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Concentric and Eccentric: Muscle Contraction or Exercise?

100%
Padulo J., Laffaye G., Ardigò L. P., Chamari K.
Journal of Human Kinetics
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2013
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vol. 37
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issue 1
5-6
2
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Effect of Three Technical Arms Swings on The Elevation of the Center of Mass During a Standing Back Somersault

76%
Mkaouer B., Jemni M., Amara S., Chaabène H., Padulo J., Tabka Z.
Journal of Human Kinetics
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2014
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vol. 40
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issue 1
37-48
EN
Arms swing during standing back somersaults relates to three different “gymnastics schools”, each is considered “optimal” by its adepts. In the three cases, technical performance, elevation and safety differ. Therefore, the aim of this study was to compare the mechanical variables of three different arms swing techniques in the performance of a standing back tucked somersault. Five high-level male gymnasts (age: 23.17±1.61 yrs; body height: 1.65±0.05 m; body mass: 56.80±7.66 kg) randomly performed standing somersaults under three conditions, each following a different arms’ swing technical angle (270°, 180° and 90°). A force plate synchronized with a three dimensional movement analysis system was used to collect kinetic and kinematic data. Significant differences were observed between somersaults’ performance. The back somersault performed with 270° arms swing showed the best vertical displacement (up to 13.73%), while the back somersaults performed with 180° arms swing showed a decrease in power (up to 22.20%). The back somersault with 90° arms swing showed the highest force (up to 19.46%). Considering that the higher elevation of the centre of mass during the flight phase would allow best performance and lower the risk of falls, this study demonstrated that optimal arms’ swing technique prior to back tucked somersault was 270°.
3
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Estimating Maximal Heart Rate with the ‘220-Age’ Formula in Adolescent Female Volleyball Players: A Preliminary Study

76%
Nikolaidis P. T., Padulo J., Chtourou H., Torres-Luque G., Afonso J., Heller J.
Human Movement
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2014
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vol. 15
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issue 3
166-170
EN
Purpose. Although maximal heart rate (HRmax) is used widely to assess exercise intensity in training, there are limited data with regards to the validity of age-based prediction equations of HRmax in volleyball players. Therefore, the aim of the present study was to compare the measured-HRmax of two prediction equations (Fox-HRmax = 220 − age and Tanaka-HRmax = 208 − 0.7 × age) in young female volleyball players. Methods. The study involved 47 volleyball players (age 13.39 ± 2.01 years, body mass 54.0 ± 10.8 kg, height 162.7 ± 10.2 cm) who performed a graded exercise field test (20 m shuttle run endurance test) to assess HRmax. Measured-HRmax values were compared with the Fox and Tanaka prediction equations. Results. The results showed that mean scores for HRmax significantly differed between measured and predicted values (p < 0.001, ŋ2 = 0.49). Post-hoc tests revealed that Fox-HRmax overestimated measured-HRmax (mean difference 5.7 bpm; 95% CI [3.0, 8.5]), whereas Tanaka-HRmax was similar to measured-HRmax (-2.2 bpm; 95% CI [-4.9, 0.4]). HRmax did not correlate with age (r = 0.16, p = 0.291). Conclusions. The results of this study failed to validate the widely used ‘220−age’ formula in volleyball players. Coaches and fitness trainers should take into account that the overestimation of HRmax by the Fox equation might lead to prescribing exercise at a higher intensity than what is targeted. Therefore, the Tanaka equation appears to offer a more accurate prediction equation of HRmax than the Fox equation in young female volleyball players.
4
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Postural Adaptations in Preadolescent Karate Athletes Due to a One Week Karate Training Camp

64%
Vando S., Filingeri D., Maurino L., Chaabène H., Bianco A., Salernitano G., Foti C., Padulo J.
Journal of Human Kinetics
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2013
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vol. 38
45-52
EN
The aim of this study was to investigate the effect of an increasing number of training hours of specific highintensity karate training on postural sway in preadolescent karate athletes. Seventy-four karatekas were randomly assigned to 1 of 2 groups: Karate Group (KG=37): age 10.29±1.68 yrs; or Control Group (CG= 37): age 10.06±1.77 yrs. The KG performed two sessions per day for 1 week in total, while the CG performed only 3 sessions during the same period. The center-of-pressure length (COPL) and velocity (COPV) were recorded under four different experimental conditions: open eyes (EO), closed eyes (EC), open eyes monopodalic left (EOL), open eyes monopodalic right (EOR), pre as well as post training intervention. Post-camp results indicated significant differences between the groups in the COPL p<0.001; an interaction of training type×time in the COPV (p<0.001) and an interaction of training type×time (p=0.020). The KG revealed an improvement in the COPL from pre to post-camp under conditions of EO [-37.26% (p<0.001)], EC [-31.72% (p<0.001)], EOL [-27.27% (p<0.001)], EOR [-21.44% (p<0.001)], while CG revealed small adaptations in conditions of EO (3.16%), EC (0.93%), EOL (-3.03%), EOR (-0.97%). Furthermore, in the KG an improvement in the COPV from pre to post-camp was observed in conditions of EO [-37.92% (p<0.001)], EC [-32.52% (p<0.001)], EOL [-29.11% (p<0.001)], EOR [-21.49% (p<0.001)]. In summary, one-week of high intensity karate training induced a significant improvement in static body balance in preadolescent karate athletes. Karate performance requires high-levels of both static and dynamic balance. Further research dealing with the effect of karate practice on dynamic body balance in young athletes is required.
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