your abs to do 90% of the work.
The Frog-Legs Sit Up
The Frog-legs Sit-up is a classic 'hack' used in sports like CrossFit specifically to isolate the abdominals by taking the 'cheating' muscles out of the equation.
Here is why it works and how it helps you get stronger:
1. It shuts down the hip flexors
When your knees are bent and feet are flat (the standard way), your hip flexors are in a prime position to pull.
By opening your knees out like a butterfly, you put the hip flexors in a shortened, mechanically disadvantaged state.
- Because the hip flexors can’t 'grip' as well, your brain is forced to recruit the abdominals to do the heavy lifting.
2. It Improves Range of Motion
Standard sit-ups are often stopped short by the hip flexors taking over.
The butterfly version allows your spine to move through a larger arc. This helps you build strength at the bottom of the movement, which is usually where people are weakest.
3. It Prevents Back Arching
By 'turning off' the hip flexors, you reduce the forward pull on your lower spine. This makes it much easier to keep your back rounded—which is exactly what you want for a sit-up.
A flat or arched back is usually what causes that 'stuck' feeling.
Note:
- Because the Frog Legs Sit-up forces the abs to work harder, you might find you can actually do fewer reps at first than you could with your feet anchored. Don't let that discourage you! That just means you've successfully stopped 'cheating' and are finally hitting the target muscle.
Quick Self-Test
Try a sit-up with your feet unanchored (nothing holding them down).
- If your feet fly up: Your hip flexors are dominant and your abs are inhibited.
- If you can't move at all: It’s a foundational core strength and "firing" issue.
N.B. If your back is tends to be stiff, particularly in the mornings, wait until later in the day to work on your sit-ups.
How to Fix It
Instead of struggling through 'bad' sit-ups, try these to wake up the right muscles:
- Eccentric Sit-Ups: Start at the top (sitting up) and lower yourself down as slowly as possible (count to 5). This builds the neural pathway without the "stuck" point.
- The 'J-Curl': Practice tucking your chin and rolling your spine down and up one inch at a time.
- Dead Bugs: These teach your TVA to stabilize your spine while your limbs move.
How do I know if my abdominals are inhibited?
And if they are, how do I activate them?
Since muscle inhibition is a neurological shutdown, you can't always just exercise your way out of it - you have to convince your brain that it’s safe to use the muscle.
The 'Lower Ab' Inhibition Test
This is the quickest way to see if your brain has 'muted' your core connection.
- The Setup: Lie on your back with your legs straight.
- The Test: Slide your hand under the small of your back (the natural arch). Now, try to squash your hand using only your stomach muscles.
- The Results:
- Active: You can crush your hand firmly without your butt lifting or your neck tensing.
- Inhibited: You struggle to close the gap, or you find yourself holding your breath or "shoving" with your heels to make it happen. If you have to hold your breath to create tension, your deep core isn't firing automatically.
How to Activate Them (The 'Wake-Up' Protocol)
If the test above was difficult, use these three steps to re-establish the connection.
1. The Tactile Cue (The Wake-Up Call)
Your brain follows your touch.
- While lying on your back, find your hip bones. Move your fingers two inches inward and one inch down.
- The Action: Cough or laugh. You’ll feel a muscle "pop" up under your fingers. That is your Transverse Abdominis (TVA).
- The Drill: Try to make that muscle firm up under your fingers without coughing. Poke it gently as you do it. This tells your brain exactly where the work needs to happen.
2. The Forced Exhale (The Neural Trick)
The diaphragm and the abdominals are neurologically linked. You can use your breath to "force" the abs to turn on.
- The Action: Take a deep breath in. As you exhale, blow out through pursed lips like you are blowing through a tiny straw.
- The Goal: Blow out until you have zero air left. You will feel your abs start to "shrink-wrap" and tighten at the very end of the breath. That is a 100% contraction.
- When you move from this routine into your actual sit-ups, keep these two things in mind:
- Exhale on the way up: Start your exhale just before you move. This 'pre-tenses' the abs so they are ready for the load.
- Look at your belly button: This keeps your chin tucked and your spine rounded. If you look at the ceiling, your back will straighten, and you’ll get "stuck" again.
3. Sensory Isometrics
Before you try a sit-up, perform a 'Stiff Plank'
- Get into a standard forearm plank.
- Instead of just hanging out there, pull your elbows toward your toes and squeeze your glutes as hard as possible.
- Do this for only 10 seconds. It 'shocks' the system into high-tension mode.
Why this helps your Sit-Up
When your abs are inhibited, your hip flexors (psoas) do all the work. Because the psoas attaches to your spine, it pulls your back into an arch. An arched back makes it mechanically impossible for the abs to shorten and pull you up.
- Activation "re-sets" your pelvis so the abs are in the right position to actually win the tug-of-war.
'Bracing' correctly versus just 'sucking in' your stomach?
This is a crucial distinction! Most people 'suck in' because they want to look thinner, but for a sit-up, sucking in actually weakens your structural integrity.
Think of your core like a tin can. A full, unopened tin can is incredibly strong; you can stand on it. But if you dent the side (sucking in), it collapses under pressure.
1. Sucking In (The 'hollow' mistake)
- What it is: Pulling your belly button toward your spine and moving your ribs upward.
- Why it fails: It uses the "vacuum" effect of your diaphragm. While it looks flat, it actually creates a narrower base. It’s hard to breathe while doing this, and it doesn't stabilize your lower back for the "pivot" part of a sit-up.
- The Feel: You feel "tight" in the front, but your back feels unsupported.
2. Bracing (The 'Shield' Technique)
- What it is: Expanding your midsection slightly in all directions (front, sides, and back) and then tightening it.
- Why it works: It creates Intra-Abdominal Pressure. This pressure acts like an internal airbag that supports your spine from the inside out.
- The Feel: It feels like you are getting ready for someone to punch you in the stomach!
Example 2: Gluteus maximus
For the Gluteus Maximus, the primary inhibitors are its functional opposites:
1. The Hip Flexors (The Primary Inhibitors)
This is the most common cause of "Gluteal Amnesia." When these muscles are tight or overactive (often from prolonged sitting), they signal the glutes to stay relaxed.
- Iliopsoas: Comprised of the psoas major and the iliacus. This is the strongest hip flexor and the glute's direct antagonist.
- Rectus Femoris: Part of the quadriceps group that crosses both the hip and the knee.
- Tensor Fasciae Latae (TFL): A muscle on the side/front of the hip that can become dominant if the glutes are weak.
2. The Synergists (The "Bullies")
Sometimes, instead of the opposite muscles inhibiting the glutes, the muscles that are supposed to help the glutes take over the job entirely. This is called Synergistic Dominance.
- Hamstrings: As we discussed, if the glutes aren't firing well, the hamstrings will try to do all the work of hip extension.
- Erector Spinae: If your glutes are "quiet," your lower back muscles will often overwork to tilt the pelvis, mimicking hip extension but actually causing back strain.
3. The Adductors (In specific ranges)
- Adductor Magnus (Anterior fibers): While the posterior fibers help the glutes extend the hip, the anterior fibers can act as flexors, contributing to that reciprocal inhibition if they are chronically tight.
Why This Matters: "Sitting Disease"
When you sit for hours, your hip flexors are held in a shortened position. Over time, they become "tight," and through reciprocal inhibition, your brain keeps the glutes in a state of neurological relaxation. This is why many people find it hard to "feel" their glutes working even when doing exercises like squats.