ECSS Paris 2023: OP-AP11
INTRODUCTION: Velocity based (strength) training (VBT) has been recognized as an effective method for controlling training volume and quality [1]. Studies have demonstrated that a training with velocity loss thresholds (VLT) results in increased maximal strength as well as improved sprinting and jumping performance compared to traditional resistance training [2]. Unfortunately, available velocity and acceleration sensors are expensive and can impose practicability issues. Hence, the objectives of this study were to evaluate (I) the accuracy of velocity perception for strength trained participants during the barbell bench press and (II) whether a single habituation session with VLT feedback can beneficially affect the perceived 20% VLT’s agreement with the true values. METHODS: Eighteen strength trained participants (n (female, male) = 10, 8; age: 26 ± 5 years; 177 ± 10 cm; 79,3 ± 27,6 kg; ≥ 2 years of bench press experience), without prior VBT experience, completed 4 individual sessions, separated by 48 h. Session 1 served as an instruction session and one repetition maximum (1RM) assessment. In session 2 and 4, the participants completed 3 sets at 80 % 1RM. For each set, the participants were instructed to give a verbal cue when they estimated a relative loss of velocity ≥ 20% (20%VLT) and continued their set until failure (≤ 1 repetitions (reps) in reserve). In session 3 the participants were familiarized with a VLT training and completed 3 sets of bench press at 70% 1RM until the 20%VLT was reached. Bench press velocity and reps were monitored, analysed for agreement and presented as bias with limits of agreement (LoA). RESULTS: The participants performed an average of 9.9 ± 2.1 reps to failure across all sets in session 2. The mean number of reps completed at the 20%VLT was 4.5 ± 1.3 and the mean velocity at 20%VLT was 0.33 ± 0.07 m/s across sets. The participants slightly underestimated the repetitions until 20%VLT by -0.3 reps (LoA [-1.7, 1.2]) which resulted in a slight overestimation of velocity at 20%VLT by 0.02 m/s (LoA [-0.05, 0.08]). There was no change after the familiarization in session 3 for the reps (bias = -0.24, LoA [-1.60, 1.12]; Cohen’s d = 0.015, p = 0.93), or velocity (bias = 0.01 m/s, LoA [-0.05, 0.07]; Cohen’s d = -0.107, p = 0.48). CONCLUSION: The analysis of agreement between the perceived and true repetitions and velocity at the 20%VLT reveals a small bias for the bench press with high load. A single habituation session does not meaningfully affect this bias. Our findings indicate that a VLT training can alternatively be applied without velocity measurement, if the athletes are moderately strength trained. Future studies should expand on the current findings with respect to different exercises and load ranges. 1. Weakley J, Mann B, Banyard H, McLaren S, Scott T, Garcia-Ramos A. Strength & Conditioning Journal. 2021;43:31–49. 2. Held S, Speer K, Rappelt L, Wicker P, Donath L. Front Physiol. 2022;13:926972.
Read CV Tim WiedenmannECSS Paris 2023: OP-AP11
INTRODUCTION: In the realm of strength and conditioning, practitioners continually strive to refine training methodologies that effectively manage fatigue levels and optimize the outcomes of resistance training. Autoregulation, a notable paradigm, involves tailoring resistance training to individual needs and capabilities through the manipulation of training variables. While existing evidence predominantly focuses on autoregulation practices within the male population, there remains a paucity of knowledge concerning the impact of autoregulation resistance training on sex-specific differences in fatiguability and resistance training performance. The aim of this study was to examine the sex differences in motor performance, neuromuscular and perceived fatigue during resistance training prescribed using traditional (TRA) and autoregulation rest redistribution training (ARRT) approaches. METHODS: Twelve resistance-trained males and twelve females completed two sessions including the bench press exercise matched for load (75% of 1-repetition maximum), volume (24 repetitions), and total rest (240 s). Sessions were performed in a randomized order with TRA consisting of 3 sets of 8 repetitions with 120 s interest rest and ARRT employing a personalized combination of clusters, repetitions per cluster, and between-cluster rest regulated with a 20% velocity loss threshold. The effects of TRA and ARRT on velocity loss, unilateral isometric peak force and rating of fatigue (ROF) were compared between males and females. RESULTS: The velocity loss was generally lower during ARRT compared to TRA (-0.47 ± 0.11%) with velocity loss being mitigated by ARRT to a greater extent among males compared to females (-0.37 ± 0.15%). Unilateral isometric peak force was greater after ARRT than TRA among males compared to females (38.4 ± 8.4N). Lower ROF after ARRT than TRA were found among males compared to females (-1.97 ± 0.55AU). Additionally, males reported greater ROF than females across both conditions (1.92 ± 0.53AU), and ARRT resulted in lower ROF than ARRT overall (-0.83 ± 0.39 AU). CONCLUSION: The ARRT approach resulted in decreased velocity loss, peak force impairment, and ROF compared to TRA in both sexes. The flexible, dynamic, and personalized nature of ARRT accounts for between-subject variability in resistance training performance and seems to accommodate individual neuromuscular capabilities and training patterns. However, male subjects exhibited more pronounced acute within-session benefits from the ARRT method compared to females. Morphological, physiological, and training-related factors underlying the sex differences in fatiguability are likely the main reasons explaining these effects. These findings emphasize the effectiveness of the ARRT paradigm in improving neuromuscular outcomes and mitigating perceived fatigue during resistance training. Additionally, a differential response to the ARRT method between sexes underscores the importance of personalized training approaches.
Read CV Antonio Dello IaconoECSS Paris 2023: OP-AP11
INTRODUCTION: The placebo effect refers to positive changes in outcomes following the administration of a placebo, while the nocebo effect pertains to negative changes. Ischemic preconditioning (IPC) involves intermittent blood occlusion followed by reperfusion of skeletal muscle, performed either before or after exercise or test. The mechanism for its purported benefit is questioned, with many have reporting that changes in performance are the result of placebo effects (1-2). Given that one major factor mediating placebo and nocebo effects is the expectation evoked after receiving an intervention (3), we investigated the placebo effect associated with IPC. This was accomplished by manipulating subjects expectations following the application of a sham-IPC intervention. METHODS: Thirty-five healthy men, experienced in resistance exercise (RE), were randomly assigned to one of the following conditions: positive (POS), negative (NEG), or no verbal manipulation (CON). No participants reported prior pneumatic cuff experience. In the 1st and 2nd visit a familiarization with maximal voluntary isometric contraction (MVIC), lower limb muscle power output, and 10RM test and retest were performed. On the 3rd visit, three maximum sets with a 10RM load were performed, representing the baseline moment. Finally, on the 4th visit, sham-IPC with either POS, NEG or CON manipulations preceded performance tests. All tests were performed unilaterally, on the subjects dominant limb. The sham-IPC intervention consisted of 3 cycles of 5-minute cuff administration (positioned on the proximal region of thigh) set at 20 mmHg of the subjects, followed by 5 minutes of "pseudo-reperfusion" at 0 mmHg, totaling 30 minutes of intervention. The CON intervention involved no cuff application, while subjects remained in a supine rest position for 30 minutes. RESULTS: Differences were observed for the number of repetitions (POS: 29.6±4.0; NEG: 24.9±4.4; CON: 26.9±2.7; p=0.019), whereby those who received positive information about IPC, significantly improved than those who received negative-information (p=0.01; ES: 1.11). No changes in MVIC peak force were found between groups (POS: 646.6±81.9; NEG: 642.3±90.9; CON: 599.5±56.5 N; p=0.06), and peak muscle power was similar across all groups (POS: 531.4±99.0; NEG: 632.7±111.1; CON: 538.5±69.4 W; p=0.11). CONCLUSION: The use of sham-IPC cuff intervention linked to positive or negative manipulation, influenced the maximum number of repetitions during a leg-extension task. Our results have important implications for researchers measuring participant expectations about their intervention, which can significantly influence performance outcomes. REFERENCES: (1) Souza, et al. 10.1371/journal.pone.0250572; (2) Marocolo, et al. 10.1007/s00421-022-05109-9; (3) Brietzke, et al. DOI:10.1007/s00421-022-05029-8 *Contact: isamjf@gmail.com
Read CV Moacir MarocoloECSS Paris 2023: OP-AP11