Why Do Running Shorts Have Liners?- (Get a Detailed Explanation)

Last Updated on October 1, 2023 by Alex PT

Running shorts liners have 3 main purposes: preventing chafing, providing support, and wicking away sweat. According to a study published in the Journal of Sports Sciences, running shorts liners can reduce the incidence of chafing by up to 50%.

Why Do Manufacturers Put Liners in Running Shorts?

Why do they put liners in running shorts

Here are some key reasons why manufacturers include liners in running shorts:

1. Improved Comfort

The liner in running shorts is tailored to provide an improved level of comfort to the wearer. It’s designed to minimize the rubbing against the skin that might cause irritation during running. This means you can run long distances without feeling uncomfortable or distracted.

2. Increased Support

Liners in runners’ shorts also provide support to the body. Most liners are designed to offer a snug fit that keeps everything in place, reducing unnecessary movement and bounce that can cause discomfort or even injury.

3. Enhanced Moisture-Wicking

A significant advantage of the liners in running shorts is their ability to absorb and wick away sweat effectively. They keep the wearer dry and cool, minimizing the risk of discomfort or chafing.

4. Reducing the need for Undergarments

As liners provide support and comfort, they actually eliminate the need for undergarments. This can be particularly beneficial for athletes who find wearing additional layers cumbersome or uncomfortable.

5. Increased Breathability

Most of the liners in running shorts are made from breathable materials, which improves air circulation. This increased ventilation keeps the wearer cool and dry, enhancing comfort during physical activity.

6. Added Coverage and Privacy

Lastly, liners in running shorts provide increased privacy and ensure adequate coverage, which is especially important during strenuous activity.

Improved ComfortMinimize skin irritation and distraction
Increased SupportReduce unnecessary movement and potential injury
Enhanced Moisture-WickingEffectively absorb and wick away sweat
Reducing Need for UndergarmentsSimplify athletes’ dressing process
Increased BreathabilityPromote air circulation and enhance comfort
Added Coverage and PrivacyEnsure private part protection during strenuous activity

Are shorts With Liners Good for running?

It is an open secret that runners value comfort while on the move. Besides the reality that not everyone is accustomed to wearing shorts with liners, the naked truth is that this gear ensures your comfort by minimizing chafing incidents that often hinder performance. Therefore, shorts with liners are critical to veteran runners and beginners as they enhance performance and ensure that your skin doesn’t get sore.

Why Do Running Shorts Have Built-In Underwear?

Different fitness pants for men and women provide various functions to protect against chafing, especially during warm conditions. Some are designed with built-in underwear, and some do not include it. Having underwear sewn into the pants helps athletes move better even when just wearing the other apparel due to their lightweight nature while providing minimal but necessary coverage.

Read more about Are You Supposed To Wear Underwear With Running Shorts

Four Benefits of Built-in Underwear

Five benefits of built-in underwear

1. They Wick Sweat and Moisture Away

The liners inside most running shorts are made with moisture-wicking material to move moisture away from your thighs and crotch area. This fabric wicks the sweat away from your body so that you don’t feel clammy while working out, which may be uncomfortable or cause chafing. Additionally, many pairs of running shorts are designed to allow maximum airflow through the legs or have side slit openings to allow runners to easily maneuver their legs as they often bend their knees during workouts.

For serious athletes and sports enthusiasts, technical workout clothing is a must. These are thinner and lighter than ordinary fabrics and create a wicking effect for heat to escape the body when it is hot outside. The material has better breathability, hence keeping your skin dry. Shorts with liners create an incredible and relaxed feeling after doing runs, workouts, or any other outdoor activities.

2. They Provide Support to Men’s Genitals

Running tights with a liner are popular among male athletes because they provide added security and storage. These tights were initially designed to hold what was needed for comfort in men, including the genital region and even small packages of tissues! Our bodies have become more well-equipped over time as we have become more athletic as our lifestyles demand it, and we can rely on things like exercise.

Are you looking for that comfortable pair of running shorts with a design that gives you the confidence to hit your target distance? Compression shorts with liners allow you to run comfortably, knowing it’s possible. This specially designed underwear for runners has lightweight materials for the liners that can provide the right amount of support during long-distance runs. Liners comprise various materials such as spandex, nylon, and viscose.

3. They Prevent Women’s Shorts from Riding Up

While most women would prefer fleece-lined shorts, they seldom have a chance to enjoy them as they need a roomy fit that wouldn’t show underwear lines. Fortunately, there’s a variety of athletic wear with built-in boxer briefs made of spandex and sweat-wicking fabric for enhanced comfort in any athletic activity. They are designed for men and women and come mainly in red and black colors, but may also come in grey or blue. Always remember that comfortable lining ensures sweat doesn’t get out of the pants.

4. They Prevent Chafing

Wearing liners with your running shorts helps prevent chafing, thus, keeping you comfortable. Chafing happens when there is a lot of rubbing over the skin from clothing moving around while you’re on the move. If the material on the fabric were to be held tightly against your body, it is unlikely that this kind of movement could happen.

When should I wear underwear with running shorts?

Whether or not you should wear underwear with running shorts depends on your personal comfort and the design of the shorts. Here are some factors to consider in detail:

1. Liner Presence: Many running shorts come with built-in liners, which are designed to replace traditional underwear. These liners are made from moisture-wicking, breathable materials and provide support, reducing the need for additional underwear. In such cases, wearing underwear is usually unnecessary and may even lead to discomfort due to added layers.

2. Fabric and Fit: If your running shorts do not have built-in liners or if you find the liner inadequate, consider the type of fabric and fit of the shorts. Look for shorts made from moisture-wicking materials that reduce friction and chafing. A snug, comfortable fit that provides support may eliminate the need for underwear.

3. Personal Preference: Some runners prefer the extra security and coverage that underwear provides, especially when wearing loose-fitting shorts. If you feel more comfortable wearing underwear, opt for moisture-wicking, seamless, or compression underwear that won’t bunch up or cause chafing.

4. Chafing and Skin Sensitivity: If you are prone to chafing or have sensitive skin, underwear can act as an additional barrier between your skin and the shorts, reducing friction and the risk of irritation. However, be mindful of the type of underwear you choose, as certain materials can exacerbate chafing.

5. Hygiene: Wearing underwear with running shorts can help keep your shorts cleaner for longer periods between washes. This may be a consideration if you are on a multi-day running trip or have limited access to laundry facilities.

6. Layering: In colder weather, you may choose to layer with thermal or compression underwear for added warmth and moisture management. In this case, you can wear underwear beneath your running shorts.

Do You Still Need to Wear Underwear When Wearing Lined Shorts?

1. Built-In Liner: Lined shorts typically come with built-in liners made of moisture-wicking and supportive material. These liners are designed to provide the necessary comfort and support, often making traditional underwear unnecessary.

2. Liner Quality: The effectiveness of the built-in liner can vary between different brands and models of shorts. Some liners are more comfortable and supportive than others. It’s essential to assess the quality of the liner in your specific shorts. If the liner provides adequate support and comfort, you may not need to wear underwear.

3. Comfort: Personal comfort is a significant factor. Some individuals may feel perfectly comfortable without underwear when wearing lined shorts, while others may prefer the added security or coverage that underwear provides. It’s essential to listen to your body and choose what feels best for you.

4. Hygiene: In hot and sweaty conditions or during extended physical activities, wearing moisture-wicking underwear beneath lined shorts can help manage sweat and odor. This can keep your shorts fresher for longer between washes.

5. Chafing and Sensitivity: If you are prone to chafing or have sensitive skin, the built-in liner may not provide enough protection. In such cases, wearing seamless or moisture-wicking underwear can act as an additional barrier, reducing the risk of irritation.

6. Layering: In colder weather, you may choose to layer with thermal or compression underwear for added warmth and insulation. In this scenario, you can wear underwear beneath your lined shorts.

7. Compression Shorts: Some runners prefer to wear compression shorts or underwear beneath lined shorts for added muscle support and improved circulation. Compression garments can enhance performance and recovery.

In summary, whether you still need to wear underwear when wearing lined shorts depends on your individual preferences and the specific circumstances of your activity. The quality and comfort of the built-in liner, as well as your personal comfort and hygiene considerations, should guide your decision.

Related Post: Is It Acceptable To Go Shopping With A Sports Bra And Shorts? (Explained!)

Frequently Asked Questions

Are you supposed to wear underwear with running shorts?

Each person’s experience with running clothes is different. When you are training, it is good to experiment with the functions of your clothing, particularly what you wear underneath your running shorts. You may feel more comfortable wearing underwear, but there are also strides in textile engineering that minimize fabric-to-skin friction while providing ample ventilation and compression. So, using a liner is not necessary. Remember, it all comes down to what makes you comfortable.

Can you cut the liner from running shorts?

The Running shorts’ liner can be cut externally. Pull out the underwear that doesn’t match your skin color as a reference and make slices where they have been sewn.

The latest running shorts have built-in underwear, and others come without. Shorts with liners are convenient as they slip in neatly inside the shorts, so you don’t have to buy another layer of underwear. However, if you find them uncomfortable, we recommend giving separate underwear a try because it has been known to offer more comfort.


Every athlete understands that the right running gear tremendously contributes to their track success. Suppose you are a beginner and unsure whether you will try running short with a liner. In that case, there is no harm in giving it a go. After all, the garment has proven to be effective due to its moisture-wicking, breathability, and comfort abilities.

Reference 1: Do Running Shorts Have Liners? If So, Why? – ThreadCurve

Reference 2: Why Do Running Shorts Have Liners? – Fitter Habits

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