Throughout 2016, we will break down the fundamentals of efficient running mechanics, and how the demands of the ultra distance – terrain, weather conditions and even gear – impact how we run. This month, we identify ideal trunk alignment and position.
The trunk – by which I mean the spine and pelvis, including the head – is the true powerhouse of running: it houses the heart and lungs, and is the chassis off which our arms and legs push and pull to propel us. By weight, it is also the heaviest part of our bodies. As such, its alignment and orientation play a vital role in our forward progress.
What Is Ideal Trunk Alignment?
Ideal trunk alignment is a challenging balance between “tall” and “forward.” “Tall” refers to the neutral head-to-tailbone alignment of the spine, where the mid-trunk is arched and chest is open: midway between over-extended, or forward slumped.
Complimenting a tall trunk is one that is forward leaning. When standing still, adequate trunk-forward orientation is just enough so that the standing weight is in the toes, yet you are not quite falling forward.
Benefits of Ideal Trunk Posture
Full lung volume. Ultrarunning is aerobic: we need a lot of oxygen, and that starts with a full breath! The ribcage is a three-dimensional bellows containing the lungs, and a neutral trunk posture is crucial to fully expand that bellows in all directions. Poor posture restricts ribcage expansion and lung volume.
To find your ideal trunk curvature, play with various postures, then take as deep a breath as possible. The position (usually slightly arched in the mid-back) at which you can inhale deepest is your ideal.
Improved stomach and nerve function. A stiff, slumped trunk decreases gastrointestinal (GI) mobility and function: it’s too cramped. Being tall keeps things flowing. Posture excellence may also keep the nerves firing properly: fascinatingly, a stiff, slumped trunk may have a negative effect on the nervous system, affecting both visceral (GI) function and even leg pain and strength!
Decreased landing forces. Not only does a forward trunk maintain momentum, but it decreases landing forces, allowing the foot to land beneath the body, instead of out in front. Over-striding in this way is a major factor in slow running, muscle fatigue and cramping and injury.
Maximum hip power. The gluteal muscles are the most powerful movers in the body, and work to extend the thigh equal to the trunk. In order to use the glutes, the runner’s trunk must be forward, so the glutes can push behind us.
Additionally, an arched spine orients the pelvis behind, accentuating hip drive even more. This tall-and-forward combination maximizes hip extension power.
Running too upright or too slumped shuts down the glutes, and runners must compensate by pushing with the quadriceps and calves. This bouncing up-and-down stride has deleterious effects on both quads and calves over a long ultra-distance race.
Simply put: no tall-and-forward trunk, no glutes!
The Core Connection. The trunk connects arms with legs, with core muscles transmitting precious power, efficiency and stability to the stride. Neutral trunk posture is vital in activating core muscles and connecting the arms – namely the shoulder blades – to the legs. A strong shoulder blade enhances hip drive, but only when the trunk remains neutral and forward. Indeed, an efficient trunk promotes true, whole-body running efficiency!
Challenges of Maintaining Efficient Trunk
Beyond simple fatigue, ultrarunning poses several unique challenges to trunk efficiency:
Trail challenges. The relentless ups and downs of a mountainous trail ultra challenge the postural muscles. On uphills, the back muscles must work double-time to keep us from slumping forward.
A forward trunk keeps our bodyweight over the legs. When fatigue and gravity challenges mount – namely on up- and downhills – there is a tendency to lean back. While this is temporarily easier, running upright is an efficiency drain over time: more landing stress, and less hip power.
Even in absence of fatigue, challenging terrain can make it more difficult to be “assertively forward,” and instead be more tentatively back-leaning, especially on technical downhills.
Gear challenges. Gear is a constant challenge: what gear can help us most while hindering least. Hydration systems pose the most significant challenges to trunk alignment.
Rear hydration packs challenge trunk posture in two ways: the pack weight shifting our center of mass backwards, and the natural tendency for the trunk to “round into” a backpack, compromising the spine-neutral position. This phenomenon creates the “rounded pack posture” commonly seen in ultra events.
Forward hydration systems are better for center of mass, but may be more restrictive to ribcage expansion.
Handheld bottles may be the best, but their effect on arm swing can also cause a loss of neutral trunk position.
Trunk posture is extraordinarily important for efficient running, with physiological, metabolic and mechanical consequences. The forces of gravity, distance, terrain and gear all conspire to literally drag us down. But some added mindfulness (and perhaps some pre-race strengthening) can help promote trunk efficiency and help you get from start to finish faster and easier.