There’s a well-known saying in strength and conditioning by Charles Poliquin that, “You can’t fire a cannon from a canoe.” You can probably imagine that if you fired a cannon from a canoe, either it wouldn’t hit where you wanted it to, or you’d sink the canoe … and likely both. Accuracy and stability require a solid platform. Similarly, a poorly developed core in a trail runner can result in mechanical inefficiencies and injury issues.
Most of us at least know a few things about anatomy and core strength, but the nuances are often overlooked. Specifically, it’s the tiny muscles called multifidi, interspinalis, and rotatores along your spine and the transverse abdominis and obliques that are really important, more so than the six-pack abs we all know about.
When the multifidi, interspinalis, and rotatores spinal stabilizers are weak or inactive, our body will either suffer the consequences of instability or find an inefficient way to create stability. The consequences of instability in the lumbar spine can create different lumbopelvic injuries, cause pain, aggravate nerves, inhibit muscle recruitment, accelerate disc degeneration and have negative effects on running economy.
If our body takes the alternate route and finds another way to create stability, it usually does so by making big muscles tight—muscles like the psoas, TFL, QL, erectors and pelvic floor—in order to do the job of the little muscles. This is non-functional stability because it often causes problems and makes us less efficient. Think of this sort of like an artist trying to create a detailed sketch drawing only with her big muscles, like her biceps, triceps and deltoids.
Anterior Trunk Stabilizers
Along with the spinal stabilizers, the transverse abdominus and obliques are also critical for trunk stability. The fibers of the transverse abdominus run from the sides of your body straight in toward your belly button. And the fibers of your internal and external obliques run in toward your belly button, but at an angle, superficial to the transverse abdominus. When the transverse abdominus contracts, it tightens inward like cinching up a corset. The obliques support this action and also prevent rotation during your running gait, helping to stabilize the lumbar spine and the pelvis.
On your next run, spend the first few miles running like normal, then every couple of minutes, focus on engaging your transverse abdominus (cinch up your corset). This might be hard at first if you’re not used to engaging that muscle, but you may notice your pace naturally gets a little faster. This is you harnessing your energy more effectively into forward movement.
In terms of running economy, the spinal stabilizers, transverse abdominus and obliques are important for reducing extra work. When you generate force with your legs and apply that force to the ground, you want it to propel yourself forward with minimal energy loss. But without good trunk stability, you can’t harness all of the force you’re producing and end up losing force in all directions. Picture Phoebe from Friends running through Central Park.
Shake It Off
It’s not realistic to think about these specific muscles all the time while running. Instead you need to use targeted strength to get these muscles strong and active so they kick in on their own. Strengthening these types of muscles often requires specific prolonged hold exercises.
This brings us to the concept of phasic shakes, a concept developed by the physical therapist Gregg Johnson. Essentially, during targeted prolonged hold exercises, you start to experience shaking. This is the result of big (phasic) muscles getting fatigued. You’ve likely experienced this with a front plank or side plank. That phasic shaking is actually good, because it’s a sign that your smaller, stabilizing (tonic) muscles will kick in as those big muscles fatigue. Ideally, the shaking would even stop once those smaller, stabilizing muscles are doing their job.
As you continue to get better at recruiting the small, stabilizing muscles, you may even get to the point where you skip the big muscles kicking in and no longer get those phasic shakes. You don’t need to do this with every exercise, just the specific ones that help recruit those smaller stabilizers. It’s always best to work with a coach or physical therapist to make sure you’re doing things correctly, but here are a few favorites.
- Baby Bug: Lie on your back, bring your knees up toward chest until you have a 90-degree bend at the hips, grab the front of your thighs and gently push straight up toward the ceiling. Think about keeping your back flat and pushing your belly button toward the floor, peeling your sacrum slightly off the ground. Hold for 45 to 60 seconds or until the phasic shakes stop.
- Quadruped Hover: From a quadruped position, tuck your toes and hover your knees one to two inches off the ground. Hold there for 45 to 60 seconds or advance this by adding some knee taps to the ground, shifting forward and back, or shifting in a circle. Make sure to think about getting long through your spine and tightening your corset.
- Physio-Ball Dead Bug: From the same position as Baby Bug, hold the physioball between the backs of your arms and fronts of your legs, squeeze arms and legs into the ball, making your back flat. Extend opposite arm and opposite leg, staying in a range where you can maintain a flat back.
- Warrior Three Hold: From the yoga pose Warrior Three, make sure your hips are parallel to the ground, reach long through your back leg and push into the ground with the other foot. Think about creating space between your lumbar spine to allow those spinal stabilizers space to do their job. You can add rotations in and out of Warrior Three when you’ve mastered the hold.
Core Strength For Running Economy
- Incorporate strength exercises that specifically target these muscles.
- Prolonged holds at relatively low intensity are critical to access these smaller muscles. It may take 30 seconds to two minutes to wake up some of these muscles, but you’ll get better at it over time. If you get the phasic shakes, try to keep holding.
- Consistency and frequency are key. For most people, this is three to four times per week, but in cases of injury, it might mean every day or twice per day for a while.
- Think about the muscle action you are trying to create. For the small lumbar stabilizers, this means lengthening the spine and creating space between the vertebrae. For the transverse abdominus and obliques, this means tightening your corset.
- Keep it simple and do the basics well before you get complicated.