2.The velocity continuum in soccer players

Laboratory evaluation »

Laboratory assessment of endurance capacity in soccer players typically involves a treadmill at progressively increasing velocities until volitional exhaustion (1). During this test gas exchange data and blood lactate values are being collected and are used to define a range of physiological markers (lactate thresholds, maximal oxygen uptake) along with their corresponding velocities (1).

Field assessment of the speed indices involves, amongst other parameters, the assessment of maximal speed (2). The continuum of the velocities associated with the above physiological parameters as well as the inclusion of maximal sprinting speed creates a locomotor profile of the player (3) that takes into consideration submaximal and maximal physiological markers as well as neuromuscular markers (Figure 1).

• Briefly V2 represents the velocity at aerobic threshold; up to this intensity energy is almost exclusively provided by the aerobic mechanism.
• V4 represents the velocity at anaerobic threshold and up to this intensity the aerobic mechanism is still the major energy source. Above this intensity energy is still provided by the aerobic mechanism but there is a progressively increasing contribution from anaerobic sources.
• Velocity at maximal oxygen uptake (or more commonly vVO2max) represents the intensity that taxes maximally the aerobic mechanism. Around and above this intensity there is a vast combination of work:rest ratios and exercise durations that provide a wide range of energy contributions from both aerobic and anaerobic sources (3, 4).
• Finally maximal sprinting speed (MSS) represents the upper neuromuscular locomotor limit (3, 4).

Laboratory evaluation »

The locomotor profile can be used to assess the contribution from anaerobic sources during the various drills. For example two players with same vVO2max but different MSS will be taxed differently during a 6 min 15:15 running based HIIT at 120%vVO2max with passive rest.

Specifically despite having the same vVO2max this workout will be more intense for the player with the lower MSS. This is due to the fact that the absolute intensity of the drill (e.g. ~22 km·h-1) will be closer to upper limit of his locomotor profile. Therefore despite that the drill is taxing the aerobic mechanisms of the players to an equal extend, the player with the lower MSS is experiencing a higher anaerobic load (3, 4).

REFERENCES

1. Ziogas GG, Patras KN, Stergiou N, Georgoulis AD. Velocity at lactate threshold and running economy must also be considered along with maximal oxygen uptake when testing elite soccer players during preseason. J Strength Cond Res, 2011; 25(2):414-419.
2. Haugen T, Tonnessen E, Hisdal J, Seiler S. The role and development of sprinting speed in soccer. Int J Sports Physiol Perform, 2014; 9(3):432-441.
3. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle: Part I: cardiopulmonary emphasis. Sports Med, 2013; 43(5):313-338.
4. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med, 2013; 43(10):927-54.