Does it matter if a baby never crawls?
This is a heavily debated topic in the world of infant and toddler development. Some babies go straight to walking. Some only belly crawl. Some babies use log rolling to get around. And some babies scoot around on their bottoms. To add to the diversity of floor mobility, some babies bottom-scoot in a “W” sit, some do so with their legs in a ring position with their feet together, and some scoot along while shifted to one side using one hand and their opposite leg to propel themselves forward. So, how important is true crawling on hands and knees?
How does crawling affect learning to walk?
Proper development of the hip joint is one of the most concrete benefits of crawling. There are two important angles in the hip that play an important roll in orthopedic development from infancy through adulthood. If these angles do not develop properly, they can lead to in-toeing (walking “pigeon toed”), out-toeing (walking “duck footed”), hip, knee, and foot pain, hip and knee joint disfunction, early onset of hip and knee arthritis, and in extreme cases, hip subluxation or dislocation.
The first angle of importance is the neck-shaft angle (NSA). At first, this angle is 135-140 degrees. This angle gradually decreases to about 125 degrees at puberty. When this angle does not decrease, excessive force is placed on the knee joints. This stress is called genu varus, otherwise known as bow-leggedness. Unfortunately, bowed knees are known to have increased stress on the insides of the knees which leads toward degenerative changes to the knee joint at an early age. In extreme cases, often associated with cerebral palsy, hip dysplagia can occur, where the ball of the hip joint does fully not fit into the pelvis or can even dislocate. Also, when the NSA does not decrease, the pelvis must tilt forward to accommodate, and this leads to a swayed lower back with overstretched and weak abdominal muscles.
The second angle is the femoral-neck anteversion (FNA). At birth, the FNA is about 40 degrees. This angle gradually degrees to about 20 degrees by 10 years old. By adulthood, this angle settles at 8-15 degrees. If this angle is too large, in-toeing results. If this angle is too small, out-toeing results. Both in-toeing and out-toeing can lead to further stress and damage to the knees and arches of the feet, leading towards pain in early adulthood.
Crawling on hands and knees is the main precursor to maturation of these hip angles: the NSA and FNA. Ideally, a baby should crawl on their hands and knees regularly for 3-4 months to promote proper orthopedic development.
Another benefit to crawling is the coordination of symmetrical, alternating patterns between different sides of the body. Crawling requires these reciprocal movements in the sagittal plane (between the left and right side), in the transverse plane (between the top and bottom), and in the coronal plane (between the front and back). Essentially, walking requires a firm neurologic imprint of these movement patterns, because walking occurs in all three planes. When a child bottom scoots or belly crawls, one or more of these movement planes gets neglected. Also, belly crawling and bottom-scooting are often not symmetrical. Babies spend hours each day moving around the floor creating and strengthening the neurologic pathways for these atypical movement patterns. In my experience, I often see significant postural and balance issues arise that lead to delayed walking with atypical walking patterns.
This child used a side-sitting bottom scoot and never crawled on her hands and knees. Now, her walking pattern is not symmetrical, as seen in the foot prints in the snow.
What about fine motor development?
There are a few important key factors in development of fine motor and play skills. Dissociation refers to the ability to use one side of the body at a time or one muscle group at a time. Dissociation is necessary for the development of bilateral coordination. Bilateral coordination refers to the ability to use both sides of the body together. One can imagine that bilateral coordination is extremely important in play. Most toys that require exploration and problem- solving function with the use of both hands working together. Bilateral coordination plays an important role in everyday activities such and tying shoes, fastening buttons, and using utensils and tools. Bilateral coordination requires the ability to cross the midline plane of the body, and crossing midline often begins when crawling occurs.
Additionally, weight bearing through the hands that occurs with crawling on the hands and knees is important for the development of hand arches. Hand arches affect the grasp patterns required for use of pencils, crayons, and feeding utensils.
A personal experience from Cyndi
I’m going to share a personal experience now. My youngest son’s motor development was atypical. He never kicked and bicycled his legs, he learned to sit late at 8 months old, he never preferred playing on his tummy as most 6-9 month old babies do, and he couldn’t roll over until he was 11 months old. When he was 12 months old, he learned to get himself into a sitting position, and he starting trying to bottom-scoot. He was still so weak that he could barely hold himself up on his hands and knees. At this point, I needed to make a choice. I knew that bottom-scooting was setting my son up for more impairment in gross and fine motor development. However, my son was now one year old. He needed to move, explore, and interact in his environment. The development of social-emotional, communication, language, and cognitive skills is highly dependent on a child’s ability to explore and interact with their environment. So, after an internal struggle, I allowed my son to develop his bottom-scooting skills, and within a week, he was scooting like a champ. Now, if my son had been 9 months old, I would’ve done my best to prevent bottom-scooting. Or if he had been able to log roll to get from point A to point B, I would’ve continued to promote crawling. But by 12 months old with no means of any independent mobility, I chose to allow mobility. Here’s the catch: I continued to work on crawling…a lot. Finally, at 14 months old, he was able to crawl short distances with significant effort, but he never crawled on his own without encouragement. Fast forward to today, and he is 2 years old. I still promote crawling activities, and we are still working with Occupational Therapy to improve the impairments that his lack of crawling has created. However, his language, communication, social, and cognitive skills are excellent, so I have no regrets on allowing the scoot.
Reference to numbers: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333666/