-The purpose of this study was to examine the relationship between cadence and oxygen consumption with exercise duratian. Ten triathletes who trained regularly were examined. The first test was always a maximal test to determine maximal oxy~ gen uptake (VOzmax). The other sessions were composed of six submaximal tests representing 80% of the maximal power reached with VOzmax (Pmax). During these tests submaximal rides with a duration of 30 min were performed. Each test represented, in a randomised arder, one of the following pedal rates: 50, 65, Bd, 95,110 rpm and a freely-chosen rate. \/0 2 , respiratory parameters, and heart rate were monitored continuously. Two periods, between the 3rd and the 6th minute and between the 25th and the 28th minute, were analysed. Results showed that when \/0 2 and heart rate were plotted against cadence, each curve could be best described by a parabolic function, whatever the period. Furthermore, a significant effect of period was fou nd on energetically optimal cadence (70 ± 4.5 vs. 86 ± 6.2 rpm, P < 0.05). Only during the second period was no significant difference found between freely-chosen cadence (83 ± 6.9 rpm} and energetically optimal cadence (P > 0.05). ln conclusion, our results suggest that during prolonged exercise triathletes choose a cadence that is close to the energetically optimal cadence. A change of muscle fibre recruitment pattern with exercise duration and cadence Would explain the shift in energetically optimal rate towards a higher pedal rate observed at the end of exercise.•

The purpose of the present study was to verify the increase in energy cost of running at the end of a triathlon. A group 11 trained male subjects performed a triathlon (15-km swimming, 40-km cycling, 10-km running). At least 1 week later the subjects ran 10-km as a control at the same pace as the triathlon. Oxygen uptake (VO2), ventilation (VE) and heart rate (HR) were measured during both 10-km runs with a portable telemetry system. Blood samples were taken prior to the start of the triathlon and control run, after swimming, cycling, triathlon run and control run. Compared to the control values the results demonstrated that triathlon running elicited a significantly higher (P < 0.005) mean VO2 [51.2 (SEM 0.4) vs 47.8 (SEM 0.4) ml.min-1.kg-1] VE [86 (SEM 4.2) vs 74 (SEM 5.3) l.min-1], and HR [162 (SEM 2) vs 156 (SEM 1.9) beats.min-1)]. The triathlon run induced a greater loss in body mass than the control run [2 (SEM 0.2) vs 0.6 (SEM 0.2) kg], and a greater decrease in plasma volume [14.4% (SEM 1.5) vs 6.7% (SEM 0.9)]. The lactate concentrations observed at the end of both 10-km runs did not differ [2.9 (SEM 0.2) vs 2.5 (SEM 0.2) m.mol.l-1]. Plasma free fatty acids concentrations were higher (P < 0.01) after the triathlon than after the control run [1.53 (SEM 0.2) to 0.51 (SEM 0.07) mmol.l-1]. Plasma creatine kinase concentrations rose under both conditions from 58 (SEM 12) to 112 (SEM 14) UI.l-1 after the triathlon, and from 61 (SEM 7) to 80 (SEM 6) UI.l-1 after the control run. This outdoor study of running economy at the end of an Olympic distance triathlon demonstrated a decrease in running efficiency.

No abstract

The antilisterial effect of enterocins A and B in meat and meat products (cooked ham, minced pork meat, deboned chicken breasts, pâté, and slightly fermented sausages [espetec]) have been shown. An infective dose of 5 to 10 most probable numbers (MPN)/g to simulate the counts of Listeria generally found in meat products was used. Enterocins at 4,800 AU/g reduced the numbers of Listeria innocua by 7.98 log cycles in cooked ham and by 9 log cycles in pâté when stored at 7 degrees C for 37 days. In deboned chicken breasts stored at 70 degrees C for 7 days, 4,800 AU/cm2 of enterocins diminished the L. innocua counts in 5.26 log cycles when compared to the control batch. In minced pork meat held at 7 degrees C for up to 6 days, 1,600 AU/g kept L. innocua counts under 3 MPN/g, while the control batch reached 50 CFU/g. In espetec sausages, 648 AU/g diminished the number of L. innocua under 50 CFU/g from the fifth day until the end of the process (12 days) while the control batch kept the initial counts (3 x 104 CFU/g). This is the first report on enterocins showing an antilisterial effect in different types of meat products.

The purpose of the present study was to examine the influence of submaximal aerobic exercise duration on simple and complex cognitive performance. Eight well-trained male subjects agreed to participate in this study (trial group). A control group of eight regularly trained male subjects was included for comparative purposes. For the trial group, the experiment involved a critical flicker fusion test (CFF) and a map recognition task performed before, every 20 min during, and immediately after, a 3-h cycling task at an intensity corresponding to approximately 60 % of VO2max. Data were obtained over two experimental sessions with fluid ingestion (F) or no fluid (NF) ingestion. For the control group the experiment was the same but without exercise and fluid ingestion. In the trial group, a significant effect of hydration status was observed on physiological parameters (p <0.05). No effect was found on cognitive performance. A significant decrease in CFF performance was observed after 120 min of exercise when compared with the first 20 min (respectively for CFFmdi: 2.6 vs. 3.8 Hz), irrespective of experimental condition. A significant improvement in speed of response (respectively: 3291 vs. 3062 msec for 20 and 120 min, respectively) and a decrease in error number (21.5 % vs. 6.0 % for 20 and 120 min, respectively) during the map recognition task were recorded between 80 min and 120 min when compared with the first 20 min of exercise. After 120 min the number of recorded errors was significantly greater indicating a shift in the accuracy-speed trade-off (6.0 % vs. 14.1 % for 120 and 180 min, respectively). These results provide some evidence for exercise-induced facilitation of cognitive function. However this positive effect disappears during prolonged exercise--as evidenced within our study by an increase in errors during the complex task and an alteration in perceptual response (i.e. the appearance of symptoms of central fatigue).

These results showed that drafting continuously behind a lead cyclist allows triathletes to save a significant amount of energy during the bike leg of a sprint triathlon and creates the conditions for an improved running performance compared with a situation where cycling is performed alternating the lead with another cyclist.

The highest cycling cadences (MOC, FCC) contribute to an increase in energy cost during cycling and the appearance of a VO2 slow component during subsequent running, whereas cycling at EOC leads to a stability in energy cost of locomotion with exercise duration. Several hypotheses are proposed to explain these results such as changes in fiber recruitment or hemodynamic modifications during prolonged exercise.

We found similar skeletal muscle endurance and fatigability in CF adults and controls and only trends for reduced muscle strength in CF which disappeared when normalized to muscle cross-sectional area. These results indicate small quantitative (reduced muscle mass) rather than qualitative (intrinsic skeletal muscle abnormalities) muscle alterations in CF with mild to moderate lung disease.