Fat availability during the submaximal exercise was enhanced by prior resistance exercise. However, augmentation of fat oxidation was observed only in the trial with shorter rest between resistance exercise and submaximal exercise bouts (RE20 trial).

The purpose of this study was to investigate the effects of long-term chicken breast extract (CBEX) supplementation, a rich source of carnosine and anserine, on relatively high intensity endurance performance. Sixteen healthy male subjects were divided into CBEX group (n = 8) and placebo group (n = 8). The CBEX group was orally administered 200 ml CBEX drink which contained 4g of carnosine and anserine per day for 30 days. The placebo group was orally administered 200ml the same taste CBEX drink which contained no carnosine and anserine. Before and after the ingestion period, the subjects performed three sessions of consecutive endurance exercise (fi rst session: 30-min at 50%V O 2 max was signifi cantly decreased after supplementation in the CBEX group. These results suggest that the long-term ingestion of carnosine and anserine could enhance muscle buffering capacity, and in turn improve relatively high intensity endurance performance such as the so-called "last spurt" resulting from attenuation of the muscle fatigue at submaximal exercise.

No abstract

The shortening of parasternal intercostal muscles (Para) and crural (Cru) and costal diaphragms (Cos) are not precisely understood. We therefore examined shortening patterns of these inspiratory muscles by using chronically implanted sonomicrometers in dogs.To avoid acute effects of surgery, measurements were performed 3 weeks after implanting the sonomicrometers. Patterns of length changes of Para, Cru, and Cos were measured during hypoxia and hypercapnia under two levels of anaesthesia.Respiratory length change (∆L) was assessed as a percentage change relative to the resting length at functional residual capacity (LFRC). Peak tidal shortening was defined as the maximal change from LFRC (∆L/LFRC). Under light anesthesia, the ∆L/LFRC was the same among the three muscle groups at all tidal volumes (VT). Under deep anaesthesia, the ∆L/LFRC both of Cru and Cos exceeded that of Para. Under light anaesthesia, the maximal shortening velocity ((∆L/LFRC)/∆t ) of Cru was greater than that of Para. Under deep anaesthesia, the (∆L/LFRC)/∆t of Para was exceeded by that both of Cru and Cos. Furthermore, the (∆L/LFRC)/∆t of each inspiratory muscle was greater during hypoxia than during hypercapnia at equal volume.We conclude that: 1) the contribution of the diaphragm to ventilation increases during deep anaesthesia; 2) the muscle shortening velocity during hypoxia or hypercapnia is lower in parasternal intercostal muscles than in the diaphragm; and 3) there is no difference in the shortening pattern between crural and costal diaphragms. Eur Respir J 1997; 10: 430-436 Among the respiratory muscles of the chest wall, the intercostal muscles and the diaphragm act as the major respiratory muscles for breathing. Several reports have suggested that parasternal intercostal muscles (Para) are the primary muscles responsible for expanding the upper rib cage during inspiration [1,2]. The diaphragm is anatomically divided into two muscles, the crural (Cru) and costal parts (Cos) [3]. In animals, the activities of the inspiratory muscles have been studied mainly by electromyography (EMG) [4,5]. These studies have demonstrated that the intercostal muscles, Cru, and Cos are activated differently. On the other hand, studies on the mechanical activities of the inspiratory muscles have focused primarily on their overall movements, i.e. the rib cage and abdominal movements, by inductive plethysmography [6], or the volume-pressure relationships of the rib cage and the diaphragm-abdomen [7]. These studies have suggested that the contribution of the rib cage and diaphragm to ventilation is altered by the magnitude of ventilation or by anaesthesia.Recently, direct measurements of the changes in the lengths of the respiratory muscles have been reported by the use of sonomicrometry [8,9]. This technique allows an accurate measurement of any change in the length of respiratory muscles in vivo. However, EASTON and co-workers [10] found that there was a transient inhibition of diaphragmatic shortening after the upper abdominal surgery require...

AbstractThe purpose of this study was to compare the physiological and morphological characteristics of J. Ndambiri, a Kenyan world-class long-distance runner (10,000 m personal best: 27:04.79), with runners belonging to the national corporate team (29:32.18±0:30.35). Oxygen uptake ( _VO 2 ), heart rate, blood lactate concentration and stride frequency were measured during submaximal exercise on a treadmill (270, 290, 310, 330, 350 and 370 m/min velocities with 1 inclination). Peak oxygen uptake ( _VO 2peak ) was determined during the maximal exercise test. In addition, morphological parameters (length of thigh and shank, maximum circumference of thigh and shank, and cross-sectional area of the trunk, thigh and shank muscles) were determined using a tape measure and magnetic resonance imaging (MRI). Ndambiri was superior to Japanese runners in terms of not only running economy (65.0 vs 69.8 ±1.9 ml/kg/min at 330 m/min), but also blood lactate concentration (1.50 vs 2.59±0.74 mmol/l at 330 m/min), heart rate (159.8 vs 170.8±4.0 bpm at 330 m/min) during the submaximal running test and _VO 2peak (80.8 vs 76.3±2.4 ml/kg/min). In addition, the morphological characteristics of Ndambiri were also quite diŠerent from those of Japanese runners. In particular, Ndambiri's maximum shank circumference was much smaller than that of Japanese runners (32.0 vs 35.8±1.8 cm). Furthermore, the crosssectional area of the gastrocnemius muscle, which composes the shank, was signiˆcantly correlated with the oxygen cost of running at 330 m/min (r＝0.700). Theseˆndings indicate that the superior performance of Ndambiri is attributable to various factors such as a higher _VO 2peak , lower blood lactate concentration and heart rate, as well as running economy. In the future, it will be necessary to clarify the factors supporting these relationships between physiological variables and morphological characteristics.