ECSS Paris 2023: CP-AP12
INTRODUCTION: Resistance training (RT) is recognized as an effective strategy for weight loss and increases in muscle mass, with positive effects on physical fitness, athletic performance, and cardiometabolic health. Dense resistance training systems have gained popularity due to their potential to increase metabolic stress and training efficiency. However, few studies have examined energy expenditure (EE) in trained adults using Rest-Pause (RP) and Sarcoplasma Stimulating Training (SST) compared with the Traditional Multiple-Set system (TMS) with equalized volume. PURPOSE: Compare energy expenditure and total mechanical load across Rest-Pause, Sarcoplasma Stimulating Training, and Traditional Multiple-Set resistance training systems with equalized volume in trained adult men. METHODS: A crossover study included 15 men (30.38 ± 2.06 years; 174.9 ± 0.07 cm; 88.40 ± 6.50 kg) with ≥3 years of resistance training experience who completed three experimental sessions (RP, SST, and TMS) in randomized order with a 72-hour washout period. One-repetition maximum (1-RM) testing was performed in the leg press (LP) and bench press (BP (ACSM, 2021), and loads were prescribed based on 1-RM values. SST consisted of sets to momentary concentric failure with intra-set rest intervals of 15–20 s, followed by a 20% load reduction and continuation to failure. RP consisted of sets to concentric failure with 20-s intra-set rest intervals until no repetitions could be completed. TMS consisted of multiple sets to failure with 1-min inter-set rest intervals. Total training volume (TL) was equalized and calculated as load × repetitions session. EE was estimated using the predictive equation by João et al. (2020). Statistical analyses included Shapiro–Wilk normality testing, one-way ANOVA with Tukey post hoc or Kruskal–Wallis tests, percentage differences (Δ%) and Spearman correlation (ρ). RESULTS: SST produced greater TL in BP (11.197±4.039kg; Δ% =58.0%) and LP (37.091±14.530 kg; Δ% = 125.7%) compared with TMS, whereas RP produced lower TL in BP and moderate TL in LP. TL was higher in SST (48.288± 18,300 kg) and RP (26,557±11,208 kg) compared with TMS (23.524±6,.818 kg). SST resulted in higher EE (181.77 kcal; Δ% =9.8%) compared with TMS (165.55 kcal), whereas RP resulted in lower EE (160.88 kcal; Δ% = −2.8%). No linear association between TL and EE was observed (RP: ρ =0.62; SST: ρ =0.09; TMS: ρ = −0.39). These findings highlight a dissociation between mechanical load and metabolic cost across resistance training systems CONCLUSION: SST resulted in greater energy expenditure and higher mechanical load compared with RP and TMS, despite equalized volume. These findings suggest that SST may be an effective strategy to maximize acute metabolic demand in trained adults. RP elicited lower EE but maintained high mechanical loading and training density, suggesting potential utility during phases focused on neuromuscular loading and muscle mass development.
Read CV Aylton Figueira JuniorECSS Paris 2023: CP-AP12
INTRODUCTION: The load–velocity profile (LVP) is widely used in velocity-based training (VBT) to prescribe load based on concentric velocity at different percentages of one-repetition maximum (1RM). However, concentric velocity is influenced by eccentric phase execution. Variations in eccentric velocity modify muscle mechanics, affecting stretch–shortening cycle (SSC) expression and neuromuscular responses, potentially altering the load–velocity relationship structure. The extent to which eccentric velocity systematic manipulation influences LVP characteristics remains unclear. This study examined how three eccentric tempo conditions (4-second [4s], voluntary [VOL], and explosive [EXP]) affect concentric velocity and power output in parallel squat. METHODS: Twelve resistance-trained males (age: 24.0 ± 1.9 years; height: 1.75 ± 0.05 m; body mass: 76.9 ± 10.0 kg; 1RM: 140.6 ± 12.3 kg) performed parallel back squats under three eccentric tempo conditions across loads ranging from 20, 40, 60, 65, 70, 75, 80, and 90%1RM. Mean velocity (MV), mean propulsive velocity (MPV), mean power (MP), and mean propulsive power (MPP) were recorded using a linear position transducer. Data were analyzed using linear mixed-effects models with random effects and heterogeneous variance structures. RESULTS: Significant eccentric tempo × load interactions were observed for MV and MPV (p < 0.001), with EXP and VOL showing steeper negative load–velocity slopes than 4s condition. Across 20–90%1RM, VOL and EXP produced higher MV and MPV than 4s, whereas EXP exceeded VOL only at ≤70%1RM, with differences diminishing at ≥75% 1RM. These patterns were reflected in higher estimated loads at 1.0 m/s, with MV-based V1 values of 36.4, 49.0, and 51.8% 1RM and MPV-based V1 values of 45.1, 56.5, and 58.8% 1RM for 4s, VOL, and EXP, respectively. MP and MPP exhibited significant linear and quadratic load effects and main effects of condition (p < 0.001), with faster eccentric execution shifted the power–load curves upward, increased curve convexity, and resulted in higher peak MP and MPP (4s < VOL < EXP) (MP: 716.7, 815.4, 860.7 W; MPP: 761.9, 888.7, 942.8 W). CONCLUSION: Eccentric tempo significantly modified the LVP by altering both velocity magnitude and load–velocity structure. 4s condition resulted in flatter load–velocity slopes and reduced estimated loads at 1.0 m/s, indicating constrained velocity expression in the low-load region. In contrast, VOL and EXP produced steeper negative slopes and higher velocities at lighter loads, with differences diminishing as load increased. Eccentric tempo also influenced the power–load relationship, as faster conditions yielded higher and more convex curves with elevated peak power, whereas the 4s condition consistently showed lower MP and MPP. These findings demonstrate that eccentric execution systematically alters velocity–load and power–load characteristics, particularly at lighter loads, highlighting the need to standardize eccentric tempo when applying LVP for load prescription in VBT.
Read CV Kuan Tsen YehECSS Paris 2023: CP-AP12
INTRODUCTION: Volleyball is an overhead sport where the shoulder joint endures high-frequency arm-swinging and ball-hitting loads during competition and training. Consequently, shoulder strength and stability are often regarded as critical factors influencing athletic performance and shoulder injury risk (1). In practical training, both machine-based and free-weight exercises can enhance shoulder joint strength. The former reduces movement variability and enhances training safety by fixing the exercise trajectory, while the latter emphasizes multi-joint coordination and core stability engagement (2). However, direct comparative studies on shoulder joint training interventions for female volleyball players remain relatively scarce. This study aims to investigate the effects of machine training versus free weight training on shoulder joint strength, stability, and athletic performance in female volleyball athletes. METHODS: This study recruited 33 healthy female volleyball athletes (aged 18–25 years) with regular training experience. Participants were randomly assigned to either a mechanical resistance training intervention or a free weight resistance training intervention for the shoulder joint strength. The training intervention lasted four weeks, with three sessions per week. shoulder joint strength, spike velocity, and stability were measured both before and after the intervention. Shoulder joint isokinetic strength was assessed at 60°/s and 180°/s. Spiking velocity was measured using a radar gun. Stability was evaluated using the closed kinetic chain upper limb stability test. Statistical analysis employed a two-factor mixed design repeated measures ANOVA with a significance level set at α = 0.05. RESULTS: The results indicate that the group × time interaction effects for all variables were not significant. Mean power during isokinetic strength testing at 60°/s and 180°/s shoulder internal rotation exhibited a main effect of time (η_p^2 = 0.300 and 0.183, respectively; p < 0.001, p = 0.013), with post-test values significantly higher than pre-test values. Both spike velocity (η_p^2 = 0.271; p = .002) and stability (η_p^2 = 0.685; p < .001) exhibited main effects of time, with post-test values significantly higher than pre-test values. CONCLUSION: This study demonstrates that a four-week shoulder joint resistance training program enhances female volleyball players' average power during shoulder internal rotation, shoulder joint stability, and spike velocity. However, no significant differences were observed between machine-based training and free weight training after the four-week intervention, indicating comparable training efficacy for both methods. Therefore, coaches and athletes may flexibly incorporate either machine-based or free-weight training into routine programs based on equipment accessibility, safety considerations, and individual athlete needs. The choice of training modality will not diminish the effectiveness of performance enhancement.
Read CV YEN CHU HUNGECSS Paris 2023: CP-AP12