How To Stop Locking Your Elbows and Knees During Workouts

Most of us have been taught to move through a full range of motion while performing resistance exercises. However, if you take this advice literally, you risk locking your elbows and knees, which can increase the risk of injuries and hinder fitness gains. Dr. Jonathan Su, the Get-Fit Guy, explains why locking is so common and how to avoid it. 

Dr. Jonathan Su, DPT, CSCS, TSAC-F, C-IAYT
5-minute read
Episode #556
The Quick And Dirty

Locking your elbows or knees is common because of:

  1. Habit
  2. Enthusiam 
  3. Fatigue

Avoid locking your elbows or knees by:

  1. Developing motor control
  2. Creating a runway
  3. Skipping the rest break

Most of us have been taught to move through a full range of motion while performing resistance exercises such as squats, pushups, and pullups. Going through a full range of motion (a.k.a. moving as far as anatomically possible) during an exercise is important for giving the muscles a more robust workout.

However, if you take this advice literally and you do happen to go all the way up and all the way down during an exercise, you risk locking or completely straightening your elbows and knees, which can increase the risk of injuries and hinder fitness gains. 

I frequently observe this common strength training mistake made by newbies and gym buffs alike. The good news is that this mistake is easy to avoid and being aware of why it happens will help make it less common. 

Why locking your elbows or knees is so common

While locking your elbows or knees during exercises like pushups, pullups, chest presses, shoulder presses, squats, leg presses, and knee extensions is a problem, it’s actually super common for three reasons:

  1. Habit: Most of us have been taught to go through a full range of motion while exercising. I’m sure most of you recall a gym teacher, sports coach, or trainer getting on your case at some point for not going all the way up and all the way down while performing an exercise. For me, it was a couple of Marine Corps drill instructors screaming “lock out your elbows recruit” in each of my ears while performing pullups and pushups. 

  2. Enthusiasm: Experienced weightlifters know that your lifting performance improves when you’re psyched up right before and during the lift. By going into what some would call “beast mode”, you can lift more weight for more repetitions than normal. You’re also more prone to locking out your elbows or knees while lifting with increased enthusiasm.

  3. Fatigue: Another common reason why people lock the elbows or knees during strength training is because of muscle fatigue. Locking transfers all the weight from the muscles to the joints, which provides the muscles a moment of rest and recovery during exercise. It’s human nature to want to reach the goals that we’ve set for ourselves. So if you’re aiming for 10 repetitions of an exercise and you feel like you’re unable to continue after 8 repetitions because of fatigue, most of us would lock out our elbows or knees for a quick rest before pushing out the last 2 reps. 

Why locking your elbows or knees is a problem

The problem with locking your elbows or knees, especially if it's done repeatedly with a load, is unnecessary stress on the joints that can lead to injuries. 

Locking your elbows causes the bony process that forms the tip of the elbow called the olecranon to slam into the bony notch on the other end known as the olecranon fossa. Repeated forceful impact of these two bones can lead to pain, tenderness, swelling, and stiffness.

The structure of the knee is different from the elbow. Instead of bone to bone contact, locking of your knees can result in the soft tissues in the back of the knee such as ligaments, tendons, and the joint capsule to overstretch. Repeated forceful overstretching of these structures can result in pain, swelling, and instability. 

How to avoid locking the elbows or knees

To avoid locking the elbows or knees seems simple right? Just stop your movement just before your elbows or knees are in a fully locked position.

If only it were that simple! The solution is actually slightly more nuanced than that because there’s a motor control component and a psychological component involved. Here are three techniques you can use to avoid locking your elbows or knees with these things in mind: 

Develop motor control 

Asking someone to simply stop just before their elbows or knees are in a fully locked position assumes that they have the motor control to do that. Motor control is defined as the ability to execute purposeful movement to carry out a goal.  

Doing this would be easy if we’re talking about large amounts of movement such as 10 to 20 degrees. Instead, we’re talking about a few degrees such that an outside observer can barely tell the difference between your elbows or knees being fully locked or not. This fine level of movement control is important because you get the most benefits from resistance exercises when you’re able to take your muscles through a full range of motion without locking out your joints. 

Being successful at this requires a fine level of motor control that you can quickly and easily develop with a warmup set using slower movements and a lighter load before a specific exercise. 

Create a runway

If you’re in beast mode and psyched up for the lift, you may be pushing so hard that you inadvertently end up locking out your elbows or knees. The solution is to create a runway that allows you to slow the momentum of the lift so that you don’t end up locking out. 

Just like how an airplane needs a runway to give it time to safely slow down and come to a stop, you may need a runway to prevent your elbows or knees from locking out. This means putting on the breaks well before you get to the end of the movement so you have time to stop before locking out. 

Skip the rest break

If you’re locking your elbows or knees for a momentary rest break, skip it! Not only will you avoid potential injuries, but you’ll also get a higher intensity workout which will be a better stimulus for your muscles to improve. 

If skipping this rest break is something you’re not willing to do, try doing it with your elbows or knees just short or locking out. This will still provide some rest for your muscles while avoiding the stress on your joints. 

5-day no lockout challenge

Let’s put this knowledge to use with a 5-day no lockout challenge! Over the next five days, your challenge is to practice the techniques provided to prevent your elbows and knees from locking out during strength training. Give it a try and let me know how you feel by emailing me at getfitguy@quickanddirtytips.com or leaving me a voicemail at 510-353-3104. I would also love to hear from you if you’ve ever been told by a gym teacher, trainer, or drill instructor to lock your elbows or knees. 

All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Dr. Jonathan Su, DPT, CSCS, TSAC-F, C-IAYT

Dr. Jonathan Su is the host of the Get-Fit Guy podcast. He is a physical therapist and fitness expert whose mission is to make fitness accessible for everyone. Dr. Su is a former U.S. Army officer responsible for injury prevention, rehabilitation, and performance optimization for soldiers in the field. He is also the author of the bestseller Six-Minute Fitness at 60+.

Got a question for Dr. Su? You can email him at getfitguy@quickanddirtytips.com or leave him a message at the Get-Fit Guy voicemail line at (510) 353-3104.