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This study aimed to compare the effects of an accentuated eccentric training programme on physical performance between men and women. Distributed in two groups by gender, 21 male and 21 female athletes performed four sets of seven repetitions of the half-squat exercise twice per week for 6 weeks. Both groups lifted the same absolute load using a rotary inertial device. To accentuate the eccentric action, the eccentric load was twice as heavy as the concentric load. Vertical jump, sprint, and change of direction (COD) performances were measured pre- and post-intervention. To measure strength gains, vertical ground reaction forces were measured for each repetition of the entire training programme. Vertical jump improved post-intervention (MG: 33.88 ± 4.94 to 35.41 ± 4.86; FG: 20.60 ± 4.62 to 22.12 ± 4.32; p < 0.001; η2p = 0.42), while sprint (MG: 3.08 ± 0.11 to 3.07 ± 0.13; FG: 3.66 ± 0.23 to 3.64 ± 0.23) and COD (MG: 7.77 ± 0.42 to 7.61 ± 0.47; FG: 8.44 ± 0.58 to 8.38 ± 0.57) remained unchanged. Concentric and eccentric forces increased for both groups from session 1 to 4 (p < 0.001; η2p >0.39), while only peak eccentric forces increased until session 12 (p = 0.009; η2p = 0.21). In conclusion, even when men are able to produce greater forces with similar loads, accentuated eccentric RT produces similar strength and strength-related adaptations in male and female athletes. [ABSTRACT FROM AUTHOR]

Since most movements on the field require athletes to produce forces in variable and unpredictable contexts, the use of training programs based on identical repetitions of an exercise may not be optimal for movement transference. Therefore, the aim of this study was to analyse the effects of unexpected eccentric load variability during resistance training in team sport players. Sixty-three men were randomly allocated to two experimental groups (Variable (VTG) and stable (STG) training group) and control group: (CG) volunteered to participate in this study. Experimental groups trained with the same average load of half-squat exercise twice a week for six weeks using rotary inertial devices (RIDs) with (VTG) and without (STG) an unexpected variability of the load. The squat force was measured for every session with force plates. Counter-movement jump (CMJ), sprint, and change of direction performances were measured pre and post-test. CMJ performance improved for VTG (p =.014; ES = 0.7) and STG (p =.005; ES = 0.79) but not for CG. Exposure to high eccentric forces with RIDs lead athletes to improve physical performance in the trained force vector but, since RIDs induce in high levels of variability per se, increasing the level of variability of the exercise will not add benefits to physical performance and training outcomes. HIGHLIGHTS The relevance of the study is to analyse if increasing the variability of the load will improve the athlete output to different physical performance tests. The exposure to eccentric overload with RIDs during the squat exercise allows to greater CMJ height improvements than those seen in the literature with RIDs without overloading the eccentric contraction. RIDs induce in high level of variability per se. Therefore, increasing the level of variability of the exercise will not add benefits to physical performance and training outcomes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if children exhibit greater variability in center of mass movement and kinetics compared with adults in vertical jumping. Countermovement jumps with arms (CMJA) and without arms (CMJ) performed by 20 female children and 20 female adults were examined using force platform. The data were analyzed using continuous methods to determine differences in variability between groups and between types of jump. Jumping variability was measured by using the average coefficient of variation of the force-, velocity-, displacement-, and rate of force development-time curves across the jump. The analysis indicated that children and adults had similar levels of variability in the CMJ but different levels in the CMJA. In the CMJA, the children had a greater coefficient of variation than adults in force- (20 ± 7% and 12 ± 6%), velocity- (41 ± 14% and 22 ± 9%), displacement- (8 ± 16% and 23 ± 11%) and rate of force development-time (103 ± 46% and 75 ± 42%) curves, as well as in force-velocity relationship (6 ± 2% and 4 ± 2%). The results of analysis suggest that the variability depends on both the level of maturation of the participants as well as the task complexity. [ABSTRACT FROM AUTHOR]