Byrne, DJ, Browne, DT, Byrne, PJ, and Richardson, N. Interday reliability of the reactive strength index and optimal drop height. J Strength Cond Res 31(3): 721-726, 2017-The purpose of this study was to investigate the interday reliability of the reactive strength index (RSI) and optimal drop height (ODH) identification from multiple drop heights. Nineteen male trained hurling players (23.1 ± 2.9 years, 83.1 ± 15.5 kg, and 182.5 ± 4.89 cm) completed 2 maximal depth jumps from 4 incremental drop heights (30, 40, 50, and 60 cm), over 2 separate testing sessions 48 hours apart. The RSI and ODH were analyzed for reliability using intraclass correlation coefficient (ICC) and coefficient of variation (CV). The RSI and ODH both demonstrated good reliability with ICC ≥0.80 (0.87 and 0.81) and CV ≤10% (4.2 and 2.98), respectively. The results of this study support the use of an incremental depth jump protocol to find the RSI and ODH in trained hurlers. It is recommended that the incremental depth jump protocol be used when assessing an athlete's reactive strength, as it allows a reactive strength profile, maximum RSI, and an ODH to be determined, all of which can provide vital information when determining an athletes training intensity and load.

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The aim of this study was to investigate the effect of two types of eccentric (ECC) overload training on strength, speed, power and change of direction in female basketball players. Twenty amateur basketball players (mean ± SD: age: 23.67 ± 6.05 years; height: 1.73 ± 0.05 m; body mass: 80.28 ± 17.67 kg) participated in a randomized trial. The players performed either flywheel inertial training (FIT) (n = 11) or tempo ECC training (TET) (n = 9) for 4 weeks, performing two sessions weekly. Performance characteristics, one repetition back squat (1RM), counter-movement jump (CMJ), squat jump (SJ), 10-metre sprint (10 m), change of direction (COD) and sit and reach flexibility (S&R) were tested pre and post intervention. Post-hoc testing revealed significant improvements in the FIT group for 1RM (p ≤ 0.001; ES = 0.59), 10 m (p = 0.003; ES = −0.54) and CMJ (p ≤ 0.001; ES = 1.04), while significant improvements were revealed in the TET group for 1RM (p = 0.007; ES = 0.71) and S&R (p ≤ 0.001; ES = 0.58). In conclusion, both FIT and TET groups demonstrated a positive training stimulus for increasing muscular strength. FIT may produce superior adaptions in CMJ and 10-m sprint, while TET may produce superior adaptions in S&R. Neither group achieved increases in either SJ or COD.

The aim of this study was to investigate the effect of four different inertial loads (0.025, 0.050, 0.075, and 0.100 kg· m²) on concentric (CON) power, eccentric (ECC) power, and ECC overload in the flywheel Romanian deadlift (RDL). Fourteen recreationally trained males (27.9 ± 6.4 years, 90 ± 10.7 kg, 180.7 ± 5.5 cm) volunteered for the study. They had a minimum of two years of resistance training experience, although none had experience in flywheel inertia training (FIT). All participants performed the flywheel RDL on a flywheel device (kBox 3, Exxentric, AB TM, Bromma, Sweden). Each set was performed using different inertial loads, those being 0.025, 0.050, 0.075, and 0.100 kg·m². For CON, ECC power, and ECC overload, there was a significant difference (p < 0.001) between inertial loadings. In conclusion, results highlight that lower inertial load leads to higher peak CON and ECC power values, precisely 0.025 kg· m². Regarding ECC overload, medium to higher loads (0.050, 0.075, and 0.100 kg·m²) will lead to higher values.

This study aimed to compare the anthropometric physical performance characteristics of Irish female international footballers at U17, U19, and Senior age groups. Fifty-five (U17, n =24, U19, n =21, Senior, n = 10) female international football players participated in this study. The subjects underwent anthropometric measurements (height and body mass) and physical performance tests countermovement jump (CMJ), reactive strength index (RSI), 10-m, 20-m, 30-m linear sprint, and yo-yo intermittent recovery test level 1 (YYIR1). No significant differences were identified between any age groups for the anthropometric measures of height and body mass. Concerning the physical tests, senior players displayed greater CMJ scores in comparison with the U17 (P = 0.040). Senior players also possessed higher levels of reactive strength with large effect sizes present (ES = 0.83 - 0.92) in comparison to all age groups. No significant differences were identified between any of the age groups across the 10-m, 20-m, 30-m, and rolling 20-m linear speed assessments. Senior players covered the greatest distance in the YYIR1 (P = 0.0001) versus the U19 and U17. These results indicate there was no difference in the anthropometric profile of the age groups assessed. However, differences in physical performance characteristics were present between age groups, thus suggesting improvements in lower limb power and aerobic endurance are achievable in adulthood as players physically mature.