The study aimed to compare the chronic eccentric-overload training effects of unilateral (lateral lunge) vs bilateral (half-squat) using an inertial device, on hypertrophy and physical performance. Twenty-seven young team sports male players performed a 4 sets of 7 repetitions of inertial eccentric overload training, biweekly for 6 weeks, distributed in unilateral lunge group (UG: age: 22.8 ± 2.9 years; body mass: 75.3 ± 8.8 kg; height: 177.3 ± 3.7 cm) and bilateral squat group (BG: age: 22.6 ± 2.7 years; body mass: 79.5 ± 12.8 kg; height: 164.2 ± 7 cm). Lower limb muscle volume, counter movement jump (CMJ), power with both (POWER), dominant (POWERd) and no-dominant leg (POWERnd), change of direction turn of 90° with dominant (COD90d) and no-dominant leg (COD90nd) and 180° (COD180d and COD180nd), and 10m sprint time (T-10m) were measured pre and post-intervention. The UG obtained an increase of adductor major (+11.1%) and vastus medialis (+12.6%) higher than BG. The BG obtained an increase of vastus lateralis (+9.9%) and lateral gastrocnemius (+9.1%) higher than UG. Both groups improved CMJ, POWER, POWERd, POWERnd, COD90 and DEC-COD90, without changes in T-10m. The UG decrease DEC-COD90nd (-21.1%) and BG increase POWER (+38.6%) substantially more than the other group. Six-weeks of unilateral / bilateral EO training induce substantial improvements in lower limbs muscle volume and functional performance, although unilateral training seems to be more effective in improving COD90 performance.

Núñez Sanchez, FJ and Sáez de Villarreal, E. Does flywheel paradigm training improve muscle volume and force? A meta-analysis. J Strength Cond Res 31(11): 3177–3186, 2017—Several studies have confirmed the efficacy of flywheel paradigm training for improving or benefiting muscle volume and force. A meta-analysis of 13 studies with a total of 18 effect sizes was performed to analyse the role of various factors on the effectiveness of flywheel paradigm training. The following inclusion criteria were employed for the analysis: (a) randomized studies; (b) high validity and reliability instruments; (c) published in a high quality peer-reviewed journal; (d) healthy participants; (e) studies where the eccentric programme were described; and (f) studies where increases in muscle volume and force were measured before and after training. Increases in muscle volume and force were noted through the use of flywheel systems during short periods of training. The increase in muscle mass appears was not influenced by the existence of eccentric overload during the exercise. The increase in force was significantly higher with the existence of eccentric overload during the exercise. The responses identified in this analysis are essential and should be considered by strength and conditioning professionals regarding the most appropriate dose response trends for flywheel paradigm systems to optimize the increase in muscle volume and force.

The aim of the study was to investigate the relationships between countermovement jump (CMJ) height and inertial power in squat and sprint variables with change of direction (COD) performance. Fifty young healthy active males participated in the study. To determine these relationships, we carried out a 10-m linear sprint test (T 10 m), vertical jump tests (CMJ and CMJ Abalakov), an assessment of power relative to bodyweight in a flywheel squat (P_bw), and 10-m COD sprints with two different turn types (COD-90° and COD-180°). T10 m showed statistically large and moderate correlations with T10 m COD-180° (r = 0.55) and T10-m COD-90° (r = 0.41), respectively. Moderate to large correlations between jumping height, linear sprinting, and sprints with COD were found (r = −0.43 to r = −0.59), and there were unclear correlations between jumping height and the loss of speed caused by executing COD (DEC-COD). P_bw showed a large correlation with CMJ Abalakov and CMJ jump height (r = 0.65 and r = 0.57, respectively), and a moderate and large correlation with T 10 m, T 10 m COD-180°, and T10 m COD-90° (r = −0.33, r = −0.38, and r = −0.54, respectively). Despite the existence of substantial correlations between variables, straight linear sprinting, jumping performance, CODs and squat power were, for the most part, separate motor qualities (R² from 14% to 34%), suggesting that all of them should be specifically assessed and trained.

The aim of this study was to describe the changes in body composition, strength and sprint performance in response to an entire competitive season of football training supplemented with 2 inertial eccentric-overload training sessions a week in young male professional soccer players. Whole body and regional composition (assessed using dual-energy X-ray absorptiometry), power output in half-squat and 40-m sprinting performance were evaluated in fourteen players. The eccentric-overload training consisted of training sessions a week of 1–2 sets of 10 exercises of upper-body and core (Day 1) and lower-body (Day 2), during the entire competitive season (27 weeks). Whole body fat mass decreased (-6.3 ± 3.6%, ES = -0.99 ± 0.54) substantially while lean mass increased (2.5 ± 0.8%, ES = 0.25 ± 0.09), with some regional differences. There was a substantial increase in half-squat power output (from 3% to 14%, ES from 0.45 to 1.73) and sprint performance (from 1.1% to 1.8%, ES from -0.33 to -0.44), however performance changes were not correlated with changes in body composition. A combined soccer and eccentric-overload training program was able to promote positive changes in body composition and physical factors relevant to both on-field performance and injury prevention in elite soccer players.

Ing competitive club-level matches. Time-motion analyses (global position system) were performed on 7 male rugby players during 5 competitive matches in a 2-day tournament. The players covered an average distance of 1,580.8 ± 146.3 m per game (14 minutes). Over this distance, 34.8% (549.7 ± 79.1 m) was spent standing and walking, 26.2% (414.8 ± 105.1 m) jogging, 9.8% (154.6 ± 53.5 m) cruising, 15.5% (244.5 ± 80.1 m) striding, 5% (79.5 ± 37.2 m) high-intensity running, and 8.7% (137.7 ± 84.9 m) sprinting. The average maximal distance of sprints, the number of sprints, the minimum distance of sprint, and the mean sprint distance over the game were 29.5 ± 11.7 m, 7.4 ± 3.9 sprints, 9.1 ± 5.7 m, and 18 ± 7.6 m, respectively. The player's work-to-rest ratio was 1:0.5. For over 75% of the game, the players were exposed to heart rates (HRs) >80% of their maximal HR. There were no statistical differences between the first and second halves in any of the variables analyzed. This study indicates that the physical demands of Rugby 7s are quite different from those encountered in other rugby codes and that the training regimes need to meet the increased overall running demands, the augmented high-intensity running actions, and the reduced work-to-rest ratios....

The aim of this systematic review was to evaluate the current evidence by assessing the effectiveness of integrative neuromuscular training programs in injury prevention and sports performance in young athletes. Different data sources were analyzed up to January 2018. Eligible studies contained information on population (young athletes), intervention (neuromuscular training), comparator (control group or another exercise intervention), outcomes (injury prevention or sport performance), and study design (randomized trials or prospective studies). The trials were restricted based on the language (English) and for publication date (after 1 January 2007). Fourteen randomized controlled trials were included: Seven included dynamic stability-related outcomes. Three assessed the coordination performing fundamental movements and sport-specific skills, while other five studies analyzed muscle strength and two assessed plyometric tests. Agility was evaluated in three studies and speed tests were also considered by four studies. Finally, fatigue resistance in three studies and injury risk in four were assessed. This review provides evidence that integrative neuromuscular training programs can enhance performance and injury prevention in young athletes, taken into account that adherence to the training program is adequate. Collectively, well-designed, randomized studies are necessary to collaborate with the present findings.