Those players younger than 14 years incurred more injuries in training and sustained more growth-related overuse disorders. Older players were more often injured during matches. Injury incidence and the frequency of overuse disorders were highest early in the season.

Anaerobic tests are divided into tests measuring anaerobic power and anaerobic capacity. Anaerobic power tests include force-velocity tests, vertical jump tests, staircase tests, and cycle ergometer tests. The values of maximal anaerobic power obtained with these different protocols are different but generally well correlated. Differences between tests include factors such as whether average power or instantaneous power is measured, active muscle mass is the same in all the protocols, the legs act simultaneously or successively, maximal power is measured at the very beginning of exercise or after several seconds, inertia of the devices and body segments are taken into account. Force-velocity tests have the advantage of enabling the estimation of the force and velocity components of power, which is not possible with tests such as a staircase test, a vertical jump, the Wingate test and other long-duration cycle ergometer protocols. Maximal anaerobic capacity tests are subdivided into maximal oxygen debt test, ergometric tests (all-out tests and constant load tests), measurement of oxygen deficit during a constant load test and measurement of peak blood lactate. The measurement of the maximal oxygen debt is not valid and reliable enough to be used as an anaerobic capacity test. The aerobic metabolism involvement during anaerobic capacity tests, and the ignorance of the mechanical efficiency, limit the validity of the ergometric tests which are only based on the measurement of work. The amount of work performed during the Wingate test depends probably on glycolytic and aerobic power as well as anaerobic capacity. The fatigue index (power decrease) of the all-out tests is not reliable and depends probably on aerobic power as well as the fast-twich fibre percentage. Reliability of the constant load tests has seldom been studied and has been found to be rather low. In theory, the measure of the oxygen deficit during a constant load test is more valid than the other tests but its reliability is unknown. The validity and reliability of postexercise blood lactate as a test of maximal anaerobic capacity are probably not better than that of the current erogmetric tests. The choice of an anaerobic test depends on the aims and subjects of a study and its practicability within a testing session.

The force-velocity relationship on a Monark ergometer and the vertical jump height have been studied in 152 subjects practicing different athletic activities (sprint and endurance running, cycling on track and/or road, soccer, rugby, tennis and hockey) at an average or an elite level. There was an approximately linear relationship between braking force and peak velocity for velocities between 100 and 200 rev.min-1. The highest indices of force P0, velocity V0 and maximal anaerobic power (Wmax) were observed in the power athletes. There was a significant relationship between vertical jump height and Wmax related to body mass.

The interests and limits of the different methods and protocols of maximal (anaerobic) power (P max) assessment are reviewed: single all-out tests versus force-velocity tests, isokinetic ergometers versus friction-loaded ergometers, measure of P max during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips), methodological (protocols) and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue) limiting P max in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions…) are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices.

The present investigation has been designed to confirm the effect of instruction (hard-and-fast instruction compared to fast instruction) upon maximal voluntary isometric force (MVF) and maximal rate of force development (MRFD) in muscle groups which differ with regards to muscle mass and usage. In addition, we took advantage of the force data collected during unilateral and bilateral leg extension, to compare the instruction effects on the indices of the bilateral deficits (BI, the differences between the data collected during bilateral extensions and the sum of the data collected during unilateral left and right extensions) with regard to MVF (BIMVF) and MRFD (BIMRFD). Force-time curves were recorded during maximal isometric contractions of the elbow flexors, the leg extensors of the take-off and lead legs and during bilateral leg extension in 26 healthy young male volunteers from the track-and-field national team of Tunisia. In the first protocol, the subjects were instructed to produce MFV as hard-and-fast as possible (instruction I). In the second protocol (instruction II) the subjects were instructed to provide MFRD, that is the most explosive force, by concentrating on the fastest contraction without concern for achieving maximal force. The present study confirmed the importance of an appropriate instruction for the measurement of MRDF The MRFD (F = 40.8, P < 0.001) were significantly higher when measured after instruction II compared to instruction I. The effect of the instruction upon MRFD were similar for muscle groups with different volumes, cortical representations and uses. The same results (F = 52.1; P < 0.001) were observed when MRFD was related to MVF [MRFD% = (MRFD/MVF) x 100]. On the other hand, MVF was similar following both instructions (ANOVA, F = 0.562; P = 0.454). Moreover, the results of the present study suggested that the effect of instruction was significantly larger for BIMRFD than for BIMVF.