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This study examined the effects of accentuated eccentric loading (AEL) on bench press velocities across a spectrum of concentric and eccentric loads. Ten strength trained men (bench press one-repetition maximum (1-RM): 124.3 ± 19.4 kg; relative strength ratio: 1.5 ± 0.2 kg∙body mass -1 ) participated. Subjects completed bench press repetitions using concentric loads from 30% to 80% 1-RM in 10% increments in each experimental session. The AEL protocols were implemented using 100% (AEL100) and 110% 1-RM (AEL110) loads during the eccentric action, while the eccentric load remained the same as the concentric for traditional loading (TRAD). Multilevel models analyzed the effects of each AEL protocol on concentric velocities across concentric loads ( p < 0.05). Faster concentric velocities were observed at 30% 1-RM and 80% 1-RM with AEL100 compared to TRAD ( p ≤ 0.05) but this effect was reduced for individuals moving the barbell through a greater displacement. Additionally, AEL110 presented a greater change in velocity from 30% to 80% 1-RM than TRAD ( p ≤ 0.05). The AEL100 protocol resulted in faster concentric velocities throughout concentric loads of 30-80% 1-RM, but AEL110 may have been too great to elicit consistent performance enhancements. Thus, the efficacy of AEL at various concentric loads is dependent on the eccentric loading and barbell displacement.

The purpose of the study was to compare the physiological responses of skeletal muscle to a resistance training (RT) program using repetition maximum (RM) or relative intensity (RI SR ). Fifteen well-trained males underwent RT 3 d·wk -1 for 10 weeks in either an RM group ( n = 8) or RI SR group ( n = 7). The RM group achieved a relative maximum each day, while the RI SR group trained based on percentages. The RM group exercised until muscular failure on each exercise, while the RI SR group did not reach muscular failure throughout the intervention. Percutaneous needle biopsies of the vastus lateralis were obtained pre-post the training intervention, along with ultrasonography measures. Dependent variables were: Fiber type-specific cross-sectional area (CSA); anatomical CSA (ACSA); muscle thickness (MT); mammalian target of rapamycin (mTOR); adenosine monophosphate protein kinase (AMPK); and myosin heavy chains (MHC) specific for type I (MHC1), type IIA (MHC2A), and type IIX (MHC2X). Mixed-design analysis of variance and effect size using Hedge's g were used to assess within- and between-group alterations. RI SR statistically increased type I CSA ( p = 0.018, g = 0.56), type II CSA ( p = 0.012, g = 0.81), ACSA ( p = 0.002, g = 0.53), and MT ( p < 0.001, g = 1.47). RI SR also yielded a significant mTOR reduction ( p = 0.031, g = -1.40). Conversely, RM statistically increased only MT ( p = 0.003, g = 0.80). Between-group effect sizes supported RI SR for type I CSA ( g = 0.48), type II CSA ( g = 0.50), ACSA ( g = 1.03), MT ( g = 0.72), MHC2X ( g = 0.31), MHC2A ( g = 0.87), and MHC1 ( g = 0.59); with all other effects being of trivial magnitude ( g < 0.20). Our results demonstrated greater adaptations in fiber size, whole-muscle size, and several key contractile proteins when using RI SR compared to RM loading paradigms.

The purpose of this study was to examine the effects of a ballistic or non-ballistic concentric-only bench press (COBP) on subsequent plyometric push-up performance. Fourteen resistance trained men completed two separate one-repetition-maximum (1RM) testing sessions followed by three randomized experimental explosive push-up sessions. These sessions combined a heavy concentric bench press with plyometric push-ups. Using a series of 3 × 10 (condition × time) repeated measures ANOVA, comparisons were made between the effects of ballistic and non-ballistic bench presses on performance of plyometric push-ups to investigate push-up performance variables. Compared with the control condition, both ballistic and non-ballistic bench presses produced lower net impulse and take-off velocity data. No differences were found between ballistic and non-ballistic conditions comparing net impulse and take-off velocity. We conclude that the magnitude of loading used in the current investigation may have caused acute fatigue which led to lower push-up performance characteristics. This information can be used to alter loading protocols when designing complexes for the upper body, combining the bench press and plyometric push-ups.

The purpose of this study was to examine the force-time differences between concentric-only half-squats (COHS) performed with ballistic (BAL) or non-ballistic (NBAL) intent across a range of loads. Eighteen resistance-trained men performed either BAL or NBAL COHS at 30%, 50%, 70%, and 90% of their one repetition maximum (1RM) COHS. Relative peak force (PF) and relative impulse from 0⁻50 ms (Imp50), 0⁻90 ms (Imp90), 0⁻200 ms (Imp200), and 0⁻250 ms (Imp250) were compared using a series of 2 × 4 (intent × load) repeated measures ANOVAs with Bonferroni post hoc tests. Cohen's d effect sizes were calculated to provide measures of practical significance between the BAL and NBAL COHS and each load. BAL COHS produced statistically greater PF than NBAL COHS at 30% (d = 3.37), 50% (d = 2.88), 70% (d = 2.29), and 90% 1RM (d = 1.19) (all p < 0.001). Statistically significant main effect differences were found between load-averaged BAL and NBAL COHS for Imp90 ( p = 0.006, d = 0.25), Imp200 ( p = 0.001, d = 0.36), and Imp250 ( p < 0.001, d = 0.41), but not for Imp50 ( p = 0.018, d = 0.21). Considering the greater PF and impulse observed during the BAL condition, performing COHS with BAL intent may provide a favorable training stimulus compared to COHS performed with NBAL intent.

The current investigation was an examination of the repetition-to-repetition magnitudes and changes in kinetic and kinematic characteristics of the back squat using accentuated eccentric loading (AEL) and cluster sets. Trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, back squat to body mass ratio = 1.8 ± 0.3) completed four load condition sessions, each consisting of three sets of five repetitions of either traditionally loaded straight sets (TL), traditionally loaded cluster sets (TLC), AEL cluster sets (AEC), and AEL straight sets where only the initial repetition had eccentric overload (AEL1). Eccentric overload was applied using weight releasers, creating a total eccentric load equivalent to 105% of concentric one repetition maximum (1RM). Concentric load was 80% 1RM for all load conditions. Using straight sets (TL and AEL1) tended to decrease peak power (PP) ( d = &minus;1.90 to &minus;0.76), concentric rate of force development (RFD CON ) ( d = &minus;1.59 to &minus;0.27), and average velocity (MV) ( d = &minus;3.91 to &minus;1.29), with moderate decreases in MV using cluster sets ( d = &minus;0.81 to &minus;0.62). Greater magnitude eccentric rate of force development (RFD ECC ) was observed using AEC at repetition three (R3) and five (R5) compared to all load conditions ( d = 0.21⁻0.65). Large within-condition changes in RFD ECC from repetition one to repetition three (∆REP 1⁻3 ) were present using AEL1 ( d = 1.51), demonstrating that RFD ECC remained elevated for at least three repetitions despite overload only present on the initial repetition. Overall, cluster sets appear to permit higher magnitude and improved maintenance of concentric outputs throughout a set. Eccentric overload with the loading protocol used in the current study does not appear to potentiate concentric output regardless of set configuration but may cause greater RFD ECC compared to traditional loading.

The purpose of the current study was (1) to examine the differences between standing and lying measures of vastus lateralis (VL), muscle thickness (MT), pennation angle (PA), and cross-sectional area (CSA) using ultrasonography; and (2) to explore the relationships between lying and standing measures with isometric and dynamic assessments of force production-specifically peak force, rate of force development (RFD), impulse, and one-repetition maximum back squat. Fourteen resistance-trained subjects (age = 26.8 ± 4.0 years, height = 181.4 ± 6.0 cm, body mass = 89.8 ± 10.7 kg, back squat to body mass ratio = 1.84 ± 0.34) agreed to participate. Lying and standing ultrasonography images of the right VL were collected following 48 hours of rest. Isometric squat assessments followed ultrasonography, and were performed on force platforms with data used to determine isometric peak force (IPF), as well as RFD and impulse at various time points. Forty-eight hours later, one-repetition maximum back squats were performed by each subject. Paired-samples t-tests revealed statistically significant differences between standing and lying measurements of MT ( p < 0.001), PA ( p < 0.001), and CSA ( p ≤ 0.05), with standing values larger in all cases. Further, standing measures were correlated more strongly and abundantly to isometric and dynamic performance. These results suggest that if practitioners intend to gain insight into strength-power potential based on ultrasonography measurements, performing the measurement collection with the athlete in a standing posture may be preferred., Competing Interests: The authors declare no conflict of interest.