I actually started this series of posts out of order by describing the joint actions and muscles at work in the front lever, an exercise often described as an excellent way of developing body tension. But I didn’t define what body tension is. We are looking for a functional definition, one that is descriptively and mechanically accurate and precise. So lets start our search for a definition by looking at what others have written on the topic.
“Body tension refers to this transfer of power through the torso where force derived from one hold enhances the use of another. On overhanging rock, for example, tension creating by pulling the lower body towards the rock with your feet improves the usability of handholds. By changing the direction of pull, the handholds feel more positive because your body weight is no longer hanging straight down from them. Just as rigidity keeps a bridge straight between points of contact with the ground, body tension maintained by your core muscles keeps your body from sagging, holding your central body mass towards the overhanging wall, suspended between points of contact. . . . Body tension requires using the lower body similarly to the way we use our arms and hands, and it demands strong core muscles to transfer forces between the lower and upper body. Think of your feet as tools for positioning your core in three-dimensional space to optimize your orientation for the moves you must make. (P. 38 Goddard and Newman, Performance Rock Climbing, 1993)
“There are two crucial aspects to body tension in climbing. The first is the strength element – with all the will in the world, if you don’t have strong core muscles then you won’t be able to keep yourself stable when things get steep. The next is the technique or ‘neuromuscular’ element, keeping your feet on small footholds requires a great deal of control and coordination on steep terrain. . .The main muscles required to keep the torso rigid when climbing on overhangs are the abominal muscles (rectus abdominis) and the lower back muscles (erector spinae). In an ideal world, these should create an equal force on either side of the spine by contracting statically (isometrically) in order to maintain posture. ” (Blog post by Neil Gresham 2009 info.rockrun.com)
“Using three points of contact, proper tension means keeping equal amounts of pressure on all three points of contact at all times. The most important aspect of body tension is the core of the body (abs) if the climber is on a steep wall and her abs are not strong enough, she will struggle to hold her legs/feet on the wall. With good body tension, the climber’s feet never lose contact with the wall.” (p. 74 Coaching Climbing, Michelle Hurni, 2003)
“In climbing vertical to overhanging rock, the core muscles of your torso play a key role in enabling your arms and legs to maximize leverage and transfer of torque from hand to foot and vice versa.” (p. 98 Training for Climbing, Eric Horst, 2003)
“The type of strength required in climbing is not necessarily sit-up strength or rather, the shortening of the abdominal muscles. Instead, it is the constant tension of the abdominal muscles under resistance.” (P. 32 Climbing Your Best, Heather Renolds Sagar, 2001)
I think that Goddard and Newman have the most nuance in that they describe using the feet to pull the body into a position that creates advantageous direction of force on the hand holds by pulling the Center of Gravity in towards the rock. Which I suspect other climbers might not think of as body tension. (While admitting the importance of what they say, I am not certain I would describe it as body tension myself.) Grisham gets points in that he is concerned not just with the anterior muscles of the trunk but also mentions the important posterior muscles, the Erector spinae; a group of six muscles on either side of the spine involved in trunk extension and lateral flexion.
But why is it that the trunk is so important to keeping the feet on? Michelle Hurni is most direct when she writes that “if a climber is on a steep wall and her abs are not strong enough she will struggle to hold her legs / feet on the wall.” But why? What is the mechanical relationship that would make the abs so important to keeping the feet on? Further, are core strength and body tension the same thing? Or are different authors attempting to describe related but different aspects of climbing movement?
On this last question I am not entirely sure. In some cases climbers seem to use the terms core strength and body tension interchangeably. Eric Horst writes in Conditioning for Climbing “Furthermore, the core muscles are what provide body tension when you’re trying to make a long reach or twisting body movement.” (p. 67).
In the end these definitions are fairly ambiguous, at times they use technical terms such as torque, and leverage, or point to specific muscles but what these things mean in context is, by and large, left unexplained.
In my next post I will begin to list what I think the mechanical and functional aspects of body tension are, but I am curious, about what other’s think. In a reply to the first post one reader mentioned the importance of distinguishing between open and closed kinetic chains. I agree with that completely and will address that issue directly. But what else? Do you think the trunk is the most important element of body tension? Do core strength and body tension describe the same thing? What is most important about body tension to you?