Physiologic and Biochemical Changes During a Triathlon Competition

Abstract

The triathlon has come to be recognized as a distinct endurance event and although a substantial body of research information exists with regard to the individual components (canoeing, cycling, running, etc.), the physiologic demands imposed by combining the respective activities into one continuous event have not yet been assessed. Twenty-three male athletes (age = 33 +/- 5.2 yr; mass = 71.79 +/- 7.42 kg; height = 176.0 +/- 7.21 cm; means +/- SD) participated in the study on the basis of informed consent. Venous blood samples, taken immediately prior to and on completion of the Iron Man Triathlon held in Johannesburg during 1983, were assayed for parameters of energy metabolism, fluid and electrolyte balance, and stress (tissue enzymes in serum). On the basis of post-race blood glucose (6.17 mmol. l-1), free fatty acids (1943 mumol. l-1), and blood lactate (3.45 mmol. l-1) changes, it was concluded that the triathlon is primarily, in an overall sense, an aerobic event. With the exception of magnesium and iron, serum electrolyte changes agreed with literature findings. However, body mass reductions (average 3.23 kg, i.e., 4.5%) indicated that the extent of dehydration is more severe in the triathlon than in comparable endurance events. Post-race enzyme levels (LD, CK, and AST) were significantly elevated, and LD negatively correlated with total performance time (P less than 0.01). The general conclusion is that the physiologic demand of the triathlon exceeds that of other comparable endurance events.

The influence of prior cycling on biomechanical and cardiorespiratory response profiles during running in triathletes

“…The ®rst may involve energetic substrates and be related to carbohydrate replacement by fat oxidation during prolonged exercise (Bulow 1988). Indeed, lipid mobilization has been reported to occur at the end of the triathlon (Van Rensburg et al 1986) concomitant to muscle glycogen depletion (Armstrong et al 1977). Unfortunately, the lack of change during TR versus CR in the present study did not agree with this hypothesis and, in contrast, the high values (>0.95) observed were consistent with the high carbohydrate dependence in endurance activities reported by O'Brien et al (1993).…”

Efeitos agudos do exercício físico prolongado: avaliação após ultramaratona de 24 horas

“…It is known that CPK levels increase after great physiological stress [10][11][12][13][14][15][16][17] , indicating intense catabolic state of skeletal muscle. The intensity and duration of physical exercise are commonly associated with CPK increase and there seems to be a predominant effect of duration 16 .…”

Cardio-pulmonary function of cyclists competing on an ascending mountain course between altitudes of 1400 m and 2800 m

“…The blood (Rensburg et al 1986;Sj6din and Jacobs 1981;Tanaka and Matsuura 1984), water balance, thermoregulation (Pugh et al 1967), work capacity (Sherman et al 1984), oxygen uptake (Maron et al 1976), diet (Sherman et al 1981) and cardiovascular system (Fox et al 1972;Maeda et al 1988) of marathon runners before, during, and after marathon and triathlon competitions have been investigated. However, there have been few investigations of cyclists, especially of those participating in races over mountainous terrain.…”