Strength training is a must-do if you want a strong, defined, and lean body Why? It builds lean muscle tissue (i.e., muscle) and boosts strength and power and that’s important for all ages. Plus, greater muscle strength and size help you stay functional and avoid frailty as you age. In addition, research shows that strength training helps prevent osteoporosis, improves balance and stability, reduces falls in older adults, and increases self-esteem and sense of accomplishment.
When strength training, there are many factors you can alter to change the stimulus you place on your muscles and get them to grow. One is the number of repetitions you do with each strength-training set. How many repetitions you can complete depends on the weight you’re using.
If you’re using a weight that’s a high percentage of your one-rep max, you’ll be able to do fewer repetitions than if you’re using a lighter weight, as muscle fatigue will set in faster. So, the higher the intensity, the fewer reps you’ll be able to complete before exhausting a muscle group.
If you’re using a lighter weight, you can do more repetitions so that the muscle spends more total time under tension. That also stimulates muscle growth and strength gains. But you won’t make significant gains if you use lighter weights and do a low number of reps. Why? You won’t fatigue the muscle. So, working a muscle to fatigue is key to muscle group. Otherwise, your progress will be limited.
Focus on the Last Two Reps
Which repetitions are the most important ones in strength training sets? The last two! It’s the final two repetitions of a strength training setting that cause the most fatigue and affect your gains the most. But there are two lines of thinking on this. One line of reasoning says you’ll make the most gains by taking strength training sets to momentary failure. Failure means your muscles are so spent that you can’t do another repetition with decent form for the time being.
Muscle failure occurs when you’ve pushed yourself to your limit and cannot lift another rep of even a partial rep with good form. Muscle failure is also referred to as “pushing yourself to exhaustion.” Your muscles are physically incapable of generating force again until they recover.
While some sources say you should take sets to failure, there are disadvantages to doing so. If you get to the end of a set with muscle fatigue, push through despite fatigue, and do the last two repetitions to failure, what have you gained? You’ve exhausted the muscle, meaning you’ve recruited as many motor units and muscle fibers as possible and created the maximal amount of muscle damage.
This type of extreme muscle stimulus can boost muscle hypertrophy. The more muscle fibers you stress or damage under a heavy load, the more aggressively the muscles will need to repair and overcompensate by building more muscle. That’s the upside of training muscles to failure.
The Downsides of Pushing Too Hard on the Last Two Reps
But what are the downsides of this approach? The biggest downside is muscle fatigue. You’ve “spent” the muscles you just worked on, and it takes time for them to recover. When you train muscles to failure, they need a longer time to recover than when you train them to a level of non-failure fatigue. In turn, this affects your ability to train at a higher intensity in future workouts. Your muscles will need more recovery time. If you don’t give them that time, you risk overtraining.
Studies show training to failure leads to more muscle damage and that adds to recovery time. A study published in the Journal of Applied Physiology found that training to failure significantly boosted the time required to restore normal muscle function and hormonal and metabolic balance.
Therefore, training to failure could affect your weekly training volume. Your muscles may be so exhausted you must cut back your total volume to allow your muscles to recover. Ultimately, training for failure, especially too often, is counterproductive. You increase your recovery time and potentially reduce your weekly training volume. If you try to push through and maintain the same training volume while lifting to failure, you risk overtraining and muscle injury. Plus, overtraining can reduce levels of the anabolic hormones your muscles need to grow.
Is There a Better Approach?
Although training to muscle failure on some sets has potential benefits; muscles respond well to a tough challenge on occasion. But training to failure too often is self-defeating. You don’t need to train to the point of muscle failure to stimulate muscle growth. You simply need to fatigue the muscle and use progressive overload, where you increase the stimulus on a muscle over time. This means monitoring how your muscles feel as you train, especially the final two reps, and stopping short of failure.
One way to do this is to stop while you still have two reps left in you. This is especially important when you do compound exercises since they’re more resource-intensive and create more fatigue. Plus, the risk of injury is greater when you train to failure with compound exercises like squats and deadlifts.
You Can Still Train to Failure on Occasion
It’s okay to train to failure on occasion but plan on giving your muscles more recovery time. The requisite 48 hours may not be enough time for complete muscle recovery. It’s not something you should do on a routine basis, and you shouldn’t see it as a prerequisite for muscle growth. So, implement failure training judiciously.
Also, keep this in mind. Your muscles are more tolerant of muscle training when you do isolation exercises as opposed to compound ones. So, consider doing it with exercises like biceps curls, triceps extensions, leg extensions, and other exercises that work one muscle group as opposed to compound exercises.
The Bottom Line
Which repetitions are the most important ones in strength training sets? The last two! It’s the final two reps of a strength training setting that cause the most fatigue and affect your gains the most.
Watch those last two reps and don’t take all your sets to failure. When you do, give your muscles extra recovery time to avoid the negative effects of inadequate muscle recovery.
References:
Morán-Navarro R, Pérez CE, Mora-Rodríguez R, de la Cruz-Sánchez E, González-Badillo JJ, Sánchez-Medina L, Pallarés JG. Time course of recovery following resistance training leading or not to failure. Eur J Appl Physiol. 2017 Dec;117(12):2387-2399. doi: 10.1007/s00421-017-3725-7. Epub 2017 Sep 30. PMID: 28965198.
IDEA Health and Fitness Association. “Hormonal Responses to Resistance Exercise Variables”
Journal of Strength and Conditioning. May 2007. “The Application of Training to Failure in Periodized Multiple-Set Resistance Exercise Programs”
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High Reps vs. Low Reps for Fat Loss: Which Works Best?
Weight Training: Low Reps or High Reps for Weight Loss?
For More Effective Workouts, Science Says You Need Exercise Variety
What Does Research Show about Partial Reps vs. Full Reps for Strength Training?
Why We Use Compound and Combo Exercises in the Low Impact Series
What Types of Exercise Cause an Afterburn?
Rep Speed: Are Fast or Slow Reps Better for Building Strength?
Do Forced Reps Make You Stronger?
Related Cathe Friedrich Workout DVDs:
STS Strength 90 Day Workout Program
All of Cathe’s Strength & Toning Workout DVDs
