The National Academy of Sports Medicine (NASM) defines muscular endurance as the ability of a muscle(s) to contract for an extended period of time. It affects the body in several different ways, including balance, neuromuscular efficiency and overall performance in a workout. Without proper muscular endurance, your ability to achieve muscular strength and power will be limited.
All the short-term effects of muscular endurance will become long term if you maintain a consistent training regimen. The first effect will be the improvement of the body's neuromuscular efficiency. Neuromuscular efficiency is defined by the NASM as the ability of the nervous and muscular systems to work together and allow muscles to work through all planes of motion. The second major effect will be the body's enhanced stability and balance. This will result is better functioning of the joints, improved flexibility, and better posture.
The long-term effects of muscular endurance relate to improving the other areas of muscular performance. One effect is muscular balance. Muscular balance is defined as the strength, power, and endurance of one muscle or muscle group compared to another. Comparisons for muscular balance are often made unilaterally such as comparing one leg to another. All these effects are made possible by the improved blood flow that results from muscular endurance training.
With a solid foundation of muscular endurance, stability and balance, you can build the most advanced components of strength. Strength endurance is the ability to move heavier weights for a prolonged period of time. It is made possible by muscular endurance but involves heavier loads for a shorter period of time. Finally, the ability of the body to move the heaviest load possible (one repetition maximum) is facilitated by the all the functional improvements that muscular endurance has made.
Training for Muscular Endurance
Training for muscular endurance involves light loads for a high repetition count or longer time duration. If going for a repetition range, 12-25 is a reasonable number. If you a training for a timed duration for each repetition, aim for 15-30 seconds total for both lifting and lowering the load. To further engage the body's neuromuscular system, the environment you are training in can be altered. Training in unstable yet controllable environments, referred to as proprioceptive-enriched environments by the NASM. Examples of this type of training would be performing a shoulder press with one leg off the floor or a chest press lying on a Swiss ball.