Cheap and effective fitness alternatives to the gym

There is a cheaper alternative: home resistance bands. And according to a new study, these giant bands work.

"The great news is that with these bands that are really inexpensive you can take exercise anywhere. They're very lightweight. You can take them traveling. You have a piece of equipment that's going to be effective," said Samantha Cassetty, R.D., nutrition director of Good Housekeeping.

"When you're using these bands you really need to work your muscles until they're fatigued and that will take 12 to 15 reps," Cassetty said. "Make you're your movements are slow and controlled both when you are pulling and when you are releasing, and that's the way you get the best, the most effective exercises."

Low-resistance bands are good for beginners to build muscle. Higher resistance bands let you work larger group muscles like your back, chest and legs.

By the way, band colors reflect the resistance level. Green is typically light. Blue is medium, and red, purple or navy is heavy. You should always replace bands if you see any holes, worn spots or tears.