I'm not sure what to make of this and without the full paper it is always hard to know what it really says. However, from the abstract they seem to be claiming that a protocol that avoids failure achieves maximum recruitment of motor units. What is interesting is that muscle fibre recruitment was higher towards the end of the 15 rep set - which was going to failure - than the heavy 3 rep max set. This is the size principle at work!
The thing about failure though is that you know that you are there. Stopping 3 reps short of failure is one thing...but unless you fail how do you know when you were 3 reps away from failure?! Fail and then you are certain you were there.
The thing about failure though is that you know that you are there. Stopping 3 reps short of failure is one thing...but unless you fail how do you know when you were 3 reps away from failure?! Fail and then you are certain you were there.
UPDATE
James Steele has now analysed this paper and offers some very insightful comments on his blog:
To Failure or Not to Failure - That is the Question....
Doug McGuff's comments are also very helpful on the Body by Science blog
Going to failure, or not, has probably been one of the most debated issues during the history of strength training. However, few studies have directly compared the physiological effect of failure vs. nonfailure strength training. The purpose of this study was to evaluate muscle activation strategies with electromyography (EMG) during heavy repetitions vs. repetitions to failure with lighter resistance.
Fifteen healthy untrained women performed a set with heavy loading (3 repetition maximum [RM]) and a set of repetitions to failure with lower resistance (∼15 RM) during lateral raise with elastic tubing. Electromyographic amplitude and median power frequency of specific shoulder and neck muscles were analyzed, and the BORG CR10 scale was used to rate perceived loading immediately after each set of exercise. During the failure set, normalized EMG was significantly lower during the first repetition and significantly higher during the latter repetitions compared with the heavy 3-RM set (p < 0.05). Normalized EMG for the examined muscles increased throughout the set to failure in a curvilinear fashion—e.g., for the trapezius from 86 to 124% maximal voluntary contraction (p < 0.001)—and reached a plateau during the final 3–5 repetitions before failure. Median power frequency for all examined muscles decreased throughout the set to failure in a linear fashion, indicating progressively increasing fatigue.
In conclusion, going to complete failure during lateral raise is not necessary to recruit the entire motor unit pool in untrained women—i.e., muscle activity reached a plateau 3–5 repetitions from failure with an elastic resistance of approximately 15 RM.
Furthermore, strengthening exercises performed with elastic tubing seem to be an efficient resistance exercise and a feasible and practical alternative to traditional resistance equipment.
Comments
This is the mantra of all failure training promoters. It's the "that's how I know I tried hard enough" rule. But the real measure of trying hard enough, or should I say adequate effort, is progress in strength AND muscle mass.
Interestingly, many of the old school pre-steroid bodybuilders did not train to failure, opting for a multiple set fatiguing protocol instead. They did pretty well. They often trained more often, up to three or four times per week, as well.
The real problem with failure training is it limits your stimulus exposure by increasing recovery time by a lot. And if you go by feel, as in "I don't feel above baseline today, I wont work out", you are really going by your CNS readiness, not your muscle readiness. Your muscles CAN recover quickly. They are designed to do so.
In the real world, very slow muscle recovery after exertion is a death sentence. But most real world activities do NOT require a failure level of exertion. So this level of exhaustion is naturally quite foreign, is mostly CNS based (this is not bullshit, despite what some might say) and takes a long time to recover from.
The take home: train to failure very infrequently. Train short of failure most often. People will see better gains in mass and strength this way, and will be able to effectively increase stimulus exposure and recovery.
As an older guy, I find doing 3-4 sets per muscle group works far better than single set to exhaustion. More than this yields little benefit and I don't recover well. I stop when I can't perform another rep in good form. I also do some endurance exercise (heresy!) because I found I lost endurance for both running and hiking when I stopped all cardio for weights. And because I train for endurance when I do cardio, I don't turn strength training into an endurance event. My sets are around 30s, using fairly heavy weights. I have also improved my running speed over my usual 2-3 mile run time.
One set to exhaustion is one way to train, and I don't think it's the most productive for many.
The only issue is that unless you are very experienced in using such a protocol, it is difficult to pre-empt failure before you reach it.