The countermeasure of strain

Many people get nervous and strain before singing. Even
professional singers are nervous before singing.
Here are two resolutions to prevent these issues.
First, is that you have to be used to singing to the point where you can recognize pushing too hard and straining. Having experience will help this awareness and ease your physical reaction to avoid the strain.
Secondly, is that you have to have flexible muscles around the throat. If you have confidence that your throat condition and awareness are good, then that balance between mental and physical state combined will relax some if not all of the nervousness before and during singing.
You can let out your voice easily as long as you have flexible muscles for vocalizing.
The recommended requirement regarding the hardness of muscles is approximately 10-20 tones for vocalizing.

Beautiful young woman singer with microphone

Note1:Stretching is effective to acquire flexibility of the muscles relevant to vocalizing.

Note2:If the muscles are flexible around the larynx, you can have space between the hyoid bone and the thyroid cartilage. This will increase blood circulation of the superior laryngeal artery, which will extend through to the thyroid foramen, and bring a lot of oxygen and nutrition to the instrinsic muscle as well as the vocal cords.
Furthermore, the vocal fold is moisturized to vibrate the vocal cords well. This assists in letting out the falsetto and extended vibration production.