High intraset variability has been considered as a potential aid in the treatment of tendinopathy by producing forces in variable and unpredictable contexts that allow the athlete to return to sport pain free. The aim of this study was to compare the intraset variability in force profiles between different rotational inertia devices (RIDs) during concentric and eccentric (ECC) phases of movement and between different moments of inertia. Thirty-nine men performed a half-squat incremental test on 2 different RIDs: a horizontal cylinder and a vertical cone-shaped axis. Intraset variabilities in vertical force and velocity were analyzed using average coefficients of variation. RID squat exercise produced force intraset variability. The ECC phase of the movement showed more intraset variability in force output than the concentric phase. ECC vertical cone-shaped shaft showed a higher intraset variability in force than ECC horizontal cylinder-shaped shaft. This study demonstrated that using an RID to provide resistance in squat training of athletes produced a high intraset variability in the application of force.
Francisco Javier Núñez, Carlos Galiano, Alejandro Muñoz-López, and Pablo Floria
Luis Suarez-Arrones, Javier Núñez, Diego Munguía-Izquierdo, Javier Portillo, and Alberto Mendez-Villanueva
To examine the effects of several matches per day on running performance and cardiovascular stress in referees during a national Rugby Sevens championship.
Seven referees, who refereed 3 matches/day, were monitored by GPS during 21 matches.
Referees’ movement patterns were relatively stable from the 1st to the 2nd match, although a substantial decrease was observed in the 2nd match for maximal and average sprint distance. A substantial decrease in the number of sprints, maximal speed, walking, distance covered at medium intensity, total and >14 km/h distance covered per minute was observed in the 3rd match in comparison with the 2nd. Compared with the 1st match, in the 3rd game referees showed a substantial decrease in maximal and average sprint distance, total walking at medium intensity, distance covered >14 km/h, and high-intensity running distance. Referees exhibited a substantial decrease in average heart rate (HR), percentage of time at >70%HRmax, and percentage of time at >90%HRmax in the 2nd match compared with the 1st. Referees’ HR responses were relatively stable from the 2nd to the 3rd match except for the HR zones of 71–80%HRmax and 81–90%HRmax and performance-efficiency index (Effindex). Substantial differences were observed in the 3rd match compared with the 1st in average HR, 81–90%HRmax, >90%HRmax, and Effindex.
This study provides evidence of reduced overall running performance and pronounced reduction in high-intensity running performance during the last match in Rugby Sevens referees refereeing 3 matches in the same day.
Luis Suarez-Arrones, Julio Tous-Fajardo, Javier Núñez, Oliver Gonzalo-Skok, Javier Gálvez, and Alberto Mendez-Villanueva
To examine the effect of repeated-sprint training (RST) vs combined RST and resistance training with superimposed vibrations on repeated-sprint ability (RSA) and lower-body power output in male rugby players.
Players were divided into 2 training groups. One group performed RST (n = 10) 2 d/wk and the other performed RST 1 d/wk and squat resistance training with superimposed vibrations on the second day (RS+ST; n = 10). The squat training was carried out with a volume similar (ie, number of sets and repetitions) to that of the RST. The training period lasted 6 wk, and it was carried out as a supplement to the regular rugby training sessions.
Substantial improvements in RSA mean time (RSAmean; +2.3%/ES: 0.77 vs +4.1%/ES: 0.91), RSA percent decrement (%Dec; –25.6%/ES: 1.70 vs –23.2%/ES: 0.99), and squat absolute power output (+5.0%/ES:0.36 vs +17.2%/ES: 0.93) were obtained in RST and RS+ST, respectively. Substantial improvements in RSA best time (RSAbest; +2.6%/ES: 0.61) and squat power output normalized to body mass (+18.6%/ES: 0.76) only occurred in RS+ST. Both pretest and posttest RSAmean were largely correlated with the RSAbest. However, there were only unclear, small to moderate correlations between individual changes in squat power output and either RSAmean or RSAbest.
Combined RST and resistance training induced improvements of greater magnitude in both repeated-sprint performance and muscle power output than the RST alone. The lack of substantial correlations between individual changes in repeated-sprint and muscle-power performance suggests that the same subjects were not systematically low or high responders to both RST and strength training.
Luis Suarez-Arrones, Javier Núñez, Eduardo Sáez de Villareal, Javier Gálvez, Gabriel Suarez-Sanchez, and Diego Munguía-Izquierdo
To describe the repeated-high-intensity activity and internal training load of rugby sevens players during international matches and to compare the differences between the 1st and 2nd halves.
Twelve international-level male rugby sevens players were monitored during international competitive matches (n = 30 match files) using global positioning system technology and heart-rate monitoring.
The relative total distance covered by the players throughout the match was 112.1 ± 8.4 m/min. As a percentage of total distance, 35.0% (39.2 ± 9.0 m/min) was covered at medium speed and 17.1% (19.2 ± 6.8 m/min) at high speed. A substantial decrease in the distance covered at >14.0 km/h and >18.0 km/h, the number of accelerations of >2.78 m/s and >4.0 m/s, repeated-sprint sequences interspersed with ≤60 s rest, and repeated-acceleration sequences interspersed with ≤30 s or ≤60 s rest was observed in the 2nd half compared with the 1st half. A substantial increase in the mean heart rate (HR), HRmax, percentage of time at >80% HRmax and at >90% HRmax, and Edwards training load was observed in the 2nd half compared with the 1st half.
This study provides evidence of a pronounced reduction in high-intensity and repeated-highintensity activities and increases in internal training load in rugby sevens players during the 2nd half of international matches.
F. Javier Núñez, Luis J. Suarez-Arrones, Paul Cater, and Alberto Mendez-Villanueva
The aim of this study was to examine the kinematics and kinetics (force, velocity, and acceleration) and blood lactate concentration with the VersaPulley (VP) device in comparison with free-weight (FW) exercise at a similar external load. Fifteen rugby players randomly performed 2 training sessions of 6 sets of 6 repetitions with 20 s of recovery between sets of the high-pull exercise with the VP and the FW. The training sessions were separated by 72 h. Barbell displacement (cm), peak velocity (m/s), peak acceleration (m/s2), mean propulsive velocity (m/s), mean propulsive acceleration (m/s2), propulsive phase (%), and mean and maximal force (N) were continuously recorded during each repetition. Blood lactate concentration was measured after each training session (end) and 3 min and 5 min later. Barbell displacement (+4.8%, small ES), peak velocity (+4.5% small ES), mean propulsive acceleration (+8.8%, small ES), and eccentric force (+26.7, large ES) were substantially higher with VP than with FW. Blood lactate concentration was also greater after the VP exercise (end +32.9%, 3 min later +36%, 5 min later +33.8%; large ES). Maximal concentric force was substantially higher with FW than VP during the 6th set (+6.4%, small ES). In the cohort and exercise investigated in the current study, VP training can be considered an efficient training device to induce an accentuated eccentric overload and augmented metabolic demands (ie, blood lactate concentration).