When it comes to exercise, something is better than nothing. There are so many health benefits associated with breaking a sweat that 15 minutes of exercise, three times each week, has been shown to increase life expectancy. That said, there are some exercises and techniques that work better than others. Avoid wasting your workout by performing ineffective moves. No matter your fitness goals, cut out these exercises to save on time, while boosting results.

1. Crunches

A flat stomach and chiseled core is an elusive exercise goal. It seems like the harder we try, the less results we see. Part of the problem is the belief that more sit ups is the secret to a six pack. In reality, moves like the crunch, sit up and leg raise aren't likely to deliver a slim stomach.

Think of it this way: any move that would have you lying on the floor is likely a waste of your time. Instead of relying on crunches to tighten your tummy, try more functional exercise that engage the entire body instead. Moves like the kettlebell swing, squat and dead-lift target multiple muscle groups, and burn more calories than other abdominal-only exercises.

2. Seated Hip Abductor/Adductor

After targeting the core, there are a whole lot of people who'd like to "tone" their legs. Again, the idea of honing in on one specific area is misguided and ineffective. Still, there's a line forming for the abductor and adductor machine. Should you wait your turn?

No, there's a better way.

Think back to what we learned about crunches--if you're laying down and targeting a small muscle group you're not burning many calories. The same is true of the abductor and adductor machine. Okay, this time you're sitting down. But, you're still not really getting the most out the movement. Skip this machine and use lateral lunges or lateral step-ups instead.

3. Seated Chest Fly

Moving onto the upper body, this machine is meant to build up some bulk in the chest and shoulders. Unfortunately, it's doing more harm than good. The position of the handles and set-up of the seat places way too much stress on the elbow and shoulder joint. Chances are also good that you're not flexible enough to complete the full range of motion, further straining your muscles.

Instead of relying on a fancy machine, trust in a more proven moves: the push-up, triceps dip and overhead military press.

4. Seated Oblique Twist

Oh boy, we're back to the core. We really do want a six pack, huh?

Like the crunch, the seated oblique twist isn't the answer we're searching for. While you're sitting down, trying to keep your core engaged is very difficult. Plus, the twisting movement is probably being initiated from the chest and shoulders, not the core. Not only does this put too much pressure on your back, it also leaves out the muscles you think you're training--the oblique. Your best bet is to forgo this fitness fiasco and sub in the cable or dumbbell wood chopper instead.

Regardless of your fitness goals, the answer to better results in less time is compound, total body movements that engage multiple muscle groups at once. This way, you'll be burning more calories, engaging stabilizing muscles and building functional strength that goes beyond the gym.