Muscle contraction is the activation of tension-generating sites within muscle fibers.In physiology, muscle contraction does not mean muscle shortening because muscle tension can be produced without changes in muscle length such as holding a heavy book or a dumbbell at the same position.n contrast, a muscle contraction is isotonic if muscle length changes but the muscle tension remains the same. Furthermore, if the muscle length shortens, the contraction is concentric.
Senior Systems Administrators with one to two decades of relevant experience report an average salary of approximately $85K. After two decades in the workforce, the average Senior Systems Administrator generally earns more than ever; median pay for this group is estimated at $92K.
Salaries by Software Expertise. The job search website Indeed.com calculates the average salary of jobs based on job titles. According to their data, the average salary of a database administrator in 2012 is $82,000, while the average salary of a senior DBA is $96,000.An SQL DBA makes $90,000 on average, while a senior SQL DBA makes $100,000. According to Indeed.com's data, a PostgreSQL DBA makes $102,000 on average.hose working in educational services had a median income of $62,580. The job search website Indeed.com calculates the average salary of jobs based on job titles. According to their data, the average salary of a database administrator in 2012 is $82,000, while the average salary of a senior DBA is $96,000.