Keywords:
1. Introduction
In many studies (Cassirame et al. Citation2017), pole vault performance has been largely related to horizontal speed achieved by athletes before take-off. This performance results from energetic interactions between the athlete and the pole in which running speed from run-up is the main entry converted in strain energy into the pole (Arampatzis et al. Citation2004). After planting the pole, athletes can transfer this kinetic energy with appropriated technical approach and may also add extra energy by means of muscular work subsequently delivered back after maximum pole bending (MPB). Even if speed is a crucial energetic source, recent international competitions highlighted number of athletes with lower speed who can achieve high performances. Those empirical findings can hurt many performance models. A previous historical study observed several take-off parameters which can be related to pole bending (Hay Citation1967). Nevertheless, that study did not involve high level vaulters and the technical approach of pole vault has significantly evolved since 1967. Thus, it is of interest to re-investigate the role of running speed in pole vault considering several performance levels, and to check 1) how speed is used for pole bending, 2) how elastic energy stored in pole is used to reach maximal height. The aim of this study was to investigate the relationships between running speed, pole bending and performance in pole vaulting.
2. Method
2.1. Participants
Measurements were collected during international meetings; All-star perche 2017 and 2018 and Perche Elite Tour in the same place which include athletes from international, national and inter-regional levels. During these two editions, best performances from each athlete were analysed within 3 levels and both sex; Men, 43 (71.2 ± 8.2 kg; 180.7 ± 4.2 cm, personal best from 4.40 to 6.16 m) Women, 40 (57.6 ± 7.3 kg; 166.4 ± 6.2 cm personal best from 3.40 to 4.91 m).
2.2. Mechanical parameters
A radar gun Stalker Pro II (Stalker ltd, Plano, United states) was placed behind the landing mat in the run-up direction to capture speed flow in MookyStalker software (Matsport, Saint-Ismier, France). Synchronization with Optojump Next system (Microgate, Bolzano, Italy) placed each side of official lane and gun radar allow to calculate take-off speed as last 0.2 second before last contact time on the floor (TkS, in m/s). Vaults were captured by high-speed camera (100 Hz, Panasonic HC-V770, Osaka, Japan) perpendicular to the middle line of the lane at 25 m and 2.5 m height. Videos obtained were analysed by Skillspector© software (Video4coach, Svendborg, Denmark) to calculate the shortest pole chord () and thus deduct pole reduction (PoR, in m) at MPB. In addition, maximal height reached by the pelvis was measured (PeH, in m) ().
Figure 1. Illustration of the 3 moments of measurement 1) Take-off, 2) MPB, 3) Maximal height of the pelvis.
2.3. Statistical analysis
Men and women data were analysed separately. For both sex, following relationships were plotted; TkS and PeH, TkS and PoR. Pearson correlation coefficient was calculated for each relation and graded following the scale previously defined (Hopkins et al. Citation2009) (0–0.1) Trivial, (0.1–0.3) Small, (0.3–0.5) Moderate, (0.5–0.7) Large, (0.7–0.9) Very Large, (0.9–1) Nearly Perfect. For each sex, inter group were also analysed with the software Statview (version 5.0). To compare results according to different conditions, a student t-test has been used by a hypothesis test (significance set at p < 0,05).
3. Results and discussion
In accordance with previous studies, relationships between take-off speed and performance were very large for both men (r = 0.82) and women (r = 0.85) () (Decker and Bird Citation2008; McGinnis Citation2008). Nevertheless, we can observe that within group relationships between TkS and PeH decreased with increase in performance level, to reach 0.15 and 0.30 respectively for men and women for international group. This point corroborates empirical findings from the field and highlights that TkS alone less explain performance for this level. It can be hypothesised that with a high level of expertise, the athlete is able to be more effective in the phases of the vault following the take-off. For instance, Schade et al. pointed out that energy gain during vault can explain difference of performance between men and women but how this energy gain is produced remain an open question (Schade et al. Citation2004).
Table 1. Pearson coefficient for each relationship.
In addition, we observed a similar effect with the relationships between TkS and PoR. For both men and women, the overall relation was large but decreased for national and international levels. For women, we noted a significant increase in TkS in accordance with level concomitant with a significant increase in PoR (Inter-regional = 104.8; National = 114.5; International= 125.60 cm). Regarding men, we noticed same significant increase in TkS for higher level but no significant increase in PoR between national and international level (Inter-regional =140.8; National = 160.1; International = 160.4). We observed that international athletes use longer grip and stiffer pole to realize their performance and probably adjust their technic to produce more energetic exchange. Those elements reinforce the fact that performance is less explained by TkS for international level.
4. Conclusions
For all relationships investigated, we can note that world class athletes have significant different results than other groups. For national and inter-regional levels, all athletes are French and practise in France whereas for international level, only 4 athletes are French (3 men 1 women). This comment suggests a national specificity regarding technical approach leading to higher relationship between speed, pole bending and use of energy provided by pole. Furthermore, specificity of international level requests more investigations to understand performance mechanism. Those athletes’ specificities and large inter-athlete variations may open the door to additional gain for performance.
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References
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