Eduardo Saez Saez de Villarreal

Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis.

Saez Saez de Villarreal, E, Kellis, E, Kraemer, WJ, and Izquierdo, M. Determining variables of plyometric training for improving vertical jump height performance: a meta-analysis. J Strength Cond Res 23(2): 495-506, 2009-Plyometric training improves vertical jump height (VJH). However, the effectiveness of plyometric training depends on various factors. A meta-analysis of 56 studies with a total of 225 effect sizes (ESs) was carried out to analyze the role of various factors on the effects of plyometrics on VJH performance. The inclusion criteria for the analysis were a) studies using plyometric programs for lower-limb muscles, b) studies employing true experimental designs and valid and reliable measurements, and c) studies including enough data to calculate ESs. Subjects with more experience in sport obtained greater enhancements in VJH performance (p < 0.01). Subjects in either good or bad physical condition benefit equally from plyometric work (p < 0.05), although men tend to obtain better power results than women after plyometric training (p < 0.05). With relation to the variables of performance, training volumes of more than 10 weeks and more than 20 sessions, using high-intensity programs (with more than 50 jumps per session), were the strategies that seemed to maximize the probability of obtaining significantly greater improvements in performance (p < 0.05). To optimize jumping enhancement, the combination of different types of plyometrics (squat jump + countermovement jump + drop jump) is recommended rather than using only 1 form (p < 0.05). However, no extra benefits were found to be gained from doing plyometrics with added weight. The responses identified in this analysis are essential and should be considered by strength and conditioning professionals with regard to the most appropriate dose-response trends for optimizing plyometric-induced gains.

Low and moderate plyometric training frequency produces greater jumping and sprinting gains compared with high frequency.

The purpose of this study was to examine the effect of 3 different plyometric training frequencies (e.g., 1 day per week, 2 days per week, 4 days per week) associated with 3 different plyometric training volumes on maximal strength, vertical jump performance, and sprinting ability. Forty-two students were randomly assigned to 1 of 4 groups: control (n = 10, 7 sessions of drop jump (DJ) training, 1 day per week, 420 DJs), 14 sessions of DJ training (n = 12, 2 days per week, 840 DJs), and 28 sessions of DJ training (n = 9, 4 days per week, 1680 DJs). The training protocols included DJ from 3 different heights 20, 40, and 60 cm. Maximal strength (1 repetition maximum [1RM] and maximal isometric strength), vertical height in countermovement jumps and DJs, and 20-m sprint time tests were carried out before and after 7 weeks of plyometric training. No significant differences were observed among the groups in pre-training in any of the variables tested. No significant changes were observed in the control group in any of the variables tested at any point. Short-term plyometric training using moderate training frequency and volume of jumps (2 days per week, 840 jumps) produces similar enhancements in jumping performance, but greater training efficiency (∼12% and 0.014% per jump) compared with high jumping (4 days per week, 1680 jumps) training frequency (∼18% and 0.011% per jump). In addition, similar enhancements in 20-m-sprint time, jumping contact times and maximal strength were observed in both a moderate and low number of training sessions per week compared with high training frequencies, despite the fact that the average number of jumps accomplished in 7S (420 jumps) and 14S (840 jumps) was 25 and 50% of that performed in 28S (1680 jumps). These observations may have considerable practical relevance for the optimal design of plyometric training programs for athletes, given that a moderate volume is more efficient than a higher plyometric training volume.

Vertical jump biomechanics after plyometric, weight lifting, and combined (weight lifting + plyometric) training.

Arabatzi, F, Kellis, E, and Saèz-Saez de Villarreal, E. Vertical jump biomechanics after plyometric, weight lifting, and combined (weight lifting + plyometric) training. J Strength Cond Res 24(9): 2440-2448, 2010-The purpose of this study was to compare the effects of an Olympic weight lifting (OL), a plyometric (PL), and combined weight lifting + plyometric (WP) training program on vertical jump (VJ) biomechanics. Thirty-six men were assigned randomly to 4 groups: PL group (n = 9), OL group (n = 9), WP group (10), and control (C) group (n = 8). The experimental groups trained 3 d·wk−1, for 8 weeks. Sagital kinematics, VJ height, power, and electromyographic (EMG) activity from rectus femoris (RF) and medial gastrocnemius (GAS) were collected during squat jumping and countermovement jumping (CMJ) before and after training. The results showed that all experimental groups improved VJ height (p < 0.05). The OL training improved power and muscle activation during the concentric phase of the CMJ while the subjects used a technique with wider hip and knee angles after training (p < 0.05). The PL group subjects did not change their CMJ technique although there was an increase in RF activation and a decrease of GAS activity after training (p < 0.05). The WP group displayed a decline in maximal hip angle and a lower activation during the CMJ after training (p < 0.05). These results indicate that all training programs are adequate for improving VJ performance. However, the mechanisms for these improvements differ between the 3 training protocols. Olympic weight lifting training might be more appropriate to achieve changes in VJ performance and power in the precompetition period of the training season. Emphasis on the PL exercises should be given when the competition period approaches, whereas the combination of OL and PL exercises may be used in the transition phases from precompetition to the competition period.

Enhancing Jump Performance After Combined vs. Maximal Power, Heavy-resistance, and Plyometric Training Alone

Sáez Sáez de villarreal, E, Izquierdo, M, and Gonzalez-Badillo, JJ. Enhancing jump performance after combined vs. maximal power, heavy-resistance, and plyometric training alone. J Strength Cond Res 25(12): 3274–3281, 2011—The purpose of this study was to examine the effects of 5 different stimuli on jumping ability and power production after 7 weeks of training. Sixty-five (47 men and 18 women) physical education students were randomly assigned to 5 experimental groups that performed: combination of all training methods (A); heavy-resistance training using full-squat exercise (i.e., 56–85% of 1 RM for 3–6 repetitions) (B); power-oriented strength training using a parallel-squat exercise (i.e., 100–130% of load that maximizes power output for 2–6 repetitions) (C); power-oriented strength training using a loaded countermovement jumping (i.e., 70–100% of load that maximizes power output for 2–5 repetitions; countermovement jump [CMJ]) (D); and plyometric jumping (E). The CMJ (cm), loaded CMJ (cm), maximum rate of force development (RFDmax) during early concentric phase of loaded CMJ (N·s−1) and power output during early concentric phase of loaded CMJ (watts) were measured before and after 7 weeks of training. Significant improvements in CMJ (from 7.8 to 13.2%) were observed in all groups. Significantly greater increases in power output during loaded jumps were observed in A (10–13%) and D (8–12%) groups compared with in the other groups. Significant increases in RFDmax were observed in A (20–30%), C (18–26%), and D (20–26%) groups. The results of this study provide evidence to suggest that if training program is designed and implemented correctly, both traditional slow velocity training and faster power-oriented strength training alone, or in combination with plyometric training, would provide a positive training stimulus to enhance jumping performance.

RELATIONSHIP BETWEEN POSTACTIVATION POTENTIATION OF KNEE EXTENSOR MUSCLES, SPRINTING AND VERTICAL JUMPING PERFORMANCE IN PROFESSIONAL SOCCER PLAYERS

Requena, B, de Villarreal, ESS, Gapeyeva, H, Ereline, J, García, I, and Pääsuke, M. Relationship between postactivation potentiation of knee extensor muscles, sprinting and vertical jumping performance in professional soccer players. J Strength Cond Res 25(2): 367-373, 2011-Little is known about the relationship between postactivation potentiation (PAP) in human muscles, assessed by enhancement of twitch torque after a conditioning maximal voluntary contraction (MVC), and performance in activities requiring power and speed. Moreover, no studies have assessed PAP in soccer players who train power and endurance simultaneously. The purpose of the present study was to examine the relationship between twitch PAP in knee extensor (KE) muscles, and sprinting and vertical jumping performance in soccer players. Fourteen professional male soccer players with mean (SD) age 20.0 (3.6) years, height 177.9 (6.9) cm and body mass 70.5 (5.7) kg) were tested for 15-m sprint time, vertical jump height in countermovement (CMJ) and squat (SJ) jumps. PAP in KE muscles was induced by a 10-s isometric MVC. Electrically evoked twitches of KE muscles were evoked before and after the conditioning MVC. Immediately after the conditioning MVC, twitch peak torque (PT) and maximal rates of torque development and relaxation were significantly potentiated. A significant negative correlation was found between 15-m sprint time and jump height in CMJ (r = −0.63) and SJ (r = −0.57). PAP of twitch PT correlated significantly positively with jump height in CMJ (r = 0.61) and SJ (r = 0.64), and negatively with 15-m sprint time (r = −0.59). In conclusion, twitch PAP in KE muscles was significantly correlated with performance in vertical jumping and sprinting in male professional soccer players, whereas the magnitude of PAP in soccer players was similar to that observed previously in power-trained athletes.

Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting.

Requena, B, García, I, Requena, F, Sáez-Sáez de Villarreal, E, and Cronin, JB. Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting. J Strength Cond Res 25(8): 2193-2204, 2011—The purpose of this study was to quantify the magnitude of the relationship between vertical jumping and maximal sprinting at different distances with performance in the traditional and ballistic concentric squat exercise in well-trained sprinters. Twenty-one men performed 2 types of barbell squats (ballistic and traditional) across different loads with the aim of determining the maximal peak and average power outputs and 1 repetition maximum (1RM) values. Moreover, vertical jumping (countermovement jump test [CMJ]) and maximal sprints over 10, 20, 30, 40, 60, and 80 m were also assessed. In respect to 1RM in traditional squat, (a) no significant correlation was found with CMJ performance; (b) positive strong relationships (p < 0.01) were obtained with all the power measures obtained during both ballistic and traditional squat exercises (r = 0.53-0.90); (c) negative significant correlations (r = −0.49 to −0.59, p < 0.05) were found with sprint times in all the sprint distances measured when squat strength was expressed as a relative value; however, in the absolute mode, no significant relationships were observed with 10- and 20-m sprint times. No significant relationship was found between 10-m sprint time and relative or absolute power outputs using either ballistic or traditional squat exercises. Sprint time at 20 m was only related to ballistic and traditional squat performance when power values were expressed in relative terms. Moderate significant correlations (r = −0.39 to −0.56, p < 0.05) were observed between sprint times at 30 and 40 m and the absolute/relative power measures attained in both ballistic and traditional squat exercises. Sprint times at 60 and 80 m were mainly related to ballistic squat power outputs. Although correlations can only give insights into associations and not into cause and effect, from this investigation, it can be seen that traditional squat strength has little in common with CMJ performance and that relative 1RM and power outputs for both squat exercises are statistically correlated to most sprint distances underlying the importance of strength and power to sprinting.

The athletic performance of elite rugby league players is improved after an 8-week small-sided game training intervention.

Abstract Seitz, LB, Rivière, M, de Villarreal, ES, and Haff, GG. The athletic performance of elite rugby league players is improved after an 8-week small-sided game training intervention. J Strength Cond Res 28(4): 971–975, 2014—The purpose of this investigation was to determine the effects of a small-sided game training intervention on the intermittent shuttle running performance, speed, and repeated sprint ability of elite rugby league players during the competitive phase of a rugby league season. Ten elite rugby league players from a Stobart Super League team academy underwent 2 small-sided game sessions per week over an 8-week period. Each session consisted of four 10-minute blocks of 1 small-sided game, interspersed with a 3-minute recovery. Changes in physical performance were assessed before and after the training intervention with an intermittent shuttle running test (30-15 Intermittent Fitness Test), speed tests (10-, 20-, and 40-m linear sprints) and a repeated sprint ability test (8 × 20-m linear sprint, departing every 20 seconds). Results showed that the 30-15 Intermittent Fitness Test (+1.29%), 10-m (−3.17%), 20-m (−1.37%), and 40-m (−0.96%) sprint times and mean sprint time (−2.11%), total sprint time (−2.11%), and percentage of sprint decrement (7.10 vs. 5.93%) during the repeated sprint ability test were significantly improved after the training intervention. Based on these results, it was concluded that an 8-week small-sided game training intervention was an effective method for improving the physical performance of elite rugby league players during the competitive phase of the season.

Association between traditional standing vertical jumps and a soccer-specific vertical jump

Abstract The present study aimed to determine the relationships between a soccer-specific vertical jump (ssVJ) test, that included common elements of a soccer VJ (e.g. run-up and intention to head), and three traditional VJ tests using elite soccer players. A secondary purpose of this study was to determine the reliability of the VJs used in the analysis. A randomised order and counterbalanced design was used to assess the relationships between these VJs [countermovement jump (CMJ), drop jump for height (DJh), drop jump for maximum height and minimum ground contact time (DJh/t) and the ssVJ]. Take-off velocity, contact time and flight time were the dependent variables of interest and compared between jumps. Intra-class correlation coefficient (ICC) and coefficient of variation (CV) were used as measures of inter-session reliability. All VJ tests were found to have high ICCs (0.89–0.99) and acceptable within-subject CVs (<7.5%). All the ssVJ dependent variables were not significantly related (r<0.44) with similar variables from the CMJ and DJh tests and only moderately related (r=~0.49) with the DJh/t test variables. In addition, the DJh/t variables were not significantly correlated (r<0.47) with DJh and CMJ test variables. In conclusion, it would seem that the proposed ssVJ test and CMJ or DJh tests assess different leg qualities and thought should be given before using them interchangeably to assess or develop the same performance measures (i.e. velocity at take-off or jump height).