Maximal Incremental Test Research Articles

Females have better metabolic flexibility in different metabolically challenging stimuli.

The first aim was to explore the difference in metabolic flexibility between sexes in response to changing exercise intensity under control conditions. The second aim was to evaluate metabolic flexibility between sexes in response to exercise intensity adding two different metabolically challenging stimuli (glycogen depletion and heat). Eleven males (22±3yrs, 176.2±4cm, 68.4±4.9kg and 60.2±4.1ml/kgFFM/min) and nine females (22±2yrs, 166.7±4.5cm, 61.9±2.9kg, 64.2±5.6 ml/kgFFM/min) performed a maximal incremental exercise test (30W every 3min) on a cycle ergometer under three conditions: control (24h high-carbohydrate diet followed by the incremental test), glycogen depletion (glycogen-depletion protocol followed by 24h low-carbohydrate diet and then the incremental test) and heat (24h high-carbohydrate diet followed by 30 min passive heating and then the incremental test in heat). In the last minute of each step, lactate was analysed, fat (FATox/FFM) and carbohydrate oxidation (CHox/FFM) and energy expenditure (EE/FFM) normalized to fat free mass was estimated by indirect calorimetry. Females presented a greater FATox/FFM as exercise intensity increases across conditions (control, glycogen depletion and heat) (p=0.006). In contrast, CHox/FFM was not significantly different between sexes at any specific intensity across conditions (p>0.05). Consequently, EE/FFM was higher in females throughout the different intensities across conditions (p=0.002). Finally, lactate concentration was not different between sexes at the same intensities across conditions (p=0.87). In conclusion, females present a greater metabolic flexibility, due to the higher FATox/FFM throughout the different intensities, regardless of whether the test is performed in a conditions emphasizing the oxidative pathway (glycogen depletion) or the glycolytic pathway (heat). Clinical trials:NCT05703100.

No evidence of improvements in energy metabolism after 1week of nitrate and citrulline co-supplementation in elite rowers.

Citrulline (CIT) and beetroot extract (BR) supplements positively impacts exercise performance in elite rowers. However, its influence on metabolic outcomes such as whole-body volumes of oxygen consumption (VO2) and carbon dioxide production (VCO2), substrate oxidation, energy expenditure (EE), and gross efficiency remains unknown. We studied the effects of 1week of daily co-supplementation of 3.5g BR (500mg NO3-) plus 6g CIT on VO2 and VCO2 kinetics, substrate utilization, EE, and gross efficiency in elite male rowers compared to a placebo and to a BR supplementation. Twenty elite rowers participated in this randomized, double-blind, placebo-controlled crossover trial completing 1week of supplementation in each group of study: Placebo (PLAG); BRG; and BR-CITG. Efficiency (70% VO2max) and performance (incremental maximal) tests were performed, and gas-exchange data were collected via indirect calorimetry. Analysis of covariance (ANCOVA) showed no mean between-condition differences on respiratory exchange ratio (RER), EE, and gross efficiency in the efficiency test (all P > 0.06), and in the performance test (all P > 0.28). Moreover, in both tests no interaction Time × Supplement effects were observed for VO2, VCO2, RER, EE, substrate oxidation, and, gross efficiency (all P > 0.12). After 1week, no effects on energy metabolism and substrate utilization were observed after the daily co-ingestion of BR extract plus CIT supplement, therefore longer (> 7days) and higher doses of supplementation might be needed to influence metabolism.

Reduced cardiovascular and metabolic responses during eccentric stepping exercise: A pilot study.

This study compared cardiovascular and metabolic responses during concentric and eccentric stepping. Eight participants (5 m, 3f; 22 ± 2 years) performed maximal concentric and eccentric ramp incremental tests on a modified stepping ergometer. Subsequently, three randomized 15-min constant-power tests were performed (1) concentric stepping at 90% of the concentric lactate threshold (LT), (2) eccentric stepping at the same power, and (3) eccentric stepping at the same oxygen uptake (V̇O2). At equivalent power (36 ± 6 W, p = 0.62), eccentric stepping resulted in 46 ± 8% lower V̇O2, 16 ± 6% lower heart rate (HR), and 11 ± 5% lower mean arterial blood pressure compared to concentric (p < 0.01). Matching V̇O2 required 65 ± 19% more power during eccentric stepping (p < 0.01). During this test, eccentric V̇O2 and HR continued to increase, resulting in a 22 ± 29% higher V̇O2 and 19 ± 16% higher HR in the final minute (p < 0.001). Reduced cardiorespiratory demand during eccentric stepping at the same power as concentric demonstrates a higher eccentric power is required to produce the same V̇O2. However, despite being below the concentric LT, eccentric V̇O2 and HR continued to increase past the predicted steady state, indicating a higher exercise intensity.

Detrended fluctuation analysis to determine physiologic thresholds, investigation and evidence from incremental cycling test.

Training zones are generally assessed by gas-exchange thresholds (GET). Several mathematical analyses of heart rate variability (HRV) are proposed for indirect GET determination. Our study aimed to investigate the accordance of the detrend fluctuation analysis (DFA α1) for determining GET with first (VT1) and second ventilatory (VT2) thresholds in well-trained subjects. Eighteen female and 38 male sub-elite cyclists performed a maximal incremental cycling test of 2-min stage duration with continuous gas exchange and HR measurements. Power output (PO), Oxygen uptake ( O2) and HR at VT1 and VT2 were compared with DFA α1 0.75 (HRVT1) and 0.50 (HRVT2). Agreements between PO, O2 and HR values were analyzed using Bland-Altman analysis. Large limits of agreement between VT1 and HRVT1 were observed for measures of O2 expressed in mL.min-1.kg-1 [-21.3; + 14.1], HR [39.2; + 26.9] bpm and PO [-118; + 83] watts. Indeed, agreements were also low between VT2 and HRVT2 for measures of O2 [-26.7; + 4.3] mL.min-1.kg-1, HR [-45.5; + 10.6] bpm and PO [-157; + 35] watts. Our results also showed a sex effect: women obtained worst predictions based on DFA α1 than men for HR (p = 0.014), PO (p = 0.044) at VT1 and (p = 0.045), HR (p = 0.003) and PO (p = 0.004) at VT2. There was unsatisfactory agreement between the GET and DFA α1 methods for VT1 and VT2 determination in both sex well-trained cyclists. Trial registrationnumber 2233534 on 2024/03/05 retrospectively registered.

Breathing variability during running in athletes: The role of sex, exercise intensity and breathing reserve

Highly trained aerobic athletes progressively use most of their breathing reserve with increased exercise intensity during whole-body exercise. Additionally, females typically present proportionally smaller lungs than males. Therefore, sex, exercise intensity, and breathing reserve use likely influence the volume and time in which respiratory parameters vary between consecutive breaths during whole-body exercise. However, breath-by-breath variability has been scarcely investigated during exercise. Accordingly, we sought to investigate breath-by-breath pulmonary ventilation (V̇E), tidal volume (VT), and respiratory frequency (fR) variability during a maximal treadmill incremental exercise test in 17 females and 18 males highly trained professional endurance runners. The breath-by-breath variability was analyzed by root mean square of successive differences (RMSSD) within 1-minute windows. Females had lower absolute and percent predicted forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) than males, as well as lower height-adjusted absolute FVC than males. V̇E and VT reserve use were similar between the sexes at peak exercise. While RMSSDV̇E and RMSSDfR did not change over exercise (P > 0.05), RMSSDVT progressively decreased (P < 0.001). RMSSDVT was negatively correlated with VT reserve use only in males. Females showed lower RMSSDV̇E than males during the entire exercise test (P < 0.001). At iso-V̇E reserve use, between-sex differences in RMSSDV̇E persisted (P = 0.003). Our findings indicate that exercise intensity decreases VT variability in professional runners, which is linked to VT reserve use in males but not females. Additionally, the female sex lowers V̇E variability regardless of exercise intensity and V̇E reserve use.

Fractional utilization of the 10-minute treadmill test velocity in running performance.

This study aimed to evaluate the applicability of the 10-minute submaximal treadmill test (T10 test), a self-paced test, in determining critical speed (CS) and predicting running performance. Specifically, we sought to identify the percentage of T10 velocity (vT10) that runners performed in official distance races, and to compare physiological and performance indicators between sexes. 60 recreational runners (n = 34 males and n = 26 females) underwent a maximum incremental test, the novel T10 test, and ran 1200-m and 2400-m on the track. Runners self-reported their best performance times. Generalized Linear Model was used to compare running performances between sexes. For both males and females, the %vT10 in 5km, 10km, and half-marathon races occurred at 107.5% and 106.5%, 99.9% and 100.8%, and 92.6% and 97.1%, respectively. There was no interaction effect (p = .520) and no main effect of sex (p = .443). There was a main effect of distance (p < .001), indicating that %vT10 in the 5km race differed from that found in the 10km race (p = .012), as well as in the half-marathon (p < .001). Our findings suggest that %vT10 values can be used to determine pace in recreational endurance runners for race distances regardless of sex.

Recovery of heart rate and heartrate variability after a maximal cardiopulmonary exercise test in novice female runners.

Previous studies have shown delayed cardiac vagal reactivation after high-intensity endurance exercise when estimated with heartrate variability (HRV). However, the recovery dynamics of RR intervals (RRI) and HRV after a maximal incremental exercise test have been studied less in non-athletic population and especially in females. The main aim of the study was to examine the recovery dynamics of RRI and HRV immediately after a maximal cardiopulmonary exercise test (CPET) in adult females. Twenty-eight healthy, novice recreational female runners (33.7 ± 4.2years) were selected to participate in this study from a larger group of participants (Run RCT). RRIs were collected continuously during a controlled rest, a CPET on a treadmill and a 15-min controlled, passive recovery. Minute-by-minute recovery dynamics were analyzed. The dynamic phase of RRI and heart rate recovery (HRR) (from 192.2 ± 9.9 to 111.4 ± 2.4, P < 0.001) occurred during the first 4.5min with HRR of 36 ± 10 beats during the first minute of the recovery. Resting heart rate was negatively associated (r = - 0.53, P = 0.016) with HRR during the recovery. No recovery of root mean square of successive RRIs (RMSSD) was detected during the 15-min recovery. RMSSD was 15.0 ± 9.2% of resting values at the end of the recovery. No recovery of vagal-derived HRV was detected immediately after a CPET in novice recreational female runners despite marked changes in sympathovagal balance, detected by rapid recovery of RRI during the first 5min after exercise cessation.

Difference in expiratory flow limitations development in normoxia and hypoxia in healthy individuals

The present study investigated the maintenance/repeatability of expiratory flow limitation (EFL) between normoxia and hypoxia.Fifty-one healthy active individuals (27 men and 24 women) performed a lung function test and a maximal incremental cycling test in both normoxia and hypoxia (inspired oxygen fraction = 0.14) on two separate visits.During exercise in normoxia, 28 participants exhibited EFL (55 %). In hypoxia, another cohort of 28 participants exhibited EFL. The two groups only partly overlapped.Individuals with EFL only in normoxia reported lower maximal ventilation values in hypoxia than in normoxia (n=5; −13.5 ± 7.8 %) compared to their counterparts with EFL only in hypoxia (n=5; +6.7 ± 6.3 %) or without EFL (n=18; +5.1 ± 10.3 %) (p=0.004 and p<0.001, respectively).EFL development may be induced by different mechanisms in hypoxia vs. normoxia since the individuals who exhibited flow limitation were not the same between the two environmental conditions. This change seems influenced by the magnitude of the maximal ventilation change.

Assessing Leg Blood Flow and Cardiac Output During Running Using Thermodilution.

Cardiac output (Q̇C) and leg blood flow (Q̇LEG) can be measured simultaneously with high accuracy using transpulmonary and femoral vein thermodilution with a single-bolus injection. The invasive measure has offered important insight into leg hemodynamics and blood flow distribution during exercise. Despite being the natural modality of exercise in humans, there has been no direct measure of Q̇LEG while running in humans. We sought to determine the feasibility of the thermodilution technique for measuring Q̇LEG and conductance during high-intensity running, in an exploratory case study. A trained runner (30 years male) completed two maximal incremental tests on a cycle ergometer and motorized treadmill. Q̇LEG and Q̇C were determined using the single-bolus thermodilution technique. Arterial and venous blood were sampled throughout exercise, with continuous monitoring of metabolism, intra-arterial and venous pressure, and temperature. The participant reached a greater peak oxygen uptake (V̇O2peak) during running relative to cycling (74 vs. 68 mL/kg/min) with comparable Q̇LEG (19.0 vs. 19.5 L/min) and Q̇C (27.4 vs. 26.2 L/min). Leg vascular conductance was greater during high-intensity running relative to cycling (82 vs. 70 mL/min/mmHg @ ~80% V̇O2peak). The "beat phenomenon" was apparent in femoral flow while running, producing large gradients in conductance (62-90 mL/min/mmHg @ 70% V̇O2peak). In summary, we present the first direct measure of Q̇LEG and conductance in a running human. Our findings corroborate several assumptions about Q̇LEG during running compared with cycling. Importantly, we demonstrate that using thermodilution in running exercise can be completed effectively and safely.

Peak Oxygen Uptake is Slope Dependent: Insights from Ground Reaction Forces and Muscle Oxygenation in Trained Male Runners

BackgroundThe aim of this study is to explore the effect of treadmill slope on ground reaction forces and local muscle oxygenation as putative limiting factors of peak oxygen uptake in graded maximal incremental running tests. Thirteen trained male runners completed five maximal incremental running tests on treadmill at − 15%, − 7.5%, 0%, 7.5% and 15% slopes while cardiorespiratory and local muscle oxygenation responses as well as ground reaction forces were continuously recorded. Blood lactate concentration and isometric knee extensor torque were measured before and after each test.ResultsPeak oxygen uptake was lower at − 15% slope compared to all other conditions (from − 10 to − 17% lower, p < 0.001), with no difference between − 7.5 and + 15% slope. Maximal heart rate and ventilation values were reached in all conditions. The negative external mechanical work increased from steep uphill to steep downhill slopes (from 6 to 92% of total external work) but was not correlated with the peak oxygen uptake reduction. Local muscle oxygenation remained higher in − 15% slope compared to level running (p = 0.003).ConclusionsSimilar peak oxygen uptake can be reached in downhill running up to − 7.5% slope. At more severe downhill slopes (i.e., − 15%), greater negative muscle work and limited local muscle deoxygenation occurred, even in subjects familiarized to downhill running, presumably preventing the achievement of similar to other condition’s peak oxygen uptake.Key PointsTrained male runners can reach like level running V̇O2peak at moderate but not at severe negative slope.Negative external mechanical work increases with increasing negative slope.At maximal intensity Vastus Lateralis muscle oxygenation is higher in steep negative slope.Knee extensor isometric muscle torque is preserved after maximal level and uphill running, but reduced after downhill running, despite lower blood lactate.Progressive reduction of V̇O2 at maximal effort with increasing negative slope might be related to the metabolic consequences of increased lower limb negative external work (i.e., eccentric muscle actions).

Performance and Fatigue Patterns in Elite Cyclists During 6 h of Simulated Road Racing.

Fatigue resistance is vital for success in elite road cycling, as repeated, intense efforts challenge the athletes' ability to sustain peak performance throughout prolonged races. The present study combined recurrent performance testing and physiological measures during 6 h simulated racing with laboratory testing to investigate factors influencing fatigue resistance. Twelve male national elite cyclists (25 ± 3 years; 76 ± 6 kg and VO2max of 5.2 ± 0.5 L/min) completed incremental power and maximal fat oxidation tests. Subsequently, they underwent field testing with physiological measures and fatigue responses evaluated through peak sprint power and 5 km time trial (TT) testing after 0, 2, 4, and 6 h of exercise. Peak power declined from 1362 ± 176 W in first sprint to 1271 ± 152 W after 2 h (p < 0.01) and then stabilized. In contrast, TT mean power gradually declined from 412 ± 38 W in the first TT to 384 ± 41 W in the final trial, with individual losses ranging from 2% to 14% and moderately correlated (r2 = 0.45) to accumulated exercise time above lactate threshold. High carbohydrate intake (~90 g/h) maintained blood glucose levels, but post-TT [lactate] decreased from 15.1 ± 2 mM to 7.1 ± 2.3 mM, while fat oxidation increased from 0.7 ± 0.3 g/min at 0 h to 1.1 ± 0.1 g/min after 6 h. The study identifies fatigue patterns in national elite cyclists. Peak sprint power stabilized after an initial impairment from 0 to 2 h, while TT power gradually declined over the 6 h simulated race, with increased differentiation in fatigue responses among athletes.

Characterization of muscle oxygenation response in well-trained handcyclists.

Peripheral responses might be important in handcycling, given the involvement of smallmusclescompared to other exercise modalities. Therefore, the goal of this study was to compare changes in muscle oxygen saturation (∆SmO2) and deoxyhemoglobin level (∆[HHb]) between different efforts and muscles. Handcyclists participated in a Wingate, a maximal incremental test and a 20-min time-trial (TT). Oxygen uptake (VO2)as well as ∆SmO2, ∆[HHb], deoxygenation and reoxygenation rates in the triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD) and extensor carpi radialis brevis (ER) were measured. ER ∆[HHb]max was 37% greater in the incremental test than in the Wingate (ES = 0.392, P = 0.031). TT mean power (W/kg) was associated with BB ∆SmO2min measured in the incremental test (r = -0.998 [-1.190, -0.806], P = 0.002) and in the Wingate (r = -0.994 [-1.327, -0.661], P = 0.006). MAP (W/kg) was associated with Wingate BB ∆SmO2min (r = -0.983 [-0.999, -0.839], P = 0.003), and Wingate peak (r = 0.649 [0.379, 0.895], P = 0.008) and mean power(W/kg) (r = 0.925 [0.752, 0.972], P = 0.003) was associated with right handgrip force. The strongest physiological predictor for TT performance was BB ∆SmO2min in the incremental test (P = 0.002, r2= 0.993, SEE 0.016W/kg), Wingate BB ∆SmO2min for MAP (P = 0.003, r2= 0.956, SEE 0.058W/kg) and right handgrip force for Wingate peak power (P = 0.005, r2= 0.856, SEE 0.551W/kg). Peripheral aerobic responses (muscle oxygenation) were predictiveof handcycling performance.

Impact of Anaerobic Exercise Integrated Into Regular Training on Experienced Judo Athletes: Running Vs. Repetitive Throws.

Kamandulis, S, Dudėnienė, L, Snieckus, A, Kniubaite, A, Mickevicius, M, Lukonaitiene, I, Venckunas, T, Stasiule, L, and Stasiulis, A. Impact of anaerobic exercise integrated into regular training on experienced judo athletes: running vs. repetitive throws. J Strength Cond Res 38(9): e489-e495, 2024-Anaerobic training in high-level athletes is of considerable interest to practitioners aiming to optimize performance. This study compared the impact of interval anaerobic training (IAT) sessions consisting of either high-intensity running or throwing that were performed twice a week together with regular judo training on the anaerobic and aerobic performance of experienced judo athletes. Employing a repeated-measures, counterbalancing, research design, 12 national team judo athletes (7 women and 5 men; mean age, 20.4 ± 0.95 years; mean judo training experience, 13.4 ± 1.4 years; competitive level, black belt first and second Dan) performed each IAT modality for 6 weeks, for a full training cycle of 12 weeks. Assessments of their anaerobic fitness (Cunningham and Faulkner Anaerobic Treadmill Test), sport-specific anaerobic fitness (Special Judo Fitness Test [SJFT]), and aerobic capacity (maximal incremental treadmill running test) were performed before, after 6 weeks, and after 12 weeks of training. The uphill running performance improved by 13.1% over the 12-week period ( p = 0.047). Simultaneously, there was a 9.0% improvement in the SJFT index and a 6.9% increase in the number of throws ( p = 0.011 and p = 0.017, respectively). Although a trend for throwing drills being more effective than interval sprint running was observed, the interaction effect lacked statistical significance ( p = 0.074). Moreover, no substantial changes were noted in aerobic endurance markers. In conclusion, this study suggests that incorporating specific and nonspecific high-intensity drills into a routine training regimen may enhance anaerobic capacity among well-trained judo athletes, potentially leading to favorable competitive outcomes.

The Myometric Assessment of Achilles Tendon and Soleus Muscle Stiffness before and after a Standardized Exercise Test in Elite Female Volleyball and Handball Athletes-A Quasi-Experimental Study.

Background: The high prevalence of injuries in female athletes necessitates a course of action that not only enhances research in this field but also incorporates improved prevention programs and regular health monitoring of highly stressed structures such as tendons and muscles. Since myometry is already used by coaches and physiotherapists, it is important to investigate whether tissue stiffness varies in different types of sports, and whether such measures are affected by an acute training session. Methods: Myometric measurements of the Achilles tendon (AT) and soleus muscle (SM) were performed in the longitudinal plane and relaxed tendon position. In total, 38 healthy professional female athletes were examined, applying a quasi-experimental study design, with subgroup analysis performed for different sports. To investigate the stiffness of the AT and SM, 24 female handball and volleyball athletes performed a standardized maximal incremental performance test on a treadmill. In this subgroup, myometric measurements were taken before and after the exercise test. Results: The measurements showed no significant difference between the mean pre- (AT: 661.46 N/m; SM 441.48 N/m) and post-exercise stiffness (AT: 644.71 N/m; SM: 439.07 N/m). Subgroup analysis for different types of sports showed significantly lower AT and SM stiffness in swimming athletes compared to handball (p = 0.002), volleyball (p = 0.000) and hammer throw athletes (p = 0.008). Conclusions: Myometry can be performed on the same day as an acute training session in healthy female professional volleyball and handball athletes. Female swimmers have significantly lower AT and SM stiffness compared to female handball, volleyball and hammer throw athletes. These results show that the stiffness differences in the AT and SM can be assessed by myometry.

Reliability of Corticospinal and Motoneuronal Excitability Evaluation during Unfatiguing and Fatiguing Cycling Exercise.

Central nervous system excitability depends on the task performed, muscle group solicited, and contraction type. However, little is known on corticospinal and motoneuronal excitability measured during locomotor exercise. This study aimed at determining the reliability of motor-evoked potentials (MEP) and thoracic motor-evoked potentials (TMEP) in dynamic mode during unfatiguing and fatiguing cycling exercise. Twenty-two participants completed four visits. Visit 1 comprised familiarization and an incremental cycling test to determine maximal power output ( Wmax ). The remaining visits encompassed unfatiguing evaluations, which included a total of eight brief bouts of moderate- (50% Wmax ) and high-intensity cycling (80% Wmax ), four at each intensity. In each bout, a set of two TMEPs, five MEPs, and one M-max were obtained. Subsequently, a fatiguing exercise to exhaustion at 80% Wmax was performed, with four sets of measurements 3 min through the exercise and four additional sets at exhaustion, both measured at 50% Wmax . Intraclass correlation coefficients (ICCs) for 5, 10, 15, and 20 MEP·Mmax -1 revealed excellent reliability at both intensities and during cycling to exhaustion (ICC ≥0.92). TMEP·Mmax -1 showed ICCs ≥0.82 for moderate and high intensity, and it was not affected by fatigability. Overall standard error of measurement was 0.090 (0.083, 0.097) for MEP·Mmax -1 and 0.114 (0.105, 0.125) for TMEP·Mmax -1 . A systematic bias associated with the number of stimulations, especially at high intensity, suggested that the evaluation itself may be influenced by fatigability. A mean reduction of 8% was detected in TMEP·Mmax -1 at exhaustion. Motoneuronal and corticospinal excitability measured in dynamic mode presented good to excellent reliability in unfatiguing and fatiguing exercise. Further studies inducing greater fatigability must be conducted to assess the sensitivity of central nervous system excitability during cycling.

Menstrual Cycle Phase Has No Influence on Performance-Determining Variables in Endurance-Trained Athletes: The FENDURA Project.

This study aimed to investigate the effect of the MC and endogenous sex hormone concentrations on performance-determining variables in three distinct MC phases in endurance-trained females. Twenty-one eumenorrheic trained/highly trained endurance athletes completed a standardized test battery during the early follicular phase (EFP), ovulatory phase (OP), and midluteal phase (MLP) for either one ( n = 7) or two test cycles ( n = 14). MC phases were determined using calendar-based counting, urinary ovulation testing, and verified with serum hormone analysis. MCs were retrospectively classified as eumenorrheic or disturbed. Disturbed MCs were excluded from analysis. The test battery consisted of 4-6 × 5-min submaximal stages with stepwise speed increases, a 30-s all-out double-poling ski ergometer test, and a maximal incremental treadmill running test. At a group level, there was no effect of MC phase or the serum concentrations of estrogen and progesterone on peak oxygen uptake (V̇O 2peak ), oxygen uptake at 4 mmol·L -1 blood lactate concentration, time to exhaustion, running economy, or mean 30-s power output (MPO 30s ). Serum testosterone concentration was positively associated with MPO 30s ( P = 0.016). Changes in V̇O 2peak from EFP to MLP were inconsistent between individuals and across cycles. None of the measured performance-determining variables were influenced by MC phase or serum estrogen or progesterone concentrations. Although some individual patterns could be observed, there was no indication that any single MC phase is consistently associated with improved or impaired V̇O 2peak on a group level.

Sex-Related and Performance Differences in Contractile Properties, ROM, Strength, and Dynamometry Performance of World-Class Flatwater Canoeists

The inclusion of women canoe in the Olympic Games reflects the growth and development that women have ahead of them in this modality. Therefore, the aim of this study was to explore sex and performance level differences in muscle contractile properties through Tensiomyography (TMG), range of motion (ROM), strength, and canoe-specific functional electromechanical dynamometry (FEMD) performance and establish performance differences between international medalists and non-medalists. Twelve male and nine female canoeists from the Spanish and Portuguese national canoe teams were assessed through TMG, ROM, strength, and canoe-specific isometric and incremental FEMD tests. Few sex and performance level differences were found in TMG and ROM; however, significant sex differences were found in the strength and FEMD tests. Male canoeists had a greater Fmax in Leg Press, Pm and Pmax in canoe position cable row, 1RM bench press and bench pull, Fm and Fpeak canoe-specific isometric FEMD test and number of strokes, and Fpeak and Pmax on the incremental FEMD test than females. International medalists showed a lower time until reaching Vmax and Pmax in Leg Press on both sides and a greater number of strokes and Fpeak in the maximal incremental FEMD test than non-medalists. This study reinforces the utility of the use of TMG and FEMD for assessing and monitoring world-class athletes.

People with type 1 diabetes exhibit lower exercise capacity compared to a control population with similar physical activity levels

AimsWe aimed to assess physical activity (PA) levels, adherence to PA guidelines, and fitness capacity in individuals with type 1 diabetes (T1D) and control population. MethodsThis cross-sectional study included 232 T1D and 248 controls. PA levels (IPAQ-SF questionnaire), adherence to guidelines (>150 min/week of moderate-to-vigorous PA), fitness capacity (VO2max, maximal incremental test on a cycle ergometer and 1RM test) were assessed, along with other clinical variables. ResultsTotal PA levels (T1D 2202 ± 1839 vs. controls 2357 ± 2189 METs/min/week), adherence (T1D 53.1 % vs controls 53.2 %), and sedentariness (T1D 27.3 % vs. controls 25.1 %) were similar between groups. However, participants with T1D exhibited significantly lower levels of VO2max (29.1 ± 10.5 vs. 32.5 ± 11.5 mlO2/kg/min, p < 0.001), work capacity (2.73 ± 1.03 vs. 3 ± 10 W/kg of body weight, p = 0.004) and strength capacity (2.29 ± 0.53 vs. 2.41 ± 0.79 kg/kg body weight in 1RM, p = 0.01) than controls, after adjusting for sex and age. ConclusionsIndividuals with T1D exhibit lower fitness capacity compared to a control population, regardless of age and sex, even when presenting similar levels of total physical activity and adherence to guidelines.

The 2-Minutes Walking Test Is Not Correlated with Aerobic Fitness Indices but with the 5-Times Sit-to-Stand Test Performance in Apparently Healthy Older Adults.

The 2-minutes walking test (2-MWT) is a valid and reliable test that has a high correlation with the distance walked in the 6-minutes walking test (6-MWT). However, to date, no study has determined the relationship between 2-MWT performance and the aerobic fitness indices obtained during a maximal incremental test to confirm if this test is a valid surrogate of aerobic fitness in apparently healthy older adults. The main objective of this work was to identify the factors associated to the performance in the 2-MWT, including aerobic fitness, functional and spatial-temporal gait parameters. Seventeen elderly adults performed a maximal incremental cycling test to determine maximum oxygen consumption (VO2max) and ventilatory thresholds (VT1 and VT2), two static standing balance tests with open and close eyes, a 5-times sit-to-stand test (5-TSTS), a handgrip test, and a 2-MWT on three different days over 2 weeks. No correlations were found between aerobic fitness indices and the distance covered in 2-MWT, but significant moderate correlations were found between the distance covered in 2-MWT and the time to perform the 5-TSTS (rho = -0.49) and with stride length (rho = 0.52) during the test. In conclusion, the 2-MWT does not seem a good test to assess aerobic capacity while it showed to be associated to the 5-TSTS performance of the elderly.

Determining V̇O2max in competitive swimmers: Comparing the validity and reliability of cycling, arm cranking, ergometer swimming, and tethered swimming

ObjectivesThis study aims to identify the optimal method for determining V̇O2max in competitive swimmers in terms of validity and test–retest reliability. DesignControlled experiment. MethodsTwenty competitive swimmers performed four maximal incremental exercise tests: cycling, arm cranking, ergometer swimming, and tethered swimming. Gas analysis was conducted to estimate V̇O2max. Validity was assessed in terms of the amount of variance of the performance on a 1500-m time trial explained by the estimated V̇O2max . Test–retest reliability was evaluated using the intraclass correlation coefficient (ICC). ResultsV̇O2max obtained from tethered swimming, ergometer swimming, and cycling explained a similar amount of variance of the 1500-m performance (R2 = 0.64, 0.64 and 0.65, respectively). However, ergometer swimming yielded significantly lower V̇O2max estimates (40.54 ± 6.55 ml/kg/min) than tethered swimming (54.40 ± 6.21 ml/kg/min) and cycling (54.39 ± 5.63 ml/kg/min). Arm cranking resulted in both a lower explained variance (R2 = 0.41) and a significantly lower V̇O2max (43.14 ± 7.81 ml/kg/min). Tethered swimming showed good reliability (ICC = 0.81). ConclusionsBicycle and tethered swimming tests demonstrated high validity with comparable V̇O2max estimates, explaining a large proportion of differences in endurance performance. Choosing between these two methods involves a trade-off between a higher practical applicability and reliability of the bicycle test and the more sport-specific nature of the tethered swimming test.