How to activate your quads
And why they aren't activating in the first place
Do you know how to activate your quads? Is neural inhibition impeding your ability to activate your quads or is it something simpler?
I've spent the last number of years both learning muscle control and teaching it. One of the most basic muscle activations that I teach is quadriceps (quads) activation. And I've taught it to people of different ages and different skill levels. And while neural inhibition may be part of the reason you can't activate your quads I'll suggest here that there may be a simpler reason.
Assuming you haven't been recently injured
First of all, let's assume that there is no problem with the actual wiring leading from your brain to your quads. And let's assume that you haven't recently injured your quads or a related muscle.
If you've just been injured, your brain may have shut down quad activation to prevent further injury. So don't go messing around if that's the case. You'll need to rest. But if that isn't the case, then read on.
The quads need opposition in order to function
The first thing to note is that in order for skeletal muscles to activate, including those that make up the quadriceps, they needs an opposing force to work against. So for example, if you flex your biceps, without allowing your elbow bend to change, your triceps will also activate. Your triceps activate so that your biceps have an opposing force to work against. In the process, your elbow, which is kept still when you "flex" your biceps, becomes stiff or stabilized.
What opposes the quadriceps?
Your hamstrings or your gastrocnemius or both. If either your gastroc or your hamstrings aren't working then that is one possible reason why your quads aren't activating.
They can't activate because they haven't got an opposing force to work against. And sure they may work in accelerated movements, or when doing a weight knee extension, or when working against body weight because they've got an external force to work against. However, in the absence of those, for controllable quads, they need the force created by opposing muscle activation to work against.
How to activate your calves
So let's say the calf muscle isn't functioning and that's inhibiting the ability of your quadriceps to activate.. What does your calf, or any other muscle, need in order to activate? A fixed or stable end point.
If you stabilize or stiffen your feet, and in particular your heel, you may find that you can activate your gastroc and that in turn allows you to activate your quads. So if you are doing knee extensions in order to activate or otherwise work on your quads, try stiffening your feet prior to the knee extension so that your gastrocnemius is anchored and thus can activate effectively.
Note that it if stiffening your feet and ankles, your your soleus, which is beneath the gastrocnemius may activate against opposing muscles at the front of the ankle. If you then try to activate your quads prior to extending your knee, your gastrocnemius may activate to provide the necessary opposition.
Anchoring and activating the hamstrings
You're quads may also fail to activate if your hamstrings for some reason are offline.
The hamstrings are a multi-joint muscle. They work on the back of your hip joint and knee joint. As with the calf muscles, the hamstrings also need a fixed endpoint to activate effectively. That could come from activating the calves, particularly the gastrocnemius, since its two tendons interlace with the hamstring tendons. However, another option is to anchor the hip bone.
Since the hamstrings attach to the sitting bone which is behind the hip joint, an option for anchoring them at the hip bone is to create a downward pull on the ASIC or the pubic bone or both.
One of the muscles that attaches to the ASIC (just below it) is the rectus femoris which is part of the quadriceps. There is also the sartorius and the tensor fascia latae. Another muscle that also may be important for resisting the pull of the hamstrings is the gracilis which attaches to the pubic bone.
Using the spinal erectors to anchor the hamstrings
Another option for anchoring the hamstrings at the hip bone is to use the spinal erectors to help create an upwards pull on the rear of the hip bone and even on the back of the sacrum. One sub-group of the spinal erectors that attaches to the back of the hip bone is the iliocostalis. Another which attaches to the long dorsal sacroiliac ligament is the lumbar portion of the thoracic longissimus.
Iliocostalis and longissimus both have attachments to the backs of the ribs.
If you slide or translate your ribcage forwards relative to your pelvis while keeping your ribcage vertical, you can allow your pelvis to tilt forwards. Try creating a downward pull on the backs of your ribs but resist it by creating a downward pull on the fronts of your ribs. You'll be exerting the iliocostalis and longissimus against the obliques and possibly the rectus femoris. You can accentuate their activation by pulling inward on the front and sides of the waist. This latter action is a function of the transverse abdominis muscle.
Prior to trying to use your hamstrings (and from there your quads), try generating tension at either side of the back of sacrum, where it connects to each hip bone. It may help if you imagine trying to tilt your sacrum forwards as if trying to flick or point the bottom tip of it rearwards. If using both legs, try to make the sensation even on both sides of the back of the sacrum. This tension comes from tensing the long dorsal sacroiliac ligament.
Adding tension to it may give you better control of your hamstrings and possibly your gluteus maximus and that in turn may give you better control of your quads.
Published: 2020 03 15
Updated: 2023 03 24
