Sometimes the smallest things can make the biggest difference. Here are three little things that could be holding you back.
If any of the below apply to you, you need to check yourself before you wreck yourself. Seriously.
1) You don't have clear objectives.
Know what you're going to do before you arrive. Without a solid game plan, a trip to the gym can quickly become a waste of time as you wander aimlessly from one piece of equipment to the next. Plot your workouts ahead of time and set clear training goals. Know what you're going to do, when you're going to do it. This will give you focus during your training.
2) You're only doing cardio.
Cardio and strength do very different things to and for your body. While cardio plays an important role in your overall fitness, there is a lot that cardio can't do for you. Resistance training, or strength training, builds strength which is essential for functionality and injury prevention. It's also great for reshaping your body and long-term weight control.
Strength training has also been proven to increase bone density and reduce the risk of osteoporosis.
Variety is the spice of life so don't limit yourself to one thing.
3) You're loading your joints more than your muscles.
It's very unlikely, if you're doing this, that you know you're doing it. Poor form is common. It will hinder your progress and can lead to serious injury.
Take some time to learn proper form; do some research, practice in front of a mirror or go to a group fitness class where you have a trained professional keeping an eye on you.
It's more beneficial to do less reps, with smaller load, in a proper form than to thrash out more reps badly. Good form gets great results.