What’s with these reps?

When you’re weight lifting, how many repetitions should you do? 6? 8? 10? 12? 15? If you’ve been lifting for a while you’ve heard all these answers, and more. “Want to build strength and power? Then 6-8 reps. Want to make your muscles noticeably larger over time? Then 8-12 reps. Want to tone your muscles without getting too big? 15 reps is your magic number.”

Does anyone really understand what any of this means? What is the magic in these numbers that will give you your desired effect? The answer is, none. Just achieving the number of repetitions is pointless. What matters is the intensity of the exercise, caused by the amount of weight you’re trying to lift. It’s the last few reps that matter, regardless of your goal. I’ll say “the magic” occurs during the last three reps. All the reps that come before those all important last three are just preparation. if I’m trying to maximize my physical strength, I’m shooting for 6, 7, or 8, reps, and the last three have to be extremely difficult to finish. The first 3-5 reps are what is necessary to get my muscle tired enough to make the magic happen on the last three reps. If you’re shooting for 15 reps in order to “tone”, the first 12 should get progressively more difficult so that by rep 13, 14, and 15, you’re barely able to finish.

Since most people, inside or outside a gym really have no clue as to what constitutes intensity, let me be clear. The last rep you try to complete should be borderline, or outright, impossible. This is true, regardless of your weight lifting goal and the number of reps you’re trying to accomplish. And don’t be afraid of overestimating yourself. 1 rep less will never ruin you or your goal. It won’t turn you into the Hulk if your only trying to “tone”. If only it were that easy to bulk up!

To sum up: whatever your reasons are for weight lifting, the last three repetitions of every set, for every exercise, should be tortuously hard. Want results? It’s not a number. It’s the effort it takes to get there!


10 thoughts on “What’s with these reps?

  1. What!! Omg my trainer told me I had to end on even numbers, if it reached impossible push through until I hit an even number. Unless of course it was 15 for some reason 15 was the only acceptable odd number. I must admit though my crazy trainer was my one and only self and I’m strangely neurotic. Great tips I will try to put my neurosis in check :/

  2. Thanks for clearing that up for me because years ago when I paid for a trainer he always wanted me to do 25 of everything. I am going to try it your way from now on to see if the results are different.
    Thanks again

    1. Hi. While all the education, training, and experience I’ve accumulated over 28 years tells me that 25 reps on any set is beyond overkill (unless there is some sports specific reason), even if you were doing 25 reps, the last 3 should be virtually impossible. That said, it’s unlikely that so many reps would be capable of generating a physiological, adaptive response from your body. In basic terms, you have to convince your body it needs to improve, and maxing out your effort at around 15 reps is the upper range to do so. Above that number, the weight is necessarily low, and unlikely to help you.

  3. Hey Scott,

    I hope all is well. I have a request to ask you. I am looking to finally start lifting weights again and I need your help. I never know how many exercises and how many reps I should do for each muscle. Could you create a basic weight lifting routine for me that touches all muscles. The only thing is when it comes to lifting, other than working out my arms I prefer to use machines instead of free weights. So if possible, please keep that in mind. I look forward to hearing from you. Thanks for the help!


    1. Seth, I emailed you a workout. If you have any questions, let me know. Please update your progress on the blog whenever you can. And when it comes to exercise, consistency is critical, just like with nutrition..

  4. What about number of sets? I was always taught to do sets of 3… not sure why though! And how much time between sets? Enough to fully recover or should the last “impossible” rep progressively come sooner?

    1. The amount of time to rest between sets is dependent on your goal. If calorie burning and toning are the goal, then 30-60 seconds. If body shaping and/or body building (muscular hypertrophy) are the goal, longer rests; usually 60-90 seconds are taken. For serious strength athletes lifting the heaviest possible loads, even longer rests are required. The point of the rest is to allow ATP stores to replenish as much as possible. The longer the rest, the more ATP is available for the next set. When working with lighter loads ATP is a less important fuel.

      The number of sets is less definitive. Every set theoretically forces more muscle fiber recruitment as the fibers from the previous set(s) are exhausted. A person never uses 100% of a muscles possible fiber, and there a multiple specialized fiber types present in every muscle for specific work needs. The traditional approach is to do 3 sets, each set getting progressively more difficult (typically increasing the amount of weight being attempted) to ensure enough muscle fibers get sufficiently stimulated to force the adaptive response (general adaptation syndrome to progressive resistance). Sometimes two is recommended, sometimes four. The number of exercises per body part is also a factor in the number of sets recommended.

      Arthur Jones, the inventor of Nautilus, Hammer Strength, and MedX exercise and testing equipment popularized the concept of High Intensity Training (HIT). He hypothesized that one set, performed to total momentary muscular failure could produce the same adaptive response as progressive resistance, in less time, and without subjecting the body to the repetitive stress he felt was responsible for most gym related injuries. Many champion body builders in the 1970’s and 80’s followed Jone’s approach, but most continue to follow more traditional methods, with equivalent success. Critics contended that Jones was underestimating the amount of stress his method was placing on tendons and connective tissue without proper warm up (the 1st and 2nd sets being used as working warmups that begin to pre-fatigue the targeted muscle).

      On the other hand, serious strength athletes will often perform double digit sets of the same exercise, say an hour of squats, or bench press, completing 10, 11, 12, or more sets of that one activity for an entire workout. In this scenario, the strength athlete might start off making each set progressively more intense (increasing weight at the expense of reps) until a max load is reached (1-3 reps), then they might start regressively unloading, tapering the amount of weight down so they can continue to train that exercise down to the last possible fibers. They are taking advantage of another training principle: specific adaptation to imposed demand. This principle states that the more a person does a specific activity, the stronger, better, more efficient they become at that specific activity. The most popular variation of this system is called GVT (German Volume Training), and is championed by world famous strength coach Charles Poliquin. The purpose is to get very strong, and specifically strong, at a particular movement, like the squat, bench press, dead lift, clean and press, etc. All other considerations are secondary to that goal.

      So which is right? I’ve personally used all these methods at one time or another since 1982. Pick the one that suits your current goals and your personality, and don’t be afraid to constantly re-evaluate your progress and your system. This is a science, but like field biologists, is heavily dependent on observation, and testing. You are your subject.

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