Conference paper

The 6th Annual Conference for Society of Chinese Scholars on Exercise Physiology and Fitness.

Below is the first paper for this conference:

Fitness profile of Chinese elite youth soccer players

Pui-lam Wong1, Patrick W.C. Lau2, Tze Chung Luk2, Karim Chamari3, Ulrik Wisloff4
1) Athlete & Scientific Services Division, Hong Kong Sports Institute, Hong Kong
2) Dept of Physical Education, Hong Kong Baptist University, Hong Kong
3) National Centre of Medicine and Sciences in Sport, Tunisia
4) Dept of Circulation & Medical Imaging, Norwegian University of Science and Technology, Norway
E-mail: delwong@alumni.cuhk.net

Introduction: In the past years, there is a rapid growth of soccer standard in Asia countries (FIFA, 2006). However, to our knowledge, the information about the fitness among Chinese elite youth soccer players is not available in the literature. Therefore, the purpose of this study was to investigate the maximal oxygen uptake (VO2max), sprint, jump, and ball shooting speed among Chinese elite youth soccer players.

Method: 47 Hong Kong elite youth soccer players (age: 13.6±0.6; weight: 52.3±9.4kg; height: 1.65±0.1m) participated in the study. Players have 2 training sessions per week each last for 90mins. Informed consent was obtained from players and their parents prior to the study. All players were free from injury at the time of data collection. VO2max test was conducted in the laboratory where the environment was well controlled (temperature: 23.7±0.8 °C; humidity: 59.2±5.5%; ambient pressure: 1010±2mmHg). The VO2max protocol has been used by elite youth soccer players and running economy was determined during the last 30s of the 4min run at 7km/h (Chamari et al, 2005). VO2 and heart rate (HR) were recorded during the whole running test. The other 3 tests were conducted outdoor where players performed: a) 30m sprints with a standing-start position, 3min rest between each of the 3 trials; countermovement jump on a portable force mat, 2min rest between each of the 3 jumps; c) 3-step shoot 4m from the goal (1m x 1m), 2min rest between each of the 8 trials. Best results of these tests were used for analysis.

Results and discussion: VO2max (relative: 58.6±5.3ml/min/kg; absolute: 3.01±0.5L/min); HRmax (199.4±7.8bpm); running economy (relative VO2: 42.5±4.4ml/min/kg; absolute VO2: 2.2±0.4L/min; HR: 161±12bpm); sprint time (5m: 1.22±0.1s; 10m: 2.04±0.1s; 15m: 2.75±0.2s; 20m: 3.45±0.2s; 30m: 4.81±0.3s); countermovement jump height (54.9±6.1cm); and ball shooting speed (77.1±9.5km/h). Compared with African players at the same age (Charami et al, 2005), Chinese elite youth soccer players have lower VO2max (65.3 vs 42.5ml/min/kg; 3.49 vs 3.01L/min) and running economy (38.8 vs 42.5ml/min/kg). To our knowledge, no comparable literature is available for sprint, jump, and ball shooting performances at the same age.

Reference
FIFA. 2006. FIFA World Ranking.
Chamari et al. 2005. BJSM, 39, pp24-28.

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This is the second paper.

Relationship between heart rate and oxygen consumption among Chinese elite youth soccer players

Tze Chung Luk1, Pui-lam Wong2, Patrick W.C. Lau1 , Karim Chamari3, Ulrik Wisloff4
1) Dept of Physical Education, Hong Kong Baptist University, Hong Kong
2) Athlete & Scientific Services Division, Hong Kong Sports Institute, Hong Kong
3) National Centre of Medicine and Sciences in Sport, Tunisia
4) Dept of Circulation & Medical Imaging, Norwegian University of Science and Technology, Norway
E-mail: mailto:delwong@alumni.cuhk.net


Introduction: The golden standard to assess aerobic ability is to measure the oxygen consumption (VO2) by using metabolic measurement device when subject running on a motorized treadmill until exhaustion (Stolen et al., 2005). However, the metabolic measurement device is expensive and may not be available to every soccer team/club. In addition, organizing one soccer team to continuously assess players’ VO2max require a huge amount of time and manpower. Therefore, heart rate (HR) has been used to estimate/predict the exercise intensity among soccer players (Esposito et al., 2004; Kemi et al., 2003). Once the relationship between HR and VO2 is established, coaches can use HR to estimate players’ VO2 in on-field situation. The purpose of this study is to examine the prediction of VO2 using HR among Chinese elite youth soccer players.

Method: 47 Hong Kong elite youth soccer players (age: 13.6±0.6; weight: 52.3±9.4kg; height: 1.65±0.1m) participated in the study. Players have 2 training sessions per week each last for 90mins. All players were free from injury at the time of data collection. VO2max test was conducted in the laboratory where the environment was well controlled (temperature: 23.7±0.8 °C; humidity: 59.2±5.5%; ambient pressure: 1010±2mmHg). The VO2max protocol has been used by elite youth soccer players (Chamari et al, 2005). VO2 and HR were recorded throughout the experiment at 5s interval.

Results and discussion: Correlation between HR and VO2 was 0.76 (p<0.001)>.

Figure 1. Prediction of VO2 using HR.


Reference
Esposito F. et al. (2004). EJAP, 93(1-2), pp167-172.
Hoff J. (2005). JSS, 23(6), pp573-582.
Kemi O. J. et al. (2003). JSMPF, 43(2), pp139-144.