What I am thinking about movement and what I think about what I am thinking.

Moving!

Fri, 23 Oct 2009 18:03:46 -0700

I have moved my blog to typepad! Here’s the new link:
http://www.donnaluder.com/somatic_mechanic/
I hope to see you there! And please, leave a comment over there! I feel all alone!

Body Language & Dogs

Tue, 20 Oct 2009 06:42:31 -0700

Malcolm Gladwell’s awesome essay on Cesar Millan, body language and dogs. Just think, we could be as skillful as dogs at reading our own inner thoughts through our body language if we only paid attention. Maybe holding a tennis ball in our mouths would help too.

Reach for your toes to assess arterial stiffness

Mon, 12 Oct 2009 13:59:23 -0700

How far you can reach beyond your toes from a sitting position (normally used to define the flexibility of the body) may be an indicator of how stiff your arteries are. Because arterial stiffness often precedes cardiovascular disease, the results suggest that this could become a quick measure of a person’s risk for heart attack or stroke. Article here.

Exercise improves body image, even while you’re still unfit

Sat, 10 Oct 2009 08:01:10 -0700

The simple act of exercise will convince you that you look better, even if you don’t! Article here.
Photo above: Creative commons.org licenses - photo from Mo Pie’s Flickr photostream

Marathons and Heart Attacks

Thu, 1 Oct 2009 07:29:24 -0700

A few years ago, when I was taking Physiology and Biomechanics of Aerobic Exercise, I had read about the curious finding of elevated troponin levels found in some marathoners after races. Troponin is a molecule found in muscle, and is the blood marker that a heart attack has occurred. Here’s an article that explains this more fully.

Vitamin D and Exercise?

Thu, 24 Sep 2009 07:08:36 -0700

The NYTimes links Vitamin D to exercise performance in this article. Brush up on your physiology today....

Split Belt Treadmill Retrains Brain After Stroke

Mon, 14 Sep 2009 07:20:27 -0700

I must have a thing for treadmills these days. This article describes how physical therapists at the University of Delaware came up with a novel idea: a split belt treadmill that can force a patient to use a stroke-impaired leg differently than they would normally. This type of intervention is training the brain by taking advantage of the cerebellum’s role in coordination.

Baby Treadmill improves cognitive development and locomotion

Sun, 13 Sep 2009 10:06:04 -0700

A tiny treadmill has been designed to help babies with Down Syndrome learn to walk earlier. Article here.

The tendue, a complex motor task

Sat, 12 Sep 2009 08:53:05 -0700

above photograph and essay by Donna Luder ©2009 all rights reserved
Today I’m going to post an essay I wrote in my Motor Control and Learning class. The assignment was to discuss the instruction of a complex motor task. A motor task is any kind of physical movement that you can do. Complex just means it is composed of multiple parts. Since I teach a lot, I have quite a bit to say on the matter! (My husband would say I have a lot to say about everything, even things I know nothing about.) Ah well, if you are interested in ballet and biomechanics and imagery, read on!

The ballet step “battement tendue” is a complex motor task and one of the most basic motor skills to the art of ballet and is performed in various versions multiple hundreds of times in a standard 90-minute ballet class. The step consists of shifting the weight from two feet to one foot (Figures 1 and 2) so that the gesture leg is free to slide along the floor until the knee, ankle, metatarsophalangeal and phalangeal joints are fully extended (see Figure 3). The gesture leg is then reversed through these movements until it returns to the beginning position or links into another dance step. Students new to ballet must master this step if they have any hope of dancing smoothly, quickly, or without injury. It is a stylized movement, specific to dance and decidedly “unnatural”.

Figure 1 Figure 2 Figure 3
From Gretchen Warren’s excellent and highly recommended text “Classical Ballet Technique”

Ballet students pass through the stages of motor learning as described in the motor learning literature. The cognitive stage (understanding what is to be done) is followed by the associative stage (how will it be done) and culminates with the autonomous stage (can reliably be regenerated even with interference from other tasks). The autonomous stage is highly desirable as ballet technique combines the tendue with arm movements, torso bending, head inclinations, epaulement (directional changes of the shoulders), musical cues, tempo changes, etc.
Cognitive Stage. The cognitive stage can be very frustrating for ballet students because a very poorly executed tendue may appear correct to an uneducated eye. A teacher must be very careful to not demand perfection, because the student really hasn’t wrapped her brain around just what is wanted. At the cognitive stage, I want the student to be able to identify a correct tendue. Obviously, it is much more difficult to communicate what a correct tendue feels like although imagery can help a great deal. The mental image of sliding the top of the foot and the lower shin under a bathmat works well in expressing the desired pressure into the floor. Until a student masters the cognitive phase, inherent feedback will provide potentially inaccurate knowledge of results (KR).
The cognitive phase can be very frustrating and boring to the student so motivation plays an important role, as well as the the timing and quantity of instruction of the student. I like to pay an enormous amount of attention to what makes a technically solid tendue in the first two exercises of the class, then allow this discussion to die a natural death as class continues. The students will continue to do tendues as preparations and linking steps for the rest of class and it would only be brow-beating to continue to harp on it. This format results in a massed practice of tendues, but not with the intense conditions of practice (detail-laden, demanding, awareness-building) from the cognitive phase.
Fitt’s law applies here because a quickly executed tendue nearly always results in a poorly executed one in this phase. If the student moves quickly, the tendency is to use the hip flexors intead of the foot and ankle plantarflexors. Speed definitely has an accuracy cost in this phase, so the detail-laden instruction of the cognitive phase is limited to these first two exercises of class, which are performed at a slow tempo.
Associative Phase. This phase represents the time where the student understands what a correct tendue is and is beginning to learn what it feels like to generate that tendue from within themselves. Most students can increase the speed without losing accuracy, although at very quick allegro tempos, some of the finer points can be lost. This is the stage where augmented feedback in the form of vivid imagery may be suggested to the student without overwhelming them. This imagery may be derived from the music (waltzes have a definite rhythm [down-up-up] that can help communicate the desired movement), spatial references (under-curves and over-curves), etc. What will speak to one student may baffle another so it is very important that I know my students and their learning style (visual, auditory, kinesthetic, spatial, musical, rhythmical, etc.) and that I am able to say the same thing 12 different ways.
Autonomous Phase. This is where the student can finally just dance. The tendue is so ingrained that it happens without a conscious instruction. It has become part of a much larger motor skill. The student’s skill is such that accuracy is rarely sacrificed for speed.
Here I would like to create a teaching plan to instruct two learners, one “motorifically challenged” and one “natural”. The center column shows those activities I would do with both types of students and the remaining columns show what special activities I would do with each type of student.

The visible skill of the students changes as they progress through the stages of motor learning. At the early stages, the dancer appears stiff and jerky. One can often see a vague shark-like expression with glassy eyes. The hands and lower arms tend to supinate in the dancer’s efforts to turn the legs out (upper and lower-limb coordination): in proper technique the humerus is internally rotated and the lower arm externally rotated while the femurs and lower legs are externally rotated. The quads are overly active and the hamstrings under-active. As the dancer gains skill, she or he moves with more fluidity and smoothness. The face begins to have expressivity and the dancer relates to the music more. The hands can soften and the fingers will lose what was originally a rigid “claw-like” stance. Dance combinations begin to move more quickly and with more complicated choreography and often combine counter-intuitive arm movement with tendue.
Below is a video of a young dancer with a beautiful tendu.
© 2009 - Donna Luder - all rights reserved. No portion may be reproduced without prior written permission of the author. Segments may be quoted and/or linked, proper attribution is included.

ACL injury in athletic girls

Wed, 9 Sep 2009 07:17:11 -0700

An entry in today’s NYTimes’ Well Blog discusses ACL injury and why girls are more likely to develop this injury than boys. There has been a lot of discussion of possible reasons in the past (the female enlarged Q-angle, the hormone bursts in female puberty etc.) but some new research has indicated trunk instability as the culprit. This is not a surprise to those of use who teach Pilates and related functional fitness protocols... you need stability of the trunk (I hate to say it because it’s so overused, but yes, the core) to maintain the knees within a safe range of motion.
I wonder, what is the incidence of ACL injury in female ballet students? We do all kinds of explosive movements, traveling steps combined with vertical jumps (big glissade forward 2x, jete, jete, repeat) and I believe all the trunk stabilizing work we do helps to protect the knees. What do you think?