Energetics of Shuttle Runs: The Effects of Distance and Change of Direction

Shuttle runs can be used to study the physiological responses in sports (such as basketball) characterized by sprints (accelerations/decelerations) and changes of direction. Purpose: To determine the energy cost (C) of shuttle runs with different turning angles and over different distances (with different acceleration/deceleration patterns). Methods: Nine basketball players were asked to complete 6 intermittent tests over different distances (5, 10, 25 m) and with different changes of direction (180 degrees at 5 and 25 m; 0 degrees, 45 degrees, 90 degrees, and 180 degrees at 10 m) at maximal speed (v approximate to 4.5 m/s), each composed by 10 shuttle runs of 10-s duration and 30-s recovery; during these runs oxygen uptake (VO2), blood lactate (La-b), and C were determined. Results: For a given shuttle distance (10 m) no major differences where observed in VO2 (similar to 33 mL.min(-1).kg(-1)), La-b (similar to 3.75 mM), and C(similar to 21.2 J.m(-1).kg(-1)) when the shuttle runs were performed with different turning angles. For a given turning angle (180 degrees), VO2 and La-b were found to increase with the distance covered (VO2 from 26 to 35 mL.min(-1).kg(-1); La-b from 0.7 to 7.6 mM) while C was found to decrease with it (from 29.9 to 10.6 J.m(-1).kg(-1)); the relationship between C and d (m) is well described by C = 92.99 x d(0.656), R-2 = .971. Conclusions: The metabolic demands of shuttle tests run at maximal speeds can be estimated based on the running distance, while the turning angle plays a minor role in determining C.