Energy cost and metabolic power of Australian football

Abstract

Rhodes University, South Africa Introduction: The objective of the current investigation was to determine the strength changes within the lower limb musculature of specialised batsmen induced by twowork bouts of differing intensities. Methods: Twenty cricket batsmen (age 22.6±4.74 years; stature 179.5±6.38 cm; mass 80.7±11.77kg) were tested. Two experimental conditions, representative of a high(HVR representing twelve sprints per over) and moderate-volume running (MVR representing six sprints per over) batting protocol were compared in a laboratory setting. Muscle strength measures were collected prior to, and following both protocols using the Cybex 6000 Isokinetic Dynamometer, and included; concentric and eccentricmeasures of both knee flexors and extensors. Peak torque, total work, average power and the hamstring to quadriceps ratio were the isokinetic strength parameters under study with sampling conducted at speeds of 60 and 270◦ s−1. Results and discussion: Both the HVR and MVR conditions resulted in significant (p<0.05) reductions in concentric and eccentric extensor and eccentric flexor peak torque at 60◦ s−1. However, expectedly, the largest changes were seen following the HVR condition. For example, peak concentric and eccentric knee extensor (EXT) (−17.17% and -16.07% respectively) and eccentric flexor (FLEX) (−17.49%) values decreased significantly (p<0.05) following the HVR condition at 60◦ s−1. In addition, concentric and eccentric total work produced by the flexors and eccentric extensors resulted in significantly (p<0.05) lower values due to the HVR condition. In contrast, the MVR condition elicited significant (p<0.05) reductions in concentric extensor average power values at speeds of 60◦ s−1, whereas the HVR protocol revealed no changes in average power for concentric or eccentric flexor and extensor values at both speeds. Thus, although strength was negatively compromised followingboth conditions, thiswas to a greater extent following the high volume sprinting condition. In conclusion, the isokinetic concentric strength decrementwas particularly exaggerated following the HVR condition while eccentric strength decrements were evident following both conditions.