What is wrong and why: Placing your hands beneath your head will strain your neck and it doesn't tighten up all your ab muscles.
Rather: Place your hands on your chest because that way you will not yank your neck as you sit up.
2. Bench Dips
What is wrong and why: Holding yourself up at the edge of a bench and using your arms to move up and down. This is very unnatural and unsafe position for your shoulders.
Rather: Stand with your feet at shoulder-width apart, holding your weight above your head with both hands and slowly lower behind your head. Make it sure that you keep your elbows close to your ears which will help it to be a firm effort.
3. Adductor and Abductor Machines
What is wrong and why: The position these machines keep you in is very unnatural for your body. When you add weight to your muscles you can actually strain them.
Rather: Do clockwork lunges. This will help to tone hard-to-hit areas, giving you more flexibility. Start at 12 o'clock and then do a front lunge, a side lunge and then a back lunge, ending up at 6 o'clock. Do it on each side three times.
4. Weighted Side Bend
What is wrong and why: If you are doing a side bend carrying a weight in your hand, you are building an oblique muscle, which will ultimately give you an appearance of a thicker middle. And if you are doing that with dumbbells, then you are putting a stress on your lower spine and doing nothing for your sides indeed.
Rather: You can do woodchoppers with the help of your dumbbells because it's easier for your back and will also help slim down love handles. Hold the weight above your head with both the hands and then use your abs to lower it down and across your body.
5. Leg Extension
What is wrong and why: Using this seated machine to lift your legs to lift the weight up and down will quickly stress your bones. It puts too much strain on your ankles and knees, which will trouble you in your old age.
Rather: Do squats either weighted or simple. Make sure to stand your legs closer together, with just the hip-width apart. This will help you to get lean legs.
6. Leg Hover
What is wrong and why: Pulling your legs upwards while lying on your back is terrible for your body. It puts a lot of strain on your back.
Rather: Do a 90-degree toe touch. First, lie on your back, lifting your legs straight up in the air. Then try to reach your arms up towards your toes and then lower back to the floor.
7. Shoulder Press Machine
What is wrong and why: Stop using the machine because you become limited with your range of motion.
Rather: Pick up dumbbells, raise your hands straight up in the air above your head, and then bring your arms up and down along your sides.