Effects of recovery type after a judo combat on blood lactate removal and on performance in an intermittent anaerobic task

Aim. The objective of this study was to verify the effects of active (AR) and passive recovery (PR) after a judo match on blood lactate removal and on performance in an anaerobic intermittent task (4 bouts of upper body Wingate tests with 3-min interval between bouts; 4WT).Methods. The sample was constituted by 17 male judo players of different competitive levels: A) National (Brazil) and International medallists (n. 5). B) State (São Paulo) medallists (n. 7). Q City (São Paulo) medallists (n. 5). The subjects were submitted to: 1) a treadmill test for determination of VO2peak and velocity at anaerobic threshold (VAT); 2) body composition; 3) a 5-min judo combat, 15-min of AR or PR followed by 4WT.Results. The groups did not differ with respect to: body weight, VO2peak, VAT, body fat percentage, blood lactate after combats. No difference was observed in performance between AR and PR, despite a lower blood lactate after combat (10 and 15 min) during AR compared to PR. Groups A and B performed better in the high-intensity intermittent exercise compared to athletes with lower competitive level (C).Conclusion. The ability to maintain power output during intermittent anaerobic exercises can discriminate properly judo players of different levels. Lactate removal was improved with AR when compared to PR but AR did not improve performance in a subsequent intermittent anaerobic exercise.

The Lactate Minimum Test protocol provides valid measures of cycle ergometer VO2 peak

Aim. The aim of the present study was to investigate the validity of the Lactate Minimum Test (LMT) for the determination of peak VO2 on a cycle ergometer and to determine the submaximal oxygen uptake (VO2) and pulmonary ventilation (VE) responses in an incremental exercise test when it is preceded by high intensity exercise (i.e., during a LMT).Methods. Ten trained male athletes (triathletes and cyclists) performed 2 exercise tests in random order on an electromagnetic cycle ergometer: 1) Control Test (CT): an incremental test with an initial work rate of 100 W, and with 25 W increments at 3-min intervals, until voluntary exhaustion; 2) LMT: an incremental test identical to the CT, except that it was preceded by 2 supramaximal bouts of 30-sec (similar to120% VO(2)peak) with a 30-sec rest to induce lactic acidosis. This test started 8 min after the induction of acidosis.Results. There was no significant difference in peak VO2 (65.6+/-7.4 ml.kg(-1).min(-1); 63.8+/-7.5 ml.kg(-1).min(-1) to CT and LMT, respectively). However, the maximal power output (POmax) reached was significantly higher in CT (300.6+/-15.7 W) than in the LMT (283.2+/-16.0 W).VO2 and VE were significantly increased at initial power outputs in LMT.Conclusion. Although the LMT alters the submaximal physiological responses during the incremental phase (greater initial metabolic cost), this protocol is valid to evaluate peak VO2, although the POmax reached is also reduced.

Exercise mode affects the time to achieve VO2max without influencing maximal exercise time at the intensity associated with VO2max in triathletes

The objective of this study was to analyze, in triathletes, the possible influence of the exercise mode (running x cycling) on time to exhaustion (TTE) and oxygen uptake (VO2) response during exercise performed at the intensity associated with the achievement of maximal oxygen uptake (IVO2max). Eleven male triathletes (21.8 +/- 3.8 yr) performed the following tests on different days on a motorized treadmill and on a cycle ergometer: 1) incremental tests in order to determine VO2max and IVO2max and, 2) constant work rate tests to exhaustion at IVO2max to determine TTE and to describe VO2 response (time to achieve VO2max-TAVO(2max) and time maintained at VO2max-TMVO2max). No differences were found in VO2max, TTE and TMVO2max obtained on the treadmill tests (63.7 +/- 4.7 ml.kg(-1).min(-1); 324.6 +/- 109.1 s; 178.9 +/- 93.6 s) and cycle ergometer tests (61.4 +/- 4.5 ml.kg(-1).min(-1); 390.4 +/- 114.4 s; 213.5 +/- 102.4 s). However, TAVO(2max) was influenced by exercise mode (145.7 +/- 25.3 vs. 176.8 +/- 20.1 s; in treadmill and cycle ergometer, respectively; p = 0.006). It is concluded that exercise modality affects the TAVO(2max) without influencing TTE and TMVO2max during exercise at IVO2max in triathletes.

Effects of Strength Training on Running Economy

The objective of this study was to compare the effect of different strength training protocols added to endurance training on running economy (RE). Sixteen well-trained runners (27.4 +/- 4.4 years; 62.7 +/- 4.3 kg; 166.1 +/- 5.0 cm), were randomized into two groups: explosive strength training (EST) (n = 9) and heavy weight strength training (HWT) (n = 7) group. They performed the following tests before and after 4 weeks of training: 1) incremental treadmill test to exhaustion to determine of peak oxygen uptake and the velocity corresponding to 3.5 mM of blood lactate concentration; 2) submaximal constant-intensity test to determine RE; 3) maximal countermovernent jump test and; 4) one repetition maximal strength test in leg press. After the training period, there was an improvement in RE only in the HWT group (HWT = 47.3 +/- 6.8 vs. 44.3 +/- 4.9 ml.kg(-1) -min(-1); EST = 46.4 +/- 4.1 vs. 45.5 +/- 4.1 ml.kg(-1) .min(-1)). In conclusion, a short period of traditional strength training can improve RE in well-trained runners, but this improvement can be dependent on the strength training characteristics. When comparing to explosive training performed in the same equipment, heavy weight training seems to be more efficient for the improvement of RE.

Changes in physiological and stroking parameters during interval swims at the slope of the d-t relationship

The slope of the distance-time relationship from maximal 200 and 400 in bouts (S(200-400)) has been increasingly employed for setting training intensities in swimming. However, physiological and mechanical responses at this speed are poorly understood. Thus, this study investigated blood lactate, heart rate (HR), stroke rate (SR), stroke length (SL) and RPE responses to an interval swimming set at S(200-400) in trained swimmers. In a 50-m pool, twelve athletes (16.5 +/- 1.2 yr, 176 +/- 7 cm, 68.4 +/- 5.4 kg, and 7.8 +/- 2.5% body fat) performed maximal 200 and 400 m crawl trials for S(200-400) determination (1.28 +/- 0.05 m/s). Thereafter, swimmers were instructed to perform 5 x 400 in at this speed with 1.5 min rest between repetitions. Three athletes Could not complete the set (exhaustion at 21.0 +/- 3.1 min). For the remaining swimmers (total set duration = 32.0 +/- 1.3 min) significant increases) (p < 0.05) in blood lactate (5.7 +/- 0.8-7.9 +/- 2.4 mmol/l), SR (29.6 +/- 3.2-32.1 +/- 4.1 cycles/min), HR (169 +/- 11-181 +/- 8 bpm) and RPE (13.3 +/- 1.6-16.3 +/- 2.6) were observed through the IS. Conversely, SL decreased significantly (p < 0.05) from the first to the fifth repetition (2.48 +/- 0.22-2.31 +/- 0.24 m/cycle). These results suggest that interval swimming at S(200-400) represents an intense physiological, mechanical and perceptual stimulus that can be sustained for a prolonged period by most athletes. (C) 2008 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of Cold Water Immersion and Active Recovery on Post-Exercise Heart Rate Variability

The aim of the present study was to investigate the potential benefits of cold water immersion (CWI) and active recovery (AR) on blood lactate concentration ([Lac]) and heart rate variability (HRV) indices following high-intensity exercise. 20 male subjects were recruited. on the first visit, an incremental test was performed to determine maximal oxygen consumption and the associated speed (MAS). The remaining 3 visits for the performance of constant velocity exhaustive tests at MAS and different recovery methods (6 min) were separated by 7-day intervals [randomized: CWI, AR or passive recovery (PR)]. The CWI and AR lowered [Lac] (p < 0.05) at 11, 13 and 15 min after exercise cessation in comparison to PR. There was a 'time' and 'recovery mode' interaction for 2 HRV indices: standard deviation of normal R-R intervals (SDNN) (partial eta squared = 0.114) and natural log of low-frequency power density (lnLF) (partial eta squared = 0.090). CWI presented significantly higher SDNN compared to PR at 15 min of recovery (p < 0.05). In addition, greater SDNN values were found in CWI vs. AR during the application of recovery interventions, and at 30 and 75 min post-exercise (p < 0.05 for all differences). The lnLF during the recovery interventions and at 75 min post-exercise was greater using CWI compared with AR (p < 0.05). For square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) and natural log of high-frequency power density (lnHF), a moderate effect size was found between CWI and PR during the recovery interventions and at 15 min post-exercise. Our findings show that AR and CWI offer benefits regarding the removal of [Lac] following high-intensity exercise. While limited, CWI results in some improvement in post-exercise cardiac autonomic regulation compared to AR and PR. Further, AR is not recommended if the aim is to accelerate the parasympathetic reactivation.

A Semi-Tethered Test for Power Assessment in Running

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stroking Parameters during Continuous and Intermittent Exercise in Regional-Level Competitive Swimmers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of exercise mode and maximal lactate-steady-state concentration on the validity of OBLA to predict maximal lactate-steady-state in active individuals

The aim of this study was to analyze the effects of exercise mode on the validity of onset of blood lactate accumulation (OBLA-3.5-mM fixed blood lactate concentration) to predict the work-rate at maximal lactate steady state (MLSSwork-rate). Eleven recreationally active mates (21.3 +/- 2.9 years, 72.8 +/- 6.7 kg, 1.78 +/- 0.1 m) performed randomly incremental tests to determine OBLA (stage duration of 3 min), and 2 to 4 constants work-rate exercise tests to directly determine maximal lactate steady state parameters on a cycle-ergometer and treadmill. For both exercise modes, the OBLA was significantly correlated to MLSSwork-rate, (cycling: r = 0.81 p = 0.002; running: r = 0.94, p < 0.001). OBLA (156.2 +/- 41.3 W) was lower than MLSSwork-rate (179.6 +/- 26.4 W) during cycling exercise (p = 0.007). However, for running exercise, there was no difference between OBLA (3.2 +/- 0.6 m s(-1)) and MLSSwork-rate (3.1 +/- 0.4 m s(-1)). The difference between OBLA and MLSSworkrate on the cycle-ergometer (r = 0.86; p < 0.001) and treadmill (r = 0.64; p = 0.048) was significantly related to the specific MLSS. We can conclude that the validity of OBLA on predicting MLSSwork-rate is dependent on exercise mode and that its disagreement is related to individual variations in MLSS. (C) 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Relationship Between Speed and Time in Running

The purpose of this study was to evaluate the effect of using different mathematical models to describe the relationship between treadmill running speed and time to exhaustion. All models generated a value for an aerobic parameter (critical speed; S(critical)). 35 university students performed 5-7 constant-speed 0%-slope treadmill tests at speeds that elicited exhaustion in similar to 3 min to similar to 10 min. Speed and time data were fitted using 3 models: (1) a 2-parameter hyperbolic model; (2) a 3-parameter hyperbolic model; and (3) a hybrid 3-parameter hyperbolic + exponential model. The 2-parameter model generated values for S(critical) (mean (+/- SD): 186 +/- 33 m.min(-1)) and anaerobic distance capacity (ADC; 251 +/- 122 m) with a high level of statistical certainty (i.e., with small SEEs). The 3-parameter models generated parameter estimates that were unrealistic in magnitude and/or associated with large SEEs and little statistical certainty. Therefore, it was concluded that, for the range of exercise durations used in the present study, the 2-parameter model is preferred because it provides a parsimonious description of the relationship between velocity and time to fatigue, and it produces parameters of known physiological significance, with excellent confidence.

Effect of an acute β-adrenergic blockade on exercise intensity corresponding to the lactate minimum

β-Adrenoreceptor blockade is reported to impair endurance, power output and work capacity in healthy subjects and patients with hypertension. The purpose of this study was to investigate the effect in eighth athletic males of an acute β-adrenergic blockade with propranolol on their individual power output corresponding to a defined lactate minimum (LM). Eight fit males (cyclist or triathlete) performed a protocol to determine the power output corresponding to their individual LM (defined from an incremental exercise test after a rapidly induced exercise lactic acidosis). This protocol was performed twice in a double-blind randomized order by each athlete first ingesting propranolol (80mg) and in a second trial a placebo, 120 minutes respectively prior to the test sequence. The blood lactate concentration obtained 7 minutes after anaerobic exercise (a Wingate test) was significantly lower after acute β-adrenergic blockade (8.6 ± 1.6mM) than under the placebo condition (11.7 ± 1.6mM). The work rate at the LM was lowered from 215.0 ± 18.6 to 184.0 ± 18.6 watts and heart rate at the LM was reduced from 165 ± 1.5 to 132 ± 2.2 beats/minute as a result of the blockade. There was a non-significant correlation (r = 0.29) between the power output at the LM with and without acute β-adrenergic blockade. In conclusion, since the intensity corresponding to the LM is related to aerobic performance, the results of the present study, are able to explain in part, the reduction in aerobic power output produced during β-adrenergic blockade.

Electromyographic validation of the trapezius and serratus anterior muscles in military press exercises with open and middle grip

Electromyographic activity of the trapezius muscle and serratus anterior muscle was analysed in 4 different modalities of military press exercises, each of them with 2 grips: open and middle. It was analyzed 24 male volunteers using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. The TS and SI muscles acted with high and very high activity in all the modalities of military press exercises. Statistically, they did not show significative difference in the performance of the exercises with open and middle grip, justifying the inclusion of this group of exercises with both grips for the physical conditioning programmes.

Electromyographic validation of the trapezius and serratus anterior muscles in rowing exercises with closed grip

Because the lack of specialized textbooks, the select of basic exercises for physical conditioning programmes is based on empirical knowledge. This fact led the authors to propose the study on electromyographic activity of the trapezius (upper portion) (TS) and the serratus anterior (lower portion) (SI) muscles in rowing exercises with closed grip in three different modalities. The tests were carried out with 24 male volunteers, 18 to 25 years old, by using a two-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. For exercises execution, a long bar made of light wood was used. TS acted significantly in the three different modalities, that is, upright, sitting and bent over, while SI acted preferentially in upright and sitting rowing exercises, justifying their inclusion as basic exercises in physical conditioning programmes.

Neuromuscular recovery of the biceps brachii muscle after resistance exercise

The aim of this study was to determine the time to restore the biceps brachii (BB) electromyographic (EMG) activity after the biceps curl (BC) exercise, at different intensities. Ten males performed initially maximal voluntary isometric contractions (MVC) of the elbow flexors, followed by one isometric submaximal contraction at 50% MVC (reference contraction). After this, four bouts of the BC at 25%, 30%, 35%, and 40% 1 RM during 1 minute (randomly assigned, with 10 minutes rest between them) were performed. During the rest intervals at preestablished moments (15 seconds, 1, 3, 5, and 10 min), isometric 50% MVC were performed. The EMG variables (root mean square [RMS], zero crossings [ZC], median frequency, [MF] and peak power [PP]) at rest were compared with reference values. Immediately after the exercise, RMS and PP increased, while ZC and MF decreased, indicating fatigue. After 1 minute most of the variables were similar to the reference. Different load levels did not affect the EMG recovery. In conclusion, the EMG variables recovered after 1 minute rest, indicating the optimal muscular condition for subsequent bouts. Copyright © Taylor & Francis Group, LLC.