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How to Do a Trunk Rotation Exercise

Reviewed by Poonam Sachdev on July 25, 2022

A trunk rotation is a type of strengthening exercise that focuses on specific parts of your upper body. Standing and sitting variations exist. 

You usually don’t need a lot of fancy equipment or a gym membership to perform trunk rotation exercises.  

What Is a Trunk Rotation?

Your trunk is the region of your body located above your hips and below your neck. It includes your back and abdomen. Sometimes, you need to twist your trunk to one side or another while keeping your lower body stationary. This general motion is a trunk rotation. 

There are ways to refine the motion and add resistance so it becomes an effective strengthening exercise. This move is good for increasing strength and flexibility in your abdomen and back. 

Most people use medicine balls for trunk rotations. The exact weight depends on your fitness level. It helps to have access to a variety of weighted medicine balls before attempting this exercise. Some variations, however, don’t require any equipment at all. 

What Muscles Does a Trunk Rotation Work?

Trunk rotation exercises involve motions that are focused around your back and abdomen. 

Trunk rotation muscles worked include your:

  • Externalabdominal obliquesThese are the outermost muscles found in your trunk. They’re found across the front and sides of your abdomen. The muscle fibers run diagonally across your body. They form a “V” shape that points down towards your legs. These muscles specifically help you bend to the side and rotate the parts of your body that are above your hips. 
  • Internal abdominal obliques. These muscles are underneath your external abdominal obliques. They also run diagonally and form a “V” shape, but this “V” points up towards your head. Like their external counterparts, these muscles help you rotate your trunk and bend your body from side to side.
  • Certain leg muscles. Muscles throughout your legs are used to support your body when you’re doing standing trunk rotations. They can also provide balance and support when you’re doing the seated version of this exercise. 
  • Certain arm muscles. You’ll need a number of muscles in your arms to hold and support the medicine ball or to keep your arms suspended in front of you if you’re not using a ball. The exercise isn’t meant to specifically strengthen these muscles but you need them to perform the exercise. 

Directions for Doing a Trunk Rotation

There are two main versions of a trunk rotation — standing trunk rotation exercises and seated trunk rotations. 

To perform a standing trunk rotation, you should follow these steps: 

  1. Stand with your feet hip-width apart and facing forward. Hold a medicine ball up by your chest. It should be pressed between your two palms with your elbows pointing out to each side.  
  2. Tighten your core muscles to stiffen your torso.
  3. Pull your shoulders down and backward. Do not arch your lower back. This completes your starting posture. 
  4. As you exhale, slowly start to rotate your upper body to the left. Your hands and the ball should remain raised and in the center of your body. Keep your head, chest, and torso in one vertical line as you move. Don’t bend your body in the direction of your movement. 
  5. Hold the rotation for a moment once you’ve moved as far left as you can safely go. Then, begin to slowly rotate to the right.  
  6. Repeat the motion on the right side then return to the left and back again in one continuous movement. 

To perform a seated trunk rotation, you should follow these steps: 

  1. Sit down on the floor or a mat. Keep your feet together, bend your knees, and press your heels into the floor. 
  2. Hold a medicine ball close to your body. Keep your spine straight and your torso perpendicular to the floor. Brace yourself by keeping your core muscles tight. This completes your starting position. 
  3. Exhale and slowly rotate your torso to the left. Do not lean backward. Keep the ball close to your body and near the middle of your torso, not drooping towards your lap. 
  4. Pause to inhale at the end of your rotation and then begin moving all the way to the right. 

The number of repetitions and sets that you should do for each of these exercises depends on your particular needs. A good general recommendation is to try eight to 12 repetitions of this exercise for three sets. Make sure to briefly rest between each set. 

Trunk Rotation Adaptations

There are many different ways to perform this exercise. Examples of variations include: 

  • Extended arm standing trunk rotations. To make a normal standing trunk rotation more difficult you can fully extend your arms while still holding a medicine ball. You’ll need to keep your arms lifted to shoulder height throughout the exercise. This increases the stress put on your abdominal muscles. 
  • Standing trunk rotations without a medicine ball. To make a standing trunk rotation easier, you don’t have to use a medicine ball at all. In this variation, you start with your arms lifted straight out in front of you. Move your left arm out to the left while your right arm continues to point forward. Rotate your torso with your arm. Open yourself up until you feel a stretch in your lower back, then return to the starting position. Repeat this move ten times then switch to moving your right arm. 
  • Seated trunk rotations with lifted legs. To increase the difficulty of seated trunk rotations you can lean back slightly to further engage your core muscles. To make them even more difficult, you can lift your heels up off of the floor. Lean halfway back to help you balance. Keep your knees bent and your feet together throughout the exercise. Keep your core muscles stiff so your back doesn’t arch. 

Benefits of Trunk Rotations

Trunk rotation exercises can work for people at a variety of fitness levels, including beginners. This move is particularly useful for athletes who focus on swinging and throwing motions in their sports. This includes people who play: 

  • Softball
  • Baseball
  • Racquetball
  • Pickleball

Trunk rotations also have a place in certain physical therapy regimens. For example, one current clinical trial is studying the effect of this exercise on the sitting and standing postures of people with scoliosis

If you have any medical conditions or concerns, you should talk to your doctor or physical therapist before attempting this exercise. 

For everyone that decides to incorporate this exercise into their routine, the benefits are widespread. Some trunk rotation benefits include: 

  • Strengthening your coreOne of the main functions of this exercise is as a strengthening activity for certain abdominal muscles. This improves your overall core strength. 
  • Improving your back’s rotational abilities. This exercise demands that you rotate your back from side to side. You can vary how quickly you do this exercise to mimic the pace and motion that you use in your particular sport. Repetition improves your body’s ability to move and decreases your chances of injury when performing similar motions in your daily life.  
  • Increasing flexibility in your back muscles. This motion stretches out your back in unique ways. It can help work out muscles that normal daily activities don’t always affect.

Trunk Rotation Mistakes to Avoid

You need to make sure that you’re doing your trunk rotations properly. Improperly done exercises can be dangerous and ineffective.  

Common trunk rotation mistakes include: 

  • Not using the right form throughout the motion. Like all exercises, it’s important to maintain the proper form every time you do a trunk rotation. This decreases your chance of injury and increases the effectiveness of the exercise. 
  • Using too much weight too quickly. This exercise can strain your muscles more than you expect. Beginners should start with a low weight. Only increase the amount when you can complete your sets with relative ease. 
  • Moving on to advanced variations too quickly. Make sure that you’ve mastered the initial forms for trunk rotations before moving on to advanced positions. Otherwise, you risk severely injuring your back and other parts of your body. 

Show Sources

SOURCES: 

Ace: “Seated Medicine Ball Trunk Rotations,” “Standing Trunk Rotation.” 

Arizona Orthopedic Physical Therapy: “Stretch of the Week: Trunk Rotations.” 

ClinicalTrials.gov: “The Effect of Sitting and Standing Posture on Trunk Rotation in Patients With Idiopathic Scoliosis.” 

National Center on Health, Physical Activity, and Disability: “Trunk Rotation Exercises with a Medicine Ball.” 

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