AEROBIC FITNESS ECOLOGICAL VALIDITY IN ELITE SOCCER PLAYERS:AMETABOLIC POWER APPROACH VINCENZO MANZI, 1 FRANCO IMPELLIZZERI, 2 AND CARLO CASTAGNA 1 1 Technical Department, Football Training and Biomechanics Laboratory, Italian Football Association (FIGC), Florence, Italy; and 2 Neuromuscular Research Laboratory, Schulthess Clinic, Zurich, Switzerland ABSTRACT Manzi, V, Impellizzeri, F, and Castagna, C. Aerobic fitness ecological validity in elite soccer players: a metabolic power approach. J Strength Cond Res 28(4): 914–919, 2014—The aim of this study was to examine the association between match metabolic power (MP) categories and aerobic fitness in elite-level male soccer players. Seventeen male professional soccer players were tested for V _ O 2 max, maximal aerobic speed (MAS), V _ O 2 at ventilatory threshold (V _ O 2 VT and %V _ O 2 VT), and speed at a selected blood lactate concentration (4 mmol$L 21 , V L4 ). Aerobic fitness tests were performed at the end of pre- season and after 12 and 24 weeks during the championship. Aerobic fitness and MP variables were considered as mean of all seasonal testing and of 16 Championship home matches for all the calculations, respectively. Results showed that V _ O 2 max (from 0.55 to 0.68), MAS (from 0.52 to 0.72), V _ O 2 VT (from 0.72 to 0.83), %V _ O 2 maxVT (from 0.62 to 0.65), and V L4 (from 0.56 to 0.73) were significantly (p , 0.05 to 0.001) large to very large associated with MP variables. These results provide evidence to the ecological validity of aerobic fitness in male professional soccer. Strength and conditioning professionals should consider aerobic fitness in their training program when dealing with professional male soccer players. The MP method resulted an interesting approach for tracking external load in male professional soccer players. KEY WORDS association football, intermittent exercise, maximal oxygen uptake, endurance, match analysis INTRODUCTION C ompetitive soccer imposes important physiologi- cal demands on players who must be physically fit to cope with game energy requests (1,22). Indeed, during an official match, players are reported to attain 80–90% and 70–80% of their maximal heart rate (HR) and oxygen uptake (V _ O 2 max), respectively. Elite-level players perform 1,200–1,400 activity changes and accumulate 150– 250 short-duration bouts (1–4 seconds) at high intensity (1,22). Despite the lower average match speed (10–12 km$90 min 21 ), soccer players may experience a remarkable glycogen depletion during the game (16). This results from the reiteration of high-intensity accelerations, decelerations, and sprints throughout the game (1,22). In soccer, physical match analysis considered mainly distances covered or time spent in arbitrary chosen running speed categories using various movement caption systems (3,22). However, the speed category approach, not accounting for match accelerations and decelerations, may provide only a partial figure of actual game physiological demands (18). Indeed, important energetic demands may be imposed to players also when speed is low but acceleration is elevated (18). Recently, a kinematic approach considering the instan- taneous interplay of player’s running speed and acceleration was proposed (18), with the aim to provide a more detailed description of match demands. With this approach, player’s activity was assumed as distance covered in arbitrary chosen energy-expenditure categories indicated as metabolic power (MP). Using this novel approach were reported higher anaerobic demands than previously found with the speed categories approach (18). This finding may affect the sup- posed importance of aerobic fitness in soccer (12,14,22). As a result, knowledge about the relationship between aerobic fitness and MP may result useful for guiding specific training intervention in soccer. Information on the association between aerobic fitness and MP categories would be also of value for understanding the nature of MP during actual match play. Indeed, a given MP, being the product of player’s instantaneous acceleration and speed, may potentially be achieved with different met- abolic pathways (18). Differently from what reported for the speed category approach, no study was published addressing the effect of intersubject variance of aerobic fitness on MP production during highly competitive matches (12,14,15,22). Informa- tion in this regard would result of great interest to pose evidence-based hypothesis helpful to guide training prescrip- tion and future training studies. Therefore, the aim of this study was to examine the association among aerobic fitness variables and match MP Address correspondence to Dr. Carlo Castagna, castagnac@libero.it. 28(4)/914–919 Journal of Strength and Conditioning Research Ó 2014 National Strength and Conditioning Association 914 Journal of Strength and Conditioning Research the TM Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.