European journal of sport science最新文献

With the development of power output sensors in the field of paddle sports and the ongoing advancements in dynamical analysis of exercise data, this study aims to model the measurements of external training intensity in relation to heart rate (HR) time-series during flat-water kayak sprint. Nine elite athletes performed a total of 47 interval training sessions with incremental intensity (light to (sub-) maximal effort levels). The data of HR, speed and power output were measured continuously and rating of perceived exertion and blood lactate concentration ([BLa]) were sampled at the end of each interval stage. Different autoregressive-exogenous (ARX) modelling configurations are tested, and we report on which combination of input (speed or power), model order (1st or 2nd), parameter estimation method (time-(in)variant) and training conditions (ergometer or on-water) is best suited for linking external to internal measures. Average model R² values varied between 0.60 and 0.97, with corresponding average root mean square error values of 15.6 and 3.2 bpm. 1st order models with time-varying (TV) parameter estimates yield the best model performance (average R² = 0.94). At the level of the individual athlete, the TV modelling features (i.e., the model parameters and derivatives such as time constant values) show significant repeated measure correlations in relation to measures of exercise intensity. In conclusion, the study provides a comprehensive description of how the dynamic relationship between external load and HR for sprint kayaking training data can be modelled. Such models can be used as a basis for improving training evaluation and optimisation.

This study investigated the effect of five consecutive days of cold-water immersion (CWI) on recovery from exercise-induced muscle damage (EIMD) in the hamstrings following maximal eccentric contraction (EC) exercise. Eighteen healthy adult women were randomly assigned to a CWI group and a control group (CG) (n = 9/group). Participants performed 10 sets of 10 repetitions of isokinetic EC at 30°/second and underwent maximum voluntary isometric contraction (MVC), delayed onset muscle soreness (DOMS) assessment, straight leg raise (SLR) test, and plasma myoglobin (Mb) measurement. The CWI group received one 14-min session of CWI treatment (14°C) at 1, 25, 49, 73, and 97 h after the EC test, whereas the CG rested in a seated position at the same five time points without receiving treatment. (1) All the dependent variables in the CWI group and CG exhibited significant changes after the EC test (p < 0.05). (2) The recovery effect in the CWI group was significantly greater than in the CG in terms of the MVC, DOMS, SLR, and plasma Mb concentration results. MVC increased by 89.3 ± 2.0% on the fourth day (p < 0.013), DOMS decreased by 15.4 ± 1.5 mm on the second day (p < 0.000), SLR increased by 86.3 ± 1.1% on the second day (p < 0.014), and plasma Mb decreased by 436.3 ± 60.8% on the third day (p < 0.014). The study indicates that five consecutive days of CWI at 14°C significantly enhance recovery from exercise-induced muscle damage in the hamstrings.

Sprinting on bends demands biomechanical adjustments compared with straight-line sprinting that results in asymmetrical force production in the lower extremities. This study aimed to assess acceleration impacts in the lower extremity and impact transmission when sprinting on bend versus straight lanes. Eight experienced sprinters (age 16.3 ± 1.7 years, mass 58.5 ± 11.4 kg, and height 1.72 ± 0.10 m), specializing in the 100, 200, and 400 m events, ran two bouts of 60 m lane heats at maximum speed on the straight lane and bend lanes one and eight (with radii of 37 and 45.10 m, respectively) of a standard 400 m track. Accelerometers on the tibias and head recorded acceleration impacts. Results revealed higher impact magnitudes in the outside leg during bend sprints compared with the inside leg (p < 0.05). Additionally, bend lanes exhibited higher impact magnitudes compared with the straight lane (p < 0.05). Asymmetrical acceleration impacts were observed during bend sprints, with greater asymmetry compared to straight sprints. However, the distribution of impact forces between the legs did not appear to be influenced by lane radius. This suggests that the specific biomechanical demands of bend sprinting differ significantly from those of straight sprinting. These findings emphasize the need for coaches to account for increased asymmetry and distinct impact patterns when training athletes for bend sprints compared to straight-line sprints.

This study aimed to examine sex differences in acute caffeine intake on repeated sprint performance. Fifty-two resistance-trained individuals (age: 24.6 ± 4.5 years and sex (female/male): 26/26) participated in a randomized, triple-blind, cross-over, and placebo-controlled study. Participants ingested 3 mg/kg caffeine or placebo and, after 60 min, performed 4 Wingate tests (Wt), consisting of a 30 s all-out lower-body sprint against an individualized resisted load, with 90 s rest periods between sprints. Mean (W_mean) and peak (W_peak) power showed an interaction between sprint and supplement (P = 0.038, η_p² = 0.095 and P < 0.001, η_p² = 0.157, respectively), but only W_peak reported a supplement and sex interaction (P = 0.049 and η_p² = 0.166). Caffeine increased W_mean in Wt3 (3.5%, P = 0.004, and g = 1.059) and Wt4 (3.9%, P = 0.012, and g = 1.091) compared to placebo. Whereas, for W_peak, caffeine increased W_peak in the Wt1 (2.9%, P = 0.050 and g = 1.01) and Wt2 (3.2%, P = 0.050, and g = 1.01) in males and in Wt3 (5.2%, P = 0.008, and g = 1.79) and Wt4 (8.1%, P = 0.004, and g = 2.27) in female participants compared to placebo. No statistically significant sex differences were found in time to reach W_peak, fatigue index. Acute caffeine intake stimulated a similar ergogenic effect on repeated sprint performance in men and women, except in peak power output, where caffeine increased performance during the first sprints in males and the last sprints in female participants.

High body mass index (BMI) and a previous running-related injury (RRI) have been highlighted as two risk factors for sustaining an RRI. However, a critical gap exists in the knowledge of whether runners with both elevated BMI and a previous RRI constitute a particularly vulnerable subgroup in terms of susceptibility to new RRIs. Therefore, the present study aimed to evaluate if those with high BMI and a concomitant history of running-related problems in the past 3 months were more prone to sustain a new RRI compared with runners with normal BMI and without previous running-related problems. This study was part of the “Garmin-RUNSAFE Running Health Study,” an 18-month cohort study. The runners completed a baseline questionnaire containing questions regarding demographic data and previous running-related problems and were asked to continuously track their running activities. The exposure were dichotomized into “no previous running-related problem” or “previous running-related problem,” and each group was further categorized into four subgroups depending on BMI. Time-to-event analysis was used to estimate the cumulative incidence risk difference (cIRD). The results highlight those with a BMI >30 kg/m² with a previous running-related problem to face the highest injury risk of 71%, whereas those with a BMI between 19 and 25 kg/m² without a previous running-related problem had the lowest injury risk of 43% corresponding to a cIRD of 28% [95% CI: 19%; 36%]. This result highlights those with high BMI and previous running-related problems as a high-risk subpopulation that would benefit from interventions of preventing running-related injuries.

Proprioception plays an important role in joint stability, and ankle sprains usually happen involving plantarflexion, internal rotation, and inversion. However, ankle 3D movement proprioception has never been measured in weight-bearing. Accordingly, the active 3-dimensional movement extent discrimination apparatus (AMEDA-3D) was developed and its reliability and validity were investigated. A total of 58 subjects volunteered for this trial, with 12 subjects with chronic ankle instability (CAI) and 12 healthy controls in the test–retest reliability study. There were 17 subjects with CAI and 17 healthy controls in the validity study. An intraclass correlation coefficient (ICC) and Minimum Detectable Change at the 90% confidence interval (MDC₉₀) were computed. AMEDA-3D scores were analysed by independent samples t-tests, and Youden's index was used to calculate the optimal AMEDA-3D cut-off for discriminating individuals with CAI. Pearson's correlation analysis was used to explore the relationship between AMEDA-3D scores and Y Balance Test (YBT), Time In Balance Test (TIB), and Cumberland Ankle Instability Tool (CAIT) scores. The main results were as follows: (1) The ICC_(3,1) value of AMEDA-3D scores was 0.817 (95% CI = 0.452–0.945) in CAI subjects. (2) The AMEDA-3D proprioceptive area under the curve score used to discriminate CAI subjects from healthy controls was 0.778, with a sensitivity of 94% and a specificity of 82%. (3) AMEDA-3D proprioceptive scores were moderately correlated with CAIT scores (r = 0.58 and p < 0.001), YBT (r = 0.47 and p = 0.005), and TIB (r = 0.68 and p < 0.001). Our findings suggest that the AMEDA-3D tool shows good reliability and validity for clinical assessment of proprioceptive deficits associated with CAI. Improved ankle 3D motor proprioception may positively impact subjects' balance control, self-rated symptoms, and function.

Active breaks are suggested to support recovery and performance in sports. Previous research in ball and team sports focused on motor performance such as repetitive sprinting or change of direction. This does not account for the interaction between motor and cognitive task demands in sports. Therefore, this study is the first to investigate the effectiveness of an active motor-cognitive break to support reactive agility performance. Twenty (7 female and 13 male) healthy trained young adults (mean age: 26 years) performed an active or passive 5 min break following a fatiguing protocol of six 100 m reactive agility runs with an intermittent break of 40 s. Prior to the experiment (pre), after fatigue (post), and following the rest condition (retention), a reactive agility test was performed using the SKILLCOURT technology. In addition, lactate, heartrate, and physical exertion were recorded. Active rest contained two motor-cognitive training tasks on the SKILLCOURT combining low to moderate physical intensity with conflict inhibition and decision-making. During passive rest, participants remained seated. When comparing post and retention agility tests, results indicate significantly stronger performance gains following the active when compared to the passive break condition (p = 0.02 and η_p² = 0.24). This was not associated with any differences in physiological parameters such as lactate, heart rate, or RPE (p ≥ 0.25). The results suggest that active motor-cognitive breaks support recovery and improve sport-related reactive agility performance. Performance gains in the active break are likely attributable to cognitive performance effects rather than physiological recovery, which may benefit athletes especially in ball and team sports.

The need for sex-segregated youth swimming is debated. A previous report indicates that male swimmers aged 10-and-under are 1%–2% faster than females in long course freestyle, butterfly, backstroke, and individual medley (IM), but not breaststroke events. Another report indicates that at age 10 males are 1%–2.5% faster than females in long course freestyle events. However, there are no evaluations for short course competitions. Therefore, the top eight performances for both sexes from the National Club Swimming Association Age Group Championships (a short course meet) for the years 2016–2023 in the 10-and-under age group were analyzed. Males were 1.16%–2.63% faster (p < 0.05; effect sizes 0.376–0.596) than females in the 50 yards (yd; 45.7 m), 100 yd (91.4 m), and 200 yd (182.9 m) freestyle, 100 yd backstroke, 50 yd breaststroke, 100 yd butterfly, and 100 and 200 yd IM. There were no significant sex-based differences in the 500 yd (457.2 m) freestyle, 50 yd backstroke, 100 yd breaststroke, or 50 yd butterfly. The individual fastest time for a female was faster than for a male in the 50, 100, and 500 yd freestyle, 50 and 100 yd backstroke, 50 and 100 yd butterfly, and 100 yd IM. Although in eight out of 12 events the individual fastest times were from females, in eight out of 12 events the average male times were significantly faster. The present data suggest that although some exceptional individual 10-and-under female swimmers do exist, their performance is not representative of the typical sex-based differences in swimming performance.

The purpose of this study was to evaluate the effects of a microcycle of high-intensity interval training (HIT) sessions with multiple short work intervals followed by an active recovery period, compared to a similar duration of regular training, on determinants and indicators of endurance performance in well-trained cyclists. The participants in the BLOCK group performed a 6-day HIT microcycle including five HIT sessions (5 × 8.75-min 30/15 s short intervals) followed by a 6-day active recovery period with reduced training load, while the regular training group (REG) performed 12 days of their regular training, including four HIT sessions. Physiological testing was performed before and after the training periods. From pre- to post- intervention, BLOCK demonstrated significantly larger improvements than REG in mean power output (PO) during the last min of the maximal oxygen uptake (VO_2max) test (PO_VO2max) (3.7 vs. 0.7%, p = 0.009, and effect size (ES) = 1.00) and mean PO during the 10-s sprint (2.8 vs. 1.9%, p = 0.028, and ES = 0.63). No significant differences between BLOCK and REG were observed for VO_2max, PO at 4 mmol·L⁻¹ [blood lactate] (PO_4mmol), 15-min maximal mean power output (PO_15-min), and gross efficiency (p = 0.156–0.919). However, there was a tendency for larger improvements in the performance index (calculated from the main performance indicators PO_VO2max, PO_4mmol, and PO_15-min) in BLOCK compared to REG (2.9% vs. 1.2%, p = 0.079, and ES = 0.71). A 6-day high-intensity short-interval microcycle followed by a 6-day active recovery period induces improvements in endurance performance indicators compared to regular training, demonstrating its potential as an efficient strategy for endurance training in well-trained cyclists.

It is unclear whether physiological responses, such as muscle oxygen saturation (SmO₂), can be considered symmetrical during cycling. This knowledge has important practical implications for both training and performance assessment. The aim of this study was to determine whether oxygenation profiles in the three active muscles of both legs were symmetrical during cycling at different intensities. Twenty-six trained cyclists and triathletes completed a graded exercise test (GXT) and an 8-min functional threshold power estimation test (8MTT) on a cycle ergometer over two nonconsecutive days. SmO₂ was bilaterally assessed using NIRS technology in the vastus lateralis, gastrocnemius medialis, and tibialis anterior. Symmetry was compared between legs in both tests, and reliability and agreement between the measurements were quantified. The main results were that SmO₂ in the three muscles assessed did not differ between legs during the GXT and 8MTT (p > 0.05). Reliability of the measures was poor to good in the vastus lateralis (ICC = 0.83–0.37), moderate to excellent in the tibialis anterior (ICC = 0.92–0.73), and poor to good for the gastrocnemius medialis (ICC = 0.80–0.24). Overall, the group variability in SmO₂ showed a narrower distribution at lower intensities, with data dispersion increasing at higher intensities. In conclusion, the SmO₂ was similar and showed symmetrical responses in both the preferred and nonpreferred limb in different muscles assessed during cycling at different intensities within a range of 10%–20%. Although individual physiological differences that might be relevant in some clinical/performance settings should not be disregarded, these findings indicate that measuring a single lower limb provides an accurate approximation of the responses in both lower limbs.