Muscles Used in Trunk Lift

Another one of the fitness tests we will do during the week is the trunk lift test. The trunk lift test is meant to measure the flexibility, strength, and even endurance of your back. In this post I will go through the main muscles that are used during this test. This week I will also post ways that you can increase your scores on this test so be sure to check that out if you are interested!

Before we go through what muscle is being used, I want to make sure we understand some key terms beforehand. As many of you remember, the trunk lift is performed when you lie on your stomach, toes pointed to the ground, hands under your thighs, and you move your upper body up as high as you can while keeping your eyes and toes down. 

 

Look familiar right? The motion this test works on is called back extension. The easiest way to explain back extension is that it is when you lean your back away from your body. In the picture below notice how she is arching her back, this is an example of back extension.

The opposite of back extension would be back flexion. This is when you stand straight and then bend to touch your toes. Below is an example of back flexion. Notice how his back is bent towards his body.

This is just to give you an example of the direction you need to go in the trunk lift test and the correct name for it. For this test, back extension is really the only direction term you need to know. Now we can get into the muscles that are used to make this movement possible. 

The trunk lift tests uses muscles in three areas: your back, stomach, and lower body. So much more simple than all the muscles used in running!

Back Muscles:

Spine Muscles: The most important muscle in the trunk lift test are the spinal muscles. The correct name for these muscles would be the erector spinae. These muscles run all the way up and down your spine. These are the muscle that make back extension (leaning your back away from your body) possible. They help you move your torso from the ground to up in the air.

Lower Back Muscles: The lower back muscles simply assist the spine muscles in the trunk lift movement. The main muscle assisting the spinal muscles is called the latissimus dorsi. This muscles is located from your lower to mid back. It essentially does the same thing as the spine muscles, help with back extension (arching the back away from your body). It helps move your torso from the ground to the air.

Abdominal Muscles:

Abdomens: If you remember from the previous post, the abdomens are the muscles of your belly. In the trunk lift test, they work to help keep your body stable when you are extending your back. When you extend your back, you have to hold the position for at least two seconds. Your abdomens assist your back in staying up for the whole two seconds. 

Lower Body:

Gluteus Maximus: Also known as your glutes, they are the muscles of your butt. These muscles help keep your legs down and also allow you to move your torso back to complete the trunk lift. It is harder to tell when someone is laying on their stomach but the back extension starts at the hips. In the first image below you can see when she arches her back, the curve begins at her hips. The glutes help make this movement possible.

Hamstrings: These are the muscles found in the back of your thigh. During the trunk lift test, these muscles have the same job as the glutes: keep legs down and allow you to move your torso back. Your lower back, glutes, and hamstrings are all connected together so it only makes sense that they work together to make many of our movements possible! 

In the next two posts I will break down the final two fitness tests: pull ups and push ups. Following those two entries, I will write how to improve your fitness test scores. If you have any questions on this information, please let me know!