Search

peer-reviewed, Alternating a resistance exercise with a plyometric exercise is referred to as "complex training". In this study, we examined the effect of various resistive loads on the biomechanics of performance of a fast stretch-shortening cycle activity to determine if an optimal resistive load exists for complex training. Twelve elite rugby players performed three drop jumps before and after three back squat resistive loads of 65%, 80%, and 93% of a single repetition maximum (1-RM) load. All drop jumps were performed on a specially constructed sledge and force platform apparatus. Flight time, ground contact time, peak ground reaction force, reactive strength index, and leg stiffness were the dependent variables. Repeated-measures analysis of variance found that all resistive loads reduced (P, ACCEPTED, peer-reviewed

peer-reviewed, Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest interval. The purpose of this study was to determine if a heavy resistive exercise causes performance enhancement of a slow stretch-shortening cycle exercise and if there is an optimal rest interval. Eighteen subjects performed countermovement jumps (CMJs) before and after a 5 repetition maximum back squat lifting protocol. This procedure was repeated 4 times over 2 days using rest intervals of 30 seconds and 2, 4, and 6 minutes. Flight time and peak ground reaction force (GRF) were the dependent variables. All jumps were performed on a specially constructed sledge and force platform apparatus. Repeated measures analysis of variance found a significant reduction in flight time at the 30-second and 6-minute interval (p< 0.05). No significant difference was found between men and women. Only the men showed an enhancement in jump performance after the 4 minute interval. The improvement window was different for each subject and an analysis of the greatest increase and decrease in flight time and peak ground reaction force was conducted, showing a significant decrease for men and women and a significant increase in flight time for men and peak ground reaction force for women. The results suggest that complex training can benefit and/ or inhibit countermovement jump performance depending on the rest interval. The individual determination of the intracomplex rest interval may be necessary in the practical setting., peer-reviewed

peer-reviewed, This study examined the relationship of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ), estimated 1RM back squat (SQ), contact time (CT) and Reactive Strength Index (RSI) for the RBJ to 30 m sprint time of sub-elite, semi-professional Rugby Union players. The results show that with the exception of SQ and CT, all variables were significantly (p < 0.001) correlated to each other (r > .575). The best determinant of predicting 30 m sprint time was RSI. The relationships of SJ, CMJ, and RBJ jump height and RSI to 30 m sprint time suggest that these rapid movements are all common in Rugby Union players. The results show that estimated 1 RM back squat has little influence on sprint performance., PUBLISHED, peer-reviewed

peer-reviewed, The full text of this article will not be available in ULIR until the embargo expires on the 30/09/2022, Performance and fitness monitoring in Rugby Union often include jumping, sprinting, and strength tests, but repeatability of and relationships between these measures are unclear. The level of interindividual variability in these relationships and their sprint time predictive capabilities are also unknown. This study examined the reliability of, and relationship between, countermovement (CMJJH), squat (SJJH), and rebound (RBJJH) jump heights, rebound jump contact time (RBJCT), estimated 1 repetition maximum back squat relative to body mass (SQBM), and reactive strength index (RSI) to 30-m sprint time of subelite, semiprofessional Rugby Union players. Measurement reliability was very good, with high average intraclass correlation coefficients (≥0.9) and low coefficient of variation (<10.1%). All variables were significantly (p < 0.01) correlated to each other (r > 0.575), except for SQBM (only related to CMJJH, r = 0.621) and RBJCT (only related to RSI, r = −0.727). SJJH and SQBM were the strongest and most consistent predictors of time to 30 m (R = 0.754 ± 0.081; SEE = 0.166 ± 0.025), but variability in SEE magnitude was observed across the group during bootstrapping. Cross-validation showed a mean difference between actual and predicted 30 m times equivalent to 0.22% of the group average time to 30 m. These results support the importance of multiple aspects of fitness training in Rugby Union players for improving performance in short-duration sprinting activities, but highlight the individual nature of their relative importance. Measures of strength and power can be used to predict short sprint performance by the strength and conditioning professional.

peer-reviewed, The purpose of this study was to examine the early-phase adaptations of traditional dynamic constant external resistance (DCER) training vs. a portable upper-body training device (Fortex). The Fortex is a concentric training device based on air resistance. Contractions using this device are slow (1.5–3 s) and have a limited range of motion. The exercises potentially allow maximal muscle action during each contraction. Healthy, sedentary men (n = 30) were assigned to begin either 8 weeks of weight training (W, n = 12) or 8 weeks of Fortex training (F, n = 9), and were compared with a control group (C, n = 9). Exercises were chosen for the W group that would train similar muscle groups and contain a similar volume of repetitions as the F group. However, movement patterns and force curves were not identical. Increases in the upper-arm cross-sectional area were not detected in any of the groups. Both training groups showed strength gains in the various strength tests that were distinct from each other. Our results indicate that both Fortex and DCER training proved effective in eliciting strength gains in sedentary men over an 8- week training period. There are, however, limitations with the Fortex in terms of progression needs and training asymmetry that indicate it should be used as a complement to other training.