Recently, a new automated carbon monoxide (CO) rebreathing method (aCO) to estimate haemoglobin mass (Hb; mass; ) was introduced. The aCO method uses the same CO dilution principle as the widely used optimised CO rebreathing method (oCO). The two methods differ in terms of CO administration, body position, and rebreathing time. Whereas with aCO, CO is administered automatically by the system in a supine position of the subject, with oCO, CO is administered manually by an experienced operator with the subject sitting. Therefore, the aim of this study was to quantify possible differences in Hb; mass; estimated with the two methods. Hb; mass; was estimated in 18 subjects (9 females, 9 males) with oCO using capillary blood samples (oCOc) and aCO taking simultaneously venous blood samples (aCOv) and capillary blood samples (aCOc). Overall, Hb; mass; was different between the three measurement procedures (; F; = 57.55,; p;
During early parenthood, walking and/or running while pushing a stroller is a common form of endurance exercise among both recreationally active individuals and athletes. Here, we investigate how pushing a stroller influences the energetic cost, gross efficiency (GE), and kinematic behavior of well-trained men and women while walking or running on flat and uphill incline. Eight men and nine women, all recreationally active, performed three 5-min submaximal tests of walking or running during four different testing sessions, in randomized order: with and without pushing a 24.3-kg stroller on a flat (1%; 6, 8/9, and 11/12 km/h for women/men) and uphill (10%; 5, 6.5/7.5, and 7.5/8.5 km/h for women/men) incline. Respiratory parameters, heart rate (HR), blood lactate concentration, and rating of perceived exertion (RPE) were determined and video-based kinematic analysis was performed in connection with all these tests. Except while walking on the flat incline, pushing a stroller increased the energetic cost of walking/running under all conditions (all; p; < 0.05). This was associated with shorter and more rapid strides on both inclines (all; p; < 0.05); however, GE was higher when pushing the stroller (; p; < 0.05). The increase in energetic cost of pushing the stroller was approximately threefold higher uphill than on the flat incline, and women were influenced more than men when running uphill at the highest speed (all; p; < 0.05). Here, we provide novel insights on the energetic cost and kinematic behavior of pushing a stroller while walking or running on flat and uphill inclines. The energetic cost of pushing a stroller was clearly higher than for unloaded exercise, coincided by shorter and more rapid strides, and especially pronounced on uphill terrain where also women were more influenced than men.
It is unknown, whether endurance training stimulates hemoglobin mass (Hbmass) and maximal oxygen uptake (V˙O2max) increases during late adolescence. Therefore, this study assessed the influence of endurance training on Hbmass, blood volume parameters, and V˙O2max in endurance athletes and control subjects from age 16 to 19 yr.; Hemoglobin mass, blood volume parameters, V˙O2max and anthropometric parameters were measured in male elite endurance athletes from age 16 to 19 yr in 6-month intervals (n = 10), as well as in age-matched male controls (n = 12).; Neither the level of Hbmass per lean body mass (LBM) (P = 0.80) nor the development of Hbmass during the 3 yr (P = 0.97) differed between athletes and controls. Hbmass at age 16 yr was 13.24 ± 0.89 g·kg LBM and increased by 0.74 ± 0.58 g·kg LBM (P < 0.01) from age 16 to 19 yr. There was a high correlation between Hbmass at age 16 and 19 yr (r = 0.77; P < 0.001). Plasma volume, blood volume, and V˙O2max were higher in athletes compared to controls (P < 0.05). Blood volume and V˙O2max increased with age (P < 0.01, similarly in both groups).; Endurance training volumes do not explain individual differences in Hbmass levels nor Hbmass and V˙O2max development in the age period from 16 to 19 yr. The higher V˙O2max levels of athletes may be partially explained by training-induced higher plasma and blood volumes, as well as other training adaptations. Since Hbmass at age 16 yr varies substantially and the development of Hbmass in late adolescence is comparably small and not influenced by endurance training, Hbmass at age 16 yr is an important predictor for Hbmass at adult age and possibly for the aptitude for high-level endurance performance.
The rim width of cross-country mountain bike wheel sets has increased in recent years, but the effect of this increase on performance remains unknown. The aim of this study was to analyse the influence of rim width on rolling resistance and off-road speed. We compared 3 tubeless wheel sets: 25 mm inner width as baseline, 30 mm width with the same tyre stiffness, and 30 mm width with the same tyre pressure. Three riders conducted 75 rolling resistance tests for each wheel set on a cross-country course. We determined rolling resistance using the virtual elevation method and calculated off-road speeds for flat and uphill conditions using a mathematical model. Baseline rolling resistance (C; r; ) was 0.0298, 90% CI [0.0286, 0.0310], which decreased by 1.4%, [0.7, 2.2] with the wider rim and the same tyre stiffness and increased by 0.9%, [0.1, 1.6] with the wider rim and the same tyre pressure. The corresponding effects on off-road speed were most likely trivial (0.0% to 0.7% faster and 0.1% to 0.6% slower, respectively). Because the effect of rim width on off-road speed seems negligible, athletes should choose the rim width that offers the best bike handling and should experiment with low tyre pressures.
What is the central question of this study? It has been assumed that athletes embarking on an 'live high-train low' (LHTL) camp with already high initial haemoglobin mass (Hb; mass; ) have a limited ability to increase their Hb; mass; further post-intervention. Therefore, the relationship between initial Hb; mass; and post-intervention increase was tested with duplicate Hb; mass; measures and comparable hypoxic doses in male athletes. What is the main finding and its importance? There were trivial to moderate inverse relationships between initial Hb; mass; and percentage Hb; mass; increase in endurance and team-sport athletes after the LHTL camp, indicating that even athletes with higher initial Hb; mass; can reasonably expect Hb; mass; gains post-LHTL. It has been proposed that athletes with high initial values of haemoglobin mass (Hb; mass; ) will have a smaller Hb; mass; increase in response to 'live high-train low' (LHTL) altitude training. To verify this assumption, the relationship between initial absolute and relative Hb; mass; values and their respective Hb; mass; increase following LHTL in male endurance and team-sport athletes was investigated. Overall, 58 male athletes (35 well-trained endurance athletes and 23 elite male field hockey players) undertook an LHTL training camp with similar hypoxic doses (200-230 h). The Hb; mass; was measured in duplicate pre- and post-LHTL by the carbon monoxide rebreathing method. Although there was no relationship (r = 0.02, P = 0.91) between initial absolute Hb; mass; (in grams) and the percentage increase in absolute Hb; mass; , a moderate relationship (r = -0.31, P = 0.02) between initial relative Hb; mass; (in grams per kilogram) and the percentage increase in relative Hb; mass; was detected. Mean absolute and relative Hb; mass; increased to a similar extent (P ≥ 0.81) in endurance (from 916 ± 88 to 951 ± 96 g, +3.8%, P < 0.001 and from 13.1 ± 1.2 to 13.6 ± 1.1 g kg; -1; , +4.1%, P < 0.001, respectively) and team-sport athletes (from 920 ± 120 to 957 ± 127 g, +4.0%, P < 0.001 and from 11.9 ± 0.9 to 12.3 ± 0.9 g kg; -1; , +4.0%, P < 0.001, respectively) after LHTL. The direct comparison study using individual data of male endurance and team-sport athletes and strict methodological control (duplicate Hb; mass; measures and matched hypoxic dose) indicated that even athletes with higher initial Hb; mass; can reasonably expect Hb; mass; gain post-LHTL.
Although a low rolling resistance is advantageous in mountain bike cross-country racing, no studies have used the virtual elevation method to compare tyres from different manufacturers as used in international competitions so far. The aims of this study were to assess the reliability of this method, to compare the off-road rolling resistance between tyres and to calculate the influence on off-road speed. Nine 29-in. mountain bike cross-country tyres were tested on a course representing typical ground surface conditions 5 or 6 times. The coefficient of rolling resistance was estimated with the virtual elevation method by 3 investigators and corresponding off-road speeds were calculated. The virtual elevation method was highly reliable (typical error = 0.0006, 2.8%; limits of agreement
To compare individual hemoglobin mass (Hbmass) changes following a live high-train low (LHTL) altitude training camp under either normobaric hypoxia (NH) or hypobaric hypoxia (HH) conditions in endurance athletes.; In a crossover design with a one-year washout, 15 male triathletes randomly performed two 18-d LHTL training camps in either HH or NH. All athletes slept at 2250 m and trained at altitudes < 1200 m. Hbmass was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre-) and immediately after (post-) each 18 d training camp.; Hbmass increased similarly in HH (916 to 957 g, 4.5 ± 2.2%, P < 0.001) and in NH (918 to 953 g, 3.8 ± 2.6%, P < 0.001). Hbmass changes did not differ between HH and NH (P = 0.42). There was substantial inter-individual variability among subjects to both interventions (i.e., individual responsiveness, or the individual variation in the response to an intervention free of technical noise): 0.9% in HH and 1.7% in NH. However, a correlation between intra-individual delta Hbmass changes (%) in HH and in NH (r = 0.52, P = 0.048) was observed.; HH and NH evoked similar mean Hbmass increases following LHTL. Among the mean Hbmass changes, there was a notable variation in individual Hbmass response, which tended to be reproducible.
The aim of this study was to compare the accuracy among a high number of current mobile cycling power meters used by elite and recreational cyclists against a first principle-based mathematical model of treadmill cycling. 54 power meters from 9 manufacturers used by 32 cyclists were calibrated. While the cyclist coasted downhill on a motorised treadmill, a back-pulling system was adjusted to counter the downhill force. The system was then loaded 3 times with 4 different masses while the cyclist pedalled to keep his position. The mean deviation (trueness) to the model and coefficient of variation (precision) were analysed. The mean deviations of the power meters were -0.9±3.2% (mean±SD) with 6 power meters deviating by more than±5%. The coefficients of variation of the power meters were 1.2±0.9% (mean±SD), with Stages varying more than SRM (p
The main aim of the present study was to quantify the magnitude of differences introduced when estimating a given blood volume compartment (e.g. plasma volume) through the direct determination of another compartment (e.g. red cell volume) by multiplication of venous haematocrit and/or haemoglobin concentration. However, since whole body haematocrit is higher than venous haematocrit such an approach might comprise certain errors. To test this experimentally, four different methods for detecting blood volumes and haemoglobin mass (Hb; mass; ) were compared, namely the carbon monoxide (CO) re-breathing (for Hb; mass; ), the indocyanine green (ICG; for plasma volume [PV]) and the sodium fluorescein (SoF; for red blood cell volume [RBCV]) methods. No difference between ICG and CO re-breathing derived PV could be established when a whole body/venous haematocrit correction factor of 0.91 was applied (p = 0.11, r = 0.43, mean difference -340 ± 612 mL). In contrast, when comparing RBCV derived by the CO re-breathing and the SoF method, the SoF method revealed lower RBCV values as compared to the CO re-breathing method (p
The purpose of this study was to analyse the effect of bike type – the 26-inch-wheel bike (26” bike) and the 29-inch-wheel bike (29” bike) - on performance in elite mountain bikers. Ten Swiss National Team athletes (7 male, 3 female) completed 6 trials with individual start on a simulated cross-country course with 35 minutes of active recovery between trials (3 trials on a 26” bike and 3 trials on a 29” bike, alternate order, randomised start-bike). The course consisted of two separate sections expected to favour either the 29” bike (section A) or the 26” bike (section B). For each trial performance, power output, cadence and heart rate were recorded and athletes’ experiences were documented. Mean overall performance (time: 304 ± 27 s vs. 311 ± 29 s; p < 0.01) as well as performance in section A (p < 0.001) and B (p < 0.05) were better when using the 29” bike. No significant differences were observed for power output, cadence or heart rate. Athletes rated the 29” bike as better for performance in general, passing obstacles and traction. The 29” bike supports superior performance for elite mountain bikers, even on sections supposed to favour the 26” bike.
Background The aims of the present study were to investigate the impact of three whole blood donations on endurance capacity and hematological parameters and to determine the duration to fully recover initial endurance capacity and hematological parameters after each donation. Methods Twenty-four moderately trained subjects were randomly divided in a donation (n = 16) and a placebo (n = 8) group. Each of the three donations was interspersed by 3 months, and the recovery of endurance capacity and hematological parameters was monitored up to 1 month after donation. Results Maximal power output, peak oxygen consumption, and hemoglobin mass decreased (p
PURPOSE: This study aims to investigate physical performance and hematological changes in 32 elite male team-sport players after 14 d of "live high-train low" (LHTL) training in normobaric hypoxia (≥14 h·d at 2800-3000 m) combined with repeated-sprint training (six sessions of four sets of 5 × 5-s sprints with 25 s of passive recovery) either in normobaric hypoxia at 3000 m (LHTL + RSH, namely, LHTLH; n = 11) or in normoxia (LHTL + RSN, namely, LHTL; n = 12) compared with controlled "live low-train low" (LLTL; n = 9) training. METHODS: Before (Pre), immediately after (Post-1), and 3 wk after (Post-2) the intervention, hemoglobin mass (Hbmass) was measured in duplicate [optimized carbon monoxide (CO) rebreathing method], and vertical jump, repeated-sprint (8 × 20 m-20 s recovery), and Yo-Yo Intermittent Recovery level 2 (YYIR2) performances were tested. RESULTS: Both hypoxic groups similarly increased their Hbmass at Post-1 and Post-2 in reference to Pre (LHTLH: +4.0%, P < 0.001 and +2.7%, P < 0.01; LHTL: +3.0% and +3.0%, both P < 0.001), whereas no change occurred in LLTL. Compared with Pre, YYIR2 performance increased by ∼21% at Post-1 (P < 0.01) and by ∼45% at Post-2 (P < 0.001), with no difference between the two intervention groups (vs no change in LLTL). From Pre to Post-1, cumulated sprint time decreased in LHTLH (-3.6%, P < 0.001) and LHTL (-1.9%, P < 0.01), but not in LLTL (-0.7%), and remained significantly reduced at Post-2 (-3.5%, P < 0.001) in LHTLH only. Vertical jump performance did not change. CONCLUSIONS: "Live high-train low and high" hypoxic training interspersed with repeated sprints in hypoxia for 14 d (in season) increases the Hbmass, YYIR2 performance, and repeated-sprint ability of elite field team-sport players, with benefits lasting for at least 3 wk postintervention.
Duplicate haemoglobin mass (Hbmass) measurements are recommended before and after altitude training sojourns to identify individual adaptations in athletes with a high level of certainty. Duplicate measurements reduce typical error (TE) and disclose measurement outliers, but are usually made on separate days, which is not a practical protocol for routine services in elite sport settings. The aim of this study was therefore to investigate whether it is safe (carboxyhaemoglobin
Abstract PURPOSE: It is unclear if hemoglobin mass (Hbmass) and red cell volume (RCV) increase in endurance athletes with several years of endurance training from adolescence to adulthood. The aim of this study, therefore, was to determine with a controlled cross-sectional approach whether endurance athletes at the ages of 16, 21, and 28 yr are characterized by different Hbmass, RCV, plasma volume (PV), and blood volume (BV). METHODS: BV parameters (CO rebreathing), VO(2max) and other blood, iron, training, and anthropometric parameters were measured in three endurance athlete groups AG16 (n = 14), AG21 (n = 14), and AG28 (n = 16) as well as in three age-matched control groups ( RESULTS: In AG16, body weight-related Hbmass (12.4 ± 0.7 g·kg(-1)), RCV, BV, and VO(2max) (66.1 ± 3.8 mL·kg·(-1)min(-1)) were lower (P < 0.001) than those in AG21 (14.2 ± 1.1 g·kg(-1), 72.9 ± 3.6 mL·kg·(-1)min(-1)) and AG28 (14.6 ± 1.1 g·kg(-1), 73.4 ± 6.0 mL·kg·(-1)min(-1)). Results for these parameters did not differ between AG21 and AG28 and among the control groups. VO(2max), PV, and BV were higher for AG16 than for CG16 (12.0 ± 1.0 g·kg(-1), 58.9 ± 5.0 mL·kg·(-1)min(-1)) but not Hbmass and RCV. CONCLUSIONS: Our results suggest that endurance training has major effects on Hbmass and RCV from ages 16 to 21 yr, although there is no further increase from ages 21 to 28 yr in top endurance athletes. On the basis of our findings, an early detection of the aptitude for endurance sports at age 16 yr, solely based on levels of Hbmass, does not seem to be possible.
Abstract BACKGROUND: Measurements of haemoglobin mass (Hb(mass)) with the carbon monoxide (CO) rebreathing method provide valuable information in the field of sports medicine, and have markedly increased during the last decade. However, several different approaches (as a combination of the rebreathing procedure and subsequent calculations) for measuring Hb(mass) are used, and routine measurements have indicated that the Hb(mass) differs substantially among various approaches. Therefore, the aim of this study was to compare the Hb(mass) of the seven most commonly used approaches, and then to provide conversion factors for an improved comparability of Hb(mass) measured with the different approaches. METHODS: Seventeen subjects (healthy, recreationally active, male, age 27.1 ± 1.8 y) completed 3 CO-rebreathing measurements in randomized order. One was based on the 12-min original procedure (CO(original)), and two were based on the 2-min optimized procedure (CO(new)). From these measurements Hb(mass) for seven approaches (CO(originalA-E); CO(newA-B)) was calculated. RESULTS: Hb(mass) estimations differed among these approaches (p < 0.01). Hb(mass) averaged 960 ± 133 g (CO(newB)), 981 ± 136 g (CO(newA)), 989 ± 130 g (CO(originalE)), 993 ± 126 g (CO(originalA,D)), 1030 ± 130 g (CO(originalB)), and 1053 ± 133 g (CO(originalC)). Procedural variations had a minor influence on measured Hb(mass). CONCLUSIONS: The relevant discrepancies between the CO-rebreathing approaches originate mainly from different underlying calculations for Hb(mass). Provided Hb(mass) enabled the development of conversion factors to compare average Hb(mass) values measured with different CO-rebreathing approaches. These factors can be used to develop reasonable Hb(mass) reference ranges for both clinical and athletic purposes.
Die Untersuchung befasst sich mit der prognostischen Bedeutung von Top-Ten-Platzierungen bei Junioren-Weltmeisterschaften und einer zusätzlichen Top-Ten-Platzierung bei U23-Weltmeisterschaften für den späteren Erfolg im Elitealter. Dabei wurden die jeweils zehn besten Athleten bei den Frauen und...Männern der Junioren-Weltmeisterschaften von 2002 bis 2006 einbezogen und deren Karriereverläufe verfolgt. Die Ergebnisse sollen bei der Talentsichtung Berücksichtigung finden.
