Bachelor of Science

This study investigated aerobic and anaerobic performance through measures of the Phosphate Decrement Test (PDT) and the Tri-level Fitness Profile ( m ). The subjects were 14 university soccer players, mean age of 24.3 years from the School of Physical Education, Nanyang Technological University. They were assigned as either midfield or non-midfield groups based on their training status and competitive experience in their respective playing positions. All subjects underwent a random order of tests which were the TFP, the Pre-Phosphate Decrement 40 m Test (Pre-PD40mT) and the PDT. The TFP was performed on a Repco EX-I0 cycle ergometer in three separate stages: the Aerobic Power Test, the 10-second Anaerobic Test and the 30-second Anaerobic Test. Work and power variables were derived from each stage of testing, During the Pre-PD40mT, the fastest of three 40 m sprint trials which was recorded and used in the calculation of the Phosphate Decrement Index (PDI) in the PDT. In the PDT, each subject executed 10 sprints of 40 m departing every 30 seconds. Additionally, the first six sprints were used to compute the Repeated Sprint Ability (RSA) score. Results revealed that midfielders were significantly taller, faster and showed less decrement as reflected in their RSA scores compared to non-midfielders. No statistical differences were found in other variables. The PDT did not show significant correlations with any of the anaerobic power and work variables measured by the TFP. Further research is recommended to determine the physiological mechanisms associated with the PDT. Both the TFP and PDT have the potential to be safe and effective tests used by soccer practitioners to assess the fitness of soccer players.