Keeping the same position for too long.
For instance: singing and maintaining too long the high or low tone range, or using a specific voice-generating technique, for instance, throat singing, too long, without changing it. It is recommended to diversify, switching between pitches in order to enhance your vocal flexibility.
Unintentional vocal muscle contraction due to mental stress:
During a vocal effort, your muscles contract and relaxvery rapidly. During a stress, your muscles relaxation is insufficient for vocal activity, and they grow rigid.
Overstrain due to excessive use of a weak vocal muscle:
For instance, in case of making a vocal effort too seldom: thus, singing on weekends only, or just once a week, is harmful.
Excessive use of stronger muscles, while neglecting the weaker ones:
Using too few muscles: for instance, using too little one’s lip muscles which help form the speech and provide additional voice amplification.
General overworking: overworking and overstraining voice-generating muscles. After an effort, muscles must rest to rebuild themselves.
Ideally, the solution is to balance rest and motion. Recovery processes take place through appropriate movement helping rendering the muscles more relaxed, flexible, and fitter.
Faithfully keeping your voice intact