Unfortunately, many women still believe that lifting heavy weights will give them bulky muscles, so they choose light or no weights and attend classes that promise "long, lean muscles" instead.
But is this information even true? (Spoiler alert: not really). Choosing the right weight for you to lift is all about how you train, not the number on the dumbbells.
It all comes down to repetitions
People lift weights for the purpose of making their muscles stronger (and, for some, to get those fat biceps or slender-looking arms). For those who want to develop large muscles, they will probably opt for a heavier weight, while people who want to become lean will stick to something small.
The truth is that there is no right strategy – both are valid choices. Lifting heavy dumbbells, kettlebells and barbells will certainly make you stronger. But lighter weights can also help you become stronger – it can take you a little longer.
It all comes down to an important factor: muscle fatigue. This means that the purpose of your workouts should be to train your muscles to the point of fatigue (i.e., when you can no longer do another rep) regardless of the weight you use. So whether you do five dumbbell curls weighing 20 pounds, or 20 repetitions weighing 5 pounds, as long as you reach muscle fatigue, you will become stronger.
And science supports this above. A 2010 study found that a group of men lifting heavy weights to the point of "failure" or muscle fatigue received the same amount of muscle strength and improved their strength as much as the other group that lifted lighter weights for more repetitions. This study in 2016 found the same results.
Some trainings that you might do with light weights include a class barre, yoga sculpting, Pilates or "sculpting". Or a lightweight workout might look like doing biceps curls with a lighter weight (such as 8-10 pounds) until you can't lift anymore with a good shape. At the other end of the spectrum, we do squats with an Olympic barbell, which will tire your muscles after just a few repetitions.
The benefits of lifting light weights
What are some reasons why you choose to lift light weights above heavy? If you have only just started exercising or are starting a new fitness program, light weights can be a good choice. "Someone can choose to train with less resistance when they learn the form for new exercises. Once they have found the form and feel at ease, they can increase the resistance," says fitness trainer Heather Marr. Other things to consider are that light weights are a good option to reduce the risk of injury – it's just less likely that you hurt yourself with a weight of 5 pounds over, for example, a weight of 50 pounds.
You can also take light weights to other types of training to add more resistance and to keep yourup to standard. For example, in some of my dance cardio classes, we do dance routines while maintaining a weight of 2 or 3 pounds, which adds resistance (my arms are always burning at the end) and makes cardio training harder. By the time I finish the number, my arms feel like they can't hold the 3-pound weights – let alone a little heavier.
That said, heavy lifting has its own advantages and can certainly increase the challenge if that is what you are looking for in your training routine.
What are the benefits of training with heavier weights?  If you want to gain muscle mass and increase your strength in the most efficient way, lifting heavy weights is a good option for you. Gaining strength is all about tiring your muscles, and heavy weights will get you there faster. It just takes longer to get tired if you curl a weight of 5 pounds against a 25 pound dumbbell. "Heavy compound exercises offer the most value for money. You are able to use the heaviest load possible and work more muscles in less time making them efficient and also beneficial for weight loss," Marr said.
And if you are looking for more cardio in your routine, you can do that with heavy weights if you are strategic about your weight training workout. "You can even perform the circuit style exercises one after the other and get the added benefit of conditioning work in one," Marr said.
How do you know when you have to lift heavier?
So suppose you have been training for a while and that the 5-pound weights don't really feel like they are doing anything. What should you do? Go heavier of course; just make sure you move at your own pace.
According to Marr, you have to work up slowly and always try to challenge yourself. "It doesn't matter in which range you work for your work sets, the last rep to two should be a serious challenge and struggle. If this is not the case, you know you need to increase the resistance," Marr said.
All science and trainer advice aside – the most important thing about your fitness and training routine is that you do something consistently . And chances are that the workout is the most fun and attractive for you, regardless of the type of weight you use.