european college of sport science

PP-PH01 Physiology 1
It is clear that some players developed significant hypohydration over the course of the match, and it would be predicted that their performance
would be reduced. None-the-less, because of the high sweat rates in some players (in the order of 2.5l/h) these individual are
unlikely to be able to prevent the development of hypohydration with the current match format.
References
Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. (2007) Med Sci Sports Exerc, 39, 377-390.
Maughan RJ, Watson P, Evans GH, Broad N, Shirreffs SM. (2007) Int J Sports Nutr Exerc Metab, 17, 583-594.
NO EFFECT OF MUSCLE FIBER TYPE ON MECHANICAL EFFICIENCY DURING CYCLE EXERCISE AT 1.5 HZ
MEDBØ, J.
NATIONALE INSTITUTE OF OCCUPATIONAL HEALTH
Background: There are conflicting views on the effect of muscle fiber type on mechanical efficiency during exercise. Former studies have
possible experimental shortcomings that may have influenced their conclusions. Therefore, in properly standardized experi-ments, the
mechanical efficiency has been determined for 23 healthy young men with different proportions the two main fiber types to study possible
effects of muscle fiber type on efficiency during cycle exercise.
Methods: Each subject cycled for 10 min at in average 19 different powers ranging from 1.0 to 4.6 W/kg (70–370 W) while the pedaling
frequency was kept constant at 1.5 Hz. The rate of energy release was determined from the steady state O2 uptake measured near the
end of each 10 min exercise period. Delta efficiency was taken as the inverse of the slope of regression of O2 uptake on power
(dP/dnO2). Gross effi-ciency at 3 W/kg was established, and finally, the efficiency was taken from each subject’s slope of O2 uptake
versus power using a common, fixed Y-intercept. Several muscle biopsies were taken from the lateral portion of the knee extensor muscle
of each subject, and muscle fibers were classified as type 1 or type 2.
Results: The proportion of type 1 fibers was 0.50 ± 0.13 (mean ± s), delta efficiency was 0.262 ± 0.010, and gross efficiency was 0.213 ±
0.005. There was no significant correlation between any efficiency measure and the proportion of type 1 fibers. A two-sided 95% confidence
interval on the data suggests that if the efficiency of the two fiber types differed, the differ-ence was less than 12%. For the same
subject the efficiency did not differ more than a few percents between low powers where type 2 fibers may be little engaged and high
powers where both fiber types are active.
Conclusion: The data support the idea that the efficiency does not differ between type 1 and type 2 fibers during cycling at 1.5 Hz.
Reference
Medbø. Acta Kinesiol Univ Tartuensis 2008; 13: 51–75
ADIPONECTIN RESPONSE TO MAXIMAL CYCLING EXERCISE IN ELITE MALE CYCLISTS
LAKHDAR ATTIA, N.
FACULTY OF MEDECINE
Introduction: Less is known about the effects of acute exercise on adiponectin concentrations (Simpson and Singh, 2008). Few studies
have investigated the adiponectin response to acute exercise in trained subjects (Jurimae et al., 2005; 2006). Actually, two trials reported
significant delayed increases (30 min) in adiponectin concentrations (Jurimae et al. 2005; 2006). The aim of the present study was to
analyse the effects of acute maximal exercise followed by 60 minutes of recovery on plasma concentration of adiponectin, insulin and
glucose in elite male cyclist.
Methods: Eleven elite male cyclists participated in this study (mean and SD) (age : 19.82 ± 4.67 years; body mass: 65.64 ± 6.09 kg;
height: 176.82 ± 7.19 cm; BMI : 20,97 ± 1.35 kg.m-2; VO2max: 59.68 ± 4.85 ml.min.kg-1). Subjects performed maximal cycling exercise
followed by 60 minutes passive recovery. Blood samples were obtained before, at the end and after 30 and 60 min of recovery.
Result: Adiponectin concentrations were unchanged after exercise and during recovery. However, insulin concentrations were significantly
lowered during recovery (-13.66, P