Energetics of best performances in track cycling.

VO2max and best performance times (BPTs) obtained during maximal voluntary trials over 1, 2, 5, and 10 km from a stationary start were assessed in 10 elite cyclists. Steady-state VO2 and peak blood lactate concentration ([La]b) were also determined in the same subjects pedaling on a track at constant submaximal speeds. The energy cost of cycling (Cc, J.m-1) was calculated as the ratio of VO2, corrected for glycolytic energy production and expressed in W, to v (m.s-1). Individual relationships between Cc and v were described by: Cc = Ccrr + k1 v2 where Ccrr is the energy spent against friction and k1 v2 is that spent against drag. Overall energy cost of cycling (Cctot) was obtained, adding to Cc the energy spent to accelerate the total moving mass from a stationary start. Individual theoretical BPTs were then calculated and compared with the actual ones as follows. The maximal metabolic power sustained at a constant level by a given subject (Emax, W) is a known function of the exhaustion time (te). It depends on his VO2max and maximal anaerobic capacity; it was obtained from individual VO2max and [La]b values. The metabolic power (Ec, W) necessary to cover any given distance (d) is a known function of the performance time over d (td); it is given by Ec = Cctot v = Cctot d td. For all subjects and distances, the t values solving the equalities Emax F(te) = Ec F(td) were calculated and assumed to yield theoretical BPTs. Calculations showed a fairly good agreement between actual and calculated BPTs with an average ratio of 1.035 +/- 0.058.

Therapeutic effect of benfluorex in type II diabetic patients on diet regimen alone.

A randomized double-blind study of benfluorex (150 mg x 3 daily) versus placebo was conducted over 3 months in 32 type II diabetic patients (24 men and 8 women, aged 52 +/- 8.4 years) with mild stable obesity [body-mass index (BMI) 27 +/- 1.6 kg/ m2], moderate fasting hyperglycemia (fasting blood glucose 9 +/- 0.5 mmol/L, HbA1c 6.7 +/- 0.9%) and moderate hyperinsulinemia (18.6 +/- 3.0 microU/mL) when on treatment with diet alone. After a 1-month placebo run-in period, subjects were randomized to benfluorex or placebo three tablets daily. Inclusion parameters and end-of-study measures were body weight, BMI, fasting blood glucose, glycemic profile, HbA1c, fasting insulinemia, basal and stimulated C-peptide, and an insulin tolerance test (0.1 U/kg). The groups were homogeneous at baseline, except for glycemic profile (higher postprandial glycemia in the group randomized to benfluorex). At the end of the study, the groups did not differ in body weight or BMI; however, HbA1c decreased more with benfluorex (6.0 +/- 1.0% versus 6.8 +/- 0.9%, p = 0.024), as did the mean glycemic profile (7.8 +/- 1.4 versus 8.5 +/- 1.7 mmol/L, p < 0.001), including a particular decrease in postprandial glycemia. The decreases in fasting blood glucose and insulinemia appeared larger with benfluorex (7.7 +/- 1.3 versus 8.4 +/- 1.6 mmol/L and 13.5 +/- 4.5 versus 16.1 +/- 5.1 microU/mL, respectively), but were not statistically significant. The increase in the insulin sensitivity index (Kitt) was greater with benfluorex (+0.54 +/- 1.4 versus +0.25 +/- 1.3%/mn), but the difference was not statistically significant. The same was observed for the stimulated C-peptide. In type II diabetics with mild obesity and hyperglycemia previously managed with diet alone, benfluorex has significant long-term effect on HbA1c and mean daily blood glucose, and tends to lower insulinemia.