Comparison of the force-, velocity- and power-time ...

Journal of Strength and Conditioning Research Publish Ahead of Print DOI: 10.1519/JSC.0000000000002448

Comparison of the force-, velocity- and power-time curves between the concentric-only and eccentric-concentric bench press exercises

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Running head: Concentric-only vs. eccentric-concentric bench press

Pestaña-Melero,1 and Amador García-Ramos1,3

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Institutional Affiliations: 1

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Authors: Alejandro Pérez-Castilla,1 Paul Comfort,2 John J. McMahon,2 Francisco Luis

Department of Physical Education and Sport, Faculty of Sport Sciences, University of

Granada, Granada, Spain. 2

Human Performance Laboratory, Directorate of Sport, Exercise and Physiotherapy,

University of Salford, Greater Manchester, United Kingdom. Faculty of Education, Catholic University of the Most Holy Conception, Concepción, Chile.

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Corresponding author:

Amador García-Ramos. 1Department of Physical Education and Sport, Faculty of Sport

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Sciences, University of Granada, Spain.

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Faculty of Education, Catholic University of the

Most Holy Conception, Concepción, Chile. Phone: (+34) 677815348, Fax: (+34) 958244369, E-mail: [email protected]

Copyright ª 2018 National Strength and Conditioning Association

Concentric-only vs. eccentric-concentric bench press

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Abstract The aim of this study was to compare the temporal and mechanical variables between the concentric-only and eccentric-concentric bench press (BP) variants. Twenty-one men (age: 22.0±4.2 years, body mass: 73.4±7.7 kg, height: 177.2±8.0 cm; one-repetition maximum [1RM]: 1.12±0.12 kg⋅kg-1) were evaluated during the concentric-only and

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eccentric-concentric BP variants using 80% 1RM. Temporal (concentric phase duration, propulsive phase duration, and time to reach the maximum values of force, velocity, and

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power) and mechanical variables (force, velocity, and power), determined using a linear velocity transducer, were compared between both BP variants. All temporal variables were significantly lower during the eccentric-concentric BP compared to the concentric-only BP

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(P < 0.05; effect size [ES] range: 0.80-2.52). Maximum force as well as the mean values of velocity and power were significantly higher for the eccentric-concentric BP compared to the concentric-only BP (all P < 0.001; ES range: 2.87-3.58). However, trivial to small differences between both BP variants were observed for mean force (ES: 0.00-0.36) as well as for maximum velocity (ES: 0.40) and power (ES: 0.41). The stretch-shortening cycle (i.e., eccentric-concentric BP) mainly enhanced force production at the early portion of the

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concentric phase, but this potentiation effect gradually reduced over the latter part of the

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movement. Finally, force was higher for the concentric-only BP during 49% of the concentric phase duration. These results suggest that both BP variants should be included during resistance training programs in order to optimize force output at different points of the concentric phase.

Key Words: stretch-shortening cycle, resistance training, kinetics, kinematics.



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INTRODUCTION Resistance training is one of the most effective methods for enhancing physical fitness and competitive performance (3,13). The bench press (BP) is probably the most commonly prescribed upper-body exercise for the general population as well as for athletes of different disciplines (e.g., powerlifters, handball players, volleyball players, etc.) (9,14,15,27). The

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popularity of the BP exercise is justified because its inclusion in resistance training programs has been shown to effectively increase maximal strength, hypertrophy, power, and muscular

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endurance (21,24,25). Results from previous studies have also shown that BP performance (assessed as the one-repetition maximum [1RM] or maximum power) is associated with an increased performance in different sport specific tasks (e.g., ball throwing velocity, punching

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speed, shot put performance, etc.) (16,18,26). In this regard, BP performance also discriminates between elite and sub-elite athletes (1,2). Therefore, due to the importance of the BP exercise, of special interest for coaches and sport scientists would be to identify the training modes for maximizing fitness and sport performance through BP training.

The concentric-only and eccentric-concentric BP exercises are two variants

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commonly incorporated during resistance training programs. The concentric-only BP can be

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executed after performing an isometric muscle action (pausing with the barbell in contact with the sternum) prior to the concentric phase (20,23) or using a mechanical brake to support the barbell (4,7). Performing the concentric-only BP in which the barbell is mechanically supported before the lifting could be used to improve the ability to produce force rapidly from an almost relaxed state of the muscles, as happens in many sport activities (10). On the other hand, the eccentric-concentric BP is characterized by including an eccentric muscle action immediately before the concentric muscle action (4,7). Such coupling of eccentric and concentric muscle actions is referred to as the stretch-shortening cycle,



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which is present in the vast majority of sport specific tasks (e.g., kicking, throwing, hitting, etc.) (5,17). Therefore, the inclusion of both BP variants (concentric-only and eccentricconcentric) during resistance training programs seems to be justified to enhance muscular fitness and, consequently, sport performance.

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The comparison of mechanical variables (i.e., force, velocity, and power outputs) between the concentric-only and eccentric-concentric BP variants can provide valuable

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information for strength and conditioning professionals. Previously researchers have shown that the stretch-shortening cycle mainly enhances the early phase of the concentric muscle action, while its potentiation effect decreases in the latter part of the concentric phase

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(5,17,29). In this regard, Newton et al. (17) revealed that the mean values of force, velocity, and power were higher in the eccentric-concentric BP throw compared to the concentric-only BP throw. However, while the maximum values of force and power were also higher for the eccentric-concentric BP throw, no significant differences between both BP variants were observed for maximum velocity and the height reached by the barbell. Similarly, Cronin et al. (4) showed that maximum force and mean velocity were also higher for the eccentric-

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concentric BP compared to the concentric-only BP variant, while mean force and maximum

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velocity did not differ between BP variants. Therefore, besides comparing the maximum and averaged values of force, velocity, and power between both BP variants, it could be important to compare these values at different points of the concentric phase through the temporal assessment of the force-, velocity-, and power-time curves.

In light of the aforementioned considerations, the present study was designed to evaluate the effect of the stretch-shortening cycle on temporal and mechanical variables during the BP exercise.



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Specifically, this study aimed to compare temporal and mechanical variables of the concentric-only and eccentric-concentric BP variants performed with 80% 1RM. Our first hypothesis was that the eccentric-concentric BP would exhibit a shorter concentric phase duration. In addition, when normalized by the concentric phase duration, we also hypothesized that the contribution of the propulsive phase and the time needed to reach the

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maximum values of force, velocity, and power would be lower for the eccentric-concentric BP. In line with previous research, our second hypothesis was that the mechanical variables

utilization of the stretch-shortening cycle (5,17).

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METHOD

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(i.e., force, velocity and power) would be higher for the eccentric-concentric BP, due to the

Experimental approach to the problem

A counterbalanced crossover design was used to compare the temporal and mechanical variables of the concentric-only and eccentric-concentric BP variants. Following two familiarization sessions with the purpose of ensuring a proper technique in both BP variants, subjects attended to the laboratory on two occasions separated by 48-72 hours. The

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first session involved the determination of the 1RM in the concentric-only BP exercise. In the

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second session, the two BP variants (concentric-only and eccentric-concentric) were evaluated with 80% 1RM. The 80% 1RM was chosen because it is a load commonly used during resistance training (28,30). The same absolute load was used for both BP variants in order to compare mechanical outputs against the same loading magnitude. The small differences in the 1RM value reported between the concentric-only and eccentric-concentric BP variants (≈ 0.06%) (7) suggests that the absolute load also represented a relative load close to the 80% 1RM for the eccentric-concentric BP variant.



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Testing sessions were conducted at the same time of the day (±1 h) for each subject and under similar environmental conditions (~22ºC and ~60% humidity). Subjects Twenty-one healthy men volunteered to participate in this study (age = 22.0 ± 4.2 years, body mass = 73.4 ± 7.7 kg, height = 177.2 ± 8.0 cm; data presented as mean ± standard

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deviation [SD]). All subjects were physically active and had at least two years of resistance training experience. The 1RM in the concentric-only bench press (BP) exercise was 81.3 ±

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6.8 kg (1.12 ± 0.12 kg⋅kg-1 body mass). No subjects reported physical limitations, health problems or musculoskeletal injuries that could compromise testing. Subjects were required to refrain from vigorous exercise for two days before each testing session. They were also

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informed of the procedures and signed a written informed consent form before initiating the study. The study protocol adhered to The Code of Ethics of the World Medical Association (Declaration of Helsinki) and was approved by the Institutional Review Board.

Testing procedures

Subjects arrived at the laboratory in a well-rested condition at the start of each testing

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session. The first testing session was used to determine the 1RM in the concentric-only BP

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following a standard incremental loading test (6). Briefly, the warm-up consisted on jogging, self-selected joint mobility exercises, and two sets of five repetitions performed against external loads of 20 and 30 kg. Thereafter, the external load was incremented from 10 to 1 kg until the 1RM load was reached. The inter-set rest was set to 4 min and 1-2 repetitions were performed with each load.



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The warm-up of the second testing session consisted on jogging, self-selected joint mobility exercises, followed by three sets of 6 repetitions at 40% 1RM, 4 repetitions at 60% 1RM, and 2 repetitions 80% 1RM, respectively. Half of the repetitions of each set were performed with the concentric-only technique and the other half of the repetitions with the eccentric-concentric technique. Afterwards, subjects rested for 5 min and then they

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performed two sets of three repetitions against the 80% 1RM loading condition. One set was performed with the concentric-only BP variant and another with the eccentric-concentric BP

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variant. The order of the two sets was counterbalanced between subjects. The recovery time between trials of the same BP variant was 15 s, while 5 min were implemented between the trials of different BP variants. The barbell was held by the mechanical brake of the Smith

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machine during the recovery periods. Two trained spotters were present at both sides of the Smith machine bar to ensure safety and to encourage the subjects to lift the barbell at the maximum possible velocity. Subjects received real-time verbal velocity performance feedback with a linear velocity transducer (T-force System; Ergotech, Murcia, Spain) immediately after each repetition to encourage them to give maximal effort (22).

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The standard five-point body contact position technique (head, upper back, and

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buttocks firmly on the bench with both feet flat on the floor) was followed in all testing sessions. Similarly, subjects self-selected the grip width, which was measured and kept constant on both testing sessions. The specific characteristics of the two BP variants are provided below: - Concentric-only BP: A mechanical brake was used to hold the bar parallel to the subjects’ nipples just above their chest at the level of the sternum (≈ 1-2 cm). From the initial position, they lifted the bar as fast as possible until their elbows reached full extension.



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- Eccentric-concentric BP: Subjects initiated the task by holding the bar with their elbows fully extended. From this position, they were instructed to perform the downward and upward phases of the lifting as fast as possible. The bar was lowered until contacting with the subjects’ chest at the level of the sternum and the concentric action ended when the subjects’ elbows reached full extension.

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Measurement equipment and data analysis Height (Seca 202, Seca Ltd., Hamburg, Germany) and body mass (Tanita BC 418

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segmental, Tokyo, Japan) were assessed in the first familiarization session. A Smith machine (Technogym, Barcelona, Spain) coupled with a linear velocity transducer (T-Force System; Ergotech, Murcia, Spain) which directly sampled the velocity of the barbell at a frequency of

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1,000 Hz was used in both testing sessions. Derived mechanical variables were calculated by the T-Force software: (a) acceleration was obtained by differentiating the velocity data with respect to time; (b) force was calculated as the product of barbell mass and total acceleration (acceleration due to gravity + acceleration of the barbell); with (c) instantaneous power calculated as the product of force and barbell velocity at each corresponding time point (8). Only the repetition with the highest mean propulsive velocity for each BP variant was

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selected for further analysis (19). Note that the concentric phase can be subdivided into a

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propulsive (force > 0) and a braking phase (force < 0) and, therefore, the propulsive phase is the concentric portion of the lift during which the barbell acceleration is greater than the acceleration due to gravity (acceleration ≥ −9.81 m⋅s-2) (23). The following variables were analysed to conduct a comprehensive analysis of the differences in temporal and mechanical variables between both BP variants: - Concentric phase duration: Time from the first positive velocity of the barbell (i.e., start of the concentric phase) until the velocity of the barbell is 0 m⋅s-1 (i.e., when the barbell reaches maximum height). The coefficient of variation (CV) was 7.06% for the concentricCopyright ª 2018 National Strength and Conditioning Association


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only BP and 4.65% for the eccentric-concentric BP. - Propulsive phase duration: Time from the start of the concentric phase until the acceleration of the barbell is lower than gravity (-9.81 m⋅s-2). The duration of the propulsive phase was expressed as a percentage of the concentric phase duration. The CV was 3.02% for the concentric-only BP and 2.60% for the eccentric-concentric BP.

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- Time to maximum values: Time from the onset of the concentric phase until reaching the maximum values of force, velocity, and power. The time to maximum values were

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expressed as a percentage of the concentric phase duration. The CV in the concentric-only BP and eccentric-concentric BP were 1.79% and 1.16% for the time to maximum velocity, and 2.72% and 2.66% for the time to maximum power, respectively. The CV of the time to

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maximum force was not calculated because it was always produced at the beginning of the concentric phase, while the CV of the time to maximum force during the concentric-only BP was 14.05%.

- Mean concentric values: Mean values of force, velocity, and power during the concentric phase. The CV in the concentric-only BP and eccentric-concentric BP were 0.12% and 0.14% for mean force, 3.02% and 6.47% for mean velocity, and 4.83% and 6.52% for

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mean power, respectively.

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- Mean propulsive values: Mean values of force, velocity, and power during the propulsive phase. The CV in the concentric-only BP and eccentric-concentric BP were 2.93% and 2.82% for mean propulsive force, 5.69% and 7.24% for mean propulsive velocity, and 7.17% and 8.29% for mean propulsive power, respectively. - Maximum values: Maximum force, velocity and power instantaneous values reached during the concentric phase. The CV in the concentric-only BP and eccentric-concentric BP were 2.51% and 18.37% for maximum force, 4.97% and 4.59% for maximum velocity, and 5.84% and 8.94% for maximum power, respectively. Copyright ª 2018 National Strength and Conditioning Association


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- Force-, velocity-, and power-time curves: Force, velocity, and power values were normalized with respect to the concentric phase duration in 1% intervals (from 1% to 100%). The values of force, velocity, and power attained at the closest time point (1 ms) to each percentage of the concentric phase duration were individually determined for each subject. Afterwards, the ensemble average of the subjects’ values at each time point (i.e., at each % of

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the concentric phase duration) were compared between both BP variants. This was to allow for direct comparison of the aforementioned kinetic- and kinematic-time curves during the

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only movement phase (i.e. concentric) which is common to both BP variants.

Statistical analyses

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Data are presented as means ± SD. Paired samples t-tests were used to compare the temporal and mechanical variables as well as the force-, velocity-, and power-time curves at each time point (i.e., from 1% to 100%) between the concentric-only and eccentricconcentric BP variants. The magnitude of the differences was also expressed as a standardized mean difference (Cohen’s d effect size [ES]) with the corresponding 95% confidence interval. The criteria to interpret the magnitude of the ES was as follows: trivial

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(< 0.2), small (0.2–0.59), moderate (0.60–1.19), large (1.2–2.0), or very large (> 2.0) (12).

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The statistical analyses were performed using SPSS software version 22.0 (SPSS Inc., Chicago, IL, USA) and statistical significance was set at an alpha level of 0.05.

RESULTS Table 1 displays the comparison of the temporal and mechanical variables between the concentric-only and eccentric-concentric BP variants. All temporal variables were significantly lower for the eccentric-concentric BP compared to the concentric-only BP. The mechanical variables (i.e., force, velocity, and power outputs) were always significantly


Concentric-only vs. eccentric-concentric bench press 10

higher for the eccentric-concentric BP than for the concentric-only BP. However, it should be noted that the magnitude of the differences of the three mechanical variables was heavily dependent of the type of variable considered. Namely, while the differences in the concentric and propulsive mean values of velocity and power were very large (ES: 2.88-3.58), trivial (ES: 0.00) and small (ES: 0.36) differences were observed for the concentric and propulsive

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mean values of force, respectively. On the other hand, very large differences were found between maximum force (ES: 2.87), but the differences were small for the maximum values

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of velocity (ES: 0.40) and power (ES: 0.41).

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***Table 1 near here***

Figure 1 shows the comparison of the averaged force-, velocity- and power-time curves between both BP variants. The most prominent difference was the increased force output at the beginning of the concentric phase (1%-12%) in the eccentric-concentric BP compared to the concentric-only BP. This result made velocity and power outputs higher for the eccentric-concentric BP from the start of the concentric phase up to the 82% and 77% of

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the concentric phase duration, respectively. However, the force output of the eccentric-

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concentric BP was similar and even diminished toward the later portion of the concentric phase compared to the concentric-only BP. In this regard, it should be noted that 49% of the concentric phase duration force output was higher for the concentric-only BP, while in only 23% of the concentric phase duration was higher for the eccentric-concentric BP.

***Figure 1 near here***



DISCUSSION The present study was designed to compare temporal and mechanical variables between the concentric-only and eccentric-concentric BP variants with a load commonly applied during resistance training programs (80% 1RM). Our first hypothesis was confirmed since the concentric phase duration was significantly reduced by a 34.9% in the eccentric-

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concentric BP. In addition, normalized by the concentric phase duration, the contribution of the propulsive phase (i.e., time when barbell acceleration is higher than gravity) as well as the

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time needed to reach the maximum values of force, velocity, and power were also significantly lower for the eccentric-concentric BP. Our second hypothesis was also confirmed since the mechanical variables were always higher in the eccentric-concentric BP

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than in the concentric-only BP. It should be also noted that in a considerable proportion of the concentric phase (49%) the force produced in the concentric-only BP was higher than in the eccentric-concentric BP. Collectively, these results could support the inclusion of both BP variants during resistance training programs since each BP variant maximizes force output at different moments of the repetition.

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The results from previous studies have shown the influence of the stretch-shortening

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cycle on different temporal variables for the BP exercise (4,5,17). For example, Newton et al. (17) reported a concentric phase duration significantly shorter for the eccentric-concentric BP throw compared to the concentric-only BP throw, while Cronin et al. (4) revealed that the time to maximum velocity also occurred earlier for the eccentric-concentric BP against a range of loads from 30%1RM to 80%1RM. In accordance with these findings, our first hypothesis was confirmed since the concentric phase duration was reduced for the eccentricconcentric BP. In addition, to the best of our knowledge, this is the first study comparing different temporal variables when normalized to the concentric phase duration between both



BP variants. The eccentric-concentric BP showed a short propulsive phase duration as well as a reduced time needed to reach the maximum values of force, velocity, and power compared to the concentric-only BP variant. Therefore, our findings not only confirm the shorter concentric phase duration following a pre-stretching of the muscles, but also reveal that when temporal variables are normalized for the duration of the concentric phase they are also

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attained earlier than during the eccentric-concentric BP. The observed differences in the points of the repetition at which the maximum values are attained could further support the

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inclusion of both BP variants during resistance training programs. Namely, while the eccentric-concentric BP would allow the maximization of force output at the beginning of the concentric phase, the concentric-only BP would allow to produce higher force in the latter

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part of the repetition.

The stretch-shortening cycle should be responsible of the large differences in mechanical outputs between the eccentric-concentric BP and the concentric-only BP. However, it should be noted that the magnitude of the differences between both BP variants markedly differed in function of the type of variable (mean concentric values, mean

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propulsive values, or maximum values) and mechanical output (force, velocity, and power)

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considered. Very large differences in favour of the eccentric-concentric BP were observed for the mean concentric and mean propulsive values of velocity and power, as well as for the maximum value of force when compared to the concentric-only BP. On the other hand, trivial to small differences between both BP variants were observed for the mean concentric and mean propulsive values of force, as well as for the maximum values of velocity and power. The variability in the magnitude of the differences between both BP variants are probably caused because the potentiation effect of the stretch-shortening cycle, which is prominent at the early phase of the concentric phase, is lost at the middle-latter portion of the repetition.



The presented findings are in line with the results reported in previous studies (5,17,29). The enhancement in force production at the beginning of the concentric phase has been typically attributed to different mechanisms such as a higher active state of the muscles, reflex activity, potentiation of the contractile properties of the muscles, and release of elastic energy (5,11). However, the benefits of the stretch-shortening cycle are rapidly lost when the

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movement is prolonged due to the inability of the muscles to produce force at fast shortening velocities (see Figure 1) (4,17). For example, the concentric phase duration of the eccentric-

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concentric BP was ≈ 773 ms (Table 1) which was likely excessive to make effective use of the different mechanisms responsible for stretch-shortening cycle potentiation throughout this entire phase. These characteristics should explain the differences in maximum values

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observed in the present study, with very large differences obtained for maximum force which is produced at the beginning of the repetition (at the 37% and 0% of the concentric duration for the concentric-only and eccentric-concentric BP, respectively), but small differences were observed for maximum velocity and maximum power that are attained in the latter portion of the repetition (≈ 75% of the concentric duration).

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The analysis of the force-, velocity-, and power-time curves normalized by the

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concentric phase duration allow us to obtain a deeper insight in the comparison between both BP variants. The most remarkable result emerged from these curves is that the mechanical outputs are maximized at different points of the repetition depending on the BP variant considered (see Figure 1). Namely, while the eccentric-concentric BP is able to produce higher values of force and power at the beginning of the repetition, the concentric-only BP should be chosen to maximize force and power in the latter part of the repetition. The higher velocity achieved earlier in the eccentric-concentric BP inevitably requires a longer deceleration phase of the barbell (23).



These results suggest that both BP variants should be utilized during resistance training programs depending on the desired adaptation since they enable the maximization of force and power production at different points of the repetition. Furthermore, it should be noted that the concentric-only BP allows to maintain muscular tension for a longer duration, and this could be beneficial for developing muscular strength and hypertrophy (4). On the

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other hand, the eccentric-concentric BP could also be recommended due to its higher specificity with sport tasks that involve the stretch-shortening cycle (4,17). Longitudinal

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studies are needed to assess the effects of training with different BP variants on maximal strength, hypertrophy and athletic development. In addition, it would be important to conduct a similar analysis to the one conducted in the present study across a range of heavier loads

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that are typically used to develop maximal strength as well as during free-weight BP variations.

PRACTICAL APPLICATIONS

Temporal and mechanical variables were highly influenced by the BP variant performed. The duration of the concentric phase as well as the contribution of the propulsive

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phase were shorter for the eccentric-concentric BP. Although the magnitude of the

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differences was influenced by the type of variable considered, the mechanical outputs (i.e., force, velocity, and power) were generally higher for the eccentric-concentric BP. It is important to note that each BP variant enabled the maximization of force and power outputs at different points of the repetition. Therefore, the mechanical differences identified in the present study between both BP variants suggest that a resistance training program should consider both variants of the BP exercise.



ACKNOWLEDGMENTS We would like to thank all the students who selflessly participated in the study. This study was supported by the Spanish Ministry of Education, Culture and Sport under a pre-doctoral grant (FPU15/03649) awarded to APC and by the University of Granada under a post-

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doctoral grant (perfeccionamiento de doctores) awarded to AGR.

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FIGURE LEGENDS Figure 1. Averaged force- (top panel), velocity- (middle panel) and power-time (bottom panel) curves across all subjects during the concentric-only (C-O) and eccentric-concentric (E-C) bench press (BP) variants. E-C BP > C-O BP, significantly greater values for eccentricconcentric bench press; E-C BP < C-O BP, significantly lower values for eccentric-

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concentric bench press. The level of significance was set at P < 0.05 (paired samples

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Student’s t-tests).


Table 1. Comparisons of temporal and mechanical variables between the concentric-only and eccentric-concentric bench press variants (n =21).

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Concentric phase duration (ms) Propulsive phase duration (%) Time to maximum force (%) Time to maximum velocity (%) Time to maximum power (%) Maximum force (N) Mean propulsive force (N) Mean concentric force (N) Maximum velocity (m·s-1) Mean propulsive velocity (m·s-1) Mean concentric velocity (m·s-1) Maximum power (W) Mean propulsive power (W) Mean concentric power (W)

Eccentric-concentric BP 773 ± 108 95.1 ± 4.62 0.00 ± 0.00 76.3 ± 13.7 64.3 ± 24.9 1274 ± 241 652 ± 57.2 621 ± 57.9 0.93 ± 0.10 0.64 ± 0.08 0.62 ± 0.06 649 ± 75.1 404 ± 53.3 383 ± 41.8

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ES (95% CI)

< 0.001 0.003 < 0.001 0.013 0.007 < 0.001 0.002 0.006 0.004 < 0.001 < 0.001 0.013 < 0.001 < 0.001

-2.52 (-3.22, -1.83) -0.87 (-1.41, -0.32) -1.78 (-2.39, -1.16) -0.80 (-1.34, -0.26) -0.92 (-1.47, -0.37) 2.87 (2.13, 3.62) 0.36 (-0.16, 0.89) 0.00 (-0.52, 0.52) 0.40 (-0.13, 0.93) 3.00 (2.24, 3.76) 3.58 (2.74, 4.42) 0.41 (-0.11, 0.94) 2.88 (2.13, 3.62) 3.13 (2.35, 3.91)

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Concentric-only BP 1043 ± 106 98.3 ± 2.40 37.2 ± 29.6 84.4 ± 4.01 80.7 ± 4.01 766 ± 66.4 631 ± 59.2 620 ± 58.0 0.89 ± 0.10 0.45 ± 0.04 0.45 ± 0.03 613 ± 97.1 281 ± 28.6 275 ± 25.2

Variables

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Mean ± SD; BP, bench press; P, P-value (paired samples Student’s t-tests); ES, Cohen’s d effect size ([eccentric-concentric BP – concentric-only BP]/SD both); 95% CI, 95% confidence interval.


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