With the exception of the plank, each exercise should be done for 10-15 repetitions. If an exercise alternates between sides, perform 10-15 repetitions on each side. Try holding the plank for 15-30 ...

Cornell University ergonomics professor Dr. Alan Hedge sets out why the 90˚ rule does more damage than good, and what the proper way to sit at your desk is. Follow TI: On Facebook More from ...