The science of human endurance
Endurance is the ability to maintain activity for an extended period of time. A muscle’s ability to resist fatigue and maintain contraction is measured in the number of repetitions. Muscle endurance and strength together constitute physical fitness. Improving muscle shape makes difficult activities easier and reduces the risk of injury.
Endurance training programs can produce small but measurable gains in muscle strength. Activities that require muscle endurance include brisk walking, running, cycling, resistance training, swimming, circuit training, aerobics, dancing, and skipping. In endurance training, the number of repetitions and the length of the muscle or group of muscles are more important than the resistance / load or the intensity / speed at which the physical activity is performed.
Endurance athletes want to maintain optimal lean muscle mass that will complement and not hinder performance. Protein contributes only 1 to 6 percent of total energy costs during endurance exercise, so it is not the primary goal of diet. The main sources of energy are fats and carbohydrates. The main goal of endurance training is to increase the anaerobic threshold as this improves the effectiveness of the training.
The three factors that affect endurance are:
1. The maximum capacity of a person to use oxygen during exercise (VO2 max)
2. Current economy
3. Lactate (or anaerobic) threshold
Improving this can help the heart work more efficiently, allowing for more intense workouts and improving performance during events. It will also help the person to appeal to a wider range of speeds. VO2 max is largely genetically determined. Research has shown that no matter what an individual’s aerobic capacity, training can only be improved by about 25 percent. Oxygen uptake in women is typically 65 to 75 percent of that of men. VO2 max also decreases with age.
Training at altitude causes an increase in the hemoglobin content in the blood. Thus, people trained at altitude, when competing at sea level, appear to have improved their aerobic performance.
It is a physiological measure of the amount of oxygen needed to run at a specific pace. The more economical the runner, the less oxygen it will take to run at this pace. Improved running economy results in decreased perceived exertion at your current running pace, increased endurance at current running pace, and the ability to run faster than current competition speed. Resistance work improves economy by eliminating wasted energy in excessive movement and stabilizing running motion. Interval running, when done correctly, trains muscles to use oxygen more efficiently when they are working hard.
The lactic threshold
This is the running speed at which large amounts of lactate begin to build up in the blood. Higher lactate levels cause soreness in the muscles, causing an athlete to reduce the level of exertion or slow down the pace. A high lactate threshold helps the athlete to run faster with less discomfort. It is a good indicator of performance in endurance events. Lactate build-up usually occurs at a rate of just below 10 km / h. It is always necessary to stimulate some degree of lactate accumulation to familiarize the muscles with the capacities of lactate elimination. When training, it is important to take at least one week out of four very easily, in order to allow the muscles to recover. Tempo running involves running a specified distance (four to six miles) at a pace just below the threshold. It is ideal for building endurance and generating lactate build-up.
Ultra-endurance competitions are defined as events that last six hours or more. These events rely on long-term preparation, sufficient nutrition, adaptation to environmental stressors and psychological strength. Successful ultra-endurance performance is characterized by maintaining a higher absolute speed over a given distance than other competitors. This can be achieved through a periodized training plan and following key training principles. Periodization is an organization of training into large, medium and small training blocks called macro-, meso- and micro-cycles. When training sequencing is properly applied, athletes can achieve a high level of competition readiness and avoid overtraining syndrome during the months of heavy training. A plan is executed according to the following training principles: overall development, overload, specificity, individualization, consistent activity and structural tolerance. Training relies heavily on the athlete’s tolerance for repetitive strain.
Today’s ultra-endurance athlete must also follow proper nutritional practices to recover and prepare for daily training and stay injury free and healthy. Ultra-endurance events require energy inputs from the three macronutrients (carbohydrates, proteins and lipids) as indicated by the duration of the event and the lower intensity.
Successful performance of an ultra-endurance event depends on preparation, and special attention is paid to nutritional requirements, injury prevention, tissue regeneration, and the avoidance of acute tissue trauma and muscle damage. overtraining. The training required for ultra-endurance events is no different from that required for other sports, in terms of the underlying principles. The holistic approach can be extended to five areas which, when combined, result in an integrated view of performance: physiology, biomechanics, psychology, tactics and health / lifestyle.
The fundamental variables of physiological stress are the intensity, duration and frequency of training. In the training process, the right balance between low, medium and high intensity movements is essential for the adaptation process. If one undertakes too many moderate or high intensity workouts, there is a significant risk of fatigue, leading to overtraining or overtraining. Training frequency refers to the number of training sessions during a given period, such as a day or a week. Training volume refers to the product of training duration and frequency (usually over a week), and training load refers to the product of the three fundamental components: frequency, duration and intensity.
Carbohydrate diets range from 5 to 7 g / kg / d (gram / body weight in kilograms / day) to 7 to 10 g / kg / d three to four days before competition. The higher the intensity, the more dependence on carbohydrates. During prolonged running events, a use of 40 to 80 g / h has been reported, while a use of more than 90 g / h is not uncommon in cycling events. Most endurance athletes report better performance and mild gastrointestinal discomfort when using liquid carbohydrates. Research has shown that fluid intake of 30-70g of carbohydrate per hour can maintain blood sugar oxidation and delay fatigue. 7.5-12% solution has been shown to minimize the risk of hypoglycemia and maximize performance.
The modern ultra-endurance athlete needs food to recover and prepare for training and the race to come. Rehydration and water balance recovery after exercise, as well as when and how to increase food intake to cope with heavy training, are essential for optimal performance.
–The author is an orthopedic consultant, Fortis Hospitals, Bannerghatta Road, Bengaluru.