The aim of this study was to investigate the relationship between linear sprint, power output obtained during a squat and change of direction (COD) performance. Fifteen elite soccer players participated in this study (age = 21.7 ± 0.72 years, body mass = 74.9 ± 9.11 kg, body height = 180.4 ± 7 cm, training experience = 9 ± 1.5 years). To examine these correlations a following battery of tests were carried out: 20-m linear sprint, one-repetition maximum (1RM) squat strength, peak power output obtained during a squat at 50% 1RM and time obtained in two 20-m COD tests with different angles of direction change (90° and 135°). In addition, COD deficits (90°-COD_DEF and 135°-COD_DEF) for both COD tests were calculated. The Spearman’s rank order correlation showed a nearly perfect statistical relationship between the 90°-COD and the 90°-COD_DEF (r = 0.9; p < 0.001). In the case of 90°-COD_DEF, there was a large statistical relationship with 135°-COD_DEF (r = 0.59; p = 0.021). Moreover, there was a nearly perfect statistical relationship between 135°-COD and 135°-COD_DEF (r = 0.91; p < 0.001). The statistically insignificant (p > 0.05) relationship between 20-m linear sprint time, power output obtained during a squat at 50% 1RM, 1RM squat strength level and both COD test, as well as both COD deficits were found. Results of the present study showed that 20-m linear sprinting speed, 1RM squat strength, power output obtained during squat at 50% 1RM and COD ability at 90° and 135° angles, are separate physical qualities. Moreover, it seems that COD deficit provides a more isolated measure of COD ability than the COD tests alone and does not must be limited to a specific angle, but provides knowledge about the COD ability in a range of other angles, at least concerning 90° and 135° COD angles.

Introduction: his study investigated the relationship between hip abductor strength (Abd), adductor strength (Add), straight accelerations and decelerations, and during changes of direction (COD 90°) performance in basketball players. Material and Methods: Fourteen basketball players participated (age = 23.6 ± 4.4 years, body mass = 86.3 ± 5.9 kg, body height = 192.3 ± 6.2 cm, training experience = 6.7 ± 2.6 years). Straight running results and running with a change of direction (COD 90°) have been described as the time (s) obtained for a given length. Following tests were carried out: maximum isometric strength test, 20-m linear sprint and 20-m COD sprint with 90° direction change angles. Following the warm-up, all athletes performed two maximal 20-m linear sprints, interspersed with 5 min rest intervals. Following the 20-m linear sprint test, the participants were provided with a 5 min rest interval before completing the COD tests. Additionally, the balance in isometric strength of the dominant and non-dominant hip Abd-Add muscles were evaluated. Two maximum attempts interspersed with one-minute rest intervals were performed. Results: The t-test revealed statistically significant higher absolute and relative isometric strength of AddR (adductor right) in comparison to AddL (adductor left). Conclusion: The results of this study show that the maximum isometric force and the relative strength of the abductor muscle group have a significant effect on changing direction running. Moreover, hip Abd and Add are typical for strength bilateral strength imbalances. Therefore, the evaluation and development of these qualities are essential for coaches to monitor and prescribe adequate training regimens.