influence of the level in pole vaulting practice on the rotator cuff

INFLUENCE OF THE LEVEL IN POLE VAULTING PRACTICE
ON THE ROTATOR CUFF STRENGTH:
A COMPARISON BETWEEN NOVICE AND EXPERT POLE VAULTERS
Frère J., Tourny-Chollet C.
Centre d’Etude des Transformations des Activités Physiques et Sportives – EA 3832,
Université de Rouen (France)
Introduction
Intensive practice of an overhead activity causes musculoskeletal alterations, particularly on
the shoulder, with specific strength balances of the rotator cuff.
Pole vaulting is composed of 8 phases: Run-up; Plant; Take-off; Swing; Rockback; Pull; Turn
and Push. During the plant, the vaulter conducts the low point of the pole into the planting
box with an abduction movement of the dominant arm (corresponding to the dominant
shoulder). As the pole is planted into the bottom of the box, the vaulter’s arms and torso are
deflected backward (Linthorne N.P., 2000) before rotating around the shoulder. At the takeoff phase, the dominant upper arm is extended directly above the vaulter’s head,
consequently, the External Rotator (ER) develops a concentric strength. The rude shock
between the pole and the box causes a hyperflexion of the shoulder, as the consequence the
Internal Rotator (IR) develop a large eccentric strength. The IR prevents the dislocation by
limiting this hyperflexion of the shoulder (Bradley J.P. et Tibone J.E., 1991).
The aim of this preliminary study is to compare the bilateral strength of the IR and ER
muscles in expert and novice pole vaulters to assess the possible alterations related to the
intensive practice of pole vaulting.
Materials & Methods
Fourteen subjects (6 experts and 8 novices) were volunteers to
participate in this study. All subjects were asymptomatic and free
from musculoskeletal shoulder injuries before and after the tests.
Two evaluation tests were performed: (1) each athlete had to
perform 3 vaults at the level of their respective personal best
performances (475 ± 59,5cm vs. 290 ± 37,4cm for experts and
novices, respectively). The trials were recorded by two video
cameras operating at 50 fields.s-1 (Panasonic®), recording the
movement from the last stride to approximately the maximum pole
bend position. Marks placed on the ground and on the pole
vaulters were used to ensure the reproducibility of the measures. Figure 1 : Angle of
humeral elevation
The articular measurement corresponded to the angle of humeral
relative to the thorax of
elevation relative to the thorax (Figure 1) of the dominant
the dominant shoulder
shoulder during the vault; (2) To measure the maximal concentric
(Con) and eccentric (Ecc) strength of the IR and ER of both
shoulders, an isokinetic dynamometer Biodex® is used. The subjects were in the seated 90°
abducted test position in the scapular plane (forward flexion of 30°) at 90°.s-1, and the range
of motion was 0° (horizontal) to 90°. Consequently, it is possible to calculate the conventional
ratios (ER Con strength divided by IR Con strength) of both shoulders. This ratio represents
the muscular balance of the joint.
A multiple correlation analysis was used to establish the link between the movement and the
measured muscular strengths relative to the performance.
Results & Discussion
Results
The measured angles of humeral elevation relative to the thorax, in the sagittal plan, were
significantly (p<0.05) higher for the experts (181,6° ± 9,6) than for the novices (168,6° ± 10),
when at toe off. The conventional ratios (Figure 2A) and the eccentric strengths of the IR
(Figure 2B) were significantly different between both shoulders, only for the expert pole
vaulters. Finally, the angle of humeral elevation relative to the thorax was correlated with the
level of performance (r= 0,63 p<0,05), and it was correlated with the eccentric strengths of the
IR (r= 0,70) for the experts group.
Figure 2: (A) Ratio ER Con/IR Con; (B) Eccentric strength of the IR. Grey: dominant shoulder; White: non
dominant shoulder
The results of this preliminary study concerning the bilateral differences of the conventional
ratios and of the eccentric strength of the IR are in agreement with the literature (Shklar A. et
Dvir Z., 1995; Wang H.-K. et Cochrane T., 2001). These ratios are not pathological, but
demonstrate the expert pole vaulters’ specificity. Moreover, the correlation between the angle
of humeral elevation, the level of performance and the eccentric strength of the IR represents
the importance of this muscular balance, for both pattern of contraction (Con & Ecc) in the
practice of pole vaulting. These results call for a complementary study, which aim will be to
orientate the training program relative to the influence of pole vaulting practice on the
shoulder joint. This complementary study will contribute to optimizing performance and to
prevent injuries such as glenohumeral instability or dislocation. Consequently, training
programs must allow this transformation and not change this specificity related to a high level
of overhead activity.
References
Bradley (J.P.) et Tibone (J.E.) - Electromyographic analysis of muscle action about the
shoulder. Clinics In Sports Medicine, 1991, vol.1, n°4, pp.789-805.
Linthorne (N.P.) - Energy loss in the pole vault take-off and the advantage of the flexible
pole. Sports Engineering, 2000, vol.3, pp.205-218.
Shklar (A.) et Dvir (Z.) - Isokinetic strength relationships in shoulder muscles. Clinical
Biomechanics, 1995, vol.10, n°7, pp.369-373.
Wang (H.-K.) et Cochrane (T.) - Mobility impairment, muscle imbalance, muscle weakness,
scapular asymmetry and shoulder injury in elite volleyball athletes. The Journal of Sports
Medicine and Physical Fitness, 2001, vol.41, pp.403-410.
Paru dans : 4th international sport sciences days : 2006 conference proceedings / entretiens de l'INSEP,
November 28-November 30 . - Paris : INSEP, 2006. pp. 141-142
INFLUENCE DU NIVEAU DE PRATIQUE DU SAUT A LA PERCHE SUR
LES FORCES MUSCULAIRES DE LA COIFFE DES ROTATEURS:
COMPARAISON ENTRE DES PERCHISTES DEBUTANTS ET EXPERTS.
Frère J. & Tourny-Chollet C.
Centre d’Étude des Transformations des Activités Physiques et Sportives
EA 3832 ; Université de Rouen
INTRODUCTION
Au saut à la perche, les Rotateurs Internes (RI) et Externes (RE) sont sollicités dans les deux modes de contraction (Concentrique
(Con) et Excentrique (Exc)) entre le planté de perche (PP) et la flexion maximale de la perche (MBP) (Figure 1ce). L’épaule
dominante du perchiste y effectue une hyperflexion suivie d’une extension 1, les RI ayant pour rôle de limiter cette hyperflexion de
l’épaule 2.
L’objectif de cette étude est de comparer les forces bilatérales des muscles RI et RE de perchistes experts avec celles de perchistes
débutants pour évaluer les éventuelles transformations liées à la pratique intensive du saut à la perche.
MATERIELS & METHODES
Quatorze sujets (6 experts et 8 débutants) ont dû effectuer 3 sauts à la
perche, en franchissant une hauteur de barre relative à leur niveau respectif
(475 ± 59,5 cm vs 290 ± 37,4 cm, respectivement). Les sauts ont été filmés
par 2 caméras numériques 50 Hz (Panasonic), de la pose du dernier appui
jusqu’à MBP (Figure 1be) afin de mesurer l’angle d’élévation thoracohuméral. Un dynamomètre isocinétique Biodex est utilisé afin de mesurer
les forces Con et Exc des RI et RE. Les tests sont effectués en position assise
le bras à 90° d’abduction dans le plan de la scapula à 90°s-1, de 0 à 90°. Le
test t de Student a été utilisé pour comparer les forces musculaires, alors
qu’une analyse de corrélation multiple a été effectuée pour faire le lien entre
les forces mesurées et les angles thoraco-huméraux filmés. Le seuil de
significativité est fixé à 5%.
RESULTATS
Figure 1: Décomposition du saut à la perche et dispositif de
mesure de l’angle thoraco-huméral.
Les angles thoracohuméraux mesurés chez les
experts (181,6°  9,6) sont
significativement supérieurs
(p<0,05) à ceux mesurés
chez les débutants (168,6° 
10) lorsque le perchiste
quitte le sol (Figure 1d).
L’angle d’élévation est corrélé
au niveau de performance (r=
0,63, p<0,05) et chez les experts
cet angle est corrélé aux forces
excentriques des RI (r= 0,70).
Figure 2 : (A) Ratio RE Con/ RI Con ; (B) Forces Exc des RI. En gris, les mesures provenant des
épaules dominantes ; en blanc, les mesures provenant des épaules non dominantes.
DISCUSSION & CONCLUSION
Les forces musculaires isocinétiques mesurées (ratio et forces) sont en accord avec la littérature scientifique 3,4. La différence
significative chez les experts, entre le ratio dominant et le non dominant, évoque une spécialisation des muscles de la coiffe des
rotateurs du côté dominant (Figure 2). Ce ratio dominant n’est pas pathologique mais est le reflet de cette spécialisation liée à la
pratique du saut à la perche à haut niveau. La corrélation entre l’angle d’élévation humérale du côté dominant et le niveau de
performance ainsi que les forces Exc des RI montre l’importance du rôle des ces muscles dans l’exécution d’un saut. Pour cela, les
programmes d’entraînement doivent tenir compte de ces adaptations sans chercher à changer cette spécificité.
1. Linthorne (N.P.) - Sports Engineering, 2000, vol.3, pp.205-218.
2. Bradley (J.P.) et Tibone (J.E.) - Clinics In Sports Medicine, 1991, vol.1, n°4, pp.789-805.
3. Shklar (A.) et Dvir (Z.) - Clinical Biomechanics, 1995, vol.10, n°7, pp.369-373.
4. Wang (H.-K.) et Cochrane (T.) - The Journal of Sports Medicine and Physical Fitness, 2001, vol.41, pp.403410.