Purpose: To compare the effects of resisted change-of-direction (COD) movements, using several relative loads, on soccer players’ physical performance. Methods: Fifty-four male soccer players were randomly assigned to 1 of the following 3 groups, which differed only in the magnitude of the external load used during the COD training: COD training without external load (COD-0; n = 16), COD training with a 12.5% body-mass external load (COD-12.5; n = 19), and COD training with a 50% body-mass external load (COD-50; n = 19). Participants performed the specific COD training twice per week for 6 wk. Before and after the training period, a battery of tests was completed: countermovement jump, 30-m running sprint (time in 10 m [T10], 20 m [T20], and 30 m [T30]), L-run test, and V-cut test. Results: Within-group comparisons showed substantial improvements in countermovement jump and T10 (likely) in COD-0, whereas countermovement jump, T10, and T20 were substantially enhanced (possibly to likely) in COD-50. COD-12.5 induced substantial improvements in all analyzed variables (likely to most likely). Between-groups comparisons showed better effects on all analyzed variables for COD-12.5 than for COD-0 (possibly to very likely), whereas COD-50 only showed possibly better effects than COD-0 on T10. In addition, COD-12.5 induced a better effect on L-run and V-cut tests than COD-50 (possibly to likely). Conclusions: These results indicate that COD training, especially moderate load (12.5% body mass) resisted COD training, may have a positive effect on COD skills, running sprint performance, and jumping ability in young soccer players.
David Rodríguez-Osorio, Oliver Gonzalo-Skok and Fernando Pareja-Blanco
Beatriz Bachero-Mena, Miguel Sánchez-Moreno, Fernando Pareja-Blanco and Borja Sañudo
Purpose: To analyze the acute and short-term physical and metabolic responses to resisted sprint training with 5 different loading conditions (0%, 20%, 40%, 60%, and 80% body mass). Methods: Fifteen male participants performed 8 × 20-m sprints with 2-minute rests between sprints with 5 different loading conditions. Subjects performed a battery of tests (creatine kinase and lactate concentrations, countermovement jump, 20-m sprint, and isokinetic knee extension and flexion contractions) at 3 different time points (preexercise [PRE], postexercise [POST], and 24-h postexercise [POST24H]). Results: Results revealed significant increases in blood lactate for all loading conditions; however, as sled loadings increased, higher blood lactate concentrations and increments in sprint times during the training session were observed. Significant increases in creatine kinase concentration were observed from PRE to POST24H for all loading conditions. Concerning physical performance, significant decreases in countermovement-jump height from PRE to POST were found for all loading conditions. In addition, significant decreases in 20-m sprint performance from PRE to POST were observed for 0% (P = .05) and 80% (P = .02). No significant differences with PRE were observed for the physical-performance variables at POST24H, except for 20% load, which induced a significant decrease in mean power during knee flexion (P = .03). Conclusions: These results suggest that the higher the load used during resisted sprint training, the higher the physical-performance impairments and metabolic response produced, although all loading conditions led to a complete recovery of sprint performance at POST24H.
Fernando Pareja-Blanco, Luis Sánchez-Medina, Luis Suárez-Arrones and Juan José González-Badillo
To analyze the effects of 2 resistance-training (RT) programs that used the same relative loading but different repetition volume, using the velocity loss during the set as the independent variable: 15% (VL15) vs 30% (VL30).
Sixteen professional soccer players with RT experience (age 23.8 ± 3.5 y, body mass 75.5 ± 8.6 kg) were randomly assigned to 2 groups, VL15 (n = 8) or VL30 (n = 8), that followed a 6-wk (18-session) velocity-based squat-training program. Repetition velocity was monitored in all sessions. Assessments performed before (Pre) and after training (Post) included estimated 1-repetition maximum (1RM) and change in average mean propulsive velocity (AMPV) against absolute loads common to Pre and Post tests, countermovement jump (CMJ), 30-m sprint (T30), and Yo-Yo Intermittent Recovery Test (YIRT). Null-hypothesis significance testing and magnitude-based-inference statistical analyses were performed.
VL15 obtained greater gains in CMJ height than VL30 (P < .05), with no significant differences between groups for the remaining variables. VL15 showed a likely/possibly positive effect on 1RM (91/9/0%), AMPV (73/25/2%), and CMJ (87/12/1%), whereas VL30 showed possibly/unclear positive effects on 1RM (65/33/2%) and AMPV (46/36/18%) and possibly negative effects on CMJ (4/38/57%). The effects on T30 performance were unclear/unlikely for both groups, whereas both groups showed most likely/likely positive effects on YIRT.
A velocity-based RT program characterized by a low degree of fatigue (15% velocity loss in each set) is effective to induce improvements in neuromuscular performance in professional soccer players with previous RT experience.
Pedro Jiménez-Reyes, Fernando Pareja-Blanco, David Rodríguez-Rosell, Mario C. Marques and Juan José González-Badillo
To determine what variables determine the differences in performance on 2 tests of squat jump (SJ) performed under light load in highly trained athletes using maximal velocity (Vmax) or flight time (FT) as the discriminating factor of SJ performance.
Thirty-two participants performed 2 maximal weighted SJs using a force platform synchronized with a linear transducer. Mean force (Fmean), mean and maximal power (Pmean, Pmax), peak force (PF), maximal rate of force development (RFDmax), and time required to attain PF (TPF) and RFDmax (TRFDmax) were analyzed. SJs were divided into 2 segments: from the initiation of force application to PF1 and from the moment after PF1 to Vmax.
Traditional significance statistics revealed significant differences in the same variables between best and worst SJs using both FT and Vmax. However, to use an approach based on the magnitude of the effect, the best SJ showed greater Pmax (83/17/0%), Pmean (85/15/0%), Fmean (71/29/0%), RFDmax1 (73/27/0%), and PF1 (53/47/0%) and lower TPF2 (0/61/39%) than the worst SJ when Vmax was used to discriminate SJ performance. However, using FT to differentiate SJ performance, no difference was observed between best and worst.
Although jump height assessed through FT is a valid measure, these results suggest that Vmax is a more sensitive variable than FT to detect differences in loaded-SJ performance.
Miguel Sánchez-Moreno, David Rodríguez-Rosell, Fernando Pareja-Blanco, Ricardo Mora-Custodio and Juan José González-Badillo
Purpose: To analyze the relationship between movement velocity and relative load (%1RM) in the pull-up exercise (PU) and to determine the pattern of repetition-velocity loss during a single set to failure in pulling one’s own body mass. Methods: Fifty-two men (age = 26.5 ± 3.9 y, body mass = 74.3 ± 7.2 kg) performed a first evaluation (T1) consisting of an 1-repetition-maximum test (1RM) and a test of maximum number of repetitions to failure pulling one’s own body mass (MNR) in the PU exercise. Thirty-nine subjects performed both tests on a second occasion (T2) following 12 wk of training. Results: The authors observed a strong relationship between mean propulsive velocity (MPV) and %1RM (r = −.96). Mean velocity attained with 1RM load (V1RM) was 0.20 ± 0.05 m·s−1, and it influenced the MPV attained with each %1RM. Although 1RM increased by 3.4% from T1 to T2, the relationship between MPV and %1RM, and V1RM, remained stable. The authors also confirmed stability in the V1RM regardless of individual relative strength. The authors found a strong relationship between percentage of velocity loss and percentage of performed repetitions (R 2 = .88), which remained stable despite a 15% increase in MNR. Conclusions: Monitoring repetition velocity allows estimation of the %1RM used as soon as the first repetition with a given load is performed, and the number of repetitions remaining in reserve when a given percentage of velocity loss is achieved during a PU exercise set.
Pedro Jiménez-Reyes, Fernando Pareja-Blanco, Carlos Balsalobre-Fernández, Víctor Cuadrado-Peñafiel, Manuel A. Ortega-Becerra and Juan J. González-Badillo
To examine the relationship between the relative load in full squats and the height achieved in jump-squat (JS) exercises and to determine the load that maximizes the power output of high-level athletes.
Fifty-one male high-level track-and-field athletes (age 25.2 ± 4.4 y, weight 77. ± 6.2 kg, height 179.9 ± 5.6 cm) who competed in sprinting and jumping events took part in the study. Full-squat 1-repetition-maximum (1-RM) and JS height (JH) with loads from 17 to 97 kg were measured in 2 sessions separated by 48 h.
Individual regression analyses showed that JH (R 2 = .992 ± .005) and the jump decrease (JD) that each load produced with respect to the unloaded countermovement jump (CMJ) (R 2 = .992 ± 0.007) are highly correlated with the full-squat %1-RM, which means that training intensities can be prescribed using JH and JD values. The authors also found that the load that maximizes JS’s power output was 0%RM (ie, unloaded CMJ).
These results highlight the close relationship between JS performance and relative training intensity in terms of %1-RM. The authors also observed that the load that maximizes power output was 0%1-RM. Monitoring jump height during JS training could help coaches and athletes determine and optimize their training loads.
Pedro Jiménez-Reyes, Pierre Samozino, Fernando Pareja-Blanco, Filipe Conceição, Víctor Cuadrado-Peñafiel, Juan José González-Badillo and Jean-Benoît Morin
To analyze the reliability and validity of a simple computation method to evaluate force (F), velocity (v), and power (P) output during a countermovement jump (CMJ) suitable for use in field conditions and to verify the validity of this computation method to compute the CMJ force–velocity (F–v) profile (including unloaded and loaded jumps) in trained athletes.
Sixteen high-level male sprinters and jumpers performed maximal CMJs under 6 different load conditions (0–87 kg). A force plate sampling at 1000 Hz was used to record vertical ground-reaction force and derive vertical-displacement data during CMJ trials. For each condition, mean F, v, and P of the push-off phase were determined from both force-plate data (reference method) and simple computation measures based on body mass, jump height (from flight time), and push-off distance and used to establish the linear F–v relationship for each individual.
Mean absolute bias values were 0.9% (± 1.6%), 4.7% (± 6.2%), 3.7% (± 4.8%), and 5% (± 6.8%) for F, v, P, and slope of the F–v relationship (SFv), respectively. Both methods showed high correlations for F–v-profile-related variables (r = .985–.991). Finally, all variables computed from the simple method showed high reliability, with ICC >.980 and CV <1.0%.
These results suggest that the simple method presented here is valid and reliable for computing CMJ force, velocity, power, and F–v profiles in athletes and could be used in practice under field conditions when body mass, push-off distance, and jump height are known.
Fernando Pareja-Blanco, Eduardo Sáez de Villarreal, Beatriz Bachero-Mena, Ricardo Mora-Custodio, José Antonio Asián-Clemente, Irineu Loturco and David Rodríguez-Rosell
Purpose: This study aimed to compare the effects of unresisted versus heavy sled sprint training (0% vs 40% body mass [BM]) on sprint performance in women. Moreover, the effects of the aforementioned loads on resisted sprint and jump performance were analyzed. Methods: Twenty-eight physically active women were randomly allocated into 2 groups: unloaded sprint training group (G0%, n = 14), and resisted sprint training with 40% BM group (G40%, n = 14). Pretraining and posttraining assessments included countermovement jump, unloaded 30-m sprint, and 20-m sprint with 20%, 40%, 60%, and 80% BM. Times to cover 0 to 10 (T10), 0 to 20 (T20), 0 to 30 (T30), 10 to 20 (T10–20), 20 to 30 (T20–30), and 10 to 30 m (T10–30) were recorded. Both groups were trained once a week for 8 weeks and completed the same training program, but with different loads (0% vs 40% BM). Results: No significant time × group interactions were observed. For unloaded sprint performance, G0% showed significant (P = .027) decreases only in T10–20, while G40% attained significant decreases in T30 (P = .021), T10–30 (P = .015), and T20–30 (P = .003). Regarding resisted sprint performance, G0% showed significant (P = .010) improvements only for the 20% BM condition. The G40% group attained significant improvements in all loading conditions (20%, 40%, 60%, and 80% BM). Both groups showed significant improvements (P < .001) in countermovement jump height. Conclusions: In physically active women, no significant differences in sprint and countermovement jump performance were detected after 8 weeks of resisted and unresisted sprint training programs. Future studies should, therefore, be devoted to how sprint training should be individualized to maximize performance.
David Rodríguez-Rosell, Felipe Franco-Márquez, Fernando Pareja-Blanco, Ricardo Mora-Custodio, Juan M. Yáñez-García, José M. González-Suárez and Juan J. González-Badillo
To analyze the effects of low-load, high-velocity resistance training (RT) combined with plyometrics on physical performance in pre-peak-height-velocity (PHV) soccer players.
Thirty young soccer players from the same academy were randomly assigned to either a strength training (STG, n = 15) or a control group (CG, n = 15). Strength training consisted of full squat exercise with low load (45–58% 1RM) and low volume (4–8 repetitions/set) combined with jumps and sprints twice a week over 6 wk of preseason. The effect of the training protocol was assessed using sprint performance over 10 and 20 m, countermovement jump, estimated 1-repetition maximum, and average velocity attained against all loads common to pre- and posttests in full squat.
STG showed significant improvements (P = .004–.001) and moderate to very large standardized effects (ES = 0.71–2.10) in all variables measured, whereas no significant gains were found in CG (ES = –0.29 to 0.06). Moreover, significant test × group interactions (P < .003–.001) and greater between-groups ESs (0.90–1.97) were found for all variables in favor of STG compared with CG.
Only 6 wk of preseason low-volume and low-load RT combined with plyometrics can lead to relevant improvements in strength, jump, and sprint performance. Thus, the combination of field soccer training and lightweight strength training could be used for a greater development of the tasks critical to soccer performance in pre-PHV soccer players.