In the first part of this series I ended off by posing the question – what if we combined high rep training with low rep training? We know that low rep training is the fastest way to build the most muscle, but high rep training can also develop your muscles, especially if you’ve neglected this style of working out in favor of the typical 8-12 rep variety that is endorsed by so many. Today I’m going to look further at high reps vs low reps and see what we can apply to build slabs of new muscle onto our growing, already muscular frames.
As I mentioned above, heavy weights and low reps has been proven time and time again (no citation necessary) to build size and strength. Just for good measure I’ll add this quote – “Performing an exercise between 3-RM (repetition maximum) and 12-RM provides the most effective number of repetitions for increasing muscular strength.”(1) This is the fastest way to get big and strong. What if you’ve already done that though? The law of diminishing returns has likely long ago kicked in and it’s time to see what can be done to further your progress.
Because it is so successful, heavy, low rep training has resulted in most or all resistance training programs recommending heavy weights and low reps exclusively. Basically every strength training or bodybuilding program recommends repetitions of 20 or less. About the only time high rep training is suggested is during a dieting phase, and that has been proven to be nonsense. Just because you do more reps does not mean you’ll build more definition. Or does it? If you build more muscle with more reps than you will in fact develop your muscles further and this will translate into more muscle separation/definition.
The old adage of heavy weight/low reps build strength and light weights/high reps build endurance, is the reason that high rep strength training is not commonly used or seriously considered as a viable training method by most trainees or their coaches. It isn’t commonly recommended to those who are most interested in increasing strength and/or size, nor does it seem to be a part of the serious endurance athletes training methods.
If light weight/high rep training is an effective tool for the endurance athlete, then surely this method would be employed by athletes competing in sports where endurance is a factor, but it is not. Even though the primary goal of endurance athletes is to improve endurance, heavy weight/low rep strength training is what is most often recommended to them. The reason strength training is believed to be beneficial for endurance athletes is that it increases the amount of force produced during contraction, resulting in an increase in power output and, presumably, endurance performance.
What about the second part of the adage though? The part that says light weights/high reps build endurance. One of the muscle factors contributing to power output is fatigue resistance. Increased resistance to fatigue is just another way of saying that the muscle’s endurance has increased. If high rep resistance training really did increase endurance then perhaps it might be a beneficial training method for endurance athletes. Now that I’ve posed a bunch of questions, let’s see what I can do to get some answers.
The first thing we need to look at is whether research supports the belief that heavy weights/low reps build strength and that light weights/high reps build endurance. It wouldn’t be the first time that someone discovered that conventional wisdom was not completely accurate.
Classic research on this topic was conducted by Thomas DeLorme in 1945 (2). DeLorme’s research indicated that heavy weights do indeed build strength while higher reps build endurance. DeLorme is even credited with the axiom that heavy weights/low reps build strength and high reps/light weights build endurance. Quite a few other research studies on this topic have supported DeLorme’s findings and this is the reason that it is now accepted as conventional wisdom.
This is not to say that DeLorme’s original axiom has gone unchallenged though. Several research studies (3,4) have found that the primary adaptation to either high or low reps is an increase in muscular strength. Even though it is accepted today that heavy weights/low reps builds strength and light weights/high reps builds endurance, the fact is that some research has challenged this belief, suggesting that high reps primarily build strength, not endurance resulting in conflicting data on the topic.
In 1982 two researchers from the University of Kentucky set out to resolve this conflict (5). Specifically, they wanted to determine the effects of three different resistance training protocols – heavy weights/low reps (6-8 reps), medium weight/medium reps (30-40 reps), and light weights/high reps (100-150 reps).
They recruited forty-three untrained, healthy subjects and trained them with the bench press exercise three times per week for nine weeks with one of three training protocols. The low rep group performed 3 sets x 6-8 reps maximum, the medium rep group performed 2 sets x 30-40 reps maximum, and the high rep group performed 1 set x 100-150 rep maximum. Resistance was adjusted as needed to ensure each subject stayed in the appropriate rep range through the training program.
Before training began each subject was tested for their individual 1 rep maximum (1-RM), relative endurance and absolute endurance. Relative endurance was determined by the maximum number of bench press repetitions each subject could complete with 40% of his 1-RM and adjusted as the 1-RM changed, while absolute endurance was measured by how many reps could be completed with 27.23 kilograms.
At the end of the study all subjects were tested again for maximum strength, relative endurance, and absolute endurance. All three groups improved maximum strength and absolute endurance. The heavy weight/low rep group decreased in relative endurance while the other two groups increased relative endurance significantly.
The results of this study support DeLorme’s axiom. Heavy weight/low reps do build strength, while light weights/high reps build endurance. However, in contrast to DeLorme’s axiom, note that all 3 rep ranges resulted in increases in maximum strength. Also all 3 rep ranges resulted in increases in endurance, with the exception of the relative endurance of the low rep group. While low reps increase maximum strength more than high reps and high reps increase endurance more than low reps, the point is that resistance training significantly increases both strength and endurance. The researchers commented on this same point.
“The reader should note, however, that with the exception of the relative endurance task for the high resistance low repetition group, all training protocols demonstrated significant improvements on each of the three criterion tests.”
Anderson and Kearney’s research went a long way to resolving the conflicting data on DeLorme’s axiom – heavy weights increase strength the most, high reps influence endurance the most, but all resistance training results in improvements in both strength and endurance.
That’s as far as I’m taking this today, and yes I know, I threw a bunch of research at you and have really proven not a whole lot other than that lifting weights will result in increases in strength, regardless of the rep range, meaning it doesn’t matter how many reps you do, you’ll build muscle. This doesn’t tell us what method of training is best though and whether combining high and low reps will lead to the most muscle. I aim to answer these questions as I delve deeper into this series. Until next time,
1. Katch, Katch, McArdle, Exercise Physiology, Energy, Nutrition, and Human Performance, 1996, Williams & Wilkins, pg. 427
2. DeLorme, Thomas L., Restoration of muscle power by heavy resistance exercise, Journal of Bone and Joint Surgery, 1945, 27:645-667.
3. Stull G, Clarke D., High-resistance, low-repetition training as a determiner of strength and fatigability, Research Quarterly, 41(2), 189-193
4. Clarke D, Stull G., Endurance training as a determinant of strength and fatigability, Research Quarterly, 41(1), 19-26
5. Anderson T, Kearney J., Effects of Three Resistance Training Programs on Muscular Strength and Absolute and Relative Endurance, Research Quarterly for Exercise and Sport, 1982, 53:1, 1-7.