Pre-exhaustion is the performance of a simple exercise followed immediately by a compound exercise targeting the same muscle group. The purpose is to pre-fatigue the targeted muscle group with the simple exercise so it is must work harder during the compound exercise, based on the belief that the muscles of the arms and legs are “weak-links” in compound exercises and limit their effectiveness for the muscles of the torso and hips.
Although I do not believe the muscles of the arms and legs are really significant weak-links in compound exercises, and that the assumption they are is based on apparent size differences rather than the actual amount of force the muscles can produce taking leverage into account (and my experiences pre-exhausting chin-ups with both arm curls and pullovers seem to support this), I have used it in many of my workouts and with my clients because it appeared to be effective and has been used with much success by high intensity training experts like Ellington Darden and Mike Mentzer. Nautilus inventor Arthur Jones liked pre-exhaustion so much he designed and built several “double-machines” specifically for performing it, including the compound leg (leg extension and leg press), compound torso (pullover, pulldown), double chest (chest fly, chest press) and double shoulder (lateral raise, shoulder press). Because of Jones’ influence pre-exhaustion became a staple of high intensity training, and you would have difficulty finding a book on high intensity training that doesn’t include pre-exhaustion in a few of the workouts.
However, based on a recent study it appears that pre-exhaustion is no more effective for improving strength in the muscles worked than performing the same exercises with a longer rest between them, or performing the compound exercises first(1). The abstract states,
Pre-exhaustion (PreEx) training is advocated on the principle that immediately preceding a compound exercise with an isolation exercise can target stronger muscles to pre-exhaust them to obtain greater adaptations in strength and size. However, research considering PreEx training method is limited. The present study looked to examine the effects of a PreEx training programme. Thirty-nine trained participants (male = 9, female = 30) completed 12 weeks of resistance training in 1 of 3 groups: a group that performed PreEx training (n = 14), a group that performed the same exercise order with a rest interval between exercises (n = 17), and a control group (n = 8) that performed the same exercises in a different order (compound exercises prior to isolation). No significant between-group effects were found for strength in chest press, leg press, or pull-down exercises, or for body composition changes. Magnitude of change was examined for outcomes also using effect size (ES). ESs for strength changes were considered large for each group for every exercise (ranging 1.15 to 1.62). In conclusion, PreEx training offers no greater benefit to performing the same exercises with rest between them compared with exercises performed in an order that prioritises compound movements.
This has a few interesting implications. It suggests that when properly performed compound exercises alone may be enough to effectively train all the larger muscle groups and many simple exercises may not be necessary for general, overall muscular strength and size increases (the neck being an exception), and two of the studies cited suggest compound exercises target all the muscles involved effectively (2) and are as effective as simple exercises for improving muscular strength and size in the muscles targeted (3).
There may still be a need for simple exercises for some muscles for optimal overall strength and size gains, such as the short head of the biceps femoris which unlike the other hamstrings muscles only crosses the knee joint and is active in knee flexion but not hip extension, and for developing a well-balanced and proportional physique some people may need to perform simple exercises to target lagging muscle groups while minimizing the work for relatively overdeveloped muscle groups. However, due to their efficiency and greater metabolic effect compound exercises should be the focus of your workouts, and I recommend including at least one of each of what I consider the six basic movements:
- Quad-Dominant Lower Body Exercise (squat, leg press)
- Glute-And-Hamstring-Dominant Lower Body Exercise (deadlift, hip extension)
- Vertical Pulling Exercise (chin-up, pull-up, pulldown)
- Vertical Pushing Exercise (standing press, shoulder press)
- Horizontal Pulling Exercise (bent-over row, compound row)
- Horizontal Pushing Exercise (bench press, chest press)
I recommend also performing both a neck flexion and extension exercise, which can be alternated with lateral flexion or rotation, since the neck is an important area but the majority of the neck muscles receive little work in compound exercises. Although the calves are worked during exercises like deadlifts and squats, if you perform exercises like leg presses and hip extensions for the lower body which do not effectively work your calves additional calf work should be performed.
To look at it another way, pre-exhaustion was not less effective than prioritizing compound exercises, either; so if you like performing pre-exhaustion in your workouts you don’t have to drop it. All the groups in the study made significant improvements in muscular strength. However, I would recommend using what I call “condensed pre-exhaustion” instead, increasing the weight for both the simple and compound exercises so you are only able to perform about half as many repetitions of each, so the total time under load of the entire pre-exhaustion sequence is the same as if you only performed one exercise. I can only speculate at this point, since I have only used this a limited number of times and with very few people, but, I suspect it might be more effective than normal pre-exhaustion.
1. James Peter Fisher, Luke Carlson, James Steele, Dave Smith. The effects of pre-exhaustion, exercise order, and rest intervals in a full-body resistance training intervention. Applied Physiology, Nutrition, and Metabolism, 2014; 1 DOI: 10.1139/apnm-2014-0162
2. Brennecke, A., Guimaraes, T.M., Leone, R., Cadarci, M., Mochizuki, L., Simao, R., et al. 2009. Neuromuscular activity during bench press exercise performed with and without the preexhaustion method. J. Strength. Cond. Res. 23: 1933–1940. doi:10.1519/JSC.0b013e3181b73b8f. PMID:19855317.
3. Gentil, P., Soares, S.R., Pereira, M.C., Cunha, R.R., Martorelli, S.S., Martorelli, A.S., and Bottaro, M. 2013. Effect of adding single-joint exercises to a multi-joint exercise resistance training program on strength and hypertrophy in untrained subjects. Appl. Physiol. Nutr. Metab. 38(3): 341–344. doi:10.1139/apnm-2012-0176. PMID:23537028.