Exercise equipment for strength training
What kinds of equipment and exercises can I use for strength training?

Free weights, such as dumbbells and kettlebells, are available in most fitness centers and for purchase.  They can improve your stability and address imbalances between the left and right sides of your body.

Weight machines are better for focusing on a single muscle.  For example, a leg-extension machine can help isolate and strengthen your quadriceps.  Bodyweight exercises typically use just your body weight, but you can add equipment such as suspension straps or elastic bands to increase the intensity.
 

Circuit training aims at keeping your heart rate elevated while you do short bouts of resistance exercises, and it's a great weapon in the battle against exercise boredom.  It's typically a quick, efficient combination of cardio and resistance training.  High-intensity workouts include functional movements, based on real-world tasks such as lifting and carrying a bag of sand, and focus on doing exercises in brief intervals at very high intensities.  These are for injury-free people who already have strength-training experience.