A great alternative to dumbbells for general fitness is the oft forgotten rubber tubing or elastic bands. They can be used in many similar exercises as free weights and with the proper program, can help improve your balance, increase muscular endurance and joint stability.
Tubing or bands are so versatile that you'll likely see them anywhere from your local fitness center to rehab clinics. They're light weight and pack small so if space is a concern then this is a good option … plus, you can take them anywhere like when you travel for business or go on vacation; it's like fitness on the go! Since they are relatively low cost, it can really be a money saver too when compared to buying free weights.
Tubing allows for good range of motion and they even allow you to combine several exercises at once such as a squat-to-curl-to-press. The exercise selection is really only limited by your imagination. Certain types of bands or tubing allow you to attach it to a door or other fixed object and that allows you to even train sport-specific movements like mimicking the motors of a golf swing or baseball bat swing allowing you to improve your performance in your sport … want to lower your golf score anyone?
Tubing and bands come in different colors and there's a reason for that. No, it's not because the marketers found that some people like yellow and some people like blue. The colors denote the resistance offered by the band. Each manufacturer may use a different color code so be aware if you are switching brands. A yellow band may be low resistance for instance while a black band may be a higher resistance … but be sure to check the coding that the brand is using.
Some things to be aware of are that the thicker bands will reach their stretch limit earlier in the in the move meaning that it may be easier at the start of the motion while getting progressively more difficult at the top end. This could affect the range of motion of the exercise and may throw off your form slightly when reaching the band's limit. For this reason it may be preferred to use two medium bands instead of one thick band. Also, because the resistance changes throughout the stretch, it's really hard to say what exactly weight each band is equivalent to. One last point I should mention about the tension is that over time with use, the band will lose its resistance so you may need to purchase more bands in the future as replacements.
Who should use bands and tubing? Because of their versatility there really is no reason not to stock up on a few different colors. Keep some at home or in your suitcase and you'll never be far away from a great workout. If your goal is to improve maximum strength or build muscle then tubing may not be the best option but for general fitness, muscular endurance or even in programs where muscular power is the focus then tubing can be a great option.