Assessment of running velocity at maximal oxygen uptake

Is test specificity the issue in assessing aerobic fitness and performance of runners? A systematic review

INTRODUCTION

Various tests have been developed to evaluate aerobic fitness and performance of runners. However, a systematic understanding of which methods are more accurate is necessary to provide coaches and the sports sciences community with useful and confident outcomes. This study aims to summarize the evidence regarding the validity, reliability and sensitivity of tests for measuring aerobic fitness and performance in runners of several background of training.

EVIDENCE ACQUISITION

A systematic search was conducted of Web of Science, PubMed and Scopus up to 31st December 2022 according to PRISMA statement guidelines. Studies that reported findings about tests covering maximal aerobic speed, final velocity achieved during the test, average running speed or other method of evaluating the reference speed during the test were included. We evaluated the risk of bias in the included articles using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). The tests were categorized into continuous incremental tests, intermittent tests and time-trial test.

EVIDENCE SYNTHESIS

A total of 23 studies met eligibility criteria. These studies contained three background of training: track and road runners (N.=15), trail runners (N.=7) and inexperienced runners (N.=1). Criterion validity was assessed in 73% of the studies, while only 41% of studies examined convergent validity. The majority of the reviewed studies (87%) ignored test-retest reliability. Test sensitivity was not reported in any study.

CONCLUSIONS

At least one aerobic fitness and performance test was identified for each types of background of training. However, some methodological aspects were not provided in the included articles. Most studies examined at least one aspect of validity (i.e., criterion or convergent-related validity), whilst few studies investigated test-retest reliability. Researchers and practitioners can use the information provided in this systematic review to select appropriate tests.

Assessing anaerobic speed reserve: A systematic review on the validity and reliability of methods to determine maximal aerobic speed and maximal sprinting speed in running-based sports

PURPOSE

Locomotor profiling using anaerobic speed reserve (ASR) enables insights into athletes' physiological and neuromuscular contributing factors and prescription of high-intensity training beyond maximal aerobic speed (MAS). This systematic review aimed to determine the validity and reliability of different methods to assess the characteristics of ASR, i.e., MAS and maximal sprinting speed (MSS).

METHODS

A comprehensive search of the PubMed and Web of Science databases was conducted according to the PRISMA guidelines. Studies were included if they reported data on validity and/or reliability for methods to assess MAS or MSS.

RESULTS

58 studies were included with 28 studies referring to MAS and 30 studies to MSS. Regarding MAS, different methods for cardiopulmonary exercise testing yielded different values (four out of seven studies) of MAS (Cohen's d (ES) = 0.83-2.8; Pearson's r/intraclass correlation coefficient (r/ICC) = 0.46-0.85). Criterion validity of different field tests showed heterogeneous results (ES = 0-3.57; r/ICC = 0.40-0.96). Intraday and interday reliability was mostly acceptable for the investigated methods (ICC/r>0.76; CV<16.9%). Regarding MSS, radar and laser measurements (one out of one studies), timing gates (two out of two studies), and video analysis showed mostly good criterion validity (two out of two studies) (ES = 0.02-0.53; r/ICC = 0.93-0.98) and reliability (r/ICC>0.83; CV<2.43%). Criterion validity (ES = 0.02-7.11) and reliability (r/ICC = 0.14-0.97; CV = 0.7-9.77%) for global or local positioning systems (seven out of nine studies) and treadmill sprinting (one out of one studies) was not acceptable in most studies.

CONCLUSION

The criterion validity of incremental field tests or shuttle runs to examine MAS cannot be confirmed. Results on time trials indicate that distances adapted to the participants' sporting background, fitness, or sex might be suitable to estimate MAS. Regarding MSS, only sprints with radar or laser measures, timing gates, or video analysis provide valid and reliable results for linear sprints of 20 to 70 m.

Determination, measurement, and validation of maximal aerobic speed

This study determined Maximal Aerobic Speed (MAS) at a speed that utilizes maximal aerobic and minimal anaerobic contributions. This method of determining MAS was compared between endurance (ET) and sprint (ST) trained athletes. Nineteen and 21 healthy participants were selected for the determination and validation of MAS respectively. All athletes completed five exercise sessions in the laboratory. Participants validating MAS also ran an all-out 5000 m at the track. Oxygen uptake at MAS was at 96.09 ± 2.51% maximal oxygen consumption ([Formula: see text]). MAS had a significantly higher correlation with velocity at lactate threshold (vLT), critical speed, 5000 m, time-to-exhaustion velocity at delta 50 in addition to 5% velocity at [Formula: see text] (T_limυΔ50 + 5%v[Formula: see text]), and Vsub%95 (υΔ50 or υΔ50 + 5%v[Formula: see text]) compared with v[Formula: see text], and predicted 5000 m speed (R² = 0.90, p < 0.001) and vLT (R² = 0.96, p < 0.001). ET athletes achieved significantly higher MAS (16.07 ± 1.58 km·h^-1 vs. 12.77 ± 0.81 km·h^-1, p ≤ 0.001) and maximal aerobic energy (E_MAS) (52.87 ± 5.35 ml·kg^-1·min^-1 vs. 46.42 ± 3.38 ml·kg^-1·min^-1, p = 0.005) and significantly shorter duration at MAS (ET: 678.59 ± 165.44 s; ST: 840.28 ± 164.97 s, p = 0.039). ST athletes had significantly higher maximal speed (35.21 ± 1.90 km·h^-1, p < 0.001) at a significantly longer distance (41.05 ± 3.14 m, p = 0.003) in the 50 m sprint run test. Significant differences were also observed in 50 m sprint performance (p < 0.001), and peak post-exercise blood lactate (p = 0.005). This study demonstrates that MAS is more accurate at a percentage of v[Formula: see text] than at v[Formula: see text]. The accurate calculation of MAS can be used to predict running performances with lower errors (Running Energy Reserve Index Paper).

Overestimation of maximal aerobic speed by the Université de Montréal track test and a 1500-m-time trial in soccer

Introduction: Maximal aerobic speed (MAS), usually measured by cardiopulmonary exercise testing (CPET) on a treadmill, is gaining popularity in soccer to determine aerobic performance. Several field tests are used to estimate MAS, although, gold standard methods are still not clarified. Therefore, this work aims 1) to compare two different CPET based methods to assess MAS and 2) to investigate the convergent validity of two common field tests to estimate MAS in soccer.

Methods: Thirteen trained male soccer players completed an CPET on a treadmill to determine two VO₂-kinetic based definitions of MAS (MAS_Plateau = speed at onset of VO₂-plateau = gold standard; MAS_30s = first speed of 30-s-interval of VO₂max), the Université de Montreal Track Test (UMTT; V_UMTT = speed of the last stage), and a 1500-m-time trial (1500-m-TT; V_1500m = average speed). MAS_Plateau, MAS_30s, V_UMTT, and V_1500m were compared using ANOVA. Additionally, limits of agreement analysis (LoA), Pearson’s r, and ICC were calculated between tests.

Results: MAS_30s, V_UMTT, and V_1500m significantly overestimated MAS_Plateau by 0.99 km/h (ES = 1.61; p < 0.01), 1.61 km/h (ES = 2.03; p < 0.01) and 1.68 km/h (ES = 1.77; p < 0.01), respectively, with large LoA (-0.21 ≤ LoA≤3.55), however with large-to-very large correlations (0.65 ≤ r ≤ 0.87; p ≤ 0.02; 0.51 ≤ ICC≤ 0.85; p ≤ 0.03).

Discussion: The overestimation and large LoA of MAS_Plateau by all estimates indicate that 1) a uniform definition of MAS is needed and 2) the UMTT and a 1500-m-TT seem questionable for estimating MAS for trained soccer players on an individual basis, while regression equations might be suitable on a team level. The results of the present work contribute to the clarification of acquisition of MAS in soccer.

A proposal to identify the maximal metabolic steady state by muscle oxygenation and VO2max levels in trained cyclists

Purpose

Near-infrared spectroscopy (NIRS) sensors measure muscle oxygen saturation (SmO2) as a performance factor in endurance athletes. The objective of this study is to delimit metabolic thresholds relative to maximal metabolic steady state (MMSS) using SmO2 in cyclists.

Methods

Forty-eight cyclists performed a graded incremental test (GTX) (100 W-warm-up followed by 30 W min) until exhaustion. SmO2 was measured with a portable NIRS placed on the vastus lateralis. Subjects were classified by VO2max levels with a scale from 2 to 5: L2 = 45–54.9, L3 = 55–64.9, L4 = 65–71, L5 =  > 71, which represent recreationally trained, trained, well-trained, and professional, respectively. Then, metabolic thresholds were determined: Fatmax zone, functional threshold power (FTP), respiratory compensation point (RCP), and maximal aerobic power (MAP). In addition, power output%, heart rate%, VO2%, carbohydrate and fat consumption to cutoff SmO2 point relative to MMSS were obtained.

Results

A greater SmO2 decrease was found in cyclists with > 55 VO2max (L3, L4 and L5) vs. cyclists (L2) in the MMSS. Likewise, after passing FTP and RCP, performance is dependent on better muscle oxygen extraction. Furthermore, the MMSS was defined at 27% SmO2, where a non-steady state begins during exercise in trained cyclists.

Conclusion

A new indicator has been provided for trained cyclists, < 27% SmO2 as a cut-off to define the MMSS Zone. This is the intensity for which the athlete can sustain 1 h of exercise under quasi-steady state conditions without fatiguing.

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Repeated sprint in hypoxia (RSH) is used to improve supramaximal cycling capacity, but little is known about the potential differences between different systems for creating normobaric hypoxia, such as a chamber, tent, or mask. This study aimed to compare the environmental (carbon dioxide (CO₂) and wet-globe bulb temperature (WGBT)), perceptual (pain, respiratory difficulty, and rate of perceived exertion (RPE)), and external (peak and mean power output) and internal (peak heart rate (HRpeak), muscle oxygen saturation (SmO₂), arterial oxygen saturation (SpO₂), blood lactate and glucose) workload acute effects of an RSH session when performed inside a tent versus using a mask. Twelve well-trained cyclists (age = 29 ± 9.8 years, VO₂max = 70.3 ± 5.9 mL/kg/min) participated in this single-blind, randomized, crossover trial. Participants completed four sessions of three sets of five repetitions × 10 s:20 s (180 s rest between series) of all-out in different conditions: normoxia in a tent (RSNTent) and mask-on (RSNMask), and normobaric hypoxia in a tent (RSHTent) and mask-on (RSHMask). CO₂ and WGBT levels increased steadily in all conditions (p < 0.01) and were lower when using a mask (RSNMask and RSHMask) than when inside a tent (RSHTent and RSNTent) (p < 0.01). RSHTent presented lower SpO₂ than the other three conditions (p < 0.05), and hypoxic conditions presented lower SpO₂ than normoxic ones (p < 0.05). HRpeak, RPE, blood lactate, and blood glucose increased throughout the training, as expected. RSH could lead to acute conditions such as hypoxemia, which may be exacerbated when using a tent to simulate hypoxia compared to a mask-based system.

A field tool for the aerobic power evaluation of middle-aged female recreational runners

This study used time to exhaustion (TTE) to predict V̇O_2max in female recreational master runners. Forty-two middle-aged women (mean = 40.5 ± 5.9 years) who had trained for recreational running performed two Université de Montréal Track Tests in the facilities of the University of Barcelona (Spain). The first was performed on a treadmill (t), the second, on an athletics track (field: f). After measuring TTE and V̇O_2max on the treadmill, a first-order equation was obtained to estimate fV̇O_2max from fTTE. No significant difference was observed between the estimated fV̇O_2max (46.5 ± 2.9 mL·kg^-1·min^-1) and the measured tV̇O_2max (46.2 ± 5.3), with a mean value of the absolute differences of less than 8% of the tV̇O_2max average. High agreement between the two V̇O_2max values was also evident, as shown by the low bias of the differences and the Bland-Altman plot. The equation obtained is of interest to evaluate performance in middle-aged female recreational runners. It will allow coaches and runners to set running paces for training and could be used in training routines to determine improvements after a training program. Moreover, these tools could be used in the field to assess the physical fitness of middle-aged women, in efforts to preserve their health and physical function.

A New Short Track Test to Estimate the V[Combining Dot Above]O2max and Maximal Aerobic Speed in Well-Trained Runners

Pallarés, JG, Cerezuela-Espejo, V, Morán-Navarro, R, Martínez-Cava, A, Conesa, E, and Courel-Ibáñez, J. A new short track test to estimate the V[Combining Dot Above]O2max and maximal aerobic speed in well-trained runners. J Strength Cond Res 33(5): 1216-1221, 2019-This study was designed to validate a new short track test (Track(1:1)) to estimate running performance parameters maximal oxygen uptake (V[Combining Dot Above]O2max) and maximal aerobic speed (MAS), based on a laboratory treadmill protocol and gas exchange data analysis (Lab(1:1)). In addition, we compared the results with the University of Montreal Track Test (UMTT). Twenty-two well-trained male athletes (V[Combining Dot Above]O2max 60.3 ± 5.9 ml·kg·min; MAS ranged from 17.0 to 20.3 km·h) performed 4 testing protocols: 2 in laboratory (Lab(1:1)-pre and Lab(1:1)) and 2 in the field (UMTT and Track(1:1)). The Lab(1:1)-pre was designed to determine individuals' Vpeak and set initial speeds for the subsequent Lab(1:1) short ramp graded exercise testing protocol, starting at 13 km·h less than each athlete's Vpeak, with 1 km·h increments per minute until exhaustion. The Track(1:1) was a reproduction of the Lab(1:1) protocol in the field. A novel equation was yielded to estimate the V[Combining Dot Above]O2max from the Vpeak achieved in the Track(1:1). Results revealed that the UMTT significantly underestimated the Vpeak (-4.2%; bias = -0.8 km·h; p < 0.05), which notably altered the estimations (MAS: -2.6%, bias = -0.5 km·h; V[Combining Dot Above]O2max: 4.7%, bias = 2.9 ml·kg·min). In turn, data from Track(1:1) were very similar to the laboratory test and gas exchange methods (Vpeak: -0.6%, bias = <0.1 km·h; MAS: 0.3%, bias = <0.1 km·h; V[Combining Dot Above]O2max: 0.4%, bias = 0.2 ml·kg·min, p > 0.05). Thus, the current Track(1:1) test emerges as a better alternative than the UMTT to estimate maximal running performance parameters in well-trained and highly trained athletes on the field.

Comparative Effects of Two Interval Shuttle-Run Training Modes on Physiological and Performance Adaptations in Female Professional Futsal Players

Teixeira, AS, Arins, FB, De Lucas, RD, Carminatti, LJ, Dittrich, N, Nakamura, FY, and Guglielmo, LGA. Comparative effects of two interval shuttle-run training modes on physiological and performance adaptations in female professional futsal players. J Strength Cond Res 33(5): 1416-1428, 2019-The purpose of this study was to analyze the effects of 2 shuttle-run interval training (SRIT) models with 1 and 3 directional changes per running bout on the aerobic and anaerobic performances of elite female futsal players. Sixteen players competing in the Brazilian National Division League took part in the study. The training protocols consisted of shuttle-run intervals organized in 4 sets of 4-minute bouts with 3 minutes of rest intervals between the sets. The SRIT models were composed of 1 (7.5 seconds running and 7.5 seconds pause [SRIT7.5×7.5]; n = 7) or 3 (15 seconds running and 15 seconds pause [SRIT15×15]; n = 9) directional changes. The athletes performed the following tests before and after a 5-week training period: incremental treadmill test (ITT), futsal intermittent endurance test (FIET) (with respective peak speeds [PSs]), and a repeated sprint ability (RSA) test. After the training period, PSFIET and speed at the second lactate turnpoint were very likely and almost certainly increased in both training regimens, respectively. SRIT15×15 induced possibly greater improvements in PSITT (+3.28%, 90% CL -0.16 to 6.82) and RSAmean (+1.17%, 90% CL -0.68 to 3.05) than SRIT7.5×7.5. In addition, SRIT15×15 resulted in a likely greater improvement in running economy (+4.33%, 90% CL -0.35 to 9.23) compared with SRIT7.5×7.5. In elite female futsal players, SRIT15×15 is a promising strategy to enhance performance-related physical fitness attributes in a short-term period (5 weeks) during the preseason, Because of its superior effects on these important aerobic and anaerobic qualities than a protocol with fewer directional changes.

The Relationship Between Lactate and Ventilatory Thresholds in Runners: Validity and Reliability of Exercise Test Performance Parameters

The aims of this study were (1) to establish the best fit between ventilatory and lactate exercise performance parameters in running and (2) to explore novel alternatives to estimate the maximal aerobic speed (MAS) in well-trained runners. Twenty-two trained male athletes ( V ˙ O_2max 60.2 ± 4.3 ml·kg·min^-1) completed three maximal graded exercise tests (GXT): (1) a preliminary GXT to determine individuals' MAS; (2) two experimental GXT individually adjusted by MAS to record the speed associated to the main aerobic-anaerobic transition events measured by indirect calorimetry and capillary blood lactate (CBL). Athletes also performed several 30 min constant running tests to determine the maximal lactate steady state (MLSS). Reliability analysis revealed low CV (<3.1%), low bias (<0.5 km·h^-1), and high correlation (ICC > 0.91) for all determinations except V-Slope (ICC = 0.84). Validity analysis showed that LT, LT+1.0, and LT+3.0 mMol·L^-1 were solid predictors of VT₁ (-0.3 km·h^-1; bias = 1.2; ICC = 0.90; p = 0.57), MLSS (-0.2 km·h^-1; bias = 1.2; ICC = 0.84; p = 0.74), and VT₂ (<0.1 km·h^-1; bias = 1.3; ICC = 0.82; p = 0.9l9), respectively. MLSS was identified as a different physiological event and a midpoint between VT₁ (bias = -2.0 km·h^-1) and VT₂ (bias = 2.3 km·h^-1). MAS was accurately estimated (SEM ± 0.3 km·h^-1) from peak velocity (V_peak) attained during GXT with the equation: MAS_EST (km·h^-1) = V_peak (km·h^-1) ^* 0.8348 + 2.308. Current individualized GXT protocol based on individuals' MAS was solid to determine both maximal and submaximal physiological parameters. Lactate threshold tests can be a valid and reliable alternative to VT and MLSS to identify the workloads at the transition from aerobic to anaerobic metabolism in well-trained runners. In contrast with traditional assumption, the MLSS constituted a midpoint physiological event between VT₁ and VT₂ in runners. The V_peak stands out as a powerful predictor of MAS.

Maximal Aerobic Frequency of Ball Hitting: A New Training Load Parameter in Tennis

Baiget, E, Iglesias, X, and Rodríguez, FA. Maximal aerobic frequency of ball hitting: a new training load parameter in tennis. J Strength Cond Res 31(1): 106-114, 2017-This study aimed (a) to evaluate a new training load parameter in tennis based on the ball-hitting frequency (Ballf) at V[Combining Dot Above]O2max occurs (maximal aerobic frequency of ball hitting, MAF) and (b) to assess the accuracy of a specific endurance tennis test (SET-Test) for predicting MAF. Thirty-five male competitive tennis players performed the SET-Test and selected physiological and performance parameters at maximal workload (MAX), and last completed stage (LS) and MAF were compared. Performance parameters (Ballf, time, stage, and hits per test) at LS were higher than at MAF (20.2 ± 1.7 vs. 18.1 ± 1.5 shots·min, 6.6 ± 0.8 vs. 5.6 ± 0.8 stages, and 189 ± 33 vs. 147 ± 27 hits; p < 0.001), and highly correlated (r = 0.72-0.77; p < 0.001). The mean difference between Ballf and stage at MAF and LS were 2.1 ± 1.1 shots·min and 1.1 ± 0.6 stages, respectively. The main physiological parameters (heart rate, V[Combining Dot Above]O2, and V[Combining Dot Above]CO2 at LS) were higher than at MAF (191 ± 9 vs. 186 ± 8 beats·min, 55.5 ± 5.9 vs. 55.0 ± 6.0 ml·kg·min and 4,724 ± 880 vs. 4,253 ± 739 ml·min; p < 0.005), and were very strongly correlated (r = 0.93-0.99; p < 0.001). We conclude that MAF can be used as a practical performance parameter to prescribe tennis-specific training, and that the SET-Test is a valid method for assessing MAF. Gas exchange measurements not being available, as a rule of thumb, most players reach their MAF at ∼1 stage (95% confidence interval: 0.9-1.2) and ∼2 shots·min (95% confidence interval: 1.7-2.5) less than their completed LS. A model for specific on-court training protocols for optimizing aerobic fitness in competitive tennis player is proposed.

The effect of two generic aerobic interval training methods on laboratory and field test performance in soccer players

The purpose of this study was to compare the effects of 2 generic aerobic training models, based on peak running velocity in Carminatti's test (PVT-CAR) in U-20 elite soccer players. Seventeen soccer players (age: 17.9 ± 1.0 years; 178.6 ± 5.0 cm; 73.6 ± 6.6 kg; 11.1 ± 1.3%) from a team competing in a national junior league took part in the study. The athletes performed a series of pre- and posttraining tests (incremental test on a treadmill to determine the maximal oxygen uptake [(Equation is included in full-text article.)], velocity at maximal oxygen uptake [(Equation is included in full-text article.)], the lactate threshold [LT], and T-CAR). The interval training models applied were with 180° direction change (T12:12; n = 9) and without direction change (T6:6; n = 8). No significant interaction (time vs. group) was observed for the majority of variables analyzed (p > 0.05), although significant main effects in time were evident regarding peak treadmill velocity (PVTREAD) (F = 56.3, p < 0.0001), (Equation is included in full-text article.)(F = 35.8, p < 0.0001), LT (F = 57.7, p < 0.0001), and PVT-CAR (F = 52.9, p < 0.0001). Moreover, there was no significant change in (Equation is included in full-text article.)between pre and posttraining period (F = 4.26, p = 0.056) in both training groups. Thus, it can be concluded that the prescribed training with and without direction change in the intensity of the PVT-CAR increases the PVTREAD, the (Equation is included in full-text article.), the LT, and the PVT-CAR similarly.

Cardiorespiratory fitness and the incidence of type 2 diabetes: a cohort study of Japanese male athletes

Background

In Japan, although the incidence of overweight (BMI ≥ 25) is still low compared with that in Europe and the United States, the prevalence of type 2 diabetes has increased over the last 15 years,. In both Japanese and Caucasian populations it has been reported that a high level of cardiorespiratory fitness protects against the development of type 2 diabetes. However, there are no reports focused specifically on athletes that investigate whether high cardiorespiratory fitness at a young age can prevent disease later in life. We examined the relationship between cardiorespiratory fitness at a young age and the development of type 2 diabetes in Japanese athletes using a cohort study.

Methods

The cardiorespiratory fitness of male alumni of the physical education department of Juntendo University, as measured by stored data of a 1,500-m endurance run in college (1971–1991) was compared with their incidence of type 2 diabetes as determined by follow-up questionnaires (2007–2009). This study used Cox’s proportional hazards models and adjusted for age, year of graduation, BMI, smoking, and sports club participation at college age.

Results

We collected data on cardiorespiratory fitness at college age and medical history survey data during 2007–2009 from 570 male alumni. The median follow-up period was 26 years (IQR: 23–29 years), and 22 men had developed type 2 diabetes. An inverse relationship was observed between incidence of type 2 diabetes and level of cardiorespiratory fitness at time of college after adjustment for age, year of graduation, BMI, smoking, and sports participation. The adjusted hazards ratio and 95% CI by category (low, medium, and high) were 1.00 (reference), 0.40 (0.14–1.13) and 0.26 (0.07–1.00) (p = 0.03 for trend).

Conclusions

A high level of cardiorespiratory fitness at a young age can help prevent type 2 diabetes later in life.

Leg stiffness decreases during a run to exhaustion at the speed at VO2max

Vertical and leg stiffness are related to running speed. In endurance running, the ability to maintain stiffness might be more important than the absolute stiffness magnitude. The purpose of this study was to examine changes in vertical and leg stiffness during an exhaustive. Six sub-elite runners (24.2, s = 4.2 years; 1.81, s = 0.03 m; 73.4, s = 4.4 kg) participated in this study. They performed preliminary tests to determine lactate threshold, lactate turnpoint, [Formula: see text]O2max, s[Formula: see text]O2max and a series of isokinetic endurance tests. During the run to exhaustion runners were videoed (50 Hz) to determine contact and flight times, from which leg (Kleg) and vertical (Kvert) stiffness were calculated. During the run Kleg showed a significant decrease [P = 0.030, effect size statistics (ES) = 0.74], however, the decrease in Kvert was non-significant and of a small magnitude (P = 0.051, ES = 0.32). The distance covered during the run was correlated with ΔKleg (r = -0.868) but not ΔKvert (r = 0.684). ΔKleg was very strongly related to Δ ground contact time (r = -0.937) and Δ step length (r = -0.957). The Δ ground contact time had a near perfect relationship with Δ step length (r = 0.995). Isokinetic measures were not significantly correlated with either ΔKleg. The ability to maintain a short ground contact time appears to be a key determinant of maintaining performance during a run to exhaustion. Minimising this is important for maintaining Kleg. Kleg was not significantly related to isokinetic measures.

Comparing two methods to assess power output associated with peak oxygen uptake in cyclists

The aim of this study was to compare 2 methods that are frequently used to calculate the power output (MAP) that is associated with peak oxygen uptake (VO2peak) in the exercise mode of cycling. One method calculates the MAP by extrapolation of the individual VO2 to submaximal power output relationships to the measured VO2peak (MAPDaniels), whereas the other method uses the minimal power output that elicits VO2peak during a graded VO2peak test (MAPBillat). Thirteen male competitive cyclists (VO2peak = 66 ± 5 ml·kg·min) performed 3 test sessions; first to determine MAPDaniels and MAPBillat; second and third sessions were used to measure the time to exhaustion during continuous cycling exercise to exhaustion (Tmax), time to 95% of VO2peak, and time ≥ 95% of VO2peak with MAPDaniels and MAPBillat. Whether it was MAPDaniels or MAPBillat that was used on the second or third test session was randomized. There was no difference between mean MAPDaniels and mean MAPBillat (380 ± 38 vs. 383 ± 34 W, respectively) and their associated Tmax, time to 95% of VO2peak, and time ≥ 95% of VO2peak during a Tmax test. In conclusion, this study did not find any difference between MAPDaniels and MAPBillat. The practical application of this study is that the choice of a method to calculate the MAP can be determined by practicality and that findings from studies using these 2 methods are comparable.

Índices fisiológicos associados com a performance aeróbia de corredores nas distâncias de 1,5 km, 3 km e 5 km

O objetivo do estudo foi analisar a associação entre os índices fisiológicos de potência aeróbia e capacidade aeróbia performance nas distâncias de 1,5 km, 3 km e 5 km. Nove corredores de endurance realizaram os seguintes protocolos: a) teste para determinação do VO2max, vVO2max e OBLA; b) 2-5 testes em dias alternados de 30 min com velocidade constante para determinar a vMLSS e c) determinação da performances. Foram empregadas correlação linear de Pearson ou Spearman e regressão múltipla para determinar as relações entre os índices e a performance nas corridas. Observou-se uma correlação significante somente da vVO2max com o tempo nas distâncias de 1,5 km (r = - 0,78) e 3 km (r = - 0,81). Dessa forma, pode-se sugerir a inclusão de sessões de treinamento em intensidade próxima ou superior à vVO2max na periodização semanal dos corredores. Com base nesses achados, foi possível concluir que a predição da performance por meio de índices de potência aeróbia e da capacidade aeróbia depende da distância e duração da prova.

Time to exhaustion at intermittent maximal lactate steady state is longer than continuous cycling exercise

The maximal lactate steady state (MLSS) represents a submaximal intensity that may be important in prescribing both continuous and interval endurance training. This study compared time to exhaustion (TTE) at MLSS in continuous and intermittent (i.e., with pauses) exercise, investigating whether physiological variables differ between these exercise modes. Fourteen trained male cyclists volunteered for this investigation and performed an incremental test, several 30-min tests to determine two MLSS intensities (continuous and discontinuous protocol), and two randomized tests until exhaustion at MLSS intensities on a cycle ergometer. The intermittent or discontinuous protocol was performed using 5 min of cycling, with an interval of 1 min of passive rest. TTE at intermittent MLSS was 24% longer than TTE at continuous exercise (67.8 ± 14.3 min vs. 54.7 ± 10.9 min; p < 0.05; effect sizes = 1.04), even though the absolute power output of intermittent MLSS was higher than continuous (268 ± 29 W vs. 251 ± 29 W; p < 0.05). Additionally, the total mechanical work done was significantly lower at continuous exercise than at intermittent exercise. Likewise, regarding cardiorespiratory and metabolic variables, we observed greater responses during intermittent exercise than during continuous exercise at MLSS. Thus, for endurance training prescription, this is an important finding to apply in extensive interval sessions at MLSS. This result suggests that interval sessions at discontinuous MLSS should be used instead of continuous MLSS, as discontinuous MLSS allows for a larger amount of total work during the exhaustion trial.

Validity and reliability of a new field test (Carminatti's test) for soccer players compared with laboratory-based measures

The aim of this study was to assess the validity (Study 1) and reliability (Study 2) of a novel intermittent running test (Carminatti's test) for physiological assessment of soccer players. In Study 1, 28 players performed Carminatti's test, a repeated sprint ability test, and an intermittent treadmill test. In Study 2, 24 players performed Carminatti's test twice within 72 h to determine test-retest reliability. Carminatti's test required the participants to complete repeated bouts of 5 × 12 s shuttle running at progressively faster speeds until volitional exhaustion. The 12 s bouts were separated by 6 s recovery periods, making each stage 90 s in duration. The initial running distance was set at 15 m and was increased by 1 m at each stage (90 s). The repeated sprint ability test required the participants to perform 7 × 34.2 m maximal effort sprints separated by 25 s recovery. During the intermittent treadmill test, the initial velocity of 9.0 km · h(-1) was increased by 1.2 km · h(-1) every 3 min until volitional exhaustion. No significant difference (P > 0.05) was observed between Carminatti's test peak running velocity and speed at VO(2max) (v-VO(2max)). Peak running velocity in Carminatti's test was strongly correlated with v-VO(2max) (r = 0.74, P < 0.01), and highly associated with velocity at the onset of blood lactate accumulation (r = 0.63, P < 0.01). Mean sprint time was strongly associated with peak running velocity in Carminatti's test (r = -0.71, P < 0.01). The intraclass correlation was 0.94 with a coefficient of variation of 1.4%. In conclusion, Carminatti's test appears to be avalid and reliable measure of physical fitness and of the ability to perform intermittent high-intensity exercise in soccer players.

The validity of incremental exercise testing in discriminating of physiological profiles in elite runners

The goal of this study was to determine whether traditional ergoespirometric incremental exercise testing carried out to the point of exhaustion could be useful in distinguishing the physiological profiles of elite runners that compete in races that lasted about 8 minutes versus those that lasted about 2 hours. Ten male marathon runners (performance time: 2:12:04, coefficient of variation (CV) = 2.33%) and 8 male 3000 m steeplechase runners (performance time: 8:37.83, CV = 2.12%) performed an incremental test on the treadmill (starting speed 10 km·h-1; increments, 2 km·h-1; increment duration, 3 min to exhaustion). Heart rate (HR), VO2, and lactate concentrations were measured at the end of each exercise level. At maximal effort, there were no differences between the groups regarding VO2max and maximal HR; however, the workload time, vVO2max and peak treadmill velocity were significantly higher in the 3000 m steeplechase group (p<0.05). At submaximal effort, there were no significant differences between groups for VO2 (ml·kg-1·min-1), HR, or lactate. Our results show that this type of testing was not sufficient for discriminating the physiological profiles of elite runners who competed in middle-distance versus long-distance events (e.g. in the marathon and the 3000 m steeplechase).

Variáveis fisiológicas e neuromusculares associadas com a performance aeróbia em corredores de endurance: efeitos da distância da prova

O objetivo deste estudo foi analisar a validade do consumo máximo de oxigênio (VO2max), velocidade associada ao VO2max (vVO2max), tempo de exaustão na vVO2max (Tlim), limiar anaeróbio (LAn), economia de corrida (EC) e força explosiva (FE) para predizer a performance aeróbia de corredores de endurance nas distâncias de 1.500m, 5.000m e 10.000m. Participaram deste estudo 11 corredores de endurance moderadamente treinados (28,36 ± 6,47 anos) que realizaram os seguintes testes: provas simuladas em uma pista de 400m em diferentes dias, nas distâncias de 10.000m, 5.000m e 1.500m; teste incremental máximo para determinar os índices VO2max, vVO2max, e LAn; um teste submáximo de carga constante para determinar a EC, seguido por um teste máximo também de carga constante a 100% da vVO2max para determinar o Tlim; e um teste de salto vertical para determinar a FE. De acordo com a análise de regressão múltipla, a vVO2max utilizada de forma isolada explicou 57% da variação de performance na prova de 1.500m. No entanto, quando o Tlim, a FE e a vVO2max foram analisados em conjunto, a explicação para a performance nessa prova foi de 88%. Nos 5.000m, o Tlim, a vVO2max e o LAn responderam por 88% da variação de performance (p < 0,05). Diferentemente, na prova de 10.000m, o LAn foi a única variável que apresentou capacidade de predição de performance. Em conclusão, a predição da performance aeróbia de corredores moderadamente treinados por meio de variáveis fisiológicas e neuromusculares é dependente da distância da prova (1.500m, 5.000m e 10.000m)

Relationship between different measures of aerobic fitness and repeated-sprint ability in elite soccer players

The main purpose of this study was to investigate the relationship between physiological variables related to aerobic fitness (maximal oxygen uptake: VO2max; the minimum velocity needed to reach VO2max: vVO2max; velocity at the onset of blood-lactate accumulation: vOBLA) and repeated sprint ability (RSA) in elite soccer players. Twenty-nine Brazilian soccer players (17.9 +/- 1.0 years; 178.7 +/- 5.2 cm; 73.6 +/- 6.7 kg; 11.1 +/- 1.3% body fat) from 2 national level teams (A, B) took part in the study. Subjects first performed an incremental test on a treadmill to determine their VO2max, vVO2max and vOBLA. After at least 48 hours, subjects performed an RSA test consisting of 7 34.2-m sprints interspersed with 25 seconds of active recovery, to determine the mean time (MT), the fastest time (FT) and the Sprint decrement (Sdec). Pearson product moment correlations and multiple regressions were used to assess the relationship between aerobic fitness and RSA variables (FT, MT, Sdec, [La] Peak). An analysis of variance, followed by a post hoc test (Tukey), was used to compare the 7 sprints of the RSA test. The level of significance was set at p < 0.05. A significant negative correlation was found between both vOBLA and vVO2max and MT during the RSA test (r = -0.49, p < 0.01; r = -0.38, p < 0.05, respectively). There were also negative correlations between Sdec and vOBLA (r = -0.54), vVO2max (r = -0.49) and VO2max (r = -0.39). The multiple regression revealed that the aerobic (vOBLA) and anaerobic (FT) components explained approximately 89% of the variance of MT. The results of this study demonstrated that RSA is more strongly correlated with vOBLA and vVO2max than the more commonly measured VO2max.

Effects of Ramadan fasting on physical performance and metabolic, hormonal, and inflammatory parameters in middle-distance runners

The Ramadan fasting (RF) period is associated with changes in sleep habits and increased sleepiness, which may affect physical performance in athletes, and may induce metabolic, hormonal, and inflammatory disturbances. In 8 middle-distance athletes (25.0 ± 1.3 years), a maximal aerobic velocity (MAV) test was performed 5 days before RF (day –5), and on days 7 and 21 of RF. The same days, saliva samples were collected to determine cortisol and testosterone concentrations before and after the MAV test. Blood samples were collected before RF (P1), at the end of RF (P2), and 1 week post RF (P3). Plasma levels of interleukin (IL)-6, a mediator of sleepiness and energy availability, were determined. We also evaluated changes in metabolic and hormonal parameters, mood state, and nutritional and sleep profiles. During RF, mean body mass and body fat did not statistically change. Compared with day –5, MAV values decreased at days 7 and 21 (p < 0.05, respectively), while testosterone/cortisol ratio values did not change significantly. Nocturnal sleep time and energy intake were lower at day 21 than before RF (day 0/P1) (p < 0.05). At the end of RF (day 31), the fatigue score on the Profile of Mood States questionnaire was increased (p < 0.001). For P2 vs. P1, IL-6 was increased (1.19 ± 0.25 vs. 0.51 ± 0.13 pg·mL–1; p < 0.05), melatonin levels were decreased (p < 0.05), and adrenalin and noradrenalin were increased (p < 0.01 and p < 0.001, respectively). At 7 days post RF, all parameters recovered to pre-RF values. In conclusion, RF is accompanied by significant metabolic, hormonal, and inflammatory changes. Sleep disturbances, energy deficiency, and fatigue during RF may decrease physical performance in Muslim athletes who maintain training. Reduction of work load and (or) daytime napping may represent adequate strategies to counteract RF effects for Muslim athletes.

Changes in EMG characteristics and metabolic energy cost during 90-min prolonged running

This study quantified the interaction of integrated electromyography (iEMG) obtained from the vastus lateralis and the metabolic energy cost of running (Cr), an index to assess running economy, during 90-min prolonged running. The iEMG during running was divided into eccentric (ECC) and concentric (CON) phases using a force platform and a knee-joint goniometer. The ratio of ECC to CON (ECC/CON ratio) significantly decreased during 90-min prolonged running in novice distance runners, which would be explained by an increase in muscle activity during the CON phase of running. The average Cr value significantly increased during 90-min prolonged running. The individual's Cr values significantly correlated with the ECC/CON ratio (r=-0.702, P<0.05). These results suggest that changes in the ECC/CON ratio and Cr value during prolonged running are associated.

Influence of exercise intensity on time spent at high percentage of maximal oxygen uptake during an intermittent session in young endurance-trained athletes

The purpose of this study was to compare, during a 30s intermittent exercise (IE), the effects of exercise intensity on time spent above 90% VO2max(t90VO2max) and time spent above 95% VO2max(t95VO2max) in young endurance trained athletes. We hypothesized that during a 30sIE, an increase in exercise intensity would allow an increase in t90VO2max and t95VO2max due to a decrease in time to achieve 90% or 95% of VO2max. Nine endurance-trained male adolescents took part in three field tests. After determination of their VO2max and maximal aerobic velocity (MAV), they performed, until exhaustion, two intermittent exercise sessions alternating 30s at 100% of MAV (IE(100)) or 110% of MAV (IE(110)) and 30s at 50% of MAV. Mean time to exhaustion (t (lim)) values obtained during IE(100) were significantly longer than during IE(110) (p < 0.01). Moreover, no significant difference was found in t90VO2max or t95VO2max) expressed in absolute or relative (%t (lim)) values between IE(100) and IE(110). In conclusion, an increased of 10% of exercise intensity during a 30s intermittent exercise model (with active recovery), does not seem to be the most efficient exercise to solicit oxygen uptake to its highest level in young endurance-trained athletes.

Objective and subjective analysis of the training content in young cyclists

The purpose of this study was to analyse the objective and subjective training for young cyclists that is prescribed by their coaches. Seven cyclists performed an incremental exercise to exhaustion before and after 14 weeks of training using an incremental test to determine their maximal oxygen uptake (VO2 max), the velocity associated with VO2 max (vVO<I>2</I>max), and the velocity associated with the ventilatory threshold (vVT). Cyclists completed a training record with the actual content and the perceived exertion of each training session during these 14 weeks. We have focused on the actual content of the training prescribed by the coaches. Analysis of the content of each session allowed us to calculate the objective training load (volume at different intensities) and to determine the subjective training load from perceived exertion ratings (training load, monotony, strain, and fitness-fatigue). The results showed that cyclists were training at a relatively low intensity and that training rating of perceived exhaustion was weak. Moreover, after 14 weeks of training, VO2 max did not change whereas vVO<I>2</I>max and vVT increased significantly. Therefore, a discrepancy may exist between what is perceived during training and the effects of training. Consequently, objective and subjective indices collected from training books provided useful information supplementary to that recorded from the physiological indices alone.Key words: training load, training book, perceived exertion, performance.

Effects of dominant somatotype on aerobic capacity trainability

PURPOSE

This study examined the association between dominant somatotype and the effect on aerobic capacity variables of individualised aerobic interval training.

METHODS

Forty one white North African subjects (age 21.4+/-1.3 years; Vo2max = 52.8+/-5.7 ml kg(-1) min(-1)) performed three exercise tests 1 week apart (i) an incremental test on a cycle ergometer to determine Vo2max and Vo2 at the second ventilatory threshold (VT2); (ii) a VAM-EVAL track test to determine maximal aerobic speed (vVo2max); and (iii) an exhaustive constant velocity test to determine time limit performed at 100% vVo2max (tlim100). Subjects were divided into four somatometric groups: endomorphs-mesomorphs (Endo-meso; n = 9), mesomorphs (Meso; n = 11), mesomorphs-ectomorphs (Meso-ecto; n = 12), and ectomorphs (Ecto; n = 9). Subjects followed a 12 week training program (two sessions/week). Each endurance training session consisted of the maximal number of successive fractions for each subject. Each fraction consisted of one period of exercise at 100% of vVo2max and one of active recovery at 60% of vVo2max. The duration of each period was equal to half the individual tlim100 duration (153.6+/-39.7 s). After the training program, all subjects were re-evaluated for comparison with pre-test results.

RESULTS

Pre- and post-training data were grouped by dominant somatotype. Two way ANOVA revealed significant somatotype-aerobic training interaction effects (p<0.001) for improvements in vVo2max, Vo2max expressed classically and according to allometric scaling, and Vo2 at VT2. There were significant differences among groups post-training: the Meso-ecto and the Meso groups showed the greatest improvements in aerobic capacity.

CONCLUSION

The significant somatotype-aerobic training interaction suggests different trainability with intermittent and individualised aerobic training according to somatotype.

Relação da potência aeróbica máxima e da força muscular com a economia de corrida em atletas de endurance

O objetivo deste estudo foi analisar a relação da potência aeróbica máxima e da força muscular (força isotônica máxima e força explosiva de salto vertical) com a economia de corrida (EC) em atletas de endurance. Vinte e seis corredores do sexo masculino (27,9 ± 6,4 anos; 62,7 ± 4,3kg; 168,6 ± 6,1cm; 6,6 ± 3,1% de gordura corporal) realizaram, em diferentes dias, as seguintes provas: a) teste incremental para a determinação do consumo máximo de oxigênio (VO2max) e sua respectiva intensidade (IVO2max); b) teste submáximo com velocidade constante para determinar a EC; c) teste de carga máxima no leg press; e d) altura máxima de salto com contramovimento (SV). O VO2max (63,8 ± 8,3ml/kg/min) foi significantemente correlacionado (r = 0,63; p < 0,05) com a EC (48,0 ± 6,6ml/kg/min). Por outro lado, a IVO2max (18,7 ± 1,1km/h), a força isotônica máxima (230,3 ± 41,2kg) e o SV (30,8 ± 3,8cm) não foram significantemente relacionados com a EC. Conclui-se que a potência aeróbica máxima explica em parte as variações interindividuais da EC em atletas de endurance. Entretanto, a força isotônica máxima e a força explosiva parecem não estar associadas com os valores de EC neste grupo de atletas.

Effects of active recovery between series on performance during an intermittent exercise model in young endurance athletes

The purpose of our study was to compare time to exhaustion ( t(lim)) and time spent at a high level of oxygen uptake (V(.)O(2)) during two high-intensity short intermittent exercises (30 s-30 s) realized with or without series. Eleven young endurance-trained athletes [16.6 (0.4) years] took part in three field tests until exhaustion: (1) a maximal graded test to measure their maximal aerobic velocity (MAV) and maximal oxygen uptake (V(.)O(2max)); (2) and (3) two randomized intermittent exercises (30 s at 110% of MAV alternated with 30 s at 50% of MAV): one alternating repetitions non-stop (IE) and another including 4 min recovery every six repetitions (IEs). The mean t(lim) measured during IEs was significantly longer than IE [respectively 960.0 (102.0) s vs 621.8 (56.2) s]. The time spent at V(.)O(2max)( t(V(.)O2max)) and the time spent above 90% of V(.)O(2max)( t(90%V(.)O2max)) did not differ significantly according to the type of exercise: with or without series [respectively t(V(.)O2max) was 158.2 (59.7) s vs 178.0 (56.5) s and t(90%<Vdot>O2max) was 290.4 (84.3) s vs 345.0 (61.6) s] but when expressed as a relative value, t(90%<Vdot>O2max) during IEs was significantly lower than during IE [respectively 36.4 (10.4)% t(lim) vs 58.3 (8.7)% t(lim)]. Despite a significant decrease ( P<0.005) of time to achieve 90% of V(.)O(2max) at the start of each series during IEs [respectively 165.0 (43.1) s for the first series and 82.5 (15.8) s for the second series ( n=6)] the time spent under 90% of V(.)O(2max) limited the t(90%V(.)O2max) during each series. In conclusion, our results showed that intermittent exercise with series does not permit an increase in the time spent at a high level of V(.)O(2); however, the athletes performed more repetitions of short intense exercise.

Training profile counts for time-to-exhaustion performance

The objective of this study was to compare the time to exhaustion (Tlim) at maximal aerobic speed (v.VO2max) in middle- and long-distance runners. Five middle-distance (MDR) and 5 long-distance (LDR) male runners, ages 28 +/- 7 years, were tested running on a treadmill, with the Université de Montréal Track Test (UMTT), on maximal velocity and on time-to-exhaustion track tests. During the laboratory test, cardiorespiratory variables (e.g., HR, .VO2max, .VCO2, .VE) were assessed. Second, running velocity at .VO2max (v.VO2max) during the UMTT was determined and HR values were recorded; also, maximal velocity on a 30-m sprint (V30) and maximal heart rate (HR max) and time to exhaustion were determined on the track. No significant difference was observed between groups during the multistage treadmill test. Significant differences were found between groups for V30 and Tlim, with MDR showing a 23% longer running time than LDR. The results of the present study demonstrated that the training profile of middle-distance and long-distance runners plays a significant role in Tlim performance when v.VO2max is obtained during a test with short-duration stages.

The oxygen uptake response running to exhaustion at peak treadmill speed

PURPOSE

Peak treadmill speed (V(max)), which is the final speed reached and sustained for a minute during a speed-incremented continuous maximal oxygen uptake ([OV0312]O(2max)) test, is an effective predictor of endurance performance. This study assesses the reliability of V(max) and [OV0312]O(2max), and examines the oxygen uptake response while running to exhaustion at V(max).

METHODS

Eleven recreationally active runners completed two speed-incremented [OV0312]O(2max) tests (test 1 and test 2) to determine [OV0312]O(2max) and V(max). In addition, the subjects completed a constant speed test (test 3) at V(max) to determine time to exhaustion (T(max)).

RESULTS

No significant differences existed between test 1 and test 2 for [OV0312]O(2max) (P = 0.68) and V(max) (P = 0.10). Means (+/- SD) for [OV0312]O(2max) and V(max) were 51.1 +/- 5.8 mL.kg-1.min-1 and 17.4 +/- 1.3 km.h-1, respectively; 95% limits of agreement for V(max) were -0.1 +/- 1.4 km.h-1. However, as heteroscedasticity was present in the [OV0312]O(2max) test data, 95% ratio limits of agreement were reported (1.01 *// 1.08). During test 3, 6 of the 11 subjects attained an oxygen uptake equivalent to their previously recorded [OV0312]O(2max). The time to attain [OV0312]O(2max) was 155.0 +/- 48.0 s, which represented 66.5% of T(max) (237.0 +/- 35.0 s). Although 5 of the 11 subjects did not attain an oxygen uptake response equivalent to that previously recorded, no significant difference existed between the oxygen uptakes for the three tests (P = 0.52).

CONCLUSION

The results of this study indicate that V(max) and [OV0312]O(2max) attained during a speed incremented maximal oxygen uptake test were reliable. However, while running at V(max), not all the subjects attained an oxygen uptake response equivalent to that previously recorded during incremental tests 1 and 2.

Methods to determine aerobic endurance

Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate data instead of blood lactate concentration ([La(-)](b)) is not valid. Added to the fact that the AT may not represent the optimal training intensity for elite athletes, it raises doubt on the usefulness of this theory without questioning, however, the usefulness of the whole [La(-)](b)-power curve to assess aerobic endurance and predict performance in long-distance events.

Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training

This article traces the history of scientific and empirical interval training. Scientific research has shed some light on the choice of intensity, work duration and rest periods in so-called 'interval training'. Interval training involves repeated short to long bouts of rather high intensity exercise (equal or superior to maximal lactate steady-state velocity) interspersed with recovery periods (light exercise or rest). Interval training was first described by Reindell and Roskamm and was popularised in the 1950s by the Olympic champion, Emil Zatopek. Since then middle- and long- distance runners have used this technique to train at velocities close to their own specific competition velocity. In fact, trainers have used specific velocities from 800 to 5000m to calibrate interval training without taking into account physiological markers. However, outside of the competition season it seems better to refer to the velocities associated with particular physiological responses in the range from maximal lactate steady state to the absolute maximal velocity. The range of velocities used in a race must be taken into consideration, since even world records are not run at a constant pace.

Calculation of times to exhaustion at 100 and 120% maximal aerobic speed

The aim was to compare physiologic responses during exhaustive runs performed on a treadmill at 100 and 120% maximal aerobic speed (MAS: the minimum speed that elicits VO2max). Fourteen subelite male runners (mean +/- SD; age = 27+/-5 years; VO2max = 68.9+/-4.6 ml/kg(-1)/min(-1); MAS = 21.5+/-1 km/h(-1)) participated. Mean time to exhaustion tlim100% at 100% MAS (269+/- 77s) was similar to those reported in other studies. However, there was large variability in individual tlim100% MAS (CV = 29%). MAS was positively correlated with VO2max (r = 0.66, p<0.05) but not with tlim100%) MAS (r = -0.50, p<0.05). tlim100% MAS was correlated with t(lim) at 120% MAS (r = 0.52, p < 0.05) and to blood pH following the rest at 120% MAS (r = -0.68, p<0.05). The data suggest that running time to exhaustion at MAS in subelite male runners is related to time limit at 120% (tlim120%) MAS. Moreover, anaerobic capacity determined by the exercise to exhaustion at 120% MAS can be defined as the variable 'a' in the model of Monod and Scherrer (1954).

Determination of the velocity associated with VO2max

PURPOSE

The theoretical velocity associated with VO2max (vVO2max) defined by Daniels (1985) is extrapolated from the submaximal VO2-velocity relationship. VO2 is generally determined by assuming that the aerobic response reacts like a linear first-order system at the beginning of square-wave exercise with a steady-state reached by the 4th minute. However, at supra-ventilatory threshold work rates, the steady state in VO2 is delayed or not attained.

METHODS

The present study was carried out to compare three values for vVO2max determined with Daniels' method, but with VO2 either measured at the 4th minute (vVO2max4), the 6th minute (vVO2max6), or after the attainment of the true steady-state (vVO2maxSS). The metabolic response during square-wave exercise at each of the three vVO2max were also assessed.

RESULTS

These velocities were significantly different (P < 0.05), but vVOmaxSS and vVO2max6 were highly correlated (r = 0.98; P < 0.05). Blood lactate concentrations measured after exercise at velocities very close to the three vVO2max were similar and the end-exercise VO2 were not different from VO2max, but the time required to elicit 95% VO2max during these three square-wave tests were significantly different.

CONCLUSION

Therefore, when vVO2max is determined by extrapolation from the submaximal VO2-velocity relationships, submaximal VO2 should be measured beyond the 6th minute of square-wave exercise (at least if it takes 30 s to reach the desired velocity) to ensure that all vVO2max reported in future studies describe a similar quantitative index.