BALANCE OF THE SEXES: The Science Behind Co-Ed Derby
BALANCE OF THE SEXES
The Science Behind Co-Ed Derby
Editorial by Billy Rae Siren
I think we were all taught this trick in high school…the one where a man and a woman both place a chair against a wall, lean forward at the waist until the tops of their heads are against the wall above the chair, then (without removing their heads from the wall) lift the chair and stand straight without bending their knees. Women generally ace this test, while men struggle to keep their balance.
But what does this have to do with skating?
In men and women, center of gravity is just different enough; it can be a great equalizer when skating. A woman’s center of gravity is statistically one inch lower and further back than a man’s. Because women by rule have a larger pelvis, they also carry more weight in their lower bodies; buttocks, hips and thighs. Men on the other hand, carry their weight above the waist, in their chest and shoulders.
Let’s break this down into several aspects of roller derby. For these examples, imagine a female skater as a pear with skates at the bottom and a male skater as a pear with skates at the stem.
Blocking:
Let’s first address the undeniable fact that men are generally larger than women. The average female will have to work at a higher proportion of their maximum strength while administering blocks than the average man. That being said, M.A.D.E. encourages women to only hit male skaters as hard as they would plan to be hit back during coed play. Raw male strength and size aside, women do have other advantages when blocking.
Any woman administering a block on a man should aim as high as legally possible. Again, imagine the male skater as the pear with skates at the stem. Should that skater be hit with force at the highest legal point of the shoulder, there is a significant chance they will go down, especially if caught upright. Male skaters are also increasingly susceptible to Tri-Blocks. The center of gravity in men is generally one inch forward and higher than in a woman, making them less balanced when pushed backwards from the chest, as during a legal Tri-Block.
Now imagine that female skater, the pear with skates at the base. How would one best take her down? Though greater hip movement, as the result of a larger pelvis, can sometimes be a benefit for women in roller derby (i.e. Booty Blocks and Hip Checks), it can also be a hindrance. A larger pelvis means a woman must shift her weight more to keep her center of gravity over her weight bearing foot. In theory, this would make a female skater more likely to be caught off balance than a male skater. While all roller derby skaters constantly shift their weight at every turn of the track, female skaters must shift their weight more to stay balanced. This also means they are more susceptible to over-rotation when receiving assists, avoiding blocks or recovering from a hit. This, factored with the lack of forward balance, would suggest legal blocks to the back on the shoulder blades to be the most successful way to take down a female M.A.D.E. skater.

Veteran M.A.D.E. skater Lady and the Trample loses her footing after a block to the shoulder blade from Ponyboy Hurtis
Assisting:
Much of the same information from above can be applied to assisting. For women, their lower and rear center of gravity makes them perfect for reaching back to provide assists. In men, their size and upper body strength makes for high-powered whips, though they will have to compensate for their high, forward center of gravity by widening their stance, allowing them to lean back.
Jumping and Juking:
A study performed by the Journal of Sports Medicine and Physical Fitness found that though a male’s center of gravity and build allows for higher, longer jumps, females compensate in other ways. According to the study performed by the Faculty of Sports Sciences at the University of Castilla-La Mancha in Toledo, Spain, because of their lower center of gravity, women “utilized a different landing pattern than the one utilized by the men,” making them less likely to suffer injury as the result of a jump and more likely to make a solid landing.
Coming off the Line:
The great Toe-Start versus Duck-Start controversy could be more scientific than one would think. Studies have shown that men can bend further at the ankles and knees than women can. Taking this into account, along with women’s rear center of gravity and men’s forward center of gravity, which method of starting would best suit each sex?
In a Toe-Start, the knees are slightly bent, little ankle movement is required and though the body’s weight is shifted forward to gain speed, the toe stops compensate for the shift in weight, much like heel lifts do for skiers.
In a Duck-Start, the knees are bent slightly more than in a Toe-Start, the ankle movement is greatly increased and though the feet are flat to the track, the weight of the body is on the balls of the feet to facilitate forward momentum and speed.
With all of this taken into account, it would suggest that Toe-Starts would be more effective for women than men and Duck-Starts would be more effective for men than women.
Of course, there will be exceptions to all of these rules. Every skater is built and trained differently. What this article should suggest, is the importance to learn one’s own body and how to compensate for its faults and best feature its strengths when skating. What this article aims to prove, is that the Modern Athletic Derby Association’s embrace of coed roller derby may not be as off kilter and far fetched as some skeptics assume.







Great photos and co-ed derby has been working since 2008 in games and 2007 in practices.