ECSS Paris 2023: OP-AP28
INTRODUCTION: Velocity-based training is an objective method of autoregulation that uses barbell velocity and velocity loss to manage and quantify resistance training (RT) sessions. However, in large team settings, electronic devices are not always available for all athletes. For this reason, the perception of barbell velocity (VP) has recently gained interest, with studies demonstrating that after a period of familiarization1,2, VP improves to practically match real velocity (VR). What is still unexplored is how fatigue affects the accuracy of VP. The aim of the present study was to investigate the effects of mental (MF) and physical fatigue (PF) on VP and perception of velocity loss (VLP). METHODS: Eleven subjects (23.16±2.12years; RT experience: 4.5±2.31 years) participated in a seven-session experimental protocol. The first four sessions aimed to familiarize subjects with VP and VLP. The last three sessions were performed in a PF, MF or control condition in a randomized order. The accuracy in perceiving concentric velocity before and after the different conditions was assessed during a test with 2 blinded-loads (heavy: ?80%1RM, medium: ? 60%1RM), in the Back Squat exercise. PF was induced by 5 x back squats at 75%1RM until exhaustion, while MF was induced by a 45-minute AX-CPT test. The control session involved watching a 45-minute unemotional documentary. VP, VLP, and physical performance assessed by a countermovement jump (CMJ), rate of force development (RFD), and maximum voluntary contraction (MVC) were measured before and after each condition. Data were analysed with a Paired t-test to compare pre- and post-fatigue protocol measurements, the level of significance applied was p<0.05. RESULTS: VP and VLP were unaffected (p>0.05) by the fatiguing protocols despite a significant reduction in VR (VRrest:0.67±0.08 m·s-1; VR PF:0.44±0.10 m·s-1; VRMF:0.51±0.13 m·s-1). Performance decreased significantly (p<0.05) after PF and MF (CMJ: -19%, -7%; RFDmax: -25%, -9%; RFD0-100ms: -22%, -9%; RFD0-200ms: -19%, -10%; MVC: -20%, -10%) Moreover, VAS reported an increase in perceived MF after AX-CPT but not after the documentary. No differences were seen in the control condition (p>0.05). CONCLUSION: Despite a significant reduction in VR, both fatiguing protocols did not alter VP during back squat. These data confirm previous studies performed with shorter protocols3 confirming that VP is a stable parameter on which practitioners can base their training despite different levels of fatigue. Furthermore, CMJ, RFD, and MVC performance were negatively affected by both conditions. While this it is well-established under PF conditions, further investigation is needed to better understand the effects of MF. References: 1. Dello Iacono, A., et al., (2023 2. Romagnoli, R., et al., (2022) 3 Romagnoli, R., et al., (2022a)
Read CV Emanuele Dello StrittoECSS Paris 2023: OP-AP28
INTRODUCTION: In road cycling, the ability to perform maximum intensity efforts after hours of racing, or durability, can make a difference between winning and losing [1]. Specifically, differences between World Class and Continental-level athletes are best observed in the fatigued state [2][3], yet the reasons behind these level-dependent variations remain unclear. The aim of this study was to clarify the effect of prolonged duration exercise with interspersed maximal efforts on performance and fatigability in recreationally-trained and elite cyclists. METHODS: Twelve recreational (maximal oxygen uptake (VO2max):61.9±7.3 mL/min/kg, Critical Power (CP):298±31W) and six elite-level cyclists (VO2max:75.8±5.4mL/min/kg, CP:378±62W) rode on a cycle ergometer for three hours in the moderate-intensity domain (90% VT1: 221±42 vs 180±22W) interspersed with three exhausting bouts destined to deplete W’ (3min all-out test, 3AOT) at 0, 90 and 180 min elapsed. Power and heart rate (HR) were continuously monitored. Blood lactate ([La]), expired gases and ratings of perceived exertion (RPE, 6-20 Borg scale) were recorded every 30 min during moderate intensity bouts. Expired gases were measured during, and lactate concentration measured 30-s after each 3AOT. Knee extensor maximal voluntary contractions (MVC) were measured after warm-up, immediately after each 3AOT, and again 10 minutes post each 3AOT. RESULTS: Elite cyclists were characterised by higher CP, VO2max, peak power (721±96 vs 591±98 W) and VT1 (244 ±45 vs 199 ±29W) than recreational cyclists. During moderate intensity cycling, there were no significant group or time differences in VO2, [La], RPE and HR. There were also no group differences in CHO consumption (2.3±0.5 vs 2.2±0.4 g/min) despite the higher absolute intensity and energy cost (20±3 vs 17±2 kcal.min-1) in the elite group. There were significant alterations from 1st to 3rd 3AOT, in total work (elite: 75±9 vs 81±10 kJ ; recreational: 62±9 vs 59±10 kJ) and [La] (elite: 13.4±3.2 vs 8.0±2.9 mmol.L-1 ; recreational: 9.2±3.9 vs 7.6±2.9 mmol.L-1). However, W decreased significantly only in recreational cyclists (10.1±1.4 vs 12.4±9.1 kJ). There were no significant changes in CP or VO2peak during the three 3AOT for both groups. Knee extensor MVC decreased only in recreational group (122±29 vs 104±32 Nm) with no differences in relative voluntary activation in both groups. CONCLUSION: The main finding of this study was that recreational athletes displayed higher fatigability than elite cyclists over the duration of the prolonged exercise. In elite athletes, initial force was not different after despite higher total work, higher work performed during each 3AOT, and higher W’ expended during each 3AOT. Elite cyclists also had similar CHO but higher FAT contribution to total energy expenditure at moderate intensity. [1] Mateo-March et al. (2021a) [2] Mateo-March et al. (2021b) [3] Van Erp et al. (2020)
Read CV Romain DEMAYECSS Paris 2023: OP-AP28
INTRODUCTION: The impact of bilateral deficit (BLD) and interlimb asymmetry (IA) on athletic performance and sports injuries is mostly unknown. It is important to understand the fatigue-related changes in BLD and IA in sports such as gymnastics, where both unilateral and bilateral jumps are involved to minimize the decrement in performance that may occur as a result of fatigue and to prevent injuries. This study aimed to investigate the fatigue-related changes in BLD and IA in young female gymnasts. METHODS: 35 young female gymnasts (aerobic and artistic) voluntarily participated in thise study. They were divided into two age groups as 9-11 years (n=19) and 12-14 years (n=16) based on their competition level and three groups based on their biological maturity level which was determined by peak height velocity (PHV): pre-PHV (n=15), PHV (n=13), and post-PHV (n=7). Anthropometric measurements were conducted for determination of physical characteristics and calculation of biological maturity. To evaluate BLD and IA, the participants performed unilateral and bilateral countermovement jump (CMJ) tests before and immediately after a fatigue protocol. The fatigue protocol consisted of 10 consecutive CMJs without rest, each preceded by a 20-meter sprint involving a 180° change of direction. The fatigue protocol was terminated either when participants failed to reach 50% of their maximum jump height for three consecutive jumps or when they reported exhaustion. Independent samples t-test was used to analyze the differences in BLD and IA between age groups, while one-way analysis of variance (ANOVA) was utilized to determine the differences among the maturity groups. The effects of fatigue-related changes were examined using mixed-design ANOVA, considering age groups and biological maturity. Scheffes post hoc test was applied in the analysis. RESULTS: The results indicated that age group and maturity level did not have a significant effect on bilateral BLD (p>0.05). However, significant fatigue effect was observed with respect to age group and maturity level (F1,33=11.699, p=0.002, n2=0.262 and F1,32=5.962, p=0.020, n2=0.157, respectively). Furthermore, significant interactions were found between age group and fatigue, as well as maturity level and fatigue (F1,33=13.705, p=0.001, n2=0.293 and F2,32=6.742, p=0.004, n2=0.296, respectively). In terms of IA, neither age group nor maturity level had a statistically significant effect (p>0.05); however, fatigue had a significant effect on both variables (F1,33=10.835, p=0.002, n2=0.247 and F1,32=9.575, p=0.004, n2=0.230, respectively). Nevertheless, the interactions between age groups and fatigue, as well as maturity level and fatigue, were not statistically significant for IA (p>0.05). CONCLUSION: This study demonstrated that fatigue influenced BLD and IA in young female gymnasts. Additionally, fatigue-related changes in BLD varied according to age and biological maturity, whereas IA did not exhibit any variations related to age and biological maturity.
Read CV Nazli OzgorECSS Paris 2023: OP-AP28