PURPOSE:This study quantified running pace and relative exercise intensity during a HYROX PRO MEN event by integrating laboratory-derived aerobic markers with competition data. METHODS:Twenty-four male HYROX PRO MEN athletes (race time: 69:58 [5:05] min:s) completed a maximal incremental treadmill test to determine second ventilatory threshold (VT2), maximal aerobic speed (vVO2max), and maximal oxygen uptake (VO2max). Within 10 days, participants competed in the official HYROX Madrid 2025 event. Running speed was calculated for each of the eight 1-km segments and the Roxzone, as well as for the total running component, defined as the combined distance of run 1 to 8 and the Roxzone (8.70 km), and expressed in absolute terms (kilometers per hour) and relative to VT2 and vVO2max. RESULTS:During laboratory testing, athletes reached a VO2max of 51.56 (5.00) mL·kg-1·min-1 (95% CI, 49.56 to 53.56), with VT2 and vVO2max occurring at 16.41 (0.87) km·h-1 (95% CI, 16.06 to 16.76), and 18.08 (0.81) km·h-1 (95% CI, 17.76 to 18.40), respectively. Competition running speed declined from 16.13 (0.97) km·h-1 (95% CI, 15.74 to 16.52) in run 1 to 13.58 (1.02) km·h-1 (95% CI, 13.17 to 13.99) in run 8, with the lowest speed in the Roxzone (10.52 [1.18] km·h-1; 95% CI, 10.05 to 10.99). Mean intensity, calculated across the 8 running segments and the Roxzone, corresponded to 84.13% (5.54%) of VT2 (95% CI, 82.66 to 87.10) and 76.33% (4.05%) of vVO2max (95% CI, 75.31 to 78.55). CONCLUSIONS:Running in HYROX PRO MEN is performed at submaximal intensities relative to VT2 and vVO2max and declines progressively across segments. Sustaining a higher relative intensity appears central to shorter total running time.
PURPOSE:To evaluate the efficacy of postmatch compensatory training (CT) in mitigating disparities in external speed load between nonstarters (with varying match exposure) and starters (>60 min match play without CT). METHODS:Forty-three professional soccer players (25 [4] y) were monitored across 68 matches using global positioning system. Players were classified as starters (G1, >60 min), nonstarters (G2, 0 min), and nonstarters (G3, 1-30 min). External load metrics included total distance, high-speed running (HSR), and sprint distance, analyzed as both absolute values and relative values (% of total distance covered, and per minutes played). CT consisted of high-intensity interval exercise (∼925 m). Generalized estimating equations with least significant difference post hoc tests were applied (P < .05). RESULTS:Significant group × intervention interactions were observed for HSR and sprint distance (P ≤ .002). Without CT, G1 showed higher HSR (585 vs 33-143 m) and sprint distance (115 vs 2-34 m) than G2 and G3 (P < .05). Following CT, both G2 and G3 markedly increased HSR (G2: 33→261 m; G3: 143→318 m; P ≤ .001), reducing differences versus G1. Sprint distance increased in G2 (2→75 m; P < .001), although G1 remained higher than G2 and G3 (P ≤ .05). Relative metrics confirmed these findings, with no between-group differences after CT. Total distance remained higher in G1 across conditions (P < .001). CONCLUSIONS:Postmatch CT effectively attenuates external speed-load disparities between nonstarters and starters in professional soccer players.
PURPOSE:The increasing professionalization of women's football has heightened the importance of appropriate load management. However, little is known about current athlete monitoring practices and stakeholder perceptions in women's football. Therefore, this study aimed to examine monitoring practices and perceptions among (1) players and (2) coaching and performance staff to identify key facilitators and barriers to effective load management. METHODS:All clubs from the Norwegian women's Premier League were invited to complete a role-specific online survey on data collection, data analysis, implementation, and evaluation of current monitoring practice. Eight clubs participated, eliciting data from 6 head coaches, 8 practitioners, and 113 players. RESULTS:Five clubs (62.5%) reported systematic monitoring; all 5 included subjective measures, and 4 collected external loads, while 1 club measured counter movement jump test. Perceived individualization of training load (7-point Likert scale) yielded median scores of 5 and 6 for monitoring players and staff, respectively, compared with 4 and 2 for nonmonitoring players and staff. The most frequently reported challenges were "players not responding" for data collection, "time constraints" for data analysis, and "lack of equipment" and "tactical considerations" for decision on load adjustment. CONCLUSION:In this cohort, athlete monitoring was widely accepted but implemented heterogeneously and constrained by available resources. The findings generate the hypothesis that monitoring may increase perceived individualization of training, with good communication and visible use of data as potential facilitators. Future research should test this hypothesis in confirmatory studies and clarify the practical value of objective readiness measures for training-load decisions.
PURPOSE:To identify the evolution of tipping points in pacing strategies between medalists (MED) and nonmedalists (NON-MED) in 10-km events of the Olympic Games (OG) and World Aquatics Championships (WC). Additionally, we characterized the temporal trends of dual participation (pool and open-water) to provide a necessary contextual framework for these competitive shifts. METHODS:Involving data from 1066 individual performances, 1-dimensional statistical parametric mapping was applied to identify relevant tipping points in swimming velocity (v) between MED and NON-MED. Dual participation rates from 4 OG (2012-2024) and 7 WC (2013-2025) editions were evaluated using quadratic regression models. RESULTS:Males MED progressively maintained higher v throughout races at the OG (2024: 1.47 m·s-1 for MED vs 1.41 m·s-1 for NON-MED) and WC (2025: 1.48 m·s-1 for MED vs 1.43 m·s-1 for NON-MED), reflecting an evolution toward sustained pacing. In women, pacing differences at the OG remained fragmented (2024: 1.31 vs 1.25 m·s-1), whereas WC data showed increasingly earlier and stronger dominance, culminating in full-race separation in 2025 (1.38 vs 1.33 m·s-1). Dual participation peaked at the 2024 OG for men (32.0%) and women (16.7%), but exhibited fluctuations and a recent decline at the WC (eg, 2025: men 5.2%, women 7.5%). CONCLUSION:Pacing strategies in elite marathon swimming have evolved, with v tipping points between MED and NON-MED shifting toward an earlier and more aggressive separation. Contextually, despite fluctuating dual-participation trends, developing physiological and tactical capacities to sustain elevated v from early stages is increasingly essential for consistent performance.
PURPOSE:Identifying physiological factors that underly elite performance in endurance sports drives the work of many practitioners and researchers. Current models outline the maximal oxygen uptake (V˙O2max), fractional utilization of V˙O2max (%V˙O2max) at lactate threshold (LT) or competition intensity, and gross mechanical efficiency or economy as key determinants of endurance performance. While the importance of V˙O2max and efficiency/economy has been confirmed repeatedly, less conclusive evidence has been presented on %V˙O2max. In this review, we provide a narrative overview of the current literature on %V˙O2max as one of the performance-determining variables in endurance sports, and whether it can be improved through training. RESULTS:Out of the 35 studies assessing the relationship between %V˙O2max and performance, only a few studies confirm a substantial relationship between %V˙O2max and performance. This holds for %V˙O2max at a specific physiological "landmark," such as LT and %V˙O2max at a competition-specific intensity. Additionally, there is limited evidence suggesting that %V˙O2max can be systematically altered through training in trained athletes. Methodological differences in the assessment of V˙O2max, LT, and endurance performance across the included studies, as well as variation in the training interventions, confound the interpretation of the findings. CONCLUSION:According to the current literature, %V˙O2max at LT or competition intensity does not seem to be a strong predictor of endurance performance. Practical recommendations on how to improve %V˙O2max via training can currently not be given. We encourage researchers to collect and publish data on %V˙O2max for a more comprehensive conclusion about its role for endurance performance.
PURPOSE:We tested the effectiveness of hand and forearm per-cooling on self-paced cycling performance in the heat. We hypothesized that continuous, localized cooling would attenuate thermal strain and improve thermal perception, thereby enhancing performance. METHODS:Ten trained cyclists (7 males and 3 females; 34 [12] y, 174.4 [8.2] cm, 75.5 [10.6] kg, 55.3 [10.7] mL·kg-1·min-1) completed 3 randomized 20-km cycling time trials in the heat (35 °C, 50% relative humidity) while immersing their forearms and hands in a circulating water bath at 10 °C, 20 °C, or 32 °C (control) throughout. RESULTS:Whole-body thermal comfort was significantly reduced in the 10 °C and 20 °C trials compared with the 32 °C trial (both P ≤ .005). However, time to completion did not improve with either 10 °C (36.6 [2.1] min) or 20 °C (36.8 [2.2] min) compared with control (37.0 [1.9] min, P = .476), nor did power output (10 °C: 202 [39] W, 20 °C: 201 [42] W, 32 °C: 202 [37] W; P = .988) or pacing strategy. Physiological strain was also not different across conditions for both mean heart rate (P = .535) and rectal temperature change (10 °C: +1.3 [0.7] °C, 20 °C: +1.3 [0.5] °C, 32 °C: +1.5 [0.4] °C; P = .153). CONCLUSION:Despite perceptual benefits, passive water immersion of the extremities did not improve time-trial performance and appears insufficient to lower the physiological strain experienced during a self-paced 20-km time trial in the heat.
PURPOSE:Although caffeine-induced increases in fat oxidation are well established under laboratory conditions, evidence during field-based exercise is limited. Therefore, this study aimed to examine the acute effects of 3 mg·kg-1 of caffeine on fat oxidation during a 1-hour field-based outdoor run performed at the individual intensity eliciting maximal fat oxidation (Fatmax). METHODS:Fourteen healthy, endurance-trained runners (11 men, 3 women; V˙O2max = 58.6 [6.3] mL·kg-1·min-1) participated in a randomized, double-blind, placebo-controlled, crossover experiment. Participants completed 1 preexperimental trial to determine V˙O2max and Fatmax, followed by 2 experimental trials. During the experimental trials, participants ingested either caffeine (3 mg·kg-1) or a placebo 60 minutes before a 1-hour run at their individual Fatmax intensity covered on a 1.97-km outdoor running course. Substrate oxidation rates and energy expenditure were measured via indirect calorimetry using a portable gas analyzer and calculated through stoichiometric equations while heart rate was continuously monitored and ratings of perceived exertion were recorded using the Borg scale. RESULTS:Caffeine significantly increased total fat oxidation during the 1-hour run (33.62 [9.23] vs 40.46 [11.32] g; P = .018; d = 0.76) and decreased carbohydrate oxidation (93.16 [37.84] vs 77.32 [30.35] g; P = .036; d = 0.66) compared with placebo, with no effect on total energy expenditure (P = .936). Caffeine also reduced the rating of perceived exertion (9 [2] vs 8 [2]; P = .024; d = 0.75) with no effect on heart rate (P = .140). CONCLUSION:Acute ingestion of 3 mg·kg-1 of caffeine enhances fat oxidation during 1 hour of running at Fatmax under field-based conditions, suggesting that caffeine may be an effective nutritional strategy to optimize fat utilization during real-world submaximal endurance exercise.
OBJECTIVE:This study aimed to investigate the sex difference in uphill performance of Master runners. We tested the hypothesis that aging would reduce this difference, with the aging-induced performance decline being smaller in females than in males. We also analyzed changes in female participation over the past 20 years, with the hypothesis that increasing participation would be associated with a narrowing of sex differences during this period. METHODS:Data were extracted from the uphill races of the World Masters Mountain Running Championships between 2004 and 2024 and consisted of n = 116 top-3 performances in male and female Master runners (aged 35-69), across 5-year age categories. RESULTS:The sex differences in uphill performance of Master runners were 22.2% (4.9%) and remained similar across ages. Over the 20-year period, sex differences remained constant. There was a linear relationship between the number of female participants and the sex-based performance differences (r = -.31, P < .05). DISCUSSION:The 22% sex difference reported in Master mountain runners is comparable to that reported in elite athletes. Contrary to our hypotheses, sex differences in uphill running performance did not change across age categories and remained stable over the past 20 years. However, sex differences appeared to narrow as female participation increased, possibly due to the small female sample (approximately 20 on average), where individual performances may have had a greater proportional impact.
PURPOSE:Current literature characterizes cross-country Olympic mountain bike pacing as a "positive strategy" (fast start followed by decline or stabilization). However, this interpretation may be confounded when a start loop (SL), a structurally distinct initial lap included to facilitate positioning, is analyzed with subsequent laps. This study aimed to (1) quantify the influence of the SL on interlap pacing variability and (2) characterize pacing across performance quartiles. METHODS:Lap-by-lap timing data were analyzed for 934 elite finishers (543 men, 391 women) across 10 major 2024 events (World Cups, World Championships, and Olympic Games). Seven events included an SL, while 3 did not. Lap speeds were normalized to each athlete's mean race speed and analyzed using generalized estimating equations to assess lap effects and lap × performance quartile (first vs fourth) interactions. Interlap variability was quantified using coefficient of variation (CV). RESULTS:When only structurally comparable laps were considered, interlap variability was consistently low. Races without an SL showed low variability (median CV < 1.0%), and similar values were observed when the SL was excluded (median CV 1.1% in men and 1.2% in women). Including the SL increased variability approximately 7-fold (median CV 8.5% men and 10.9% women; P < .05). Lap × performance quartile interactions were event-dependent and small. Lower-performing finishers tended to start relatively faster and finish relatively slower than top performers. CONCLUSIONS:Excluding the SL reveals relatively stable interlap pacing in elite cross-country Olympic mountain biking with limited between-lap variations, whereas its inclusion substantially inflates variability and accentuates apparent fast-start behavior.
PURPOSE:This study aimed to examine the effect of Nike ZoomX Vaporfly Next% 2 (VF) on running economy (RE) in trained to highly trained long-distance runners during a prolonged treadmill run (20 km), and whether VF could maintain the RE benefits over time compared with a conventional training shoe (TS). METHODS:Fourteen trained to highly trained runners participated in 2 test sessions, completing a 20-km treadmill run in VF on one day and TS on another. Oxygen uptake, respiratory exchange ratio, and heart rate were measured throughout the run, and RE was calculated from the final 2 minutes of each stage (0, 5, 10, 15, and 20 km). Shoe order was randomized. RESULTS:Ten participants completed both test days. RE was consistently lower in VF compared with TS throughout the running protocol, accompanied by lower oxygen consumption. No significant shoe × distance interaction was observed, indicating that the difference between shoe conditions remained stable over the 20-km run. Both shoes showed a nonsignificant tendency toward deteriorating RE over time. CONCLUSIONS:VF demonstrated lower metabolic cost and superior RE compared with TS during prolonged treadmill running. However, the progression of RE over time did not differ between shoe conditions, suggesting that VF provided a stable metabolic advantage rather than reducing the rate of RE deterioration.
PURPOSE:To investigate how world-class cross-country skiers integrate strength training into day-to-day endurance training during a successful season. METHODS:Seventeen Olympic/World Championship/World Cup medalists (10 males and 7 females; 28.4 [2.7] y) provided detailed training logs of their best season. Training volume, frequency, and sequencing of endurance and strength sessions (categorized as core, heavy, or specific strength) were analyzed. RESULTS:Strength training comprised ∼ 6% of annual training time (∼50 h·y-1) and was performed about every 5 days (∼76 sessions·y-1) on average. Athletes predominantly engaged in core and heavy strength exercises, and female skiers accumulated significantly more heavy strength training (∼20 h·y-1) than males. Strength sessions occurred on days with reduced endurance load. Nearly 90% of the strength workouts were combined with an endurance session (on average 44 min of low-intensity exercise). High-intensity endurance sessions were seldom conducted on the same day as strength training, and almost never within the same workout. Endurance training volume and load on strength-training days were significantly lower compared with the preceding and following days. CONCLUSIONS AND PRACTICAL APPLICATIONS:World-class skiers incorporate strength training strategically once or twice per microcycle, pairing these sessions primarily with low-load endurance sessions and spacing them to avoid overlap with high-intensity endurance workouts. This pattern of concurrent training reflects practical strategies intended to maximize temporal spacing between training forms and to support the maintenance of overall training quality.
PURPOSE:A key issue for practitioners is the ability to handle the increased quantity of data provided by wearable microtechnology and the identification of which metrics provide actionable insights in players training responses. The aim of this study was to investigate the ability of principal component analysis (PCA) to reduce the number of variables assessed in a player monitoring program and verify the consistency of variables retained across different age groups of an elite youth soccer academy. METHODS:A PCA was conducted to reduce the dimensionality of training and match data recorded by 145 players from Under 15 to Under 19 squads. The variables assessed included Global Positioning System metrics, heart rate measures, and players session rating of perceived exertion values (n = 82). RESULTS:Seven principal components were extracted for each age group, describing 67.6% to 68.7% of variability. Inconsistencies were observed in the number of variables retained (range: 24-28) and their loadings between the different age groups. These differences in metrics retained and strength of their contributions indicate that PCA outcomes cannot be generalized across the different age groups. CONCLUSIONS:General themes and constructs of load were observed across the 4 age groups, including measures of volume and intensity for both internal and external loads. The inconsistencies show that employing a PCA approach with a wide array of variables may not be practical for use in an applied environment, where the application of a conceptual framework can aid the selection process.
PURPOSE:The aim of this study was to investigate the longitudinal associations between peak force (PF) in the isometric start position pull (ISPP), isometric transition position pull (ITPP), and isometric mid-thigh pull (IMTP) with weightlifting performance. METHODS:A retrospective longitudinal analysis was conducted using isometric assessment and performance data collected over a period of up to 3 years from 7 international-level female weightlifters (age 26.8 [7.4] y; body mass 59.9 [7.0] kg). The dependent variables were absolute (Total) and allometrically scaled competition performance (Totala). The independent variables were absolute (ISPP, ITPP, IMTP) and allometrically scaled (ISPPa, ITPPa, IMTPa) PF in the 3 pull positions and Time (3-mo intervals). Separate linear mixed models were used to examine their longitudinal associations. RESULTS:The ISPP and ISPPa showed significant positive associations with Total and Totala (P < .01), explaining 31% and 12% of the variance. Time as a fixed factor was not significant (P > .05), and reduced models (omitting Time) explained greater variance of 45% and 18%, respectively. The ITPP, IMTP, ITPPa and IMTPa were not significant in full models, yet reduced models identified these as significant predictors (P < .05) but with poorer model fit. CONCLUSIONS:The ISPP demonstrates the strongest and most stable longitudinal predictor of weightlifting performance, supporting its use as a primary assessment for monitoring performance changes.
PURPOSE:Researchers have examined many factors that could influence sport climbing success following the sport's Olympic debut in 2020; however, balance has strangely been overlooked. This study evaluated both static and dynamic balance in experienced, competitive sport climbers relative to nonclimbing, physically active controls. METHODS:Climbers (20 men, 17 women) and controls (10 men, 10 women) completed both static and dynamic balance tests. Static balance was assessed using the Balance Error Scoring System, while dynamic balance was evaluated by the lower quarter Y-balance test and upper quarter Y-balance test. Spearman rho correlation coefficients were used to quantify strength of relationships among balance scores and climbing grade, and a 1-way analysis of variance with sex as a covariate and Bonferroni post hoc analysis was done to determine statistical differences between controls, intermediate, and advanced climbers. RESULTS:Significantly more errors (P < .001) were observed in the Balance Error Scoring System test for the control group (12.4 [5.4]) than the intermediate (7.8 [3.3]) and advanced (7.5 [2.3]) climbers. There was a significant difference between the climbers and the control group (P < .001) for the lower quarter Y-balance test and upper quarter Y-balance test, with the controls scoring lower than climbers for each limb, but no significant difference was found between intermediate and advanced climbers. The relationship between static and dynamic balance was moderate (ρ = -.324 to -.565). Climbing grade was weakly correlated with dynamic balance (ρ = .202 to .350). CONCLUSIONS:Experienced climbers develop and rely on superior balance as an integral aspect of their climbing performance.
PURPOSE:The aim of this systematic review was to investigate the influence of menstrual cycle (MC) phases on performance-determining parameters in female football players. METHODS:A systematic search was conducted in PubMed and SPORTDiscus (last updated January 2026) following PRISMA guidelines. Studies were eligible if they included eumenorrheic female football players and assessed at least one quantitative performance outcome across 2 or more defined MC phases. Outcomes were categorized into aerobic performance (eg, total running distance, Yo-Yo tests), sprint and high-intensity running, and agility and power-related parameters (eg, jumps, change in direction). Methodological quality and MC phase verification were assessed using a modified version of an existing quality tool. Outcomes were synthesized using a structured, domain-based comparison across MC phases. This review was not registered. RESULTS:Fifteen prospective observational studies (total n = 210) met inclusion criteria. Evidence for MC phase effects on performance was inconsistent. Five studies reported reduced aerobic and/or sprint performance in the early follicular phase compared with the late follicular or mid-luteal phases, while 10 studies found no differences. No consistent effect of MC phase was observed on agility and power-related outcomes. Methodological limitations across studies included small sample sizes, inconsistent MC phase verification, and variability in performance tests. CONCLUSIONS:Current evidence suggests that aerobic and sprint performance may be slightly impaired during the early follicular phase in female football players, but findings remain inconclusive. Standardized protocols and hormonal confirmation of MC phases are needed to clarify the impact of hormonal fluctuations on sport-specific performance.
PURPOSE:Kayak marathon competitions entail several laps and frequent portages in all boat classes. Race demands related to modern elite kayak marathon competition rules have not been evaluated. This investigation characterized mean race speed, lap and portage speeds, frequency of speed changes, and heart rate (HR) responses in elite paddlers of both sexes. METHODS:During the 2022 European Marathon Championships, national team marathon paddlers in the K1 and K2 classes (N = 30, 15 women) wore a chest belt with integrated global positioning system and HR sensors. RESULTS:Elite kayak marathon paddlers maintain an exercise intensity of 85% to 91% HRmax irrespective of sex and boat type. Mean and peak paddling speeds were lower for women compared to men (P values ranging: .001-.001). In K1, men had more relative speed shifts of both 5% to 10% (35.6 [16.3] vs 25.5 [10.6]; P = .0283) and above 10% (P values ranging .0283-.0003). In K2, there were no statistical differences in speed shifts. In all boat classes, mean boat speed of the final 100 m was always significantly faster than the mean speed of the first part of the lap (P values ranging: .0105-.00000001). Portage running speed varied by 9.4% between sexes. CONCLUSIONS:During marathon races, world-class kayak paddlers sustain a mean of 85% to 91% HRmax for a prolonged period (121-129 min), with men in K1 having more speed shifts of 5% to 10% compared to women. To handle race demands, we therefore suggest that on-water training for both sexes include high-intensity steady-state exercise interspersed by frequent, more intense speed bouts.
PURPOSE:Increased total hemoglobin (Hb) mass is a physiological adaptation to altitude training; however, considerable individual differences have been observed in this response. This study aimed to determine the relationship between changes in total Hb mass (Hbmass) and conditioning indices during altitude training at an elevation of 1700 m. METHODS:Sixteen male long-distance runners participated in an altitude training camp at 1700 m for 9 to 23 days. The Hbmass was determined using a carbon monoxide rebreathing method. Daily conditioning indices, including arterial oxygen saturation (SpO2), heart rate (HR), SpO2/HR ratio, subjective ratings of fatigue, sleep depth, training intensity, sleep duration, and daily running distance, were measured or recorded each morning. RESULTS:Hbmass increased by 1.4% (1.9%) on average, with individual changes ranging from -2.1% to 4.6% (-18 to 35 g). A significant positive correlation was observed between ΔHbmass and duration of stay at altitude (r = .695, P = .003). In the multiple regression analysis, duration of stay (B = .235, P = .001) and the SpO2/HR ratio (B = -4.462, P = .001) were identified as significant predictors of Hbmass change (R2 = .819). CONCLUSION:These findings suggest that increases in Hbmass may occur even at an altitude of 1700 m when sufficient exposure duration is ensured. Furthermore, the SpO2/HR ratio may serve as a practical indicator reflecting individual physiological responses during altitude training.
