Sustainability of critical power determined by a 3-minute all-out test in elite cyclists

Critical power (CP) is a theoretical workload representative of an athlete's maximal sustainable pace. Recent research has validated a 3-minute all-out test on a cycle ergometer for determining CP; however, few studies have investigated the sustainability of CP using this test. The purpose of this study was to determine the sustainability of CP established during the 3-minute test and the determinants of sustainability. A group of elite cyclists (N = 21) performed a VO2max test, 3-minute all-out test, and a time to exhaustion (TTE) trial at CP on 3 different days separated by at least 24 hours. Expired gases were collected during all trials and analyzed for VO2 and VCO2. Heart rate was measured by telemetry. Multiple regression was used to determine predictors of sustainability with significance predetermined at p < 0.05. VO2max was measured at 58.9 ± 5.6 ml·kg(-1)·min(-1), ventilation breakpoint at 44.9 ± 5.7 ml·kg(-1)·min(-1) (75% VO2max), and maximum heart rate at 179 ± 10 b·min(-1). Peak power (PP) in the 3-minute all-out test was measured at 738 ± 170 W, and CP was determined at 305 ± 32 W or 79% of VO2max. The VO2 at CP was 55.4 ± 6.9 ml·kg(-1)·min(-1), representing 94% of measured VO2max. The mean TTE at CP was 14.79 ± 8.38 minutes. The difference score of PP - CP significantly predicted TTE (r = 0.65, p < 0.05). No other measured variables contributed to this prediction. Based on sustainability, these data suggest that the 3-minute all-out test may overestimate CP in elite cyclists, which could lead to overtraining if CP determined with this test is used to identify training intensities.     

Muscle fiber recruitment and the slow component of O2 uptake: constant work rate vs. all-out sprint exercise

The slow component of pulmonary O(2) uptake (Vo(2)) during constant work rate (CWR) high-intensity exercise has been attributed to the progressive recruitment of (type II) muscle fibers. We tested the following hypotheses: 1) the Vo(2) slow component gain would be greater in a 3-min all-out cycle test than in a work-matched CWR test, and 2) the all-out test would be associated with a progressive decline, and the CWR test with a progressive increase, in muscle activation, as estimated from the electromyogram (EMG) of the vastus lateralis muscle. Eight men (aged 21-39 yr) completed a ramp incremental test, a 3-min all-out test, and a work- and time-matched CWR test to exhaustion. The maximum Vo(2) attained in an initial ramp incremental test (3.97 ± 0.83 l/min) was reached in both experimental tests (3.99 ± 0.84 and 4.03 ± 0.76 l/min for all-out and CWR, respectively). The Vo(2) slow component was greater (P < 0.05) in the all-out test (1.21 ± 0.31 l/min, 4.2 ± 2.2 ml·min(-1)·W(-1)) than in the CWR test (0.59 ± 0.22 l/min, 1.70 ± 0.5 ml·min(-1)·W(-1)). The integrated EMG declined by 26% (P < 0.001) during the all-out test and increased by 60% (P < 0.05) during the CWR test from the first 30 s to the last 30 s of exercise. The considerable reduction in muscle efficiency in the all-out test in the face of a progressively falling integrated EMG indicates that progressive fiber recruitment is not requisite for development of the Vo(2) slow component during voluntary exercise in humans.     

Mechanically braked elliptical Wingate test: modification considerations, load optimization, and reliability

The 30-second, all-out Wingate test evaluates anaerobic performance using an upper or lower body cycle ergometer (cycle Wingate test). A recent study showed that using a modified electromagnetically braked elliptical trainer for Wingate testing (EWT) leads to greater power outcomes because of larger muscle group recruitment. The main purpose of this study was to modify an elliptical trainer using an easily understandable mechanical brake system instead of an electromagnetically braked modification. Our secondary aim was to determine a proper test load for the EWT to reveal the most efficient anaerobic test outcomes such as peak power (PP), average power (AP), minimum power (MP), power drop (PD), and fatigue index ratio (FI%) and to evaluate the retest reliability of the selected test load. Delta lactate responses (ΔLa) were also analyzed to confirm all the anaerobic performance of the athletes. Thirty healthy and well-trained male university athletes were selected to participate in the study. By analysis of variance, an 18% body mass workload yielded significantly greater test outcomes (PP = 19.5 ± 2.4 W·kg, AP = 13.7 ± 1.7 W·kg, PD = 27.9 ± 5 W·s, FI% = 58.4 ± 3.3%, and ΔLa = 15.4 ± 1.7 mM) than the other (12-24% body mass) tested loads (p < 0.05). Test and retest results for relative PP, AP, MP, PD, FI%, and ΔLa were highly correlated (r = 0.97, 0.98, 0.94, 0.91, 0.81, and 0.95, respectively). In conclusion, it was found that the mechanically braked modification of an elliptical trainer successfully estimated anaerobic power and capacity. A workload of 18% body mass was optimal for measuring maximal and reliable anaerobic power outcomes. Anaerobic testing using an EWT may be more useful to athletes and coaches than traditional cycle ergometers because a greater proportion of muscle groups are worked during exercise on an elliptical trainer.     

Laboratory versus outdoor cycling conditions: differences in pedaling biomechanics

The aim of our study was to compare crank torque profile and perceived exertion between the Monark ergometer (818 E) and two outdoor cycling conditions: level ground and uphill road cycling. Seven male cyclists performed seven tests in seated position at different pedaling cadences: (a) in the laboratory at 60, 80, and 100 rpm; (b) on level terrain at 80 and 100 rpm; and (c) on uphill terrain (9.25% grade) at 60 and 80 rpm. The cyclists exercised for 1 min at their maximal aerobic power. The Monark ergometer and the bicycle were equipped with the SRM Training System (Schoberer, Germany) for the measurement of power output (W), torque (Nxm), pedaling cadence (rpm), and cycling velocity (kmxh-1). The most important findings of this study indicate that at maximal aerobic power the crank torque profiles in the Monark ergometer (818 E) were significantly different (especially on dead points of the crank cycle) and generate a higher perceived exertion compared with road cycling conditions.     

Differences in muscle activation between submaximal and maximal 6-minute rowing tests

This study aimed to establish the differences in muscle activation between a 6-minute simulated race (all-out test) and a submaximal (blood lactate [LA] concentration 4 mmol·L(-1)) 6-minute effort (submax test) on a rowing ergometer. Eleven healthy, well-trained subjects performed the submax test followed after 1-hour rest by the all-out test. Surface electromyographic (sEMG) signal of muscles gastrocnemius medialis (GC), rectus femoris (RF), vastus lateralis (VL), biceps femoris, gluteus maximus (GM), erector spinae (ES), lower latissimus dorsi (LD_lo), upper latissimus dorsi (LD_up), brachioradialis (BR) and biceps brachii (BB), and other biomechanical, biochemical, and respiratory parameters were monitored during rowing. During the all-out test, the subjects covered a longer distance with larger average power output, higher stroke frequency, LA concentration, and oxygen consumption compared to the submax test (p < 0.05). During the submax test, the average rectified values (ARVs) of sEMG signal increased significantly only in the RF and LD_lo muscles. During the all-out test, the ARVs of the RF, VL, and GM muscles increased (p < 0.05), whereas the MDFs of the RF, ES, and LD_lo muscles decreased (p < 0.05). Compared to the submax test, the ARVs of the GC, RF, VL, LD_lo, LD_up, and BB muscles were significantly higher during the all-out test. However, only for the RF muscle, the all-out test resulted in a significantly lower MDF value compared to the submax test. The most involved muscles that would need special attention in training seem to be the leg and shoulder girdle extensors and arm flexors but not the trunk and hip extensors.     

Heart rate and perceived exertion during self-selected intensities for exergaming compared to traditional exercise in college-age participants

Exergames may be useful for promoting physical activity in younger populations. Heart rate (HRs) responses and rating of perceived exertion (RPE) at self-selected intensities were compared in college-age participants during 2 modes of exergame activity vs. traditional exercise. Thirty-seven participants (men: 20, women: 17) completed 3 30-minute self-selected intensity trials: (a) video game interactive bicycle ergometer (GB) (CatEye GB300), (b) interactive video dance game (Dance Dance Revolution [DDR]), and (c) traditional cycle ergometer (CE) while watching television. Mean HR, peak HR (PkHR), and minutes above target HR (THR) were significantly higher for GB (144 ± 22 b · min(-1) [57% HR reserve (HRR)], 161 ± 23 b · min(-1), and 22.5 ± 11.1 minutes) than for DDR (119 ± 16 b · min(-1) [37% HRR], 138 ± 20 b · min(-1), and 11.2 ± 11.9 minutes) or for CE (126 ± 20 b · min(-1) [42% HRR], 144 ± 24 b · min(-1), and 14.2 ± 12.6 minutes). The RPE was significantly higher for GB (4.2 ± 1.5) and CE (3.8 ± 1.2) than for DDR (2.7 ± 1.3). Recovery HR (RecHR) (15 minutes postexercise) was significantly higher for GB (91 ± 14 b · min(-1)) than for DDR (80 ± 11 b · min(-1)) and neared significance vs. CE (84 ± 14 b · min(-1), p = 0.059). No difference in PkHR, RecHR, or minutes above THR was observed between DDR and CE. Session RPE was significantly higher for GB (4.6 ± 1.7) and CE (4.1 ± 1.6) than for DDR (2.8 ± 1.5). All modes elicited extended proportions of time above THR; GB: 75%, DDR: 37%, and CE: 47%. Results support that exergames are capable of eliciting physiological responses necessary for fitness improvements. Practitioners might consider exergames as periodic activity options for clients needing motivation to be regularly active.     

All out anaerobic capacity tests on cycle ergometers. A comparative study on men and women

We have studied the effects of the braking force on the results of an anaerobic capacity test derived from the Wingate test (an all out 45 s exercise on a Monark 864 cycle ergometer against a given force at the fastest velocity from the beginning to the end of the test). Seven men and seven women participated in the study and performed a total of 63 all-out tests against different braking forces. The same subjects performed a force-velocity test on the same cycle ergometer. Since the relationship between force and velocity is approximately linear for peak velocities between 100 and 200 rev X min-1 (Pérès et al. 1981a, b; Nadeau et al. 1983; Vandewalle et al. 1983) we characterized each subject by three parameters: P0 (the intercept of the force-velocity regression line with the force axis), V0 (the intercept of the regression line with the velocity axis) and Wmax (maximal power). The relationship between force and mean power was parabolic for the all-out anaerobic capacity test. In the present study the optimal force (the force giving the maximal value of mean power during an all out test) was higher for the men (approximately 1 N X kg BW-1) than the force proposed by others (0.853 N X kg BW-1 for Dotan and Bar-Or 1983). However, because of the parabolic relationship between force and mean power, the mean power which corresponds to the optimal force was approximately the same in both studies.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of the immediate effects of resistance, aerobic, and concurrent exercise on postexercise hypotension

A comparison of the immediate effects of resistance, aerobic, and concurrent exercise on postexercise hypotension. The influence of resistance exercise (RE), aerobic exercise (AE), and concurrent exercise (CE) on postexercise hypotension (PEH) is not known. We investigated the immediate blood pressure (BP) lowering effects of exercise after RE, AE, and CE sessions among healthy subjects. Twenty-one men (20.7 ± 0.7 years) performed 4 experimental sessions each in a within-subject design: control (CTL-seated rest for 60 minutes), RE (3 sets at 80% 1RM for 8 exercises, including upper and lower limbs), AE (7-minutes warm-up followed by 50 minutes of cycle ergometer exercise at 65% VO?peak and 3-minute cooldown), and CE (2 sets at 80% 1RM for 6 exercises among those which composed the RE session, plus 20 minutes of cycle ergometer exercise at 65% VO?peak, 7-minute warm-up and 3-minute cooldown, exactly in this order). The total duration of each exercise session was approximately 60 minutes. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were assessed by ambulatory monitoring at rest (20 minutes) and every 10 minutes after the exercise during 120 minutes while in the laboratory. The duration of the decrease in SBP was longer after AE and CE (120 minutes) compared to RE (80 minutes); and for DBP after AE (50 minutes) compared to CE (40 minutes) and RE (20 minutes) (p < 0.05). The magnitude of the decrease in SBP and DBP was similar after all exercise sessions and significantly different from CTL (p < 0.05) (SBP: RE = 4.1 ± 2.0 mm Hg, AE = 6.3 ± 1.3 mm Hg, CE = 5.1 ± 2.2 mm Hg; DBP: RE = 1.8 ± 1.1 mm Hg, AE = 1.8 ± 1.0 mm Hg, CE = 1.6 ± 0.6 mm Hg). It was concluded that exercise sessions combining aerobic and resistance activities are as effective as AE sessions and more effective than RE sessions to promote PEH.     

Influence of training status on maximal accumulated oxygen deficit during all-out cycle exercise

The influence of training status on the maximal accumulated oxygen deficit (MAOD) was used to assess the validity of the MAOD method during supramaximal all-out cycle exercise. Sprint trained (ST; n = 6), endurance trained (ET; n = 8), and active untrained controls (UT; n = 8) completed a 90 s all-out variable resistance test on a modified Monark cycle ergometer. Pretests included the determination of peak oxygen uptake ( O_2peak) and a series (5–8) of 5-min discontinuous rides at submaximal exercise intensities. The regression of steady-state oxygen uptake on power output to establish individual efficiency relationships was extrapolated to determine the theoretical oxygen cost of the supramaximal power output achieved in the 90 s all-out test. Total work output in 90 s was significantly greater in the trained groups (P<0.05), although no differences existed between ET and ST. Anaerobic capacity, as assessed by MAOD, was larger in ST compared to ET and UT. While the relative contributions of the aerobic and anaerobic energy systems were not significantly different among the groups, ET were able to achieve significantly more aerobic work than the other two groups, while ST were able to achieve significantly more anaerobic work. Peak power and peak pedalling rate were significantly higher in ST. The results suggested that MAOD determined during all-out exercise was sensitive to training status and provided a useful assessment of anaerobic capacity. In our study sprint training, compared with endurance training, appeared to enhance significantly power output and high intensity performance over brief periods (up to 60 s), yet few overall differences in performance (i.e. total work) existed during 90 s of all-out exercise.     

Dynamic calibration of mechanically, air- and electromagnetically braked cycle ergometers

In this study we measured the accuracy of the following types of cycle ergometer against the criterion of a dynamic calibration rig (DCR): 35 friction-braked (Monark), 5 research-grade air-braked (Repco) and 5 electromagnetically braked (2 Siemens, 1 Elema-Schonander, 1 Ergoline, l Warren E. Collins). Monark ergometer power outputs over the range 58.9–353.2 W significantly (P < 0.001) underestimated those registered by the DCR with mean accuracies of 91.7–97.8%. The least accurate individual reading for each of the six up-scale (0–353.2 W) power outputs ranged from 81.6␣to␣91.6%; corresponding down-scale (353.2–0 W) accuracies were 85.1–92.5%. A hysteresis effect was furthermore evident for this ergometer in that up-scale measurements were significantly (P < 0.05) greater than down-scale ones. In addition, when the oldest [mean (SD): 11.3 (2.3) years old] and newest [1.4 (0.8) years old] eight ergometers were compared, the latter were significantly (P < 0.05) more accurate over the range 117.7–294.3 W. Apart from the two lowest power outputs of 47␣W (62.2–96.0% accuracy) and 127 W (88.0–97.7% accuracy), the individual up-scale and down-scale accuracies of the Repco ergometers ranged from 98.0 to 104.2% for power outputs of 272.7–1137.8 W and the means were not significantly different from those of the DCR. There was also no evidence of hysteresis. Except for the initial power output of 50 W (40 rev/min: 83.8–99.2% accuracy; 60 rev/min: 93.2–122.6% accuracy), the␣individual accuracies of the electromagnetically braked ergometers ranged from 89.3 to 101.4% over the up-scale range of 100–400 W, and none of the means were significantly different from those of the DCR. The variability of individual errors for the preceding data emphasises that all cycle ergometers should be validated against the criterion of a DCR if accurate power outputs are required. Accepted: 19 February 1998     

A novel cardiopulmonary exercise test protocol and criterion to determine maximal oxygen uptake in chronic heart failure

Cardiopulmonary exercise testing for peak oxygen uptake (Vo(2peak)) can evaluate prognosis in chronic heart failure (CHF) patients, with the peak respiratory exchange ratio (RER(peak)) commonly used to confirm maximal effort and maximal oxygen uptake (Vo(2max)). We determined the precision of RER(peak) in confirming Vo(2max), and whether a novel ramp-incremental (RI) step-exercise (SE) (RISE) test could better determine Vo(2max) in CHF. Male CHF patients (n = 24; NYHA class I-III) performed a symptom-limited RISE-95 cycle ergometer test in the format: RI (4-18 W/min; ～10 min); 5 min recovery (10 W); SE (95% peak RI work rate). Patients (n = 18) then performed RISE-95 tests using slow (3-8 W/min; ～15 min) and fast (10-30 W/min; ～6 min) ramp rates. Pulmonary gas exchange was measured breath-by-breath. Vo(2peak) was compared within patients by unpaired t-test of the highest 12 breaths during RI and SE phases to confirm Vo(2max) and its 95% confidence limits (CI(95)). RER(peak) was significantly influenced by ramp rate (fast, medium, slow: 1.21 ± 0.1 vs. 1.15 ± 0.1 vs. 1.09 ± 0.1; P = 0.001), unlike Vo(2peak) (mean n = 18; 14.4 ± 2.6 ml·kg(-1)·min(-1); P = 0.476). Group Vo(2peak) was similar between RI and SE (n = 24; 14.5 ± 3.0 vs. 14.7 ± 3.1 ml·kg(-1)·min(-1); P = 0.407); however, within-subject comparisons confirmed Vo(2max) in only 14 of 24 patients (CI(95) for Vo(2max) estimation averaged 1.4 ± 0.8 ml·kg(-1)·min(-1)). The RER(peak) in CHF was significantly influenced by ramp rate, suggesting its use to determine maximal effort and Vo(2max) be abandoned. In contrast, the RISE-95 test had high precision for Vo(2max) confirmation with patient-specific CI(95) (without secondary criteria), and showed that Vo(2max) is commonly underestimated in CHF. The RISE-95 test was well tolerated by CHF patients, supporting its use for Vo(2max) confirmation.     

Comparison between a 30-s all-out test and a time-work test on a cycle ergometer

The relationship between the amount of work (Wlim) performed at the end of constant-power exhausting exercise and exhaustion time (tlim) has been studied for supramaximal exercise [105%, 120%, 135% and 150% of the individual maximal aerobic power, (MAP)] performed on a Monark cycle ergometer in nine men. The Wlim--tlim relationship was described by a linear relationship (Wlim = a + b . tlim). Intercept a was roughly equivalent to the work produced during a 1-min exercise performed at MAP. Slope b was equal to 79% of MAP. Intercept a has been correlated with the total amount of work (AW) performed during a 30-s all-out test supposed to assess anaerobic capacity. Intercept a was significantly (p less than 0.05) correlated with AW. The anaerobic capacity was not depleted at the end of the all-out test, as the mechanical power at the 30th s of this test was approximately equal to twice MAP. However, AW was significantly higher than intercept a. It was likely that the value of intercept a was an underestimation of the maximal anaerobic capacity because of the inertia of the aerobic metabolism. Indeed, an exponential model of the Wlim--tlim relationship, which takes the interia of the aerobic metabolism into account, shows that a linear approximation of the Wlim--tlim relationship yields a systematic underestimation of the anaerobic capacity. Consequently, intercept a of the Wlim--tlim relationship is not a more accurate estimation of the anaerobic capacity than the AW performed during a 30-s all-out test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maximal lactate steady-state independent of recovery period during intermittent protocol

Barbosa, LF, de Souza, MR, Corrêa Caritá, RA, Caputo, F, Denadai, BS, and Greco, CC. Maximal lactate steady-state independent of recovery period during intermittent protocol. J Strength Cond Res 25(12): 3385-3390, 2011-The purpose of this study was to analyze the effect of the measurement time for blood lactate concentration ([La]) determination on [La] (maximal lactate steady state [MLSS]) and workload (MLSS during intermittent protocols [MLSSwi]) at maximal lactate steady state determined using intermittent protocols. Nineteen trained male cyclists were divided into 2 groups, for the determination of MLSSwi using passive (VO(2)max = 58.1 ± 3.5 ml·kg·min; N = 9) or active recovery (VO(2)max = 60.3 ± 9.0 ml·kg·min; N = 10). They performed the following tests, in different days, on a cycle ergometer: (a) Incremental test until exhaustion to determine (VO(2)max and (b) 30-minute intermittent constant-workload tests (7 × 4 and 1 × 2 minutes, with 2-minute recovery) to determine MLSSwi and MLSS. Each group performed the intermittent tests with passive or active recovery. The MLSSwi was defined as the highest workload at which [La] increased by no more than 1 mmol·L between minutes 10 and 30 (T1) or minutes 14 and 44 (T2) of the protocol. The MLSS (Passive-T1: 5.89 ± 1.41 vs. T2: 5.61 ± 1.78 mmol·L) and MLSSwi (Passive-T1: 294.5 ± 31.8 vs. T2: 294.7 ± 32.2 W; Active-T1: 304.6 ± 23.0 vs. T2: 300.5 ± 23.9 W) were similar for both criteria. However, MLSS was lower in T2 (4.91 ± 1.91 mmol·L) when compared with in T1 (5.62 ± 1.83 mmol·L) using active recovery. We can conclude that the MLSSwi (passive and active conditions) was unchanged whether recovery periods were considered (T1) or not (T2) for the interpretation of [La] kinetics. In contrast, MLSS was lowered when considering the active recovery periods (T2). Thus, shorter intermittent protocols (i.e., T1) to determine MLSSwi may optimize time of the aerobic capacity evaluation of well-trained cyclists.     

Single bouts of exercise affect albumin redox state and carbonyl groups on plasma protein of trained men in a workload-dependent manner.

The purpose of this study was to investigate the effect of single bouts of exercise at three different intensities on the redox state of human serum albumin (HSA) and on carbonyl groups on protein (CP) concentrations in plasma. Trained men [n = 44, maximal oxygen consumption (Vo(2max)): 55 +/- 5 ml.kg(-1).min(-1), nonsmokers, 34 +/- 5 years of age] from a homogenous population, volunteers from a police special forces unit, were randomly assigned to perform on a cycle ergometer either at 70% (n = 14), 75% (n = 14), or 80% (n = 16) of Vo(2max) for 40 min. Blood was collected before exercise, immediately after the exercise test (IE), and 30 min after each test (30M) and 30 h after each test (30H). The reduced fraction of HSA, human mercaptalbumin (HMA), decreased at all three exercise intensities IE and 30M, returning to preexercise values by 30H (P < 0.05). HMA was primarily oxidized to its reversible fraction human nonmercaptalbumin 1 (HNA1). CP concentrations increased at 75% of Vo(2max) IE and 30M with a tendency (P < 0.1) and at 80% Vo(2max) IE and 30M significantly, returning to preexercise concentrations by 30H (P < 0.01). These results indicate that the HSA redox system in plasma is activated after a single bout of cycle ergometer exercise at 70% Vo(2max) and 40 min duration. The extent of the HSA modification increased with exercise intensity. Oxidative protein damage, as indicated by CP, was only significantly increased at 80% Vo(2max) intensity in this homogenous cohort of trained men.     

Time course for recovery of peak aerobic power after blood donation

Peak aerobic power (VO2peak) is decreased after blood donation, but the time course for full recovery is unknown. We measured VO2peak and exercise time to fatigue before and weekly for 4 weeks after 450-ml blood donation at a blood donor clinic, to determine the time course of recovery. Twelve moderately active individuals (2 women, 10 men; 24.3 ± 5.2 years) of average aerobic fitness (based on their VO2peak relative to normative values) completed VO2peak exercise tests before donation, the day after donation, and at weekly intervals for 4 weeks after donation. VO2peak was determined by an incremental exercise test on a cycle ergometer. At baseline, mean absolute and relative VO2peak values were 4.06 ± 0.92 L·min(-1) and 46.6 ± 7.0 ml·kg(-1)·min(-1), respectively. VO2peak was significantly decreased on day 1 (3.85 ± 0.89 L·min(-1); 44.0 ± 6.5 ml·kg(-1)·min(-1)) and during week 2 (3.91 ± 0.97 L·min(-1); 44.5 ± 7.2 ml·kg(-1)·min(-1)) after blood donation (p < 0.05), and recovered at week 3 after donation. Time to fatigue and peak heart rate were not significantly affected by blood donation. We conclude that blood donation causes a significant decrease in VO2peak for between 2 and 3 weeks. The practical application of this study is that aerobic power in people of average fitness will be decreased, up to 3 weeks after donating blood. Despite this, there is no effect of blood donation on performance as measured by time to fatigue during an incremental test on a cycle ergometer.     

Blood lactate in trained cyclists during cycle ergometry at critical power

The purposes of this investigation were to determine the validity of critical power (CP) as a measure of the work rate that can be maintained for a very long time without fatigue and to determine whether this corresponded with the maximal lactate steady-state (lass,max). Eight highly trained endurance cyclists (maximal oxygen uptake 74.1 ml.kg-1.min-1, SD 5.3) completed four cycle ergometer tests to exhaustion at pre-determined work rates (360, 425, 480 and 520 W). From these four co-ordinates of work and time to fatigue the regression of work limit on time limit was calculated for each individual (CP). The cyclists were then asked to exercise at their CP for 30 min. If CP could not be maintained, the resistance was reduced minimally to allow the subject to complete the test and maintain a blood lactate plateau. Capillary blood was sampled at 0,5,10,20 and 30 min into exercise for the analysis of lactate. Six of the eight cyclists were unable to maintain CP for 30 min without fatigue. In these subjects, the mean power attained was 6.4% below that estimated by CP. Mean blood lactates (n = 8) reached a steady-state (8.9 mmol.l-1 SD 1.6) during the last 20 min of exercise indicating that CP slightly overestimated lass,max, Individual blood lactates during the last 20 min of exercise were more closely related to the gamma-intercept of the CP curve (r = 0.78, P less than 0.05) than either CP (0.34, NS) or mean power output (r = 0.42, NS).     

Sprint performance-duration relationships are set by the fractional duration of external force application

We hypothesized that the maximum mechanical power outputs that can be maintained during all-out sprint cycling efforts lasting from a few seconds to several minutes can be accurately estimated from a single exponential time constant (k(cycle)) and two measurements on individual cyclists: the peak 3-s power output (P(mech max)) and the maximum mechanical power output that can be supported aerobically (P(aer)). Tests were conducted on seven subjects, four males and three females, on a stationary cycle ergometer at a pedal frequency of 100 rpm. Peak mechanical power output (P(mech max)) was the highest mean power output attained during a 3-s burst; the maximum power output supported aerobically (P(aer)) was determined from rates of oxygen uptake measured during a progressive, discontinuous cycling test to failure. Individual power output-duration relationships were determined from 13 to 16 all-out constant load sprints lasting from 5 to 350 s. In accordance with the above hypothesis, the power outputs measured during all-out sprinting efforts were estimated to within an average of 34 W or 6.6% from P(mech max), P(aer), and a single exponential constant (k(cycle) = 0.026 s(-1)) across a sixfold range of power outputs and a 70-fold range of sprint trial durations (R2 = 0.96 vs. identity, n = 105; range: 180 to 1,136 W). Duration-dependent decrements in sprint cycling power outputs were two times greater than those previously identified for sprint running speed (k(run) = 0.013 s(-1)). When related to the respective times of pedal and ground force application rather than total sprint time, decrements in sprint cycling and running performance followed the same time course (k = 0.054 s(-1)). We conclude that the duration-dependent decrements in sprinting performance are set by the fractional duration of the relevant muscular contractions.     

Physiological correlates of skating performance in women's and men's ice hockey

The purpose of the current investigation was to identify relationships between physiological off-ice tests and on-ice performance in female and male ice hockey players on a comparable competitive level. Eleven women, 24 ± 3.0 years, and 10 male ice hockey players, 23 ± 2.4 years, were tested for background variables: height, body weight (BW), ice hockey history, and lean body mass (LBM) and peak torque (PT) of the thigh muscles, VO2peak and aerobic performance (Onset of Blood Lactate Accumulation [OBLA], respiratory exchange ratio [RER1]) during an incremental bicycle ergometer test. Four different on-ice tests were used to measure ice skating performance. For women, skating time was positively correlated (p < 0.05) to BW and negatively correlated to LBM%, PT/BW, OBLA, RER 1, and VO2peak (ml O2·kg(-1) BW(-1)·min(-1)) in the Speed test. Acceleration test was positively correlated to BW and negatively correlated to OBLA and RER 1. For men, correlation analysis revealed only 1 significant correlation where skating time was positively correlated to VO2peak (L O2·min(-1)) in the Acceleration test. The male group had significantly higher physiological test values in all variables (absolute and relative to BW) but not in relation to LBM. Selected off-ice tests predict skating performance for women but not for men. The group of women was significantly smaller and had a lower physiological performance than the group of men and were slower in the on-ice performance tests. However, gender differences in off-ice variables were reduced or disappeared when values were related to LBM, indicating a similar capacity of producing strength and aerobic power in female and male hockey players. Skating performance in female hockey players may be improved by increasing thigh muscle strength, oxygen uptake, and relative muscle mass.