Muscular endurance is the ability to create maximum force for a maximum amount of time. The amount of force becomes smaller as time increases. Anaerobic and aerobic are the two main types of muscular endurance, but there are other meaningful types of endurance, as well. Improving endurance is of great importance to both professional athletes and non-professionals alike. Various training regimens can improve endurance, but different types of endurance may require different programs; it’s important to know the distinctions.
Why Endurance Training
Conditioning/endurance training causes muscular adaptations, forcing muscles to work more efficiently even when not exercising. When the neuromuscular system faces increased demands, it adapts with increases in muscular function. A key adaptation is an increase in mitochondria with an increase in respiratory capacity. One consequence of the adaptations induced in muscle by endurance exercise is that the same work rate requires a smaller percentage of the muscles’ maximum respiratory capacity. Another valued adaptation of endurance training is the increased utilization of fat, with a proportional decrease in carbohydrate utilization, during submaximal exercise. The muscles actually work more efficiently and burn off more fat doing so, even when not exercising at one’s peak performance.
Endurance and Cellular Changes
Mitochondria metabolize many of the damaging byproducts of anaerobic exercise, which is why anaerobic performance can be improved by improving aerobic endurance. Thus, endurance training’s effect on mitochondria is significant. Research has shown that endurance exercise training induces an increase in the mitochondrial content of skeletal muscle. That’s not the only adaptation, even to mitochondria: Skeletal muscle mitochondria undergo an alteration in composition in response to endurance training, with some enzymes increasing two to threefold. Endurance training changes how muscles work on a cellular level, even transforming muscle fibers from one type to another.
Anaerobic Muscular Endurance and Training
Anaerobic endurance is characterized by energy use for a very short period of time, less than ten seconds. In an anaerobic state, the muscles need more energy than is readily supplied, so they use energy reserves to fuel activity. Adenosine Triphosphate (ATP) is the preferred energy source, which may become depleted in as little as three seconds. When ATP is depleted, the muscles use Phosphate-Creatine (PC) to create more ATP. Both are exhausted within about ten seconds, at which point the muscles begin glycolysis, or the breakdown of carbohydrates for energy. While glycolysis restores the ATP stores, it also produces hydrogen ions, causing that familiar burning sensation in one’s muscles. Glycolysis may last for up to sixty seconds, though the body soon turns to aerobic forms of energy.
In terms of anaerobic training, the periodization technique has become the mainstay in the majority of weight training programs. The periodized program is a method of changing workouts over time to allow for better recovery and therefore greater gains in strength. It seeks the ideal stress-to-recovery relationship so as to maximize muscular adaptations. Studies have shown that order and intensity of training affect endurance results: Gradual increases in volume and decreases in intensity may result in greater gains in muscular endurance than the classic strength programs that gradually increase intensity and decrease volume regardless of the frequency of these alterations.
Aerobic Muscular Endurance and Training
Aerobic endurance is characterized by longer periods of exertion and the body’s use of oxygen to create energy. It is slower-paced than is anaerobic activity, but it can continue for significantly longer periods of time. This is the energy system used for running marathons or swimming many miles. The oxygen prevents muscles from producing lactate. Aerobic endurance provides the basic foundation of human activity.
Those who want to increase pure aerobic endurance might follow an extensive volume endurance training regimen where intensity is low, but distance is high. This might be the preference of distance runners, cyclers, and so on. Alternately, athletes can follow an intensive endurance training regimen, which increases the intensity of the workout with slightly less volume. It has been characterized as giving the most aerobic benefit for the time input.
Endurance Training Continued:
People seeking to improve endurance must be mindful of the type of endurance. Different types may require different training regimens to achieve peak performance. There exists a continuum from pure endurance athletes to pure power athletes, from those that depend on aerobic endurance to anaerobic endurance. Many athletes fall somewhere in between, with a mix of aerobic and anaerobic endurance requirements, like the soccer player who needs to be able to run for the whole game, but also to sprint after the ball. Where someone falls in that continuum affects what type of endurance training is most useful.
Threshold training is extended training at one’s peak performance level. A person’s threshold is the highest intensity that can be sustained for a long period of time, usually an hour. It’s a good predictor of competition performance, so improving it is often a key goal for athletes. Everyone is different, but the threshold is determined by the level of waste build-up in one’s system; one way to improve the body’s waste-removal process is to improve aerobic endurance.
High-intensity interval training (HIIT) has been a commonly-used training technique in recent years. By intercutting durations of exercise at peak performance with durations at lower intensity, athletes can conceivably do more volume at their threshold level than they could if they worked straight through at their threshold. All of these training regimens increase demand on the muscles, thus causing them to increase performance.
Sweet spot training falls between intensive endurance training and threshold training. It’s the point at which an athlete is maximizing effort but can still get in a significant volume, thus achieving a training effect. It’s considered a good way to increase speed and power at the threshold, but it is quite a slog. It’s not as grueling as threshold training, of course.
Endurance Training for Non-Professional Athletes
Non-professional athletes have different physical characteristics than professional athletes. A professional athlete will have a lower heart rate, an enlarged heart, increased cardiac output, and even increased muscle enzymes. Yet endurance is necessary even for non-professionals, for those who just want to participate in recreational sports. Stamina, being able to last the full competition while remaining alert, is essential. Given the time limitations most people have ? due to working jobs and living lives, rather than training full-time ? intensive endurance training is likely the best option for improving aerobic endurance within a manageable time commitment.
But non-professional athletes should make sure never to start out with threshold training. Doing so is both inefficient and likely to cause injury, which undermines the very point of the training. Still, if they go about it smartly, training will help improve endurance for non-professional athletes and professionals alike.