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The purpose of this investigation was to determine the acute effects of back squats on countermovement jump performance across multiple sets using a strength-power potentiation complex training protocol. Fifteen elite volleyball players performed three unloaded countermovement jumps (CMJ) following three repetitions of the back squat performed at either 65% or 87% of 1-RM, respectively, repeated for 10 sets. A control session of three CMJs was also repeated for 10 sets. Mean jump height performance was enhanced compared to performing CMJs only irrespective of which intensity was used (65% 1-RM: +3.3 ± 2.2% [CI: 1.0 to 5.6]; 87% 1-RM: 2.6 ± 1.9% [CI: 0.7 to 4.5]). Subjects with a greater relative strength possessed a very likely large (97%; ES = 1.51) chance of improvement in jump height across 10 sets of the protocol prescribed using the intensity of 87% 1-RM and a likely moderate (89%; ES = 0.94) and very likely large (97%; ES = 1.76) chance of improvement in maximum concentric impulse (N·s) using intensities of 65% and 87%1-RM, respectively. Performance (jump height and maximum concentric impulse) may be enhanced across 10 sets of the strength power potentiation complex training protocol prescribed irrespective of intensity, with a greater effect observed for the subjects with a greater relative strength and with the 87% 1-RM heavy load back squat condition. In practice, coaches should consider the athlete’s strength level when designing such a complex training protocol to generate any post-activation potentiation effect across multiple alternating sets to enhance jump performance.

The aims of this study were to 1) investigate the influence of ground travel on wellness measures, and 2) examine the possible influence of travel distance and fitness on the magnitude of these possible changes. Compared with home matches, wellness measures showed moderate-to-large impairments of wellness of soccer players for away matches the day prior to the match (D-1) (range; +5 to 68%, [90%CL 1-88]; standardized difference: range; +.6 to +1.75 [.1-2.07]) and small-to-large impairments the day of the match (D-0, range; +7 to +68.1 [-1.6-87.5]; standardized difference, range; +.24 to 1.78, [-.06-2.15]), respectively. There were large and very large negative relationships between the increases of fatigue (r = -.84, 90%CL -.95; -.56) or soreness (at D-1 r = -.80, -.93; -.84) and players’ fitness. There were also very large positive correlations between actual wellness measures and traveling distance to away locations (r range; .70 to .87). Ground travel-induced impairment of wellness is associated with fitness and distance of away locations in young soccer players. Simple wellness questionnaires could be used to effectively monitor young soccer players’ freshness and readiness to train or compete during away games.

The aims of the present study were to examine: 1) the validity and reliability of a new timing system to assess running kinematics during change of direction (COD), and 2) the determinants of COD-speed. Twelve young soccer players performed three 20-m sprints, either in straight line or with one 45º- or 90º- COD. Sprints were monitored using timing gates and two synchronized 100-Hz laser guns, to track players’ velocities before, during and after the COD. The validity analysis revealed trivial-to-small biases and small-to-moderate typical errors of the estimate with the lasers compared with the timing gates. The reliability was variable-dependent, with trivial- (distance at peak speed) to-large (distance at peak deceleration) typical errors. Kinematic variables were angle-dependent, with likely lower peak speed, almost-certainly slower minimum speed during the COD and almost-certainly greater deceleration reached for 90º-COD vs. 45º- COD sprints. The minimum speed during the COD was largely correlated with sprint performance for both sprint angles. Correlations with most of the other independent variables were unclear. The new timing system showed acceptable levels of validity and reliability to assess some of the selected running kinematics during COD sprints. The ability to maintain a high speed during the COD may be the determinant of COD-speed.

While a relative age effect (RAE) has been reported in handball, such analyses do not consider the actual playing time during competitions, which may actually have more impact on matches performance in matches. The objective of the present study was to examine the RAE on playing time during international competitions with respect to playing positions. Team compositions (477 players) of the quarter finalists of the 2012 Olympic Games, 2013 World Championships, and 2014 European Championship were analyzed. Month and year of birth where collected in the starting list of each team for center, left and right backs, left and right wings, goalkeepers and pivots. Players were categorized into birth quartile (Q1 Jan–Mar; Q2 Apr–Jun; Q3 Jul–Sep; and Q4 Oct–Dec) and as odd/even year. Playing times were retrieved from official statistics. Data were analyzed for practical significance using magnitude-based inferences. We observed a strong selection bias towards players born earlier within a two-year selection period for all playing positions (Chi-square, p, Iako je utjecaj relativne dobi igrača potvrđen u rukometu, takve analize ne uzimaju u obzir stvarno vrijeme provedeno u igri tijekom natjecanja, a što može snažnije utjecati na uspješnost tijekom utakmice. Cilj je ovog istraživanja bio utvrditi utjecaj relativne dobi igrača na vrijeme igranja tijekom međunarodnih natjecanja s obzirom na igračku poziciju. Analizirane su postave nacionalnih selekcija (477 igrača) koje su igrale četvrtinu finala na Olimpijskim igrama 2012. godine, Svjetskom prvenstvu 2013. te Europskom prvenstvu 2014. godine. Informacije o mjesecu i godini rođenja za srednje, lijeve i desne vanjske igrače, lijeva i desna krila, vratare i kružne napadače prikupljeni su iz službenih startnih popisa svake momčadi. Igrači su podijeljeni u kvartile definirane prema datumu rođenja (Q1 – siječanj do ožujak, Q2 – travanj do lipanj, Q3 – srpanj do rujan i Q4 – listopad do prosinac) te prema tomu jesu li rođeni u parnoj ili neparnoj godini. Vrijeme provedeno u igri za svakog igrača dobiveno je iz službenih statistika. Veličina učinka analizirana je u odnosu na minimalnu značajnu praktičnu vrijednost. Uočili smo snažnu selekcijsku pristranost prema igračima koji su rođeni ranije unutar dvogodišnjeg selekcijskog perioda za sve igračke pozicije (χ2, p