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A within-subject analysis of the effects of remote cueing on pelvic alignment in dancers.

Good alignment is a hallmark of skillful dancing. (1,2) It facilitates efficient execution of dance movements, and many authors of dance training textbooks believe it reduces the risk of injury. (1-4) One area of the body at which good alignment is especially important is the pelvis. The pelvis is the transition between the torso and lower extremities, and proper alignment in this region may promote efficient locomotion, balance, and control. (2,3,5,6)

While some physical therapists (PTs), kinesiologists, and biomechanists use the anterior superior iliac spines (ASIS) and the pubic symphysis to assess pelvic alignment, (5,7) it has been more common for dance researchers to use the relationship between the ASIS and the posterior superior iliac spines (PSIS) to make that assessment in dancers (8-12) and nondancers. (13-15) The relationship between the plane these landmarks describe and the horizon is used to determine pelvic tilt. If the plane is tipped forward (anterior spines are lower than posterior spines when standing), the alignment is described as "anterior pelvic tilt." When the opposite is true, the alignment is labeled "posterior pelvic tilt." Measurements of pelvic alignment in standing position reveal anterior tilt to be a common problem for dancers and non-dancers alike, (2,5,8) with ranges of 1[degrees] to 23[degrees] of anterior tilt. (10,13-15) What degree of pelvic tilt is normal and ideal for dancers is only beginning to be determined empirically. (8) Logic might suggest identifying ideal pelvic alignment as a position in which the pelvis is balanced on the heads of the femurs, (6,16) but the validity of such an approach remains to be demonstrated.

Strategies for assessing pelvic alignment in dancers have been evolving over the past 15 years. Fitt and colleagues (9) and McLain and associates (12) had experts evaluate alignment from photographs and videotapes taken before and after the application of specialized training techniques. Other researchers have used two-dimensional, video-based motion capture systems to assess pelvic alignment during and following specific dance movements. (10,11)

Deckert and colleagues (8) assessed pelvic alignment in dancers by measuring single-frame images extracted from video recordings of dancers performing ballet barre exercises. Although they chose points in the exercises at which dancers might be expected to have their pelvises neutrally aligned, they found that 70% of the first-year dancers in a major university dance program used a degree of anterior pelvic tilt that exceeded the amount their teachers judged acceptable. With six hours of individual tutoring, including anatomy lessons, conditioning exercises, and practice with feedback, they were able to reduce anterior pelvic tilt in three dancers who had long histories of pelvic misalignment and to sustain the improvements for three to nine weeks of training and follow-up.

In an early study by Azrin and colleagues, (17) the staff at a psychiatric hospital were able to improve their posture by wearing a device that signaled when a problematic posture (rounded shoulders with thoracic kyphosis) was occurring. The researchers in the current study developed a comparable procedure using a remotely-activated pager to deliver alignment cues to dancers as they performed ballet barre exercises. The purpose of this within-subject study was to explore whether remote, tactile cueing held promise for improving pelvic alignment in dancers.

Materials and Methods

Subjects and Setting

Two dancers in a professional training program at a major public university participated in the study. Dancers who displayed any degree of anterior pelvic tilt were invited to volunteer for the study. Participants were selected on the basis of the primary investigator's (PI) assessment of their potential to benefit from training. A third dancer was selected to participate, but after some delay decided she could not attend the observation and training sessions that were scheduled prior to the morning technique classes. The study was approved by the University's Human Subjects Committee, and the dancers signed consent forms before the study began.

[FIGURE 1 OMITTED]

Both participants were female and 20 years of age. At the time of the study, Dancer 1 had been dancing consistently for 9 years. Her dance training included ballet, various forms of African dance, Caribbean carnival dance styles, and modern dance. She had many years of experience performing in all areas of her training. Dancer 2 had been dancing for 16 years. Her main areas of study were ballet and modern dance, but she also had experience with pointe, hip-hop, tap, and improvisation. She also had many years of experience as a performer.

Observation and training occurred in a 21 x 20 ft (6.4 x 6.1 m) faculty studio, with only the three investigators present. The studio was equipped with a sound system, mirrors that were covered with a curtain during this study, and a ballet barre attached to one wall. The dancers were asked to wear a form-fitted top, ballet shoes, and tight fitting shorts that had a pocket sewn into the front to hold a remote pager. Two small, circular cutouts over the right ASIS and the right PSIS allowed reflective markers to be securely attached directly to the dancers' skin.

A digital camcorder was placed 13 ft (4 m) to the right of the dancer. The camera was affixed to a tripod that was adjusted to maintain the camera lens at the height of the dancer's pelvis. To ensure consistent placement of the camera, the position of the tripod legs was marked with an indelible marker, its orientation was checked with a built-in level, and its location in the studio was marked with floor tape of a contrasting color. The camera zoom was adjusted to show an area extending from the bottom of the dancer's rib cage to the floor, so that the entire lower extremity could be seen in the images used for analysis. The dancer was asked to stay between two strips of floor tape so she would remain within the camera's field of view. The second and third authors shared the role of videographer.

Before training began, a physical therapist (PT) performed a series of tests to determine whether either dancer had any physical limitations that might interfere with improvements in pelvic alignment. Assessments were made of hip flexor length, lumbo-pelvic stability, hip extensor strength, and passive internal and external hip rotation. (18-20) Based on the results of these tests, and the PT's general knowledge of these dancers, it was concluded that neither dancer had any relevant physical limitations.

Measuring Pelvic Alignment

Pelvic alignment in the sagittal plane was the primary dependent variable for this study. At the beginning of the study, the researchers agreed on marker placement for each dancer. Temporary tattoo paint (Harquus, Stow, Ohio) was used to mark and regularly refresh an "x" placed directly over the centers of the right ASIS and PSIS.

At the beginning of each session a graduate assistant with special experience in the dance sciences, but who was not otherwise involved with the study, used toupee tape to attach a three-dimensional reflective marker over the center of each "x." To reduce the possibility of bias, this assistant left as soon as the markers were placed. She was never present during observations or training, and she remained blind to the experimental conditions throughout the study. During videotaping light from a transparency projector was used to illuminate the reflective markers.

The dancers were observed separately, twice a week, for approximately 20 minutes each. They were given a warm-up that included five ballet barre combinations and then asked to perform a sixth, more comprehensive combination that was videotaped and used for the alignment assessments. The dancers were given adequate time to learn the combinations, and the PI called out the movements as needed, as teachers often do in ballet classes.

Following each observation session the PI extracted eight still images from the videotape at pre-specified, objectively definable moments when pelvic alignment might be expected to be neutral (last frame before the dancer began the next movement). The images selected were chosen to be comparable to the images used by Deckert and colleagues. (8) However, we substituted degage front returning from back for releve fifth position after degage to include an image with one leg off the floor. The images used for measurement were as follows:

1. Bottom of demi-plie in first position,

2. Top of releve in first position,

3. Standing fifth position after grand plie,

4. Standing fifth position after circular port de bras,

5. Standing on one leg after a quick tendu pas de cheval front,

6. Standing on one leg after demi rond de jambe from front to side,

7. Standing on one leg after demi rond de jambe from back to side, and

8. Degage front leg returning from the back.

Measurements of pelvic alignment were made on the eight still images taken from the recording by using an image analysis software program (ImageJ, http://rsb.info.nih.gov/ij/) to connect the centers of the reflective markers and compare the line described with the horizon. A mean was calculated for the eight images measured for each dancer during each session.

To evaluate measurement reliability the third author, a graduate student in dance, independently measured 15% of the images chosen at random from the collection of images measured by the PI. Agreement was achieved if the difference between the two measurements was one degree or less. Inter-observer agreement was calculated by dividing the number of agreements by the number of agreements plus disagreements and converting the proportion to a percentage. Overall, inter-observer agreement was 81%.

Cue Training

Training occurred twice a week for approximately 20 minutes each session. For this phase of the study, each dancer was given a 2-1/2 x 3-1/2 x 1-inch (6 x 8.5 x 2.5-cm) wireless personal pager to place in the pocket sewn into the front of her exercise shorts (Weisound, http://www.nextag.com/wirelesspersonal-pager). Each training session began with reminding the dancer of what constitutes ideal alignment at the pelvis. The dancer was asked to stand in parallel first position facing the barre while the PI placed the dancer's pelvis in a position that appeared to balance it on the heads of the femurs. For both dancers, this correction involved reducing anterior pelvic tilt.

The dancer was then invited to relax into her normal standing position, the PI activated the pager by pressing its remote button, and asked the dancer to find ideal alignment on her own, so she could practice correcting her alignment. The pager vibrated four times (approximately 2 seconds), usually stopping just as the alignment correction was completed. The PI watched and helped the dancer find ideal alignment as needed. This pattern was repeated three times with the legs parallel and three times with the legs turned out in first position. Then the whole pattern was repeated with the dancer facing to the right, her left hand on the barre. The dancer was asked to hold the final turned out first position for approximately three seconds while being recorded. Later, a still image was extracted from this brief video clip and used to measure ideal alignment for each dancer.

The mean of nine measurements taken for Dancer 1 and five measurements taken for Dancer 2 was used as our best estimate of ideal pelvic alignment for each dancer. Ideal alignment averaged 11.2[degrees] for Dancer 1 and 2.3[degrees] for Dancer 2. To corroborate these assessments a technique teacher for both dancers, a former professional dancer who is recognized internationally for her teaching ability, was invited to attend the beginning of session 11. She was asked to place each dancer in what she considered to be ideal alignment, which she appeared to do with some enthusiasm, much as a sculptor might mold clay. A three second video clip of this alignment was made, and a still image was extracted and measured. The degree of anterior tilt judged ideal by these measurements was 12.2[degrees] for Dancer 1 and 2.2[degrees] for Dancer 2. Thus, the alignments judged ideal by the PI and the dancers' technique teacher differed by 1[degrees] or less for both dancers.

For the second phase of training, each dancer performed the same series of five ballet combinations with the pager still placed in the front of the shorts. The second or third author administered alignment cues (first seven and last five training sessions, respectively) by activating the remote pager whenever he or she saw excessive anterior tilting or anticipated that it was about to occur. The vibration of the pager prompted the dancer to give special attention to her pelvic alignment. The criterion for administering cues was left to the judgment of the researcher, but our intent was to give enough cues to help each dancer improve her alignment but not so many as to distract her from performing the barre combinations.

As a check on independent variable integrity, the research assistant acting as the videographer tallied the number of cues administered for each exercise. A mean of 3.4 alignment cues per exercise was administered for Dancer 1 (range: 1 to 7), and a mean of 3 cues per exercise was administered for Dancer 2 (range: 2 to 5). The average number of cues per exercise remained consistent throughout training.

After the dancer performed the five training combinations the pager was removed and the dancer was videotaped performing the sixth and final combination. Cues were never delivered during the performance of the final combination, which was used to assess the effects of training. Later, the PI extracted the specified images and measured the degree of anterior tilt using the image analysis software.

Experimental Design

The experimental design involved the following three conditions:

1. Baseline: Each dancer was led through the five ballet warm-up combinations with no special cueing related to pelvic alignment. A sixth, comprehensive combination was videotaped for analysis of pelvic alignment. Both dancers began this phase at the same time.

2. Alignment Cueing for Dancer 1: Dancer 1 received training with the remote pager during the five warm-up combinations and then performed the final combination for videotaping with the pager removed. Dancer 2 continued under baseline conditions.

3. Alignment Cueing for Dancer 2: Dancer 2 received training with the remote pager during the five warm-up combinations and then performed the final combination for videotaping with the pager removed. Dancer 1 continued with training and observations.

Alignment training was initiated independently for each dancer once the degree of anterior tilt appeared to be at or near the same level for at least three consecutive sessions. Dancer 1 was in baseline for five sessions and alignment training for 12 sessions; Dancer 2 was in baseline for 12 sessions and alignment training for five sessions. The first three baseline observations for Dancer 2 could not be used because one of the markers was not clearly visible in several of the images specified for measurement, but the nine remaining observations were sufficient to satisfy the criterion for changing from baseline to intervention. This sequence of conditions constitutes a multiple-baseline-across-subjects experimental design. The data were graphed and analyzed using visual inspection, as is common in within-subject experiments. (21,22)

Social Validity

At the end of the study the dancers were asked to rate, on a 7-point scale, 1. how important they felt good pelvic and lower-back alignment is for dancers, 2. whether the training methods were appropriate to the purpose, 3. whether they noticed any changes in their alignment during training, and 4. whether the benefits achieved were worth the time invested. The dancer's ballet teacher was asked to complete a parallel questionnaire.

Results

Figure 2 displays the average degree of anterior tilt for all sessions during baseline, training for Dancer 1, and training for Dancer 2.

Pelvic alignment for Dancer 1 averaged 13.2[degrees] of anterior tilt during baseline and decreased to an average of 10.9[degrees] during training. Alignment for Dancer 2 averaged 3.9[degrees] of anterior tilt during baseline and decreased to an average of 2.9[degrees] during training. These improvements were sustained for 12 and five sessions (6 and 2-1/2 weeks) following the initiation of training. The final seven training sessions for Dancer 1 were lower than all her baseline observations. All five training sessions for Dancer 2 were lower than seven of her nine baseline observations.

[FIGURE 2 OMITTED]

Table 1 displays the mean degree of anterior tilt for each of the eight positions measured. The position in which the dancers displayed the most anterior tilt was "fifth position after circular port de bras," as forecast by Krasnow and colleagues. (23) Anterior tilt was lower following training in all positions except "last degage" for Dancer 2. Dancer 1 reduced her anterior tilt the most at the "bottom of demi-plie," immediately following "tendu back to side," and at the top of "first position releve," while Dancer 2 reduced her anterior tilt the most during "tendu front to side" and in the two "fifth positions." For a few positions ("bottom of plie" and "last degage" for Dancer 1, both of the "tendus" and "last degage" for Dancer 2) the dancers actually decreased anterior tilt beyond what was considered their ideal standing alignment.

Social Validity

At the end of the study the dancers rated good alignment at the pelvis and lower back as important (7 of 7), and they rated the cue training as appropriate (6.5 of 7). Both dancers said their alignment improved during the study (6 of 7), and they felt the benefits received from training were worth the time invested (5.5 of 7). Both dancers also commented independently that the study made them more aware of their pelvic alignment.

The dancers' ballet teacher rated good alignment at the pelvis and lower back as important for dancers (7 of 7), and she rated alignment as having improved during the period in which the study was conducted (5.5 of 7 for Dancer 1 and 6 of 7 for Dancer 2). She also commented on the need for dancers to engage in individualized training beyond technique classes to facilitate the maintenance of new movement habits.

Physical Therapy Assessment

At the end of the study we asked the same PT to re-evaluate each dancer using the same tests she administered prior to training. Dancer 1 improved from a rating of 2+ to 4 on the lumbo-pelvic stabilization test, and she modestly improved her performance on the hip flexor length test from less than 180[degrees] in one hip and equal to 180[degrees] in the other to greater than 180[degrees] in both hips. Dancer 2 improved from a rating of 2- to 3 on the lumbo-pelvic stabilization test, and she improved her performance on the hip flexor length test from less than 180[degrees] to greater than 180[degrees] in both hips. Measurements of hip strength and passive rotation did not change for either dancer.

Discussion

This study used a multiple baseline experimental design (21,24) to assess the effects of remote tactile cueing on two dancers' pelvic alignment in the sagittal plane. Repeated measurements allowed each dancer's alignment before cue training to be compared to her own alignment during and following training, thereby eliminating a major source of variability (between participants) and directly displaying variability for each participant across all sessions. Pelvic alignment improved consistently only when training was implemented, suggesting that the cue training procedure and not other uncontrolled variables was responsible for the improvements observed.

The cue training procedure improved pelvic alignment for both dancers. Dancer 1 reduced her anterior tilt by 2.3[degrees] (17% of her baseline), while Dancer 2 reduced her anterior tilt by 1[degrees] (28% of her baseline). By the end of training (12 sessions for Dancer 1 and five sessions for Dancer 2) alignment for both dancers stabilized very near the degree of tilt determined to be ideal for each dancer by the PI and one of their teachers.

Social validity ratings by the dancers and their ballet teacher show unanimous agreement that good alignment at the pelvis is important. All credited cue training with improving alignment. They found the training approach appropriate to the purpose, and the dancers judged the benefits of the training to be worth the time they invested. The fact that alignment improved for both dancers to levels determined to be their ideal suggests that the cue training procedure yielded modest yet practically significant improvements in dancer alignment. When working with elite performers a small improvement may be all that is needed to optimize performance. (21)

Comparisons, Special Findings, and Suggestions for Future Research

The degree of anterior pelvic tilt observed in this study is within the range of measurements reported by previous researchers assessing standing pelvic alignment in dancers and non-dancers (group averages ranged from 6[degrees] to 13[degrees], and measurements for individuals ranged from 1[degrees] to 23[degrees]). (10,13,15,25,26) The improvements achieved in the current study are about 1[degrees] less than those reported by Deckert and colleagues (8) in absolute terms, but are comparable in terms of the percentage of improvement over baseline. This suggests that the dancers in the current study may not have had as far to improve before reaching their ideal alignment, perhaps due to differences in participant selection criteria.

In response to an open-ended question on the social validity questionnaire, the dancers in the current study independently reported a change in their alignment awareness and attributed that change to participation in the study. Deckert and colleagues (8) concluded that changing awareness was probably a key functional component in their training intervention. The same is likely true for the current study.

An unanticipated benefit was revealed by comparing PT assessments made before and after training. Assessments of the dancers' lumbopelvic control and hip flexor length improved even though these capacities were not explicitly targeted by the intervention. This finding suggests that a change in movement habits may lead to physical changes that make good alignment easier to achieve. Although the dancers reported that they had not otherwise changed their training habits, it would be prudent to consider these improvements speculative until further research can rule out possible alternative explanations.

The pager used for cue training was always removed before the dancers performed the final combination, so the measurements reported are first-level generalization measures. The fact that the dancers were able to align their pelvises in the absence of the cueing device is encouraging. Future research might extend assessments to dancers' regular technique classes and over time to determining the durability of change.

Differences in the measurements for the eight positions that were averaged to assess pelvic alignment (Table 1) reveal that pelvic alignment varies even at moments when alignment might be expected to be neutral. For a few positions anterior tilt was less than what was considered each dancer's ideal. Whether these measurements represent over-corrections or simply the functional range of pelvic alignment for dancers performing movements like those used in this study might be taken as the focus of future research. Such studies might use multiple trials within sessions to permit comparisons across trials as a means of assessing alignment stability, an approach suggested by Chatfield (27) for studying acquisition of repeatable movement patterns.

A potentially more important consideration relates to the fact that the alignment angles identified as ideal were conspicuously different for the two dancers (11.2[degrees] vs. 2.3[degrees] of anterior tilt). Ideal alignment as measured using the ASIS and PSIS landmarks appears to differ across dancers. If ideal alignment of the pelvis turns out to be at equilibrium (a point of balance) there is likely to be considerable variability in alignment measurements across dancers, and perhaps even within individuals as their bodies change with training. While the alignment of bony landmarks might be used to help dancers get close to their ideal alignment, the dancers' own kinesthetic and proprioceptive sensations are likely to be needed to fine-tune alignment. As alignment approaches ideal, teachers will probably need to use other clues to help dancers improve, such as tension holding patterns and overall body balance. Ultimately, only the dancers themselves may know when they have finally achieved their ideal alignment.

Methodological Considerations and Limitations

We used a stricter definition of agreement (a difference of one degree or less) than previous researchers for determining the reliability of the measurement system employed in this study. Deckert and colleagues (8) used two degrees, and others have recommended as much as five degrees as an acceptable difference between observers. (14) The fact that we were able to achieve a high level of inter-observer agreement using a higher standard suggests that dancer capacities can be measured reliably. In addition, the alignments judged ideal by the PI and the dancers' teacher differed by one degree or less for both dancers, suggesting that ideal pelvic alignment is an assessment on which dance teachers can agree, even though it is subtle and may be difficult for those without specialized training to see.

One limitation of this study is the possible influence of reactivity to the experimental conditions. Measurements of pelvic alignment for Dancer 2 were closer to ideal before training than we imagined they might be based on informal observations of her work in technique classes. It took several weeks during baseline for her alignment to stabilize enough to satisfy the criterion for initiating training. A majority of the dancers in the Deckert and colleagues (8) study had their highest anterior tilt measurements during the third week that measurements were taken, which is consistent with a reactivity explanation for why alignment assessments might initially reveal less anterior tilting than researchers expect. Performing solo in front of three researchers and a video camera might be expected to influence many dancers' performance, and it seems reasonable that it would take time for this influence to subside enough for dancers to perform naturally. Future researchers should be alert to the potential effect of reactive influences and might look for ways to minimize such influences so that measurements made during experiments with dancers will be representative of their performance in non-research conditions.

Another possible limitation is the use of only two dancers. We studied two dancers intensively (twice a week for eight weeks) in an effort to understand the mechanisms that influence pelvic alignment in dancers, and to refine the method for measuring pelvic alignment in the studio. Although the combination of conditions employed meets the minimum threshold for demonstrating experimental control in multiple-baseline experiments, adding a third participant may have made the results more compelling. (21,24) In addition, while the use of small-N within-subject experimental designs does not necessary limit generality, (21,22) it is possible that these dancers were unique in ways that limit the generality of the findings. Prudence suggests that the results of the current study be considered provisional until more studies can be conducted to corroborate them. (28)

Implications and Conclusions

The member of the research team who administered alignment cues during the first six training sessions was a dance conditioning faculty member with more than ten years experience in delivering a variety of movement training programs. It is possible that special training will be required for others to achieve comparable levels of effectiveness in using the cueing procedure. However, during the last five training sessions the graduate student who had been videotaping the sessions assumed responsibility for administering the alignment cues, with no discernable decrement in cueing effectiveness. Therefore, it is also possible that cueing alignment is a skill that experienced dance teachers have already mastered, and the use of that skill will transfer to the cueing procedure as naturally as it did for the second coach in this study. Future research might address this question explicitly.

We conducted this evaluation of the remote cueing approach under controllable conditions: one teacher working with one dancer at a time in a private studio. Under these conditions, we might have been able to achieve similar results by having the teacher call out the corrections, as Deckert and colleagues (8) appear to have done as part of their training protocol. Perhaps the most appealing aspect of the remote cueing approach we evaluated in this study is the possibility of combining it with other aspects of dancers' training. Future research might assess the effects of having an alignment coach deliver remote cues during the barre portion of a regular ballet class to reduce additional time required for training. Conducting training in the dancers' normal training setting may also have implications for the generalization of new alignment habits. A less conspicuous pager than the one we used would make in-class cueing more practical. If those who administer alignment cues can learn to see ideal alignment reliably, at a distance and without attaching reflective markers, the procedure may be adaptable to a variety of dance training settings.

As the parameters for effective alignment cueing become better understood, it may become possible to construct a device, perhaps incorporating an accelerometer, that dancers can wear during a portion of their classes (barre, for example) to continually monitor alignment at the pelvis and automate the delivery of feedback when alignment varies from some pre-determined standard. If such a device could be calibrated to the limits of acceptable alignment, and those limits progressively adjusted by the dancer's teacher prior to class, ideal alignment might be shaped gradually without the need for moment-by-moment attention from the teacher or an alignment coach.

Deckert and colleagues (8) showed that dancers' pelvic alignment can be improved with as little as six hours of individual tutoring involving anatomy lessons, core-control training, and practice with feedback. The results of the current study suggest that dancers can improve their alignment with frequent and well-timed reminders administered while they are performing typical ballet barre exercises. The results also indicate that changes in alignment habits produced by training of this sort may actually improve physiological capabilities that can make ideal alignment easier to achieve. This study and Deckert's allude to potentially important benefits that may arise from individualizing some of the training that dancers receive.

Acknowledgments

The authors wish to thank Jennifer Deckert and Erin Petscher for their contributions to the design of the study, and Blythe Barton, Tyressa Judge, Gerri Houlihan, and Anjali Austin for their assistance in making the measurements and ratings.

Caption: Figure 1 Small cut-outs on the shorts allowed the reflective markers to be attached to the skin in the center of "X"s marking the right ASIS and PSIS. A pocket on the front of the shorts held the pager during cue training.

Caption: Figure 2 Degree of anterior pelvic tilt for each dancer during baseline and remote cue training.

References

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This study was conducted in the Department of Dance at Florida State University. Kimberly M. Holt, M.F.A., is now at Valdosta State College in Georgia. Tom Welsh is at Florida State University. Jaclyn Speights, M.A., is now in the Lowndes County School District in Mississippi.

Correspondence: Kimberly M. Holt, M.F.A., Assistant Professor, Department of Communication Arts, Valdosta State College, Valdosta, Georgia 31698; kim. holt525@gmail.com.
Table 1  Mean Degree of Anterior Tilt for All Observations Sorted by
Position, Condition, and Dancer

                              Baseline    Intervention   Difference *
Dancer 1

  Bottom of demi-plie            7.2           3.7           3.6
  Releve first                  15.8          12.5           3.3
  Fifth after grand-plie        17.7          14.8           2.9
  Fifth after port de bras      18.2          16.2           2.0
  Tendu back to side            11.3           6.7           1.7
  Tendu front to side           14.4          12.0           2.4
  Fast tendu front              13.0          12.0           0.9
  Last degage                    7.3           6.3           1.0

Dancer 2

  Bottom of demi-plie            2.9          2.5            0.4
  Releve first                   4.3          3.0            1.3
  Fifth after grand-plie         5.4          3.8            1.6
  Fifth after port de bras       7.6          5.9            1.7
  Tendu back to side             3.2          1.9            1.3
  Tendu front to side            2.7          0.8            1.9
  Fast tendu front               4.1          3.6            0.6
  Last degage                    0.9          1.4           -0.5

* Baseline minus intervention.
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Title Annotation:Original Article
Author:Holt, Kimberly M.; Welsh, Thomas M.; Speights, Jaclyn
Publication:Journal of Dance Medicine & Science
Date:Jan 1, 2011
Words:5963
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