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Scientific Programme

Applied Sports Sciences

OP-AP33 - Training and Testing / HIIT

Date: 07.07.2026, Time: 13:30 - 14:45, Session Room: 4BC (STCC)

Description

Chair TBA

Chair

TBA
TBA
TBA

ECSS Paris 2023: OP-AP33

Speaker A Bert MI Celie

Speaker A

Bert MI Celie
Université Libre de Bruxelles, Faculté des Sciences de la Motricité
Belgium
"Impact of a 12-Week Self-Paced High-Intensity Interval Training Program on Cardiorespiratory Parameters"

INTRODUCTION: Different training modalities are traditionally used in endurance sports to maximize performance, including moderate-intensity continuous training (MICT) and interval-based methods such as high-intensity interval training (HIIT) or Sprint Interval Training (SIT). Few recent studies have shown that Self-Paced interval training could be of added value to the sports specific literature and practice. The aim of this study was to evaluate the effects of a 12-week self-paced high-intensity interval running program on VO₂max, lactate thresholds, and ventilatory thresholds. Additionally, the study examined the influence of training adherence and mean session intensity on physiological adaptations. METHODS: Twenty moderately active adults (10 men, 10 women) participated in this study. Pre- and post-intervention assessments included DXA body composition analysis and a graded treadmill exercise test measuring VO2peak and lactate tresholds. The 12-week training program consisted of three weekly running sessions: two self-paced high-intensity interval sessions and one low-intensity endurance session. Exercise intensity was self-regulated but retrospectively monitored using heart rate and ratings of perceived exertion. Statistical analyses were performed using paired t-tests, and Pearson correlation testing, or Wilcoxon and Searman correlation tests depending whether normality was guaranteed. RESULTS: VO₂peak values (p < 0.001) and the anaerobic threshold (p = 0.04) significantly increased after 12 weeks of self-paced training while the aerobic treshold did not evolve significantly. Anthropometric indices such as fat mass significantly decreased (−4.7%, p = 0.021), while lean body mass percentage slightly increased (+0.96%, p = 0.03). No significant correlations were found between changes in peak VO₂ and mean training intensity (p = 0.416) or adherence (p = 0.776). CONCLUSION: A 12-week self-paced high-intensity interval training program can induce significant improvements in cardiorespiratory fitness and body composition, even without strict intensity prescription. The absence of correlations between physiological adaptations and mean intensity or adherence suggests a complex and individualized training response, in which perceived exertion and other factors may play a key role. This training modality may represent a practical and effective alternative in autonomous training or reconditioning contexts.

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ECSS Paris 2023: OP-AP33

Speaker B Jack Bone

Speaker B

Jack Bone
McMaster University, Department of Kinesiology
Canada
"The Effect of Habitual Activity and Training Status on Exercise Tolerance During Acute High Intensity Interval Training Prescribed Using Critical Power Model-Derived Estimates of Workload"

INTRODUCTION: High intensity interval training (HIIT) intensity prescription is commonly expressed relative to maximal heart rate or oxygen uptake (1). An alternate approach involves anchoring intensity to the metabolic threshold critical power (CP; 1). CP denotes a ‘fatigue threshold’ that distinguishes the intensity at which physiological responses to exercise can (CP) be stabilized (2). Work prime (W’) denotes the finite, exhaustible amount of work that can be performed above CP. Characterizing intensity relative to CP and W’ depletion may reduce variability in exercise tolerance between individuals (3) but this could be influenced by habitual activity and training status. We investigated this issue using a HIIT protocol in which intensity was prescribed based on CP and two different depletion rates of W′. We hypothesized that habitually active individuals who train regularly would have higher exercise tolerance compared to those who are insufficiently active. METHODS: Healthy adults were recruited into one of two groups based on a participant classification framework (4): Less Trained [LT, n=18 (13 males, 5 females)] did not meet the typical weekly guideline for aerobic physical activity; More Trained [MT, n=17 [12 males, 5 females)] met the guideline and trained regularly for competition. LT and MT differed in peak oxygen uptake (V̇O2peak; (37.0 ml·kg-1·min-1 [95% CI = 33.7 – 40.3] vs 61.0 ml·kg-1·min-1 [95% CI = 57.7 – 64.3] and CP (124 W [95% CI = 108 – 139] vs 232 W [95% CI = 216 – 249]), respectively (both p<0.001), but not W’ (16.1 kJ [95% CI = 14.2 – 17.9] vs; 17.7 [95% CI = 15.8 – 19.6] p=0.18). Participants performed two trials in a randomized, crossover, single-blind manner. Each involved a 5-min warmup followed by 4x4-min bouts, with bouts set at a standardized workload designed to deplete 10% (HIIT10) or 50% (HIIT50) of total W’, with 3-min recovery between. Exercise tolerance was estimated by assessing the proportion of the 4x4-min work bouts completed in each trial and expressed as %W’ depleted (W’D%W’) and in kJ (W’DkJ). Data were analyzed with linear mixed models (LMM) with Group*Condition*Bout interactions and a random intercept for participant. RESULTS: LMM analyses revealed that MT had greater W’D%W’ (42.8 %W’ [95% CI = 39.0 – 46.5] vs 32.7 %W’ [95% CI = 29.1 – 36.3]; p=0.043) and W’DkJ (8.1 kJ [95% CI = 7.1 – 9.1 kJ] vs 4.2 kJ [95% CI = 3.2 – 5.1 kJ]; p=0.012) during bout four in HIIT50 compared to LT. Neither W’D%W’ nor W’DkJ were different across groups in HIIT10 (p>0.05 for both). CONCLUSION: Habitual activity and training status affected exercise tolerance during acute HIIT prescribed at CP+50% W’ but not CP+10% W’. Classifying intensity based on CP+%W’ may enhance the precision of HIIT prescription but exercise tolerance is impacted by participant classification and W’ depletion rate. Reference PMID: (1) 37804419; (2) 27031742; (3) 36710454; (4) 34965513 Supported by NSERC, Canada.

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ECSS Paris 2023: OP-AP33

Speaker C APOSTOLOS PAPANDREOU

Speaker C

APOSTOLOS PAPANDREOU
NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS, EXERCISE
Greece
"PHYSIOLOGICAL AND MOLECULAR RESPONSES TO DIFFERENT INTENSITIES OF INTERVAL AND CONTINUOUS TRAINING IN NATIONAL-LEVEL KAYAK ATHLETES"

INTRODUCTION: Performance in the 500-m kayak event relies on the integration of aerobic and anaerobic metabolism, functional power production, paddling economy, and the ability to sustain high intensities close to the second ventilatory threshold (VT₂). High-intensity interval training (HIIT) and sprint interval training (SIT) are widely used time-efficient strategies; however, the interaction between functional performance indices and molecular adaptations to different intensity domains remains insufficient regarding elite paddlers. METHODS: Thirty-two national-level kayak athletes were allocated to four groups: HIIT (110% VO₂peak), SIT (≈140% VO₂peak/VO₂max), COMB (HIIT+SIT +continuous training), and control (CON). Athletes completed 18 training sessions over six weeks. Measurements included VO₂max, blood lactate concentration ([La²⁺]), HRmax, power output at VO₂max (POVO₂max), paddling economy (POPE), power output at VT₂ (POVT₂), and 500-m time-trial performance, assessed at PRE, POST, and after 15 and 30 days of detraining. Resting concentrations of IL-6 and VEGF-A were measured at PRE and POST. Data were analyzed using two-way repeated-measures ANOVA and Pearson correlation analysis (ΔPOST–PRE). RESULTS: VO₂max exhibited only modest, non-significant time effects, primarily in the HIIT group. In contrast, functional determinants of performance (POVO₂max, POPE, and POVT₂) improved significantly in HIIT, SIT, and COMB, accompanied by meaningful improvements in 500-m performance, with partial attenuation during detraining. Resting IL-6 decreased significantly following HIIT and SIT, while VEGF-A increased significantly only after HIIT. Correlation analysis identified VT₂ as a central determinant of performance, with changes in POVT₂ strongly associated with changes in 500-m time. CONCLUSION: HIIT, SIT, and combined training induce substantial improvements in functional performance determinants and 500-m kayaking performance, despite minimal changes in VO₂max. VT₂ emerges as a functional “hub” integrating central and peripheral adaptations, including power production, economy, and molecular responses (IL-6, VEGF-A), appears to be a more sensitive indicator of competitive performance than VO₂max in national-level kayak athletes.

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ECSS Paris 2023: OP-AP33