This study aimed to assess the association of the mechanical variables derived from the force-velocity (FV) profile (i.e. theoretical maximal force [F 0 ], velocity [V 0 ] and maximal power output [P max ]) with change of direction (COD) performance in soccer, basketball and tennis players. Fifty-four male athletes (soccer n = 23; tennis n = 16; basketball n = 15) were assessed for the vertical (Vrt) and horizontal (Hzt) FV profiles, COD with the dominant (D) and nondominant (ND) legs, using the modified 505 test, and sprint. Hzt FV profile parameters showed stronger associations with performance than Vrt FV profile in the three sports. Specifically, the Hzt parameter most strongly associated with COD performance was F 0 in tennis (r =-0.83; p<0.001) and P max in soccer and basketball (r =-0.79; p<0.001). Associations between sprint times and COD test ranged from (r = 0.73 to 0.82) in soccer players, (r = 0.74 to 0.87) in tennis players and (r = 0.62 to 0.85) in basketball players, respectively (p<0.05). Considering the whole sample and the random effect of the type of sports, an improvement in sprint acceleration (i.e. one N/kg increase in F 0 and one W/kg in P max) was associated with-0.15 s and-0.04 s to complete the 505 test, respectively. In conclusion, our results suggest the potential usefulness of assessing the Hzt FV profile to maximize acceleration capabilities through training interventions which, in turn, may translate into improved COD performance. However, further longitudinal and experimental research is needed to confirm this hypothesis.

Baena-Raya, A, Jim énez-Reyes, P, Romea, ES, Soriano-Maldonado, A, and Rodríguez-P érez, MA. Gender-specific association of the sprint mechanical properties with change of direction performance in basketball. J Strength Cond Res 36(10): 2868-2874, 2022-We evaluated the gender-specific associations between the mechanical variables derived from the horizontal force-velocity (FV) profile (i.e., theoretical maximal force [F 0 ], velocity [V 0 ], maximal power output [Pmax], peak ratio of the effective horizontal component [RF peak ], and the force application technique index [D RF ]) and the change of direction (COD) performance for basketball players. Seventy-one players (23 women and 48 men) were assessed for the horizontal FV profile and COD using the modified 505 and V-cut tests. The FV profile parameters were significantly higher for the men than those for the women. The F 0 , RF peak , and Pmax were strongly associated with performance in the 505 test (women r range 5 20.72 to 20.82; men: r range 5 20.67 to 20.75; p , 0.001) and the V-cut test (women r range 5 20.68 to 20.76; men r range 5 20.45 to 20.50; p , 0.001), as well as with a lower COD deficit (women r range 5 0.58 to 0.75 (p , 0.01); men r range 5 0.49 to 0.54; all p , 0.001). For the women, a 1 N•kg 21 increase of the F 0 was associated with 20.20 seconds and 20.56 seconds in the 505 and V-cut tests, respectively, and 0.16 seconds for the COD deficit. In the men, it was associated with 20.13 seconds and 20.37 seconds in the 505 and V-cut tests, respectively, and 0.10 seconds for the COD deficit. F 0 , RF peak , and Pmax are the most determinant sprint mechanical properties to successfully COD and reduce the COD deficit. The horizontal FV profile assessment is recommended for diagnosing and prescribing a training program for basketball players.

Understanding the relationship between mechanical variables derived from actions such as jumping, sprinting, or ballistic bench press throwing and sport-specific performance moves is of scientific and practical interest for strength and conditioning coaches for improving training programs. We examined the association between mechanical variables derived from the force-velocity (FV) profiles of the aforementioned actions and spike and serve ball speeds in elite volleyball players. Twenty-two male elite volleyball players (age: 24.3 ± 4.5 years; height: 1.89 ± 0.06 m; body mass: 86.3 ± 8.6 kg) were tested in two sessions. Squatting, sprinting, and bench press throwing FV profiles were determined in the first session, while spike and serve ball speeds were assessed in the second session. The theoretical maximal force (F0) of vertical jumping, the theoretical maximal velocity of sprinting, and the F0 of bench press throwing in ascending order, were strongly associated (rs range 0.53–0.84; p<0.05) with spike and serve ball speeds. These mechanical variables explained 20%-36% of the variability in spike and serve ball speeds, with a greater influence on the serve speed. These results suggest that assessing jumping, sprinting, and bench press throwing force-velocity profiles might help provide player-specific training programs and optimize performance in these technical-tactical actions in male elite volleyball players.

The aims of this study were: (i) to analyse the load-velocity relationship in the bilateral leg-press exercise in female breast cancer survivors, (ii) to assess whether mean velocity (MV) or peak velocity (PV) show stronger relationship with the relative load, and (iii) to examine whether linear (LA) or polynomic (PA) adjustment predict the velocities associated with each %1RM with greater precision. Twenty-two female breast cancer survivors (age: 50.2 ± 10.8 years, weight: 69.6 ± 15.2 kg, height: 160.51 ± 5.25 cm) completed an incremental load test until 1RM in the bilateral leg-press exercise. The MV and the PV of the concentric phase were measured in each repetition using a linear velocity transducer, and were analysed by regression models using LA and PA. A very close relationship of MV (R 2 = 0.924; p < 0.0001; SEE = 0.08m . s −1 by LA, and R² = 0.952; p < 0.0001; SEE = 0.063 m . s −1 by PA) and PV (R² = 0.928; p < 0.0001; SEE = 0.119 m . s −1 by LA and R² = 0.941; p < 0.0001; SEE = 0.108 m . s −1 by PA) with %1RM were observed. The MV of 1RM was 0.24 ± 0.03 m•s −1 , whereas the PV at 1RM was 0.60 ± 0.10 m . s −1 . A comprehensive analysis of the bilateral leg-press load-velocity relationship in breast cancer survivors is presented. The results suggest that MV is the most recommendable velocity variable to prescribe the relative load during resistance training, and that the PA presents better accuracy to predict velocities associated with each %1RM, although LA is sufficiently valid to use this model as an alternative to the quadratic model. The implications for resistance training in breast cancer are discussed.

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Baena-Raya, A, Díez-Fern ández, DM, L ópez-Sagarra, A, Martínez-Rubio, C, Soriano-Maldonado, A, and Rodríguez-P érez, MA. Novel curvilinear sprint test in basketball: reliability and comparison with linear sprint. J Strength Cond Res 37(9): e535-e540, 2023-This study (a) evaluated the reliability of a curvilinear sprint (CS) test to assess kinetic and kinematic outcomes in basketball players, (b) compared the kinetic and kinematic outcomes derived from curvilinear vs. linear sprints (LS), and (c) examined the association of both the CS and LS with change of direction (COD) performance. Thirty young basketball players (17 men and 13 women) competing at the national level (i.e., Spanish Basketball National League) performed a novel CS test around the 3-point line (the 3-point line CS test) to the right and left sides. The maximum and average values of acceleration (ACC), velocity (VEL), and centripetal force (CentF) were measured using Local Positioning System technology (WIMU PRO, Realtrack Systems S.L., Almería, Spain). All outcomes showed a high relative (intraclass correlations coefficient $ 0.90) and absolute (coefficient of variation [CV] , 5%) reliability, except the maximal CentF to the right (CV 5 5.41%) and left sides (CV 5 7.72%). Linear sprints displayed higher ACC and VEL outputs compared with the 3-point line CS test (all p , 0.001). Both sprinting tests were very large to nearly perfect associated with COD performance (LS r range from 20.71 to 20.86; CS r range from 20.68 to 20.94; p , 0.001), and the curvilinear ACC max was the kinematic outcome most strongly associated with COD performance (r range from 20.73 to 20.94). In conclusion, the 3-point line CS test is reliable to measure CS performance in basketball and presents different kinetic and kinematic features than LS.

The aim of the present study was to analyze the association of the sprint force-velocity profile [Hzt FV profile] variables with change of direction [COD] performance in female futsal players. Twelve female futsal players (age: 19.83 ± 4.2 years; body height: 160.75 ± 8.37 cm; body mass: 57.64 ± 8.3 kg) volunteered to be evaluated in the following assessments: Hzt FV profile, 505 test, modified 505 test [M505test] and V-cut test. The Spearman’s correlation coefficient [rs] (p < 0.05) was used to determine the relationship of the mechanical variables of the sprint (maximum power output [Pmax], maximum horizontal force production [F0] and maximum velocity [V0]) with COD performance. V0 showed a very large significant association with the 505 test (rs = -0.767; 90% CI: (-0.92 to -0.43); p < 0.01) and a large association with the V-cut test (rs = -0.641; 90% CI: (-0.86 to -0.21); p < 0.05), whereas Pmax was strongly associated with results of the 505 test (rs = -0.821; 90% CI: (-0.94 to -0.55); p < 0.01) and largely associated with the V-cut test results (rs = -0.596; 90% CI: (-0.84 to -0.14); p < 0.05). In conclusion, maximal power and velocity output during sprinting are determinant factors to successful COD in 180º and 45º cuts, thus, the Hzt FV profile should be assessed in female futsal players to better understand the influence of sprint mechanical properties on COD performance and prescribe individualized training programs

The aim of this study was to examine the concurrent validity and reliability of a functional electromechanical dynamometer (FEMD) to assess the isometric mid-thigh pull (IMTP) kinetic variables: peak force (PF), rate of force development (RFD), and time-specific force values (50-, 100-, 150-, and 200-ms). Twenty-seven male collegiate athletes (age: 22.9 ± 1.9 years; stature: 184.8 ± 10.4 cm; body mass: 84.2 ± 11.8 kg) performed four IMTP trials simultaneously on a force platform and the FEMD. The PF variables calculated from performance of the IMTP on both devices were reliable (CV < 3%; ICC > 0.90) and valid (bias < 13.9 N; random error < 52.1 N; r = 1.00), but they showed heteroscedasticity of the errors ( R2 > 0.23). The RFD (CV > 10.88%; ICC < 0.76) and initial force (CV > 8.81%; ICC < 0.76) variables did not reach an acceptable reliability for any device, but they showed strong associations between them ( r range = 0.53–0.69). These results indicate that the FEMD is an acceptable alternative to assess athlete’s maximal force production (i.e. PF), but the data collected with FEMD and force plates should not be used interchangeably.