ECSS Paris 2023: OP-AP40
INTRODUCTION: Contextual interference (CI) refers to the alteration of a training pattern structure by disrupting practice continuum throughout unrelated tasks (1). The interference effect has been shown to enhance motor skill learning by challenging the ability to integrate various motor patterns. A previous study in powerlifters found that the CI group had a greater improvement in 1RM execution technique than control (2). However, in that study CI was generated by dart-throwing, and the authors explained that using such unrelated task could have been a limit of their CI intervention. For this reason, we decided to address this concern and use a distinct yet pertinent CI secondary task. Our hypothesis was that high CI training would further improve technical execution. METHODS: Fifteen amateur powerlifters were randomly assigned into two groups (high and low CI) for a six-week powerlifting training program, using the seal row exercise between bench press sets to create interference. Performance was tested as 1RM bench press and max velocity lift (MVL) at baseline (t0 by 1RM test), week two (t1 by MVL), week four (t2 by MVL), week six (t3 by MVL) and week eight (t4 by MVL). Technical execution was evaluated at the same timepoint by means of 13 technical items Likert Scale (used in powerlifting competition). RESULTS: Two-way repeated measure (TWRM) ANOVA was performed to test whether CI affected two groups’ strength at a different rate over time. There was no group x time interaction (F (3.48, 45.28) = [1.407], p = 0.250), nor main effect of group in strength capacity (F (1,13) = [0.057], p=0.816), but a statistically significant main effect of time (F (3.48, 45.28) = [9.397], p < 0.001). Wilcoxon Test with Bonferroni corrections showed significant comparisons respectively at: t0 – t3 (p = 0.025), t0- t4 (p = 0.047), t1-t3 (p = 0.015), t1-t4 (p = 0.035). Technical execution was also tested using TWRM ANOVA. Global technique entailed analyzing all 13 items and resulted in a main effect of time (F (64.832) = [3.045], p < 0.001), with no interaction nor main effect of group. Whereas an item-by-item analysis showed: an effect of group (F (1,13) = [4.675], p = 0.050] for item 1 (dorsal arch); an interaction group x time (F (2.98, 38.76) = [4.118], p = 0.013) for item 2 (scapula adduction). CONCLUSION: Both groups of powerlifters significantly improved their strength. However, our more pertinent CI task did not induce a greater strength improvement. Our CI task did show some effects on bench-press technical execution, in particular scapula adduction. Further studies should focus on the appropriate choice of CI tasks. REFERENCES 1. Magill RA, Hall KG. A review of the contextual interference effect in motor skill acquisition. Hum Mov Sci. settembre 1990;9(3–5):241–89. 2. Naimo MA, Zourdos MC, Wilson JM, Kim JS, Ward EG, Eccles DW, et al. Contextual interference effects on the acquisition of skill and strength of the bench press. Hum Mov Sci. giugno 2013;32(3):472–84.
Read CV Simone MontenegroECSS Paris 2023: OP-AP40
INTRODUCTION: The present study explored acute responses of heart rate (HR) variability (HRV) metrics and selected hemodynamic parameters during the recovery phase following two exercise bouts of different intensity. The main focus was to advance current research by incorporating the non-linear index alpha 1 of detrended fluctuation analysis (DFAa1), providing additional qualitative information about autonomic nervous system regulation and reorganization during passive recovery. METHODS: Recreationally active female (n=13) and male (n=13) participants (age: 24.8±4.0 years, body mass: 68.3±10.8 kg, height: 171.2±9.6 cm, habitual physical activity: 7.3±3.5 h/week) were included in the study. In a first session a graded exercise test was conducted to determine peak HR (HRPEAK) and peak oxygen consumption (VO2PEAK) for exercise intensity prescription. In a second and third session, participants completed an endurance training with moderate intensity (MOD) on a treadmill and an exergaming training with vigorous intensity (VIG) in a randomized and counterbalanced order. Before and up to 45 minutes after the respective exercise sessions, RR-interval and hemodynamic measurements (peripheral systolic, SBP; diastolic blood pressure, DBP; pulse wave velocity, PWV) were conducted (supine body position). Blood lactate concentration (BLC) was measured before and immediately after the exercise bouts. RESULTS: Internal load analysis of MOD vs. VIG revealed significant differences and appropriate prescription of intensity domains for mean %HRPEAK (~66% vs 86%), %VO2PEAK (~48% vs. 66%), as well as for blood lactate concentration (~1 mmol/l vs. 5 mmol/l). The present data showed significant main effects of time, intensity, and their interaction for all RR-interval outcomes, PWV, and SBP. Higher exercise intensity resulted in greater perturbations during recovery, delayed reorganization, and decreased values of linear HRV metrics. DFAa1 demonstrated a stronger correlated reorganization and overcompensation after VIG, with higher values throughout the evaluated recovery process. CONCLUSION: The present data suggests that VIG transiently delays the recovery of cardiac parasympathetic activity and the normalization of correlation properties of HR time series. Regarding acute early and delayed recovery processes, higher correlation properties may reflect more order (less complexity) and interaction of involved physiological subsystems, supporting the assumption of increased systemic control to process the demands of higher exercise intensity. The assessment of standardized post-exercise (e.g., submaximal test procedures, benchmark workouts) linear and non-linear HRV metrics could serve as a valuable tool for fine-tuning monitoring processes in endurance athletes. By evaluating recovery states, acute fatigue, and overreaching phenomena it can complement resting physiology analysis. This could potentially help to guide structuring micro-cycle programming tailored to individual cardiac reactivation patterns.
Read CV Thomas GronwaldECSS Paris 2023: OP-AP40
INTRODUCTION: Incremental tests to determine maximal power output and maximal oxygen uptake (VO2max) are often conducted as a prior parameter to determine resistance parameters for subsequent submaximal, maximal and supramaximal exercise tests. Incremental tests rely heavily on aerobic metabolism while supramaximal tests rely heavily on anaerobic metabolism [1,2]. Since oxidative capacity is associated with a predominance of slow-twitch muscle fibers, this may suggest that anaerobic capacity in those with high oxidative capacity might be reduced compared to those with lower aerobic capacity. This study aimed to determine the association between incremental and supramaximal exercise capacity. METHODS: Seventy-one physically active males (age 26±5 y, body mass 77.9 ± 11.2 kg) performed an incremental cycling test to determine Powermax (Wmax) prior to a familiarization and main visit to perform a cycling capacity test at 110% of Wmax (CCT110%). All cycling was performed on a cycle ergometer (Lode Excalibur, The Netherlands). The incremental test started at a power output of 100 W and increased by 6 W until exhaustion. The last completed stage plus the fraction of time spent in the final non-completed stage multiplied by 6 W was defined as a participant’s Wmax. The CCT110% started with a 10-min warm-up at 100 W, followed by 15 s at 80% of individual Wmax, 15 s at 95% Wmax followed by 110% Wmax until exhaustion. Time to exhaustion (TTE) and total work done (TWD) were recorded as the outcome measures. Pearson correlations were performed to evaluate the correlations between Wmax (absolute [aWmax] and relative [rWmax] to body mass) and CCT110% performance (TTE and the TWD). The significance level was set at p < 0.05. RESULTS: There was a positive association between rWmax and TWD (r = 0.290: 0.06 < 95%CI < 0.49; p = 0.014), and between aWmax and TWD (r = 0.734: 0.60 < 95%CI < 0.82; p < 0.001) indicating that a higher Wmax is associated with a greater TWD. However, no significant correlation was found between rWmax and TTE (r = -0.076: -0.30 < 95%CI < 0.16; p = 0.529), and between aWmax and TTE (r = 0.220: -0.01< 95%CI < 0.43; p = 0.065). CONCLUSION: These data highlight a significant relationship between Wmax and TWD during the CCT110%. This is likely a reflection of the higher power output during the test. However, the absence of a correlation between Wmax and TTE suggests that an individual’s ability to sustain effort at 110% Wmax is not reflective of their incremental test performance and challenges the notion that a higher oxidative capacity is inherently linked to reduced anaerobic performance. Future studies should investigate additional metabolic and neuromuscular factors influencing performance at supramaximal intensities. REFERENCES: [1] Hawkins et al. (2007) Med Sci Sports Exerc. 39(3): 574. [2] Özçelik et al. (2002) Turk. J. Med. Sci. 32(1): 10. Funding: FAPESP – Grant No. [2023/16704-9]
Read CV Juliana MurasakiECSS Paris 2023: OP-AP40