Differences between genders in anaerobic capacity during a supramaximal effort

Aim: The present study aimed to verify if there is a difference between genders in anaerobic capacity estimated by energetic equivalents of glycolytic and phosphagen pathways (AC[La-]+EPOCfast). Methods: In this way, 8 men and 8 women (physical education students) were subjected to the following sequence of tests: session 1) graded exercise test to measure the maximal oxygen consumption (VÖ½ O2max) and intensity associated with VÖ½ O2max (iVÖ½ O2max); sessions 2 to 3) familiarization with supramaximal effort at 115% of iVÖ½ O2max; session 4) supramaximal effort at 115% of iVÖ½ O2max to measure AC[La-]+EPOCfast. Results: The AC[La-]+EPOCfast was lower in women compared to men when expressed in absolute and relative values (-38.11%; p=0.01 and -25.71%; p=0.03, respectively). A non-significant difference was observed in performance in the supramaximal effort (-12.08%; p=0.15), besides which, a likely negative inference was observed when comparing women to men. In addition, energetic equivalents of the glycolytic pathway (e[La- ]) were also lower in women when expressed in relative and absolute values (-47.01%; p=0.001 and -36.71%; p=0.001, respectively), however no statistical difference was found for energetic equivalents of the phosphagen pathway (ePCr) (p>0.05). Conclusion: The AC[La-]+EPOCfast is lower in women compared to men, mainly due to differences in the glycolytic pathway.(AU)

Differing effects of aquatic movement in either deep or shallow water on the physiological responses among middle-aged, female and recreational synchronized swimmers / 体力科学

This study examined the physiological response to different water depths in recreational synchronized swimming. Nine middle-aged, female, recreational swimmers carried out the same team free routines in deep water (deep-water synchronized swimming: DWS) and shallow water (shallow-water synchronized swimming: SWS). Heart rate (HR) was measured continuously during each performance, combined with estimation of metabolic equivalent (MET) values using individual linear regression equations of HR-oxygen uptake. These equations were created using the results of 12 water activities. Blood lactate concentration and systolic blood pressure were measured at the 1/3 and 2/3 stages and immediately after each performance period. HR and estimated METs during DWS (mean±SD, 152.9±7.5 beats·min^-1 and 7.3±1.2) were significantly higher than those measured during SWS (131.8±11.3 beats·min^-1 and 5.7±0.8). Blood lactate concentration and systolic blood pressure measured immediately after DWS were significantly higher than those measured after SWS. With DWS, blood lactate concentration at the 2/3 stage and immediately after the performance were significantly higher than those measured at the 1/3 stage, whereas in SWS no significant difference was found in these values at any time period. In conclusion, the exercise intensity of DWS was high and SWS moderate. The predominant sources of energy may be phosphocreatine stores and aerobic metabolism during these performances. It is possible that glycolysis may also play an important role in energy requirements during the 2/3 stage and immediately after a DWS performance.

Métodos de quantificação de carga de treinamento em exercício realizado no máximo estado estável de lactato / Methods of quantification of training load in exercise performed at maximal lactate steady state

O objetivo do presente estudo foi comparar e correlacionar as estimativas de impulso de treinamento (TRIMP) propostos por Banister (TRIMPBanister), Stagno (TRIMPStagno) e Manzi (TRIMPManzi). Os participantes foram submetidos a um teste progressivo em cicloergômetro, com registro da frequência cardíaca e da concentração de lactato sanguíneo. Em uma segunda ocasião, realizaram 30 min. de exercício na intensidade correspondente ao máximo estado estável de lactato, a partir do qual foram calculados o TRIMPBanister, TRIMPStagno e TRIMPManzi. Os valores médios de TRIMPBanister (56,5 ± 8,2 u.a.) e TRIMPStagno (51,2 ± 12,4 u.a.) não diferiram entre si (P > 0,05) e foram altamente correlacionados (r = 0,90), com boa concordância, ou seja, viés reduzido e limites de concordância relativamente estreitos. O TRIMPStagno e TRIMPManzi (73,4 ± 17,6 u.a.) apresentarem alta correlação (r = 0,93), mas com diferença significantes entre eles; ainda, se mostraram pouco concordantes. As estimativas de TRIMPBanister e TRIMPManzi não foram diferentes (P = 0,06) e apresentaram alta correlação (r = 0,82), com baixa concordância. Assim, conclui-se que os métodos de TRIMP não são equivalentes. Na prática, parece ser prudente monitorar o processo de treinamento assumindo apenas uma das estimativas.

The aim of the present study was to compare and correlate training impulse (TRIMP) estimates proposed by Banister (TRIMPBanister), Stagno (TRIMPStagno) and Manzi (TRIMPManzi). The subjects were submitted to an incremental test on cycle ergometer with heart rate and blood lactate concentration measurements. In the second occasion, they performed 30 min. of exercise at the intensity corresponding to maximal lactate steady state, and TRIMPBanister, TRIMPStagno and TRIMPManzi were calculated. The mean values of TRIMPBanister (56.5 ± 8.2 u.a.) and TRIMPStagno (51.2 ± 12.4 u.a.) were not different (P > 0.05) and were highly correlated (r = 0.90). Besides this, they presented a good agreement level, which means low bias and relatively narrow limits of agreement. On the other hand, despite highly correlated (r = 0.93), TRIMPStagno and TRIMPManzi (73.4 ± 17.6 u.a.) were different (P < 0.05), with low agreement level. The TRIMPBanister e TRIMPManzi estimates were not different (P = 0.06) and were highly correlated (r = 0.82), but showed low agreement level. Thus, we concluded that the investigated TRIMP methods are not equivalent. In practical terms, it seems prudent monitor the training process assuming only one of the estimates.

DEVELOPMENT OF ACCUMLATED AND TEMPORARY FATIGUE DURING REPEATED CYCLING SPRINTS / 体力科学

The purpose of this study was to determine whether accumulated and temporary fatigue could be separately observed in repeated cycling sprints (RCS) with combined short and long recovery periods. Eight male performed three RCS with 35-sec (RCS₃₅), 350-sec (RCS₃₅₀) and combined 35-sec and 350-sec recovery periods (RCS_comb). RCS_comb consisted of ten 10-sec cycling sprints (CSs) with 35-sec and 350-sec recovery periods before the 5^th and 9^th CS. In RCS_comb, peak power output (PPO) was restored in the 5^th and not in 9^th CS. Blood lactate concentration ([La]) progressively increased, but there were no significant differences among conditions despite the difference in PPO. In RCS_comb, mean power frequency determined on the vastus lateralis was correlated with PPO and oxygen uptake before CSs (preVO₂) showed high in short recovery periods and low values in long recovery periods. Accumulated and temporary fatigue cannot be explained by effects of preVO₂ and [La].

Exercise intensity during a free routeine in well trained synchronized swimmers / 体力科学

A study was conducted to clarify the exercise intensity and metabolic condition during a free routine of synchronized swimming with respect to heart rate (HR), blood lactate concentration (La) and the rate of perceived exertion (RPE) . Six well trained female synchronized swimmers participated as subjects. HR during the free routine was measured continuously. La and RPE during the free routine were measured intermittently from the start to end of each stage. Maximum heart rate (swimmingHRmax : S-HRmax) was determined by measurement of maximum oxygen uptake using a swimming flume. Peak blood lactate concentration (Peak La) was measured after the maximum front crawl stroke of 100 m. The average values and S. D. of S-HRmax and Peak La were 180.0±3.8 beats · min<SUP>-1</SUP> and 9.6 ± 1.0 mmol · 1<SUP>-1</SUP>, respectively. Average values, S. D. and ranges of HR and %S-HRmax during the free routine were 137.6±25.5 (60-180) beats · min<SUP>-1</SUP> and 76.5± 14.3 (34.5-96.8) %, respectively. HR during the free routine showed a decrease in the breath-holding phase. Average values and S. D. of La, %Peak La and RPE at the fourth stage were 5.4±1.2mmol·1<SUP>-1</SUP>, 57.0±17.2% and 17.7±0.8, respectively. La, %Peak La and RPE at the fourth stage were significantly higher than those at the other stages, and La, %Peak La and RPE at the third stage were significantly higher than those at the second stage. These results suggested that the overall intensity of the free routine was moderate, but that part of the free routine included high-intensity activity and the percentage of anaerobic metabolism during the free routine increased in the final stages

METABOLIC ADAPTATIONS TO ENDURANCE TRAINING MONITORED BY BLOOD LACTATE CONCENTRATION IN MALE RATS / 体力科学

We studied the effects of 8 weeks of endurance training on the metabolism in rats. Different treadmill speeds, which corresponded to 2 mM and 4 mM blood lactate concentrations, were used to vary the intensity of the endurance training. After 8 weeks of training, blood lactate concentrations had decreased whereas β-hydroxyacyl-CoA dehydrogenase activity had increased. Citrate synthase activity in the m.extensor digitorum longus (EDL), and m.tibialis anterior (TA) of rats trained at the 4 mM level was higher than in rats trained at the 2 mM level and in control rats. In addition, muscle glycogen content in the hindlimb was higher and muscle TG content in the m.soleus (SOL) was lower in trained rats. These results suggest that training at 4 mM level significantly increases muscle mitochondrial oxidative capacity, and fatty acids are utilized as an energy source regardless of exercise intensity at least in the 2 to 4 mM intensity range. We concludes that an intensity of 4 mM is a useful level with which to elucidate the various adaptations to endurance training.

LT (LACTATE THRESHOLD) IN 10-12 YEAR OLD BOYS DURING TREADMILL RUNNING / 体力科学

The influence of daily physical exercise on oxygen utilizing capacity of working muscle investigated by means of measureing lactate threshold (LT) during progressive treadmill running from the comparison between soccer group (S group: N=12, 11.9±0.1 years of age) and control group (C group ; N=14, 11.8±0.1 years of age) . LT<SUB>1</SUB> was determined as the point where blood lactate concentration (La) increased from rest level, and LT<SUB>2</SUB> was determined by the gradient, La/VO<SUB>2</SUB>. body weight<SUP>-1</SUP> (2 mM/10 ml. kg<SUP>-1</SUP>, min<SUP>-1</SUP>) .<BR>LT<SUB>1</SUB> and LT<SUB>2</SUB> in S group were significantly higher than those in C group expressed with absolute and relative values of VO<SUB>2</SUB> (1. min<SUP>-1</SUP>, ml. kg<SUP>-1</SUP>. min<SUP>-1</SUP>, % VO<SUB>2</SUB>max) . No significant differences in La, ventilation responses, and heart rate at the point of LT<SUB>1</SUB> and LT<SUB>2</SUB> were observed between S and C group, La showed slight decrease and was kept at lower level in S group with increase of VO<SUB>2</SUB>, compared with C group. On the contrary, La in C group began to increase at lower level of VO<SUB>2</SUB>. From our previous longitudinal study of LT in non-athletic children, we observed that LT shifted to lower level with growth. It was sugesed that La curve of S group, such shift had not occurred. Differences of these patterns in VO<SUB>2</SUB> and La between athletic children and non-athletic children were similar to those observed in adults athletes and non-athletes.<BR>In conclusion it was supposed that sufficient daily physical training in 10-12 year of age might increase oxygen utilizing capacity of leg working muscle during running exercise.