Many parents would be surprised to know that backpacks weighing as little as nine pounds are enough to possibly injure the average third grader. Improper backpack weight, fitting, and use can cause harm, especially to children with growing muscles and joints. Approximately 55% of students carry a backpack that is heavier than the recommended guideline of 10% of the student’s total body weight.¹

Often when pre-teens are referred to a physical therapist for pain, the therapist directs the patient to bring his/her backpack for examination and proper fitting. One-third of school-aged children report experiencing back pain that caused them to visit a doctor, miss school, or abstain from physical activities.²

Measuring the low back (medically referred to as the lumbar spine) response to the back pack load is important in assessing pain. Studies have shown that the weight of a back pack compresses the lumbar disc and changes the natural curvature of the spine.³ Injury can occur when children, in trying to adapt to a heavy load, use harmful postures such as arching their back, leaning forward or, if only one strap is used, leaning to one side. These postural adaptations can cause spinal compression and/or improper alignment, and may hamper the proper functioning of the back and lead to pain.

A too-heavy load also causes muscles of the back to work harder, leading to strain and fatigue. This leaves the back more vulnerable to injury. A heavy load may also cause stress or compression to the shoulders and arms. When nerves are compressed, the child may experience tingling or numbness in the arms and/or hands.

Fitted and worn correctly and not overloaded, a backpack is supported by some of the strongest muscles in the body: the back and stomach/abdominal muscles. These muscles work together to stabilize the back and hold the body in proper postural alignment. When purchasing, packing, and fitting a backpack there are simple guidelines parents should follow.

Physical therapists recommend the following features when choosing a backpack:

  • Check for fit. Pay close attention to the positioning of a backpack on the child’s back. It should be in the centered;
  • The size of the backpack should match the size of the child;
  • The bottom of the backpack should rest in the contour of the low back and be approximately two inches above the waist. Avoid having it sag down over the buttocks;
  • A padded backing will reduce pressure and prevent the pack’s contents from digging into the child’s back;
  • Backpacks should have two shoulder straps;
  • Padded, contoured shoulder straps will reduce pressure and discomfort on the chest and shoulders;
  • Shoulder straps should be adjustable and fit comfortably so that the arms move freely. No pinching!
  • A waist belt to help distribute some of the load off of the back and shoulders and onto the pelvis;
  • Compression straps on the sides or bottom of the backpack that, when tightened, compress the contents of the backpack and stabilize the articles; and
  • Reflective material so that the child is visible to drivers.

Physical therapists recommend the following tips for safe backpack use:

  • Make frequent stops at the school locker to prevent carrying too many books or papers;
  • Organize contents so that the heavier items are closer to the child’s back and secured low within the bag; and
  • Avoid slinging the backpack over one shoulder. Using only one strap causes one shoulder to bear the weight of the bag and can strain muscles. Using only one strap causes the spine to curve. By wearing both shoulder straps, the weight of the pack is evenly distributed. No strain, no curvature.

Some children may find backpacks with wheels a good option. Be aware however, that wheeled backpacks may present problems, such as:

  • Being heavier even before they are loaded down with books and papers;
  • Difficult getting them up and down stairs;
  • Difficult getting them into school locker spaces; and
  • Difficulty getting them across streets and intersections.

If a wheeled backpack is chosen, be sure that the handle can be extended to a proper height to avoid twisting or a bent posture when walking.

So how do you know if a backpack may be causing injuries?

  • Pain when wearing the backpack
  • Tingling or numbness in the arms or hands; and
  • Red marks on the shoulders or back.

In additional to initially making sure a backpack fits properly and does not place excessive weight on the child’s spine, muscles, and shoulders, parents should ask their children each day if their backpack is causing any of the above symptoms. If pain is present, the backpack’s cargo should be lessened or the backpack should be adjusted to properly fit the child.

If pain persists, physical therapists are highly-educated, licensed health care professionals who can help reduce pain and improve or restore health– in many cases without expensive surgery or the side effects of prescription medications. Parents should remember to bring their child’s backpack to the appointment for weighing and proper fitting.

¹Graduate Program in PT, Simmons College (2001, Feb 12) Children’s Backpacks are too Heavy
² Ibid
³Spine (Phila Pa 1976). 2010 Jan 1;35(1):83-8.FROM: SPINE (Phila Pa 1976) 2010 (Jan 1); 35 (1): 83–88; Neuschwander TB, Cutrone J, Macias BR, Cutrone S, Murthy G, Chambers H, Hargens AR.


Laurie Kendall Ellis, PT, is the Executive Director of the American Physical Therapy Association, Private Practice Section. In her role as Executive Director, Laurie has overseen day-to-day operations of PPS since 2009. She also served on the board of directors for PPS from 2001-2006 and served as editor of Impact Magazine, the official publication of the Private Practice Section, from 2006-2008.

An entrepreneur and a physical therapist, Laurie has practiced PT in Connecticut for over 30 years and serves as Principal and Co-Owner of Allied Health and Rehabilitation in West Haven, CT. There, she specializes in rehabilitation and occupational physical therapy.

In addition to being a practicing physical therapist and executive director of PPS, Laurie serves as Director of the board of the Connecticut Physical Therapy Association. Laurie graduated from Quinnipiac University in Hamden, CT with a B.S. in Physical Therapy. She divides her time between Alexandria, VA and Connecticut.