To investigate the different ways of assessing the running velocity at which maximal oxygen uptake (VO2max) occurs, or maximal aerobic velocity (vamax), 32 well-trained runners (8 female and 24 male) were studied. The vamax and the running velocity corresponding to a blood lactate concentration of 4 mmol.l-1 (vla4) were measured during a progressive treadmill session. Within the week preceding or following the treadmill measurement the subjects completed a Université de Montreal Track-Test (UMTT). The velocity corresponding to the last stage of this test (vUMTT) was slightly higher than vamax: 6.08 m.s-1, SD 0.41, vs 6.01 m.s-1, SD 0.44 (P less than 0.03) but these two velocities were strongly correlated (r = 0.92, P less than 0.001). The heart rate values corresponding to these velocities were similar and well correlated (r = 0.79, P less than 0.01); the corresponding blood lactate values had similar mean values: 10.5 mmol.l-1, SD 2.7 vs 11.8 mmol.l-1, SD 2.5, but were not correlated. Both vamax and vUMTT correlated well with the best performance sustained over 1500 m during the season. These results suggest that the UMTT provides a value of vamax as accurately as a treadmill measurement and that either could be used to measure the running velocity corresponding to VO2max. The v1a4 was 86.6%, SD 2.6 of vamax; these two velocities correlated strongly. Thus, in well trained runners, v1a4, when measured with a well-defined procedure, corresponds to a constant fraction of vamax and depends then on VO2max and the energy cost of running.

The effects of 7 weeks of sprint training (repeated 5-s all-out sprints) on maximal power output (Wv,max) determined during a force-velocity test and a 30-s Wingate test (Wpeak) were studied in ten students [22 (SD 2) years] exercising on a cycle ergometer. Before and after training, muscle biopsies were taken from vastus lateralis muscle at rest for the ten subjects and immediately after a training session for five of them. Sprint training induced an improvement both in peak performances by 25% (Wv,max and Wpeak) and in the 30-s total work by 16%. Before sprint training, the velocity reached with no load (v0) was related to the resting muscle phosphocreatine (PCr) stores (r = 0.87, P < 0.001). The training-induced changes in v0 were observed only when these PCr stores were lowest. This pointed to a possible limiting role of low PCr concentrations in the ability to reach a high velocity. The improvement in performances was linked to an increase in the energy production from anaerobic glycolysis. This result was suggested in muscle by the increase in lactate production measured after a training session associated with the 20% higher activity of both phosphofructokinase and lactate dehydrogenase. The sprint training also increased the proportion of slow twitch fibres closely related to the decrease in fast twitch b fibres. This result would appear to demonstrate an appropriate adaptive reaction following high-intensity intermittent training for the slow twitch fibres which exhibit a greater oxidative capacity.

The aim of the present study was to test the hypothesis that peak power output (Ppeak) sustained during maximal incremental testing would be an overall index of rowing ergometer performance over 2000 m (P2000), and to study the influence of selected physiological variables on Ppeak. A group of 54 highly trained rowers (31 heavyweight [HW] and 23 lightweight [LW] rowers) was studied. Body mass, maximal oxygen uptake ((.-)VO(2max)), oxygen consumption corresponding to a blood lactate of 4 mmol. l (-1) expressed in percentage of (.-)VO(2max) (V.O (2)La4 %), and rowing gross efficiency (RGE) were also determined during the incremental test. In the whole group Ppeak was the best predictor of P2000 (r = 0.92, p < 0.0001). Body mass (r = 0.65, p < 0.0001), V.O (2max) (r = 0.84, p < 0.0001), (.-)VO 2)La4 % (r = 0.49, p < 0.0001) and RGE (r = 0.35, p < 0.01) were significantly correlated with P2000 as well. To take the influence of body mass into account, (.-)VO(2max) was related to kg (0.57). Ppeak was significantly related to body mass (r = 0.56, p < 0.0001), (.-)VO(2max) x kg (-0.57) (r = 0.63, p < 0.0001), (.-)VO(2)La4 % (r = 0.45, p < 0.001) and RGE (r = 0.34, p < 0.05). Multiple regression analysis indicated that the above parameters taken together explained 82.8 % of Ppeak variation in the whole group. It was also demonstrated that Ppeak was the best predictor of P2000 when LW and HW groups were considered separately. It was concluded that, by integrating the main physiological factors of performance, Ppeak is an overall index of physiological rowing capacity and rowing efficiency in heterogeneous as well as in homogeneous groups. It presents the further advantage of being easily measured in the field.

The aim of the present study was to investigate the relationships between heart rate variability (HRV) changes and both training variations and performances in elite swimmers. A secondary purpose was to measure catecholamine urinary excretion in elite swimmers to validate the HRV indices of sympathetic activity during training. Thirteen swimmers (4 females and 9 males) were tested before and after 4 weeks of intense training (IT) and 3 weeks of reduced training (RT). At the end of each period, the swimmers participated in an official competition of their best event. Individual performances were expressed as percentage of the previous season's best performance. Spectral analysis was used to investigate RR interval variability. HRV indices failed to show any significant changes between the study periods (p>0.05). Pre-IT HF was correlated with performance (r=0.45; p=0.05) and HFnu (r=0.59; p<0.05) during RT. On the other hand, once RT was completed, HFnu was correlated positively to performance (r=0.81; p<0.01) and negatively to fatigue (r=- 0.63; p<0.03). Conversely, the indices of sympathetic activity, i.e., LFnu and LF/HF ratio were inversely related to performance (both r=- 0.81; p<0.01); total fatigue score was correlated to the changes in HFnu (r=- 0.63; p<0.03) and in the LF/HF ratio (r=0.58; p<0.05). Changes in the adrenaline/noradrenaline ratio over the follow-up period were related to the changes in the LF/HF ratio (r=0.45; p<0.03). In highly trained swimmers coping well with a training program, including 4 weeks of IT followed by 3 weeks of RT, HRV indices were unaltered. On the other hand, after the 3 weeks of RT, HFnu was positively related to performance and inversely related to the fatigue score. Thus, elevated initial HF levels could be important in the parasympathetic activity increases during taper and, hence, in swimming performance improvement.

The effect of a 40-week training program on the anaerobic threshold (AT) was studied in five subjects (35 +/- 5 yrs). The training program consisted of a bicycle ergometer exercise 1 h per day 3 days a week at a work load corresponding to 80%-85% of VO2 max. Before training (S0) and at the 10th, 20th, 30th, 40th weeks (S10, S20, S30, S40) of the training program, ventilatory AT (AT vent), lactate AT (AT lact), and 4 mmol AT were estimated using a graded exercise test. In the same period, another test (1) to determine VO2 max, maximal work load (MWL), and net efficiency (2) and a 1-h endurance exercise requiring 85%-90% of VO2 max were performed. After training, AT increased significantly by 10%, 11%, and 18% in AT vent, AT lact, and AT 4 mmol, respectively. MWL and net efficiency increased by 22% and 14% respectively, and there was no significant increase in VO2 max. The AT increase at S20 was delayed as compared to the change in MWL (S10). It is hypothesized that an AT increase provides good evidence for modifications of the muscular oxidative capacities during an endurance training program. A part of this paper is devoted to (1) the study of the reproducibility of AT estimation, (2) a comparison to other methods for determining the definition of AT, and (3) the correlations between the three methods utilized for AT estimation.