C D1 D2
Gait cycle (%)
Hi
le
e
rees)
adductionabduction
D: p < 0052 vs. C .
D1 vs 2: p < 0 05. D .
0 102030405060708090100
–10
–8
–6
–4
–2
0
2
4
6
8
Figure 2: Hip movement in the frontal plane during gait
(C – controls; D1 – dancers before rehabilitation; D2 –
dancers after rehabilitation).
Table 1: Maximal values (mean±SD) of selected
kinematic variables.
Variable C D1 D2
Ankle dorsal flexion*/& 7.8±7.5 14.2±3.3 13.5±3.1
Knee internal rotation * 23.0±8.7 14.9±8.3 23.9±21.3
Knee external rotation * 0.9±6.4 -7.1±6.8 -1.1±11.2
Hip abduction * / & -6.1±2.3 -9.3±2.0 -8.6±1.8
Hip adduction # 5.6±3.0 6.8±1.5 5.8±1.8
Legend:
C – controls; D1 – dancers before rehabilitation;
D2 – dancers after rehabilitation;
Statistically significant differences (p < 0.05):
* between controls and dancers before rehabilitation;
& between controls and dancers after rehabilitation;
# between dancers before and after rehabilitation.
4 DISCUSSION
The observed increased dorsal ankle flexion in
dancers can be explained by special ballet position
(e.g. grand plié, demi-plié), which require excessive
range of dorsal ankle flexion. If the foot is
frequently forced into extreme range of movements,
it loses ability to support the medial arch and act as a
shock absorption. Dancers subsequently overload
the medial part of the foot. This causes increased
pronation (Rusell, 2010). Insufficient range of
movement in hips together with hyperpronation is
compensated by increased external tibia rotation,
which was demostrated in dancers before
rehabilitation. This causes greater medial load of the
knee, which can predispose to injury (Cimelli and
Curran, 2012; Clippinger, 2007). In addition,
chronic ankle instability is often associated with hip
abductor weakness (Rusell, 2010). The increased
range of hip can be caused by inadequate
coordination between adductors and abductors.
The results show that six-week long
rehabilitation did not affect performance of walking
in professional dancers. However, the observed
parameters in dancers after rehabilitation can predict
improved alignment of these joints during gait,
which may reduce stress load being applied on the
lower limb´s structures. The results confirm that the
long-term rehabilitation should be a necessary part
of comprehensive care about dancers to improve
their ballet techniques and prevent injuries.
ACKNOWLEDGEMENTS
This work was supported by the Ministry of
Education, Youth and Sport of the Czech republic
(grant number MSM 6198959221) and Faculty of
Physical Culture (grant number FTK_2012:031).
REFERENCES
Leanderson, J., Eriksson, E., Nilsson, C., Wykman, A.,
1996. Proprioception in classical ballet dancers.
American Journal of Sports Medicine. 24(3), 370-4.
Clippinger, K.,
2007. Dance anatomy and kinesiology.
Human Kinetics, Champaign, 1
st
edition.
Russell, J. A., 2010. Acute ankle sprain in dancers.
Journal of Dance Medicine and Science. 14(3), 89–96.
Miller, C., 2006. Dance medicine: Current concepts.
Physical Medicine and Rehabilitation Clinics of North
America, 17(4), 803–811.
Lung, C.-W., Chern, J.-S., Hsieh, L.-F., Yang, S.-W.,
2008. The differences in gait pattern between dancers
and non-dancers. Journal of Mechanics. 24(4), 451–
457.
Gilbert, C. B., Gross, M. T., Klug, K. B., 1998.
Relationship between hip external rotation and turnout
angle for the five classical ballet positions. Journal of
Orthopaedic and Sports Physical Therapy. 27(5),
339–347.
Cimelli, S. N., Curran, S. A., 2012. Influence of turnout on
foot posture and its relationship to overuse
musculoskeletal injury in professional contemporary
dancers. Journal of the American Podiatric Medical
Association. 102(1), 25-33.