Journal: International Journal of Sports Physiology and Performance

Abbreviation

Publisher

Human Kinetics

Journal Volumes

ISSN

1555-0265

Description

Filters

2021 - 20255
Reset filters

Search Results

Publications 1 - 5 of 5
  • Conventional Testing Produces Submaximal Values for Oxygen Uptake in Elite Runners
    Item type: Journal Article
    Beltrami, Fernando G.; Noakes, Timothy D. (2021)
    International Journal of Sports Physiology and Performance
    Purpose: This study aimecd to investigate whether elite athletes could reach higher values of maximal oxygen uptake (˙VO2max) during a decremental exercise test in comparison with a traditional incremental test, as recently demonstrated in trained individuals. Methods: Nine male runners (age 25.8 [5.1] y, season best 10-km time 31:19 [1:50]) performed, on different days, 3 maximal uphill (5% grade) running exercise tests in fixed order: an incremental test (INC1), a V-shape exercise test (where speed started at 0.5 km·h−1 higher than the top stage finished during INC1 and was slowly decreased during 5.5 min, when it was again increased in similar fashion to the INC tests), and a final incremental test (INC2). Results: ˙VO2max during the V-shape exercise test was higher than during INC1 (6.3% [3.0%], P = .01), although running speed was lower (16.6 [1.7] vs 17.9 [1.6] km·h−1, P = .01). Performance was similar between INC1 and INC2, but ˙VO2max during INC2 was higher than INC1 (P < .001). During the V-shape exercise test, 5 participants reached the incremental part of the test, but ˙VO2 did not increase (Δ˙VO2=52[259]mL⋅min−1, P = .67), despite higher running speed (approximately 1.1 km·h−1, P < .01). Heart rate, pulmonary ventilation, breathing rate, and respiratory exchange ratio measured at ˙VO2max were not different between tests. Conclusion: A decremental exercise test of sufficient intensity can produce higher ˙VO2max than a traditional incremental test, even in elite athletes, and this is maintained during a subsequent incremental test.
  • Physiological Profiles of Male and Female CrossFit Athletes
    Item type: Journal Article
    D'Hulst, Gommaar; Hodžić, Deni; Leuenberger, Rahel; et al. (2024)
    International Journal of Sports Physiology and Performance
    Objective: To (1) establish extensive physiological profiles of highly trained CrossFit® athletes using gold-standard tests and (2) investigate which physiological markers best correlate with CrossFit Open performance. Methods: This study encompassed 60 participants (30 men and 30 women), all within the top 5% of the CrossFit Open, including 7 CrossFit semifinalists and 3 CrossFit Games finalists. Isokinetic dynamometers were employed to measure maximum isometric and isokinetic leg and trunk strength. Countermovement-jump height and maximum isometric midthigh-pull strength were assessed on a force plate. Peak oxygen uptake (VO₂peak) was measured by a cardiopulmonary exercise test, and critical power and W′ were evaluated during a 3-minute all-out test, both on a cycle ergometer. Results: Male and female athletes’ median (interquartile range) VO₂peak was 4.64 (4.43, 4.80) and 3.21 (3.10, 3.29) L·min⁻¹, critical power 314.5 (285.9, 343.6) and 221.3 (200.9, 238.9) W, and midthigh pull 3158 (2690, 3462) and 2035 (1728, 2347) N. Linear-regression analysis showed strong evidence for associations between different anthropometric variables and CrossFit Open performance in men and women, whereas for markers of cardiorespiratory fitness such as VO₂peak, this was only true for women but not men. Conventional laboratory evaluations of strength, however, manifested minimal evidence for associations with CrossFit Open performance across both sexes. Conclusions: This study provides the first detailed insights into the physiology of high-performing CrossFit athletes and informs training optimization. Furthermore, the results emphasize the advantage of athletes with shorter limbs and suggest potential modifications to CrossFit Open workout designs to level the playing field for athletes across different anthropometric characteristics.
  • Determination of Ventilatory Thresholds Using Near-Infrared Spectroscopy in Recreational Endurance and CrossFit Athletes
    Item type: Journal Article
    Arnet, Janik; Knaier, Raphael; Schoch, Raphael; et al. (2025)
    International Journal of Sports Physiology and Performance
    To define training zones, ventilatory thresholds (VTs) are commonly established by cardiopulmonary gas-exchange analysis during incremental exercise tests. Portable near-infrared spectroscopy (NIRS) devices have emerged as a potential tool for detecting these thresholds by monitoring muscle oxygenation. This study evaluated the accuracy of NIRS measurements to determine VTs or critical power (CP) based on muscle oxygen saturation and assesses the device's consistency across 2 constant-load tests. Data from 2 crosssectional studies involving trained recreational endurance athletes (26 from study 1) and CrossFit athletes (59 from study 2) were examined. Incremental ramp tests on a cycle ergometer were performed and followed by either a constant-load test (study 1) or a CP test (study 2). When comparing power output or heart rate between NIRS-derived breakpoints and VTs, weak to moderate agreement was found. Mean differences in power output and heart rate ranged from 16.8 to 22.4 W and 3.8 to 6.0 beats-min-1 at the first threshold and 27.4 to 31.2 W and 7.1 to 7.8 beats-min-1 at the second threshold. Comparing with CP, mean differences ranged from -0.4 to 0.4 W and -0.6 to 0.9 beats-min-1. Test-retest reliability showed moderate agreement, with a mean bias of 1.2 percentage points between constant-load tests. Thus, NIRS may not be accurate for determining VTs or CP during exercise due to limited agreement in power output or hear rate, notable variability on individual level, and moderate reproducibility.
  • Comparison of Physiological Responses and Muscle Activity During Incremental and Decremental Cycling Exercise
    Item type: Journal Article
    Beltrami, Fernando G.; Froyd, Christian; Mauger, Alexis R.; et al. (2022)
    International Journal of Sports Physiology and Performance
    Objective: To investigate whether a cycling test based on decremental loads (DEC) could elicit higher maximal oxygen uptake (˙VO2max) values compared with an incremental test (INC). Design: Nineteen well-trained individuals performed an INC and a DEC test on a single day, in randomized order. Methods: During INC, the load was increased by 20 W·min−1 until task failure. During DEC, the load started at 20 W higher than the peak load achieved during INC (familiarization trial) and was progressively decreased. Gas exchange and electromyography (EMG) activity (n = 11) from 4 lower-limb muscles were monitored throughout the tests. Physiological and EMG data measured at ˙VO2max were compared between the 2 protocols using paired t tests. Results: ˙VO2max during the DEC was 3.0% (5.9%) higher than during INC (range 94%–116%; P = .01), in spite of a lower power output (−21 [20] W, P < .001) at ˙VO2max. Pulmonary ventilation (P = .036) and breathing rate (P = .023) were also higher during DEC. EMG activity measured at ˙VO2max was not different between tests, despite the lower output during DEC. Conclusions: A DEC exercise test produces higher ˙VO2max in cycling compared with an INC test, which was accompanied by higher pulmonary ventilation and similar EMG activity. The additional O2 uptake during DEC might be related to extra work performed either by the respiratory muscles and/or the less oxidatively efficient leg muscles.
  • Cardiorespiratory Responses to Constant and Varied-Load Interval Training Sessions
    Item type: Journal Article
    Beltrami, Fernando G.; Roos, Elena; von Ow, Marco; et al. (2021)
    International Journal of Sports Physiology and Performance
    Purpose: To compare the cardiorespiratory responses of a traditional session of high-intensity interval training session with that of a session of similar duration and average load, but with decreasing workload within each bout in cyclists and runners. Methods: A total of 15 cyclists (maximal oxygen uptake [(V)over dotO(2)max] 62 [6] mL.kg(-1).min(-1)) and 15 runners ((V)over dotO(2)max 58 [4] mL.kg(-1).min(-1)) performed both sessions at the maximal common tolerable load on different days. The sessions consisted of four 4-minute intervals interspersed with 3 minutes of active recovery. Power output was held constant for each bout within the traditional day, whereas power started 40 W (2 km.h(-1)) higher and finished 40 W (2 km.h(-1)) lower than average within each bout of the decremental session. Results: Average oxygen uptake during the high-intensity intervals was higher in the decremental session in cycling (89 [4]% vs 86 [5]% of (V)over dotO(2)max, P= .002) but not in running (91 [4]% vs 90 [4]% of (V)over dotO(2)max, P = .38), as was the time spent >90% of (V)over dotO(2)max and the time spent >90% of peak heart rate. Average heart rate (P < .001), pulmonary ventilation (P < .001), and blood lactate concentration (P < .001) were higher during the decremental sessions in both cycling and running. Conclusions: Higher levels of physiological perturbations were achieved during decremental sessions in both cycling and running. These differences were, however, more prominent in cycling, thus making cycling a more attractive modality for testing the effects of a training intervention.
Publications 1 - 5 of 5