Environmental Influences on Performance
Assignment – SSD 108
Environmental influences on Performance
Ismail Iqbal DIPLOMA IN EXERCISE AND SPORTS SCIENCE Batch 3 SSD/2012/24
1. “Marathon race organizers should be mindful of weather conditions during the race ‘
Discuss the above statement on a scientific
marathon footrace is among the most physiologically demanding endurance events in the world. Competitive runners typically maintain a pace corresponding to 70-90% of their maximal aerobic capacity [3,15,20] for more than 2 h. At maximal mechanical efficiency, more than 80% of the energy required for this task is transferred as heat to the body core [9]. Moreover, the rate of endogenous heat production associated with a 2-h 10-min marathon estimated from ordinary heat-balance equations [9] is approximately 1400 kcal·h-1. This metabolic heat must be dissipated to the surrounding environment, or body temperature will rise to physiologically dangerous levels.
Lind [13] has demonstrated that core temperature is independent of climate over a temperature range he has termed the "prescriptive zone." It has been demonstrated that the width of the prescriptive zone progressively narrows as metabolic rate increases. Thus, climate begins to affect physiological responses to exercise at relatively cooler temperatures during activities that elicit high metabolic rate compared with those eliciting lower metabolic rates. More recently, it has been demonstrated that endurance performance is indeed impaired when exercising in warm versus more temperate laboratory conditions and that air temperatures of approximately 10°C seem optimal for endurance exercise [10]. One criticism of these and other laboratory findings is that typical airflows used for indoor testing situations are well below those encountered when running or cycling outdoors over the ground. The lack of appropriate airflow substantially reduces the combined heat transfer coefficient [9] and may overestimate
Environmental influences on Performance
Ismail Iqbal DIPLOMA IN EXERCISE AND SPORTS SCIENCE Batch 3 SSD/2012/24
1. “Marathon race organizers should be mindful of weather conditions during the race ‘
Discuss the above statement on a scientific
marathon footrace is among the most physiologically demanding endurance events in the world. Competitive runners typically maintain a pace corresponding to 70-90% of their maximal aerobic capacity [3,15,20] for more than 2 h. At maximal mechanical efficiency, more than 80% of the energy required for this task is transferred as heat to the body core [9]. Moreover, the rate of endogenous heat production associated with a 2-h 10-min marathon estimated from ordinary heat-balance equations [9] is approximately 1400 kcal·h-1. This metabolic heat must be dissipated to the surrounding environment, or body temperature will rise to physiologically dangerous levels.
Lind [13] has demonstrated that core temperature is independent of climate over a temperature range he has termed the "prescriptive zone." It has been demonstrated that the width of the prescriptive zone progressively narrows as metabolic rate increases. Thus, climate begins to affect physiological responses to exercise at relatively cooler temperatures during activities that elicit high metabolic rate compared with those eliciting lower metabolic rates. More recently, it has been demonstrated that endurance performance is indeed impaired when exercising in warm versus more temperate laboratory conditions and that air temperatures of approximately 10°C seem optimal for endurance exercise [10]. One criticism of these and other laboratory findings is that typical airflows used for indoor testing situations are well below those encountered when running or cycling outdoors over the ground. The lack of appropriate airflow substantially reduces the combined heat transfer coefficient [9] and may overestimate