1. There's no point working out beyond 45-55 minutes
Yes, 45-55 minutes. Studies have shown that this is the ideal and most effective time frame to devote to working out. Rutherford says beyond this time frame our bodies start producing excessive cortisol which can negatively affect the results we receive in the weights room (and with any other form of exercise for that matter). "We basically want to do something to the point where it has created stimulus to the body but not to the point where it stresses us out."

Related story: How to overcome your biggest health obstacle: motivation 

2. It's okay to do the same workout moves for awhile
Yes variety is important in exercise to avoid boredom and hitting a plateau but in terms of strength conditioning it's also important to give your body a chance to adapt to certain workout moves.

"There are opposing laws in any strength conditioning. That's the laws of adaptation and the laws of variation, if you're always varying something you never get better at it like swinging a tennis racquet. But do the same things too long and you adapt and you plateau," says Rutherford. "To combat this you should have a plan of attack [of moves] that you can try and improve on every week."

Related story: Double or nothing: does training together as a couple actually work?

3. Change up your workout every 4-6 weeks
As Rutherford mentioned, it's great to stick to your plan of attack but it's also important not to get too comfortable. Studies have shown the most effective time to switch up your workout is between 4-6 weeks. In this time frame your body has had enough time to adapt and master certain workout moves before the results you get from working out start to plateau. 

Related story: The 8 health and fitness lies every woman needs to stop telling herself