Muscle failure, also known as muscular fatigue, is the point at which your muscle can no longer perform a specific movement or lift a certain weight.
Muscular failure can come in various forms, such as concentric, eccentric, and isometric.
Concentric failure occurs when your muscle cannot lift the weight during the lifting phase of an exercise. For example, if you perform a bicep curl and cannot lift the weight on the final repetition, you have reached concentric failure.
Eccentric failure, also known as negative failure, occurs when your muscle cannot control the weight during the lowering phase of an exercise. This is what happens when you perform a bicep curl and cannot lower the weight slowly or under control on the final rep.
Isometric failure occurs when your muscle cannot generate enough force to perform a static exercise. Static exercises are part of isometric training. In this type of training, you contract a specific muscle and keep it under continuous tension for a certain period without movement.
So, for example, isometric failure occurs when you can no longer hold the position (for the required time) while performing a plank.
Since failure shows that a muscle or muscle group has been pushed to its absolute limit, muscle failure is usually applied as a measurement of progress in resistance training. Reaching muscular failure can also increase the risk of injury, especially if reaching failure results in you neglecting good form and technique.
That said, you definitely shouldn't aim to reach muscular failure for every set you do, as this can easily lead to overtraining and stunt your results over time. You can still build muscle while mostly training with 1-2 RIR (Reps in Reserve), and you should be selective about when you do choose to train to absolute failure. In general, you can train to failure with isolation movements like biceps curls fairly often, but with complex and injury-prone movements like the squat and bench press you should train to failure infrequently and always with a spotter.
In addition, several additional conditions, such as exhaustion, dehydration, inadequate nutrition, and poor sleep, can contribute to early muscle failure. It's crucial to fuel your body with healthy foods, drink plenty of water, and get enough restful sleep to avoid premature muscle failure.
Training hard to the point of muscle failure is important for building muscle. With the Alpha Progression app you can create a perfect training plan and track your training success.