From a functional anatomy standpoint, the core has two primary jobs:
1) to resist unwanted movement at the trunk in all three planes
2) to link the upper and lower halves to create and exert maximal force. In other words, the core isn't supposed to create movement; it's supposed to prevent it.
Why does it matter? As it relates to sprinting, the ability to resist excess movement at the trunk – AKA, core stability – is one of the primary factors that can make or break an athlete's sprinting mechanics. The reason is two-fold.
First, core stability is the key to preventing any potential energy leaks – or mechanical issues, in this case – from occurring. If an athlete runs with side-to-side arm action, it doesn't necessarily mean that they lack basic motor control. On the contrary, the case may be that they're unable to withstand the rotary forces imposed upon the trunk during the sprinting motion, in which case the arms may move across the body as a result.
Second, keeping the trunk locked into place enables the extremities to be leveraged to produce maximal force. This is in line with Dr. Stuart McGill's "proximal stability for distal mobility" concept, which essentially means that a stiffer core enables the arms and legs to move more efficiently and through a larger range of motion. Since both of these factors are crucial for maximizing force production and gaining more ground on each step, core stability is pivotal for maximizing sprint speed.
However, the problem is that there aren't many exercises that target core stability in an integrative, full-body manner. For example, the staple "anti-movement" exercises like ab wheel rollouts, Pallof presses, and side plank variations don't require the arms, legs, and hips to work actively and independently of one another. That's not to say that those exercises aren't useful. We use them quite frequently with our athletes – but rather that they're geared less toward sprinting and more toward core stability in general.
Considering that, the following four exercises can be a game-changer for honing in on core stability in a more "sprint-specific" manner. Like the previously mentioned exercises, they force the core to remain stable; however, they also force the arms, legs, and hips to work actively and independently of one another at the same time. Here's why (and how) they work.
The hanging mini-band march involves similar muscle actions to the sprinting motion in that it 1) reinforces active hip flexion throughout a full range of motion, 2) forces a strong knee drive against the resistance of the mini-band, and 3) requires tucking the ribs down, so to speak, to maintain a neutral spinal position.
These three factors make the hanging mini-band march mostly applicable to sprinting, as each component is at the core (no pun intended) of optimal sprinting mechanics. Think about it: at top speed, a sprinter can only create maximal power if their hips and knees reach 90 degrees of flexion. Likewise, doing so while putting as much force into the ground as possible requires actively driving the knee up before bringing it back down. At the same time, maintaining a neutral spine is crucial for preventing any postural breakdowns from occurring.
Together, these factors make the hanging mini-band march a three-in-one exercise with a direct carryover to improved sprinting mechanics.
Like the hanging mini-band march, the sprinter dead bug can be categorized as sprint-specific to an extent, albeit in a few different ways.
When performed correctly, the sprinter dead bug involves a powerful isometric push from the stationary leg into knee and hip extension – the action that occurs before ground contact – while the spine remains neutral. Second, it reinforces ankle dorsiflexion, or a toes-up position, which is crucial for a powerful foot strike. Third, the setup involves pre-setting the hips into 90 degrees of flexion, which – as mentioned previously – is a key component of proper sprinting mechanics. Lastly, the limbs are working reciprocally, which further likens the sprinter dead bug to a sprint's motion.
These actions coincide; the isometric lower body push with the spine in neutral, the dorsiflexed position of the ankles, the pre-setting of the hips at 90 degrees, and the reciprocal motion of the limbs. There aren't many core-based movements that check as many boxes as the sprinter dead bug related to speed.
For the most part, the medicine ball dead bug is similar to the sprinter dead bug. However, what separates it is that it requires the non-working limbs – that is, the arm and leg in contact with the medicine ball – to remain strong and stable while actively driving toward one another.
In other words, whereas the sprinter dead bug involves pushing "out" against an immovable force, the medicine ball dead bug involves pushing "in," albeit with the addition of the opposite arm doing the same. In this case, the inward push's primary benefit is that it amplifies the feel of a completely braced core. If tension is lost in either limb at any point, the medicine ball will inevitably dropdown.
Also, the medicine ball dead bug is similar to the hanging mini-band march in that it involves an active knee drive against resistance. The medicine ball doesn't move as the mini-band does; still, reinforcing the feel of driving the knee into an optimal position can work wonders for dialing in proper sprint mechanics.
As mentioned previously, resisting excess rotation at the trunk is crucial to maximize power and prevent potential energy leaks. One of the components of anti-rotation core training that often falls under the radar is resisting rotation while moving dynamically. The ability to remain healthy and stable throughout the entire trunk while moving at high speeds is pivotal.
In this regard, the split stance rotational medicine slam fits the bill exceptionally well. The core is forced to stabilize the trunk while linking up the shoulders and hips while withstanding the high-velocity slam's dynamic rotary forces. Moreover, the split stance component throws a hip stability challenge into the mix, as the hips have to work hard to avoid shifting, swaying or tipping over.
Since sprinting is the most dynamic activity that the human body can perform, this makes the split stance rotational medicine ball slam extremely applicable related to the violent nature of the sprinting motion. Just as the torso needs to remain stable while sprinting to maximize power, so too does it need to stay stable during the split stance rotational medicine ball slam.