Fitness Instructions should take out what is called professional Indemnity and public liability insurance, these will help to protect both the instructor and the client in the case of any injuries or accidents.
Gymnastics can cause injuries from the various movements done. Injuries can range from sprains to breaks. Find injury information and advice here: http://www.gymnasticsrescue.com/
Sports that involve a sharp pull to the arm can cause several different types of injuries. One of the most common injuries is called rotator cuff syndrome.
The most serious one is death. However there are several types of plague so it would depend on which you mean.
the basic kind of physical fitness are push up, curls up, running, etc.
This is a decision that you will have to make based on what kind of Fitness program are you looking to do, or what kind of hours that they offer. Planet Fitness is a great Fitness center but may or may not be right for you based on their hours of operation and programs that they offer.
There were every kind of injuries you could imagine - and many you could not.
Skill-related fitness
Personal fitness trainers design fitness programs for private clients or small groups. The kind of the experiences they need are to have work experience, appropriate certification and to be successful educators.
maladaptive behavior
contusion,abrasion
If facial injuries are severe, NOTHING should be assumed.