I am often asked: Should I lift heavy or light weights? Won’t lifting heavy make me bulk up? Isn’t lifting light weight just a waste of time? And while I know many trainers would disagree, my answer is that both types of training can offer significant benefits. You’ve probably heard many experts down play the effect of lightweight training, saying they just aren’t enough to offer any kind of real challenge or stimulus for your muscle (and if you are only doing a few reps here and there with them, never reaching muscular fatigue, I would agree). And on the other end of the spectrum, I’ve heard a few experts suggest that lifting anything over three pounds is a recipe for enormous bulk in women (to be clear, I’m not saying this at all – women DO need to be able to lift heavier loads, and do it quite often just during daily activities alone).

One major thing to consider is what exactly heavy and light loads mean to your body, at this stage of your fitness journey. If you are just starting out with strength training, or returning from a long hiatus, what some may consider ‘lighter’ weights may be plenty of resistance to fatigue your muscles while still allowing you to be able to maintain good form, alignment and control over the weight. It may take some time for you to master the exercises with a much lighter amount of weight before it’s appropriate (or safe) for you to increase to the next level. You can also adjust the amount of repetitions (or repeating the number of times you do the same exercise) to help add more challenge to your muscles without yet adding more weight if your body isn’t quite ready for it. On the other hand, if you have been training for years, at the same weight range, and are no longer seeing positive progress, it may be time to consider up leveling in terms of your load. And, there may be some exercises or workouts that really require a ‘light’ resistance load (if, for instance, you are targeting the rotator cuff muscles, heavy weight is going to be too much for certain angles or movements), and conversely, if you are training with certain power movements, or using a lower rep scheme, heavy weights may be the most effective option.

The good news is, if you prefer lifting lighter, studies show that when worked to the point of fatigue, lighter weights can be just as effective at building muscle and strength. In fact, one recent study published in the Journal of Applied Physiology found similar benefits when comparing strength training with heavier loads and less reps to lighter loads using more reps. As reported by Science Daily, one of the lead study authors Cam Mitchell, a PhD candidate in the Department of Kinesiology, noted, “we found that loads that were quite heavy and comparatively light were equally effective at inducing muscle growth and promoting strength.” A separate study, published in the journal Applied Physiology, Nutrition, and Metabolism, also found that using lighter weights and higher repetitions was equally effective in stimulating muscle proteins when compared to heavier intensity and lower repetitions. Researchers also note that an “additional benefit of the low-intensity workout is that the higher repetitions required to achieve fatigue will also be beneficial for sustaining the muscle building response for days.”

Personally, I’m a fan of both types of training, but believe that the choice of which you decide to use depends on your body, your experience and fitness level, personal goals, the workouts, rep and set counts, and tempo you prefer to use (faster paced routines, for example, can increase your risk of injury if you are moving with very heavy loads). While it’s true that you’ll need to use less reps to get the job done with heavier weight loads, you’ll also need to be using excellent form and control as the potential strain or stress it will put on your joints increases with the weight you lift. If, for example, your goal is to put on a significant amount of muscle mass in a short amount of time, lifting light probably isn’t going to be the best or more efficient method for you, but it’s still not a smart idea to jump right into heavy weights without the proper level of mastery of strength and stabilization first, which can require building up to those heavier lifts. On the other hand, if you suffer from joint issues or simply don’t have access to heavier loads (if you train at home, for example) lighter weight training may be a more appropriate fit for you, especially when paired with high enough reps and/or supersets to help you reach muscular fatigue. I think the right program can offer a combination of the two types of training for maximum safety and benefit, but it’s always important to pay attention to how your body feels and responds to your workouts so that you’ll be able to stick with them for the long term (because, as one of my favorite sayings goes, ‘consistency trumps intensity’ every single time). All of the research, experts, advice etc. is great, but the bottom line is that you know your body best, so be sure to focus on what works and feels best to you.

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Tell me, what kind of weight do you like to use during your strength training workouts? What are your thoughts on this debate?

Sources: Canadian Science Publishing (NRC Research Press). “Building muscle without heavy weights.” ScienceDaily, 26 Apr. 2012. Web. 13 Jan. 2013. McMaster University. “Light weights are just as good for building muscle, getting stronger, researchers find.” ScienceDaily, 30 Apr. 2012. Web. 13 Jan. 2013.