Maximal Blood Lactate Concentration Research Articles

Repeated-Sprint Training in Hypoxia Induced by Voluntary Hypoventilation in Swimming.

Repeated-sprint training in hypoxia (RSH) has been shown as an efficient method for improving repeated-sprint ability (RSA) in team-sport players but has not been investigated in swimming. We assessed whether RSH with arterial desaturation induced by voluntary hypoventilation at low lung volume (VHL) could improve RSA to a greater extent than the same training performed under normal breathing (NB) conditions. Sixteen competitive swimmers completed 6 sessions of repeated sprints (2 sets of 16 × 15 m with 30 s send-off) either with VHL (RSH-VHL, n = 8) or with NB (RSN, n = 8). Before and after training, performance was evaluated through an RSA test (25-m all-out sprints with 35 s send-off) until exhaustion. From before to after training, the number of sprints was significantly increased in RSH-VHL (7.1 ± 2.1 vs 9.6 ± 2.5; P < .01) but not in RSN (8.0 ± 3.1 vs 8.7 ± 3.7; P = .38). Maximal blood lactate concentration ([La]max) was higher after than before in RSH-VHL (11.5 ± 3.9 vs 7.9 ± 3.7 mmol/L; P = .04) but was unchanged in RSN (10.2 ± 2.0 vs 9.0 ± 3.5 mmol/L; P = .34). There was a strong correlation between the increases in the number of sprints and in [La]max in RSH-VHL only (R = .93, P < .01). RSH-VHL improved RSA in swimming, probably through enhanced anaerobic glycolysis. This innovative method allows inducing benefits normally associated with hypoxia during swim training in normoxia.

Do maximal aerobic power and blood lactate concentration affect Specific Judo Fitness Test performance in female judo athletes?

The Special Judo Fitness Test (SJFT) has become the test most widely used by coaches and physical trainers for assessment of competitors’ judo-specific physical aptitude and training programme prescription. The aim of this study was to investigate the relationship between the SJFT performance indices and both maximal aerobic power and the level of blood lactate concentrations in female judo athletes. Seventeen female judokas (age: 21.9±1.6 years, body mass: 74.6±27.4 kg, height: 164.5±8.6 cm; BMI: 27.1±8.0 kg · m-2) took part in this study. All participants performed the SJFT, 20 m multi-stage shuttle run test (MSRT), and 30 m straight sprint test (SST), from which we calculated both acceleration (10 m) and the maximal anaerobic speed (MAnS: flying 20 m sprint). A blood sample was taken 3 min after the SJFT. The number of throws was significantly correlated with estimated VO2max (r=0.795, p=0.0001) and both acceleration (r=0.63, p =0.006) and MAnS (r=0.76, p=0.0004). Peak blood lactate recorded after the SJFT was 13.90±1.39 mmol · l-1. No significant correlation was found between blood lactate concentration and the SJFT performance indices. The lack of significant correlation between blood lactate and SJFT performance suggests that lactic anaerobic metabolism has no effect on this type of judo-specific supra-maximal exercise. The observed results can provide coaches and strength and conditioning professionals with relevant information for the interpretation of SJFT performance and the prescription of specific training programmes for female judo athletes.

Bayesian Estimation of Small Effects in Exercise and Sports Science.

The aim of this paper is to provide a Bayesian formulation of the so-called magnitude-based inference approach to quantifying and interpreting effects, and in a case study example provide accurate probabilistic statements that correspond to the intended magnitude-based inferences. The model is described in the context of a published small-scale athlete study which employed a magnitude-based inference approach to compare the effect of two altitude training regimens (live high-train low (LHTL), and intermittent hypoxic exposure (IHE)) on running performance and blood measurements of elite triathletes. The posterior distributions, and corresponding point and interval estimates, for the parameters and associated effects and comparisons of interest, were estimated using Markov chain Monte Carlo simulations. The Bayesian analysis was shown to provide more direct probabilistic comparisons of treatments and able to identify small effects of interest. The approach avoided asymptotic assumptions and overcame issues such as multiple testing. Bayesian analysis of unscaled effects showed a probability of 0.96 that LHTL yields a substantially greater increase in hemoglobin mass than IHE, a 0.93 probability of a substantially greater improvement in running economy and a greater than 0.96 probability that both IHE and LHTL yield a substantially greater improvement in maximum blood lactate concentration compared to a Placebo. The conclusions are consistent with those obtained using a ‘magnitude-based inference’ approach that has been promoted in the field. The paper demonstrates that a fully Bayesian analysis is a simple and effective way of analysing small effects, providing a rich set of results that are straightforward to interpret in terms of probabilistic statements.

Effect of Gender, Energetics, and Biomechanics on Swimming Masters Performance.

The purpose of this study was to analyze the effect of gender and energetics on biomechanics and performance of masters swimmers over 1 season. Twenty-five masters swimmers (14 male and 11 female) were assessed 3 times (TP1, TP2, and TP3) during a season (male personal record in 200-m freestyle event: 173.00 ± 31.41 seconds: female personal record in 200-m freestyle event: 200.73 ± 25.02 seconds). An incremental 5 × 200-m step test was selected to evaluate velocity at 4 mmol·l⁻¹ of blood lactate concentration (v4), maximal blood lactate concentration after exercise (La(peak)), maximal oxygen uptake (V̇O2max), stroke frequency, stroke length (SL), stroke index (SI), and propelling efficiency of the arm stroke (η(p)). The 200-m freestyle performance and average swimming velocity (v200) were also monitored. Significant differences were observed between males and females for the 200-m freestyle performance, SL, SI, and La(peak). Performance (205.18 ± 24.47 seconds; 197.45 ± 20.97 seconds; 193.45 ± 18.12 seconds), SL (1.69 ± 0.17 m; 1.79 ± 0.13 m; 1.78 ± 0.15 m), SI (1.68 ± 0.31 m²·c⁻¹·s⁻¹; 1.83 ± 0.27 m²·c⁻¹·s⁻¹; 1.85 ± 0.27 m²·c⁻¹·s⁻¹), η(p) (0.32 ± 0.04; 0.33 ± 0.03; 0.33 ± 0.04), and V̇O2max (38.71 ± 3.44 ml·kg⁻¹·min⁻¹; 43.43 ± 3.71 ml·kg⁻¹·min⁻¹; 43.95 ± 7.02 ml·kg⁻¹·min⁻¹) have changed significantly throughout the season (TP1, TP2, and TP3, respectively) in female swimmers. In male, significant changes were found in η(p) (0.33 ± 0.07; 0.36 ± 0.05; 0.36 ± 0.06) and V̇O2max (41.65 ± 7.30 ml·kg⁻¹·min⁻¹; 45.19 ± 6.55 ml·kg⁻¹·min⁻¹; 50.19 ± 9.65 ml·kg⁻¹·min⁻¹) over the season (TP1, TP2, and TP3, respectively). Gender presented a significant effect on SL (TP2: η(p)² = 0.29; TP3: η(p)² = 0.37), SI (TP2: η(p)² = 0.25), and La(peak) (TP3: η(p)² = 0.42). v4 (TP1: η(p)² = 0.23), SL (TP1: η(p)² = 0.46), SI (TP1: η(p)² = 0.78; TP2: η(p)² = 0.37; TP3: η(p)² = 0.32), and η(p) (TP1: η(p)² = 0.28) had a significant effect on performance. Male masters swimmers have better performance, SL, SI, and La(peak) than female counterparts. Female masters swimmers enhanced significantly the 200-m freestyle performance over the season due to the improvement in swimming technique (SL, SI, and η(p)) and energetic factors (v4 and V̇O2max). Nonsignificant improvements were observed for the males' performance. Gender has a significant effect on SL, SI, and La(peak). Therefore, performance is more dependent on technical factors than energetics.

Verification criteria for the determination of Vo2 MAX in the field.

The purpose of this study was to evaluate if a verification test (VT) performed in the field offers more confident results than do traditional criteria in the determination of maximal oxygen uptake ((Equation is included in full-text article.)). Twelve amateur runners (age, 36.6 ± 6.6 years) performed a maximal graded field test and after 15 minutes of passive recovery a supramaximal test to exhaustion at 105% of their velocity associated with (Equation is included in full-text article.)(v(Equation is included in full-text article.)). Traditional criteria and 2 different verification criteria were evaluated. Verification criteria were (a) maximal oxygen uptake achieved in the VT ((Equation is included in full-text article.)) must be ≤5% higher than (Equation is included in full-text article.), and (b) no significant differences of means between tests. All participants met the first verification criterion although significant differences were found between (Equation is included in full-text article.)and (Equation is included in full-text article.)(59.4 ± 5.1 vs. 56.2 ± 4.7 ml·kg·min, p < 0.01). The criteria for the plateau, peak heart rate (HRpeak), maximum respiratory exchange ratio (RERmax), and maximum blood lactate concentration ([La]max) were satisfied by 75, 66, 92, and 66 of the participants, respectively. Kappa coefficients gave a significant and substantial agreement beyond chance between traditional criteria (p < 0.001). Despite the substantial agreement, traditional criteria induced the rejection of participants that might have achieved a true (Equation is included in full-text article.)with HRpeak and [La]max being the more stringent criteria for amateur runners. A verification protocol in the field using the criterion based on individual analysis is recommended.

Test–retest reliability of second lactate turnpoint using two different criteria in competitive cyclists

The aim of this study was to determine the relative and absolute reliability of second lactate turnpoint using fixed and individual blood lactate method in competitive cyclists. Twenty-eight male, well-trained cyclists (30.2 ± 10.1 years, 72.0 ± 7.4 kg, 177.3 ± 4.7 cm) were recruited to participate in this study. Cyclists completed two incremental cycling tests to exhaustion over a period of 7 days to determine their peak power output, maximal oxygen uptake, maximal heart rate, maximal blood lactate concentration and two lactate turnpoint criteria. The fixed blood concentration criterion (3.5 mM) and an individual criterion were assessed by a lactate-power curve, considering power output, heart rate and oxygen uptake. The main finding of this study was that both lactate turnpoint criteria showed identical low within-subject variation for power output (2.8% coefficient of variation). High values for test–retest correlations ranging from r = 0.70 to r = 0.94 were found for all variables in both threshold criteria. In conclusion, the individual and fixed method to determine the second lactate turnpoint showed similar high absolute and relative reliability in competitive cyclists.

High Intensity Training and Energy Production During 90-Second Box Jump in Junior Alpine Skiers

Alpine ski races can last up to 2.5 minutes and have very high metabolic demands. One limiting factor for performance is insufficient aerobic energy supply. We studied the effects of an 8-day interval training block on aerobic capacity (VO2max) and performance and physiology during the 90-second box jump test (BJ90), a maximal performance test employed to simulate the metabolic demands of alpine ski racing, in elite junior skiers. After 10 high-intensity interval training sessions, performed as cycling, running, or an obstacle course, VO2max increased in all subjects by 2.5 ± 1.9 ml · minute(-1) · kg(-1) (4.3 ± 3.2%), as did maximal blood lactate concentration in a graded cycling test (before: 11.7 ± 1.3 mmol · L(-1), after: 14.8 ± 1.8 mmol · L(-1), both parameters p ≤ 0.05). Performance (total jumps) and aerobic energy contribution (63.3 ± 2.8%) during the BJ90 did not increase as hypothesized; however, subjects altered their pacing strategy, which may have counteracted such an effect. Additionally, the present data support the practicality of the performance test used for mimicking the demands of alpine skiing.

Physiological and metabolic responses as function of the mechanical load in resistance exercise

The present study aimed to investigate the relationship between the mechanical load during resistance exercise and the elicited physiological responses. Ten resistance-trained healthy male subjects performed 1 set of resistance exercise each at 55%, 70%, and 85% of 1 repetition maximum for as many repetitions as possible and in 4 training modes: 4-1-4-1 (4 s concentric, 1 s isometric, 4 s eccentric, and 1 s isometric successive actions), 2-1-2-1, 1-1-1-1, and explosive (maximum velocity concentric). Mean concentric power and total concentric work were determined. Oxygen uptake (V̇O2) was measured during exercise and for 30 min post exercise. Total volume of consumed oxygen (O2 consumed) and excess post-exercise oxygen consumption (EPOC) were calculated. Maximum blood lactate concentration (LAmax) was also determined. V̇O2 exhibited a linear dependency on mean concentric power. Mean concentric power did not have a detectable effect on EPOC and LAmax. An augmentation of total concentric work resulted in significant linear increase of O2 consumed and EPOC. Total concentric work caused a significant increase in LAmax. In general, a higher mechanical load induced a larger physiological response. An increase in mean concentric power elicited higher aerobic energy turnover rates. However, a higher extent of total concentric work augments total energy cost covered by oxidative and (or) glycolytic pathways.

THE COMPETITIVE DEMANDS OF ELITE MALE RINK HOCKEY

The aim of this study was to simulate the activity pattern of rink hockey by designing a specific skate test (ST) to study the energy expenditure and metabolic responses to this intermittent high-intensity exercise and extrapolate the results from the test to competition. Six rink hockey players performed, in three phases, the 20-metre multi-stage shuttle roller skate test, a tournament match and the ST. Heart rate was monitored in all three phases. Blood lactate, oxygen consumption, ventilation and respiratory exchange ratio were also recorded during the ST. Peak HR was 190.7±7.2 beats · min−1. There were no differences in peak HR between the three tests. Mean HR was similar between the ST and the match (86% and 87% of HRmax, respectively). Peak and mean ventilation averaged 111.0±8.8 L · min−1 and 70.3±14.0 L · min−1 (60% of VEmax), respectively. VO2max was 56.3±8.4 mL · kg−1 · min−1, and mean oxygen consumption was 40.9±7.9 mL · kg−1 · min−1 (70% of VO2max). Maximum blood lactate concentration was 7.2±1.3 mmol · L-1. ST yielded an energy expenditure of 899.1±232.9 kJ, and energy power was 59.9±15.5 kJ · min−1. These findings suggest that the ST is suitable for estimating the physiological demands of competitive rink hockey, which places a heavy demand on the aerobic and anaerobic systems, and requires high energy consumption.

Mechanical Load and Physiological Responses of Four Different Resistance Training Methods in Bench Press Exercise

The purpose of the study was to compare the mechanical impact and the corresponding physiological responses of 4 different and often practically applied resistance training methods (RTMs). Ten healthy male subjects (27.3 ± 3.2 years) experienced in resistance training performed 1 exhausting set of bench press exercise until exhaustion for each of the following RTMs: strength endurance (SE), fast force endurance (FFE), hypertrophy (HYP), and maximum strength (MAX). The RTMs were defined by different lifting masses and different temporal distributions of the contraction modes per repetition. Mean concentric power (P), total concentric work (W), and exercise time (EXTIME) were determined. Oxygen uptake (V[Combining Dot Above]O2) was measured during exercise and for 30 minutes postexercise. Mean V[Combining Dot Above]O2, volume of consumed O2, and excess postexercise oxygen consumption (EPOC) were calculated over 30 minutes of recovery. Maximum blood lactate concentration (LAmax) was also determined postexercise. The P was significantly higher (p < 0.01) for FFE and MAX compared with that for SE and HYP. The W was significantly higher for FFE than for all other RTMs (p < 0.01), and it was also lower for SE than for MAX (p < 0.05). EXTIME for SE was significantly higher (p < 0.01) than for all other RTMs, whereas EXTIME for MAX was significantly lower (p < 0.01) than for all other RTMs. Mean V[Combining Dot Above]O2 was significantly higher during FFE than during all other RTMs (p < 0.01). Consumed O2 was significantly higher (p < 0.05) during SE than for HYP and MAX, and it was also significantly higher for FFE and HYP compared with MAX (p < 0.05). The LAmax was significantly higher after FFE than after MAX (p < 0.05). There were no significant differences in EPOC between all RTMs. The results indicate that FFE and MAX are adequate to train muscular power despite the discrepancy in the external load. Because FFE performance achieves the highest amount in mechanical work, it may also elicit the highest total energy expenditure. The FFE challenges aerobic metabolism most and SE enables the longest EXTIME, indicating both are appropriate to enhance aerobic muscular capacities. The EPOC and LA values may indicate that energy needs covered by anaerobic metabolism are not higher during HYP and MAX compared with the RTM of lower external load.

USEFULNESS AND METABOLIC IMPLI-CATIONS OF A 60-SECOND REPEATED JUMPS TEST AS A PREDICTOR OF ACROBATIC JUMPING PERFORMANCE IN GYMNASTS

Gymnastics floor exercises are composed of a set of four to five successive acrobatic jumps usually called a “series”. The aims of the study were: 1) to relate the acrobatic gymnastics performance of these series with a repeated jumps test of similar duration (R60), 2) to study the relation between R60 and physiological parameters (heart rate and blood lactate), and the performance obtained in different kinds of jumps, 3) to confirm whether R60, executed without a damped jumping technique, can be considered an anaerobic lactic power test. Twenty male and twenty-four female gymnasts performed three repeated jumps tests for 5 s (R5), 10 s (R10) and 60 s (R60) and vertical jumps, such as drop jumps (DJ), squat jumps (SJ) and countermovement jumps (CMJ). We assessed heart rate (HR) and blood lactate during R10 and R60. The average values of the maximal blood lactate concentration (Lmax) after R10 (males = 2.5±0.6 mmol · l−1; females = 2.1±0.8 mmol · l−1) confirm that anaerobic glycolysis is not activated to a high level. In R60, the Lmax (males = 7.5±1.7 mmol · l−1 females = 5.9±2.1 mmol · l−1) that was recorded does not validate R60 as an anaerobic lactic power test. We confirmed the relation between the average power obtained in R60 (R60Wm) and the acrobatic performance on the floor. The inclusion in the multiple regression equation of the best power in DJ and the best flight-contact ratio (FC) in R5 confirms the influence of other non-metabolic components on the variability in R60 performance, at least in gymnasts.

Effect of recovery mode on postexercise vagal reactivation in elite synchronized swimmers

This study investigated the effect of whole-body cryostimulation (WBC), contrast-water therapy (CWT), active recovery (ACT), and passive condition (PAS) protocols on the parasympathetic reactivation and metabolic parameters of recovery in elite synchronized swimmers who performed 2 simulated competition ballets (B1 and B2) separated by 70 min. After determining maximal oxygen consumption (V̇O(2max400)) and blood lactate concentrations ([La(-)](b400)) during a 400-m swim trial, 11 swimmers performed 1 protocol per week in randomized order. Heart rate variability (HRV) was measured at rest (PreB1), 5 min after B1 (PostB1), before B2 (PreB2), and 5 min after B2 (PostB2). V̇O(2peak) was measured at PostB1 and PostB2, and [La(-)](b) was measured at PostB1, PreB2, and PostB2. PostB1 V̇O(2peak) and V̇O(2max400) were similar, but PostB1 [La(-)](b) was higher than [La(-)](b400) (p = 0.004). Each ballet caused significant decreases in HRV indices. At PreB2, all HRV indices had returned to PreB1 levels in the CWT, PAS, and ACT protocols, whereas the WBC protocol yielded a 2- to 4-fold increase in vagal-related HRV indices, compared with PreB1. WBC and ACT both increased [La(-)](b) recovery, compared with PAS (p = 0.06 and p = 0.04, respectively), and yielded an increased V̇O(2peak) from B1 to B2; however, it decreased after PAS (+5.4%, +3.4%, and -3.6%; p < 0.01). This study describes the physiological response to repeated maximal work bouts that are highly specific to elite synchronized swimming. In the context of short-term recovery, WBC yields a strong parasympathetic reactivation, and shows similar effectiveness to ACT on the metabolic parameters of recovery and subsequent exercise capacity.

Effect of stage duration on maximal heart rate and post-exercise blood lactate concentration during incremental treadmill tests

ObjectivesThis study compared the responses during maximal incremental treadmill tests of 1-min, 2-min, and 3-min stage durations mainly in terms of maximal heart rate (HRmax) and peak blood lactate concentration (LApeak). DesignRepeated-measures. MethodsThirty-four male, recreational, endurance-trained runners (40±13 years) performed three tests on a motorized treadmill. The tests started at 8kmh−1 with increments of 1kmh−1 every 1min for the short-stage protocol, every 2min for the intermediate-stage protocol, and every 3min for the long-stage protocol. LApeak was defined for each subject as the highest value among the lactate concentrations determined at the end of each test and at the third, fifth and seventh minutes after test, during passive recovery. ResultsAnalysis of variance revealed a significant effect of the stage duration on the HRmax (p=0.003) and LApeak (p=0.001). The HRmax was higher in the intermediate-stage compared to the short-stage protocol (184.8±12.7 vs. 181.8±12.1beatsmin−1, p<0.001), but no significant differences were found between the long-stage (183.1±12.1beatsmin−1) and the intermediate-stage or short-stage protocols (p>0.05). The LApeak was lower in the long-stage compared to the short-stage and intermediate-stage protocols (7.9±2.2 vs. 9.4±2.2 and 9.2±1.9mmolL−1, respectively, p<0.05). Further, blood lactate reached peak concentration at the fifth minute after test for all the protocols. ConclusionsThus, HRmax and LApeak depend on the stage duration of the incremental test, but the moment at which blood lactate reaches peak concentration is independent of the duration. Further, we suggest 2-min stage duration protocols to determine HRmax.

Variations in Functional and Morphological Characteristics of Elite Polish Field Hockey Players in a Complete Macrocycle

The purpose was to evaluate a hypothesized model of change during a training and competition macrocycle in a sample of elite field hockey players. Subjects were 11 members of the Polish national team. Players were measured and tested four times through a complete macrocycle. Variables included body mass, %Fat (BIA), aerobic endurance, maximal running speed, speed-endurance and blood lactate concentrations after the endurance, speed and speed-endurance tests. Significant changes occurred in %Fat, aerobic endurance and blood lactate concentrations at different phases of the macrocycle. Mean changes for the total sample did not follow the hypothesized model for speed, aerobic endurance and speed-endurance between specific periods of the macrocycle. Variability among individual players was considerable and emphasized the importance of individualizing training protocols during a macrocycle. The results highlighted the need to consider specific functional capacities (speed, aerobic endurance, speed-endurance) of individual athletes in addition to technical and tactical skills.

The Influence of Dribbling on Repeated Sprints in Young Soccer Players

The purpose of the study was to examine the effect of soccer dribbling on performance indices and physiological responses during repeated sprints (6 × 30-m) test, in straight and slalom run, of young (13.1 ± 0.4 y) soccer players. In the straight run repeated sprints test: Ideal (fastest) sprint time and total sprint time were significantly faster without dribbling (37.24 ± 2.56 versus 40.68 ± 2.84 and 38.50 ± 2.47 versus 41.78 ± 2.81 s, p&lt;0.001, respectively). There was no significant difference in performance decrement between repeated sprints test with and without dribbling. Maximal heart rate and blood lactate concentrations were significantly higher in repeated sprints test without dribbling (185 ± 17 versus 178 ± 12 beat/min and 8.7 ± 0.3 versus 6.9 ± 0.6 mmol/l, p&lt;0.05, respectively). In the slalom run repeated sprints test: ideal sprint time and total sprint time were significantly reduced (50.58 ± 3.04 versus 73.30 ± 5.59 and 51.63 ± 2.83 versus 74.05 ± 5.75 s, p&lt;0.001, respectively) and performance decrement significantly greater without dribbling (2.12 ± 1.55 vs 1.02 ± 1.40 %, p&lt;0.001, respectively). Blood lactate concentration was significantly higher in repeated sprints test without dribbling (8.6 ± 0.6 versus 6.9 ± 0.8 mmol/l, p&lt;0.05, respectively). There was no significant difference in maximal heart rate between repeated sprints test with and without dribbling. There were no significant differences in repeated sprints test performance indices in straight and slalom runs with and without dribbling between defensive and offensive players and between starting squad and substitute players. It was concluded that the additional motor tasks due to dribbling and slalom reduce speed and physiological responses in repeated maximal short sprints. Anaerobic fitness capabilities, dribbling skills and anthropometric measures are unable to distinguish between starting squad or substitute players, and between offensive and defensive players at this age.

The Level of Lactic Acidosis Affects Lactate Minimum in a Heart Rate-Based Lactate Minimum Test

The aim was to investigate whether the level of lactic acidosis in the first part of a heart rate-based lactate minimum test affects the lactate minimum heart rate and performance. We tested 15 men (age: 31 ± 6 years, height: 179 ± 6 cm, body mass: 75.6 ± 7.6 kg and V˙O(2peak) 50.3 ± 10.0 ml · min (- 1) · kg( - 1)). They all completed 2 lactate minimum tests following 2 different protocols during the first part of the test, i. e., i) a maximal test until exhaustion to provoke extensive lactacidaemia and ii) a submaximal test abandoned 3 stages earlier than the maximal test to provoke significantly lower but still considerable lactacidaemia. The second part of the lactate minimum test was identical for both runs. It consisted of a heart rate-based incremental test to determine the lactate minimum and the corresponding lactate minimum heart rate and performance. Results showed a significantly higher maximal blood lactate concentration at the end of the maximal test compared to the submaximal test (9.7 ± 2.7 vs. 6.0 ± 2.0 mmol · l( - 1), P<0.001). Also mean lactate minimum heart rate (160 ± 12 vs. 144 ± 13 bpm, P<0.001) and performance (200 ± 40 vs. 170 ± 35 W, P<0.001) were significantly higher after the maximal test compared to the submaximal test. We conclude that the first part of the heart rate-based lactate minimum test needs to be performed until exhaustion to receive reliable and meaningful results.

Effects of load and training modes on physiological and metabolic responses in resistance exercise

The aim of the study was to examine the effects of three different loads (LOAD) in combination with four different exercise modes (MODE) on physiological responses during and after one fatiguing bout of bench press exercise. Ten resistance-trained healthy male subjects performed bench press exercise each at 55% (LOW), 70% (MID) and 85% (HIGH) of 1 repetition maximum (1RM) for as many repetitions as possible and in four training modes: 4-1-4-1 (4-s concentric, 1-s isometric, 4-s eccentric and 1-s isometric successive actions), 2-1-2-1, 1-1-1-1 and MAX (maximum velocity concentric). Oxygen uptake [Formula: see text] was measured during exercise and for 30-min post-exercise. Maximum blood lactate concentration (blood LA(max)) and heart rate (HR(max)) were also determined. Number of repetitions (REPS) and exercise time (EXTIME) were recorded and accumulated lifted mass (MASS), defined by REPS × lifted mass, was calculated. LOAD had a significant effect on REPS (LOW > MID > HIGH, p < 0.01). A significant increase of REPS was obtained exercising at a faster MODE except from 1-1-1-1 to MAX (p < 0.01). EXTIME significantly decreased with increasing LOAD (LOW > MID > HIGH, p < 0.01 for all) and faster MODE (4-1-4-1, 2-1-2-1, 1-1-1-1 > MAX; p > 0.01). MASS decreased significantly with increasing LOAD (p < 0.01) but increased with a faster MODE (p < 0.05) with the exception of 1-1-1-1 to MAX. MODE had a significant effect on VO(2) (4-1-4-1 > MAX; p < 0.05). LOAD had a significant effect on consumed O(2) during exercise (LOW > MID and HIGH; p > 0.01) and on blood LA(max) (LOW and MID > HIGH; p < 0.01). The data indicate that physiological responses on different resistance exercises depend on both the load and the velocity mode.

Effects of optimal pacing strategies for 400-, 800-, and 1500-m races on the [Vdot]O2 response

The aim of this study was to compare the evolution of oxygen uptake ([Vdot]O2) in specifically trained runners during running tests based on the 400-, 800-, and 1500-m pacing strategies adopted by elite runners to optimize performance. Final velocity decreased significantly for all three distances, with the slowest velocity in the last 100 m expressed relative to the peak velocity observed in the 400 m (77%), 800 m (88%), and 1500 m (96%). Relative to the previously determined [Vdot]O2max values, the respective [Vdot]O2peak corresponded to 94% (400 m) and 100% (800 and 1500 m). In the last 100 m, a decrease in[Vdot]O2 was observed in all participants for the 400-m (15.6 ± 6.5%) and 800-m races (9.9 ± 6.3%), whereas a non-systematic decrease (3.6 ± 7.6%) was noted for the 1500 m. The amplitude of this decrease was correlated with the reduction in tidal volume recorded during the last 100 m of each distance (r = 0.85, P < 0.0001) and with maximal blood lactate concentrations after the three races (r = 0.55, P < 0.005). The present data demonstrate that the 800 m is similar to the 400 m in terms of decreases in velocity and [Vdot]O2.

Heart rate, blood lactate concentration, and time–motion analysis of female basketball players during competition

The aim of this study was to examine the physiological demands and movement patterns of female basketball players after changes in the rules of the game. Nine varsity players were studied during nine official games. Each game was videotaped to identify the frequencies of the main movements performed, heart rate was recorded continuously, and blood samples were collected to determine blood lactate concentration when the competition rules allowed. The main results showed that the players performed on average 652 ± 128 movements per game, which corresponded to a change in activity every 2.82 s. Mean heart rate was 165 ± 9 beats · min−1 (89.1% of maximum heart rate) for total time and 170 ± 8 beats · min−1 (92.5% of maximum) for live time. Mean blood lactate concentration was 5.2 ± 2.7 mmol · l−1 (55.9% of maximum blood lactate concentration). In addition, heart rates were significantly higher in the first half than the second half of games. These results indicate: (1) a greater physiological load compared with previous studies on female players tested before the rules modification (Beam & Merrill, 1994; McArdle et al., 1971) and (2) lower movement frequencies compared with male players competing under modern rules (Ben Abdelkrim et al., 2007). These observations must be taken into account by coaches and conditioning specialists working with female players.

Respiratory Alkalosis Enhances Sprint Performance

Glycolysis dominates energy provision in long sprint events like 200 to 400 m running, 50 m swimming, 500 m speed skating or short term flat out testing like the Wingate Anaerobic Test (WAnT). High glycolytic rates lead to the accumulation of lactate and a drop in pH with an impeding effect on glycolytic key enzymes. After bicarbonate ingestions an increase in minimum power has been reported in the WAnT. However, many athletes are reluctant to use this legal ergogenic aid because it is ingested 2 to 3 hours pre exercise and may also cause performance detrimental side effects like severe gastrointestinal distress and diarrhea. PURPOSE: To examine the effect of a controlled hyperventilation-induced hypocapnic alkalosis (HYP) on WAnT performance and metabolism. METHODS: Ten male subjects (age: 26.6+ 4.9 yrs, height: 184.4+ 6.1 cm, body mass: 81.0+ 7.2 kg) performed a WAnT after a standardised preparation without (CON) or with HYP in randomised order. Mechanical power (Pmech), blood lactate concentration (BLC) and acid base status and oxygen uptake were analysed. RESULTS: HYP decreased (p < 0.05) pCO2 (22.5+ 1.6 vs. 40.5+ 2.8 mmHg) and increased (p < 0.05) pH (7.61+ 0.03 vs. 7.41+ 0.01) pre WAnT. Average Pmech (713.5+ 43.9 vs. 681.1+ 40.8 W), maximum BLC (15.2+ 2.0 vs. 14.4+ 1.9 mmol l-1) and the increase in pCO2 during WAnT (14.7+ 3.3 vs. 3.5+ 2.7 mmHg) were higher (p < 0.05), minimum pH (7.16+ 0.03 vs. 7.15+ 0.02) was unchanged, and oxygen uptake during WAnT (867+ 191 vs. 940+ 184 ml) was lower (p < 0.05) at HYP than at CON. CONCLUSIONS: Controlled hyperventilation-induced hypocapnic alkalosis increased WAnT performance based on an increase in the glycolytic energy, which is higher than a corresponding decrease in aerobic energy.