Growing feels like a deep, throbbing ache in your legs, usually in the thighs, calves, shins, or behind the knees. It can also show up as muscle tightness, a strange sense of clumsiness, or itchy skin that seems to stretch. These sensations are most noticeable during childhood and adolescence, and they tend to hit hardest at night. Between 3% and 37% of children experience what doctors call “growing pains,” depending on the population studied, and the discomfort is real even though growth itself isn’t technically damaging anything.
The Classic Ache in Your Legs
The most recognizable sensation of growing is a dull, throbbing pain deep in the muscles of both legs. It’s not sharp or localized to a single joint. Instead, it spreads across the front of the thighs, the calves, or the area behind the knees. The pain almost always affects both sides, which is one reason doctors distinguish it from injuries or joint conditions that tend to favor one leg.
This aching typically strikes in the late afternoon or evening and fades by morning. Sometimes it’s intense enough to wake a child from sleep in the middle of the night. Some children also get belly pain or headaches during these episodes. The discomfort comes and goes over weeks or months, with pain-free stretches in between. It mainly affects kids between ages 3 and 12, with a peak around age 6, which is interesting because that age isn’t actually part of the fastest growth phase.
Why It Happens at Night
Your body releases growth hormone in a large burst when you first enter deep sleep. In studies measuring hormone levels across the night, this initial surge lasted between 1.5 and 3.5 hours and was by far the biggest release of the day. Smaller pulses sometimes followed during later deep sleep phases. If you fall asleep later than usual, the surge simply shifts to match your new sleep onset. This tight connection between deep sleep and growth hormone release helps explain why growing discomfort clusters around bedtime and the overnight hours, when bones and tissues are most actively responding to hormonal signals.
What’s Happening Inside Your Bones
Long bones grow from specialized zones near their ends called growth plates. These are made of cartilage cells arranged in columns. The cells go through a lifecycle: they rest, then multiply rapidly, then swell to several times their original size. Eventually they die on schedule and are replaced by bone-forming cells that arrive along with new blood vessels. This process of cartilage turning into bone is how your arms, legs, and spine get longer.
The growth plate itself doesn’t appear to send pain signals directly. Researchers haven’t found evidence that the ossification process triggers nerves in the bone. The aching you feel is more likely coming from the muscles, tendons, and other soft tissues that are being pulled and stressed as the skeleton underneath them changes length.
Muscles and Tendons That Can’t Keep Up
One of the more uncomfortable parts of growing is the mismatch between bone growth and everything attached to it. Bones lengthen first, and the muscles and tendons that wrap around them take longer to catch up. Tendon tissue has a much slower turnover rate than muscle. The protein collagen in tendons has a half-life roughly ten times longer than the main proteins in muscle, which means tendons remodel and adapt far more slowly.
This lag creates a feeling of persistent tightness, especially in the calves and the fronts of the thighs. During a growth spurt, you might notice that stretches you could do easily a few months ago now feel restricted. In young athletes, this imbalance between muscle strength and tendon stiffness can become significant enough to increase the risk of tendon injuries, particularly when rising levels of hormones during puberty accelerate muscle development even further ahead of tendon adaptation.
Feeling Clumsy and Uncoordinated
If you’ve ever felt like your body suddenly doesn’t move the way it used to, growth is a likely explanation. During the adolescent growth spurt, bones in the arms and legs grow from the ends outward, with the hands and feet lengthening before the upper arms and thighs. This changes the weight distribution of your limbs and increases their resistance to rotation, so movements that used to feel automatic now require more force and different timing.
Your brain’s internal map of your body dimensions hasn’t caught up yet. The sensory systems that track where your limbs are in space need time to recalibrate. Researchers describe this as a temporary disruption in neuromuscular control, postural stability, and coordination between limbs. It’s sometimes called “adolescent awkwardness,” and it’s a normal part of the process. For most people, coordination returns as the brain adjusts to the new proportions, though the awkward phase can last several months during the fastest period of growth.
Skin Stretching and Stretch Marks
Rapid height gain puts mechanical stress on the skin, particularly across the back, hips, thighs, and knees. When the deeper layers of skin can’t stretch fast enough, the collagen fibers tear and produce stretch marks. In adolescents, these marks first appear as raised, reddish lines (sometimes slightly itchy or tender) before gradually fading to pale, slightly indented scars over time.
These stretch marks occur in otherwise healthy, non-obese teenagers and are directly associated with the adolescent growth spurt. The skin over rapidly growing areas can also feel tight or mildly itchy even without visible marks, simply from being pulled taut over expanding tissue.
When Growth Spurts Peak
The most intense physical sensations of growth tend to coincide with peak height velocity, the period when you’re gaining height fastest. For girls, this peaks around age 12 on average. For boys, it’s closer to age 14. There’s a wide normal range, though, with about a year and a half of variation in either direction being common.
Most girls reach their fastest growth rate before their first period. About 71% have already passed peak height velocity by the time menstruation begins. Boys tend to hit their peak growth later in puberty. During these spurts, it’s not unusual to gain 3 to 4 inches in a single year, and the sensations of tightness, aching, and clumsiness are typically strongest during this window.
When the Pain Signals Something Else
Normal growing pain is symmetrical (both legs), muscular (not in the joints), and gone by morning. Pain that consistently affects only one leg, centers on a specific joint, causes swelling or redness, or is still present when your child wakes up follows a different pattern. Joint pain that persists daily for six weeks or longer can be an early sign of juvenile arthritis, where the immune system attacks healthy joint tissue and causes chronic inflammation.
Limping, fever alongside joint pain, or pain that gets worse rather than better over weeks are all reasons to get an evaluation. Growing pains, by contrast, don’t cause limping, don’t produce swelling, and don’t interfere with normal activity during the day.
Easing the Discomfort
Gentle massage is one of the most effective and immediate ways to relieve growing pain. Rubbing the sore muscles in the thighs and calves often brings noticeable relief within minutes. A heating pad on a low setting, placed on the legs before bed, helps relax the tight tissue. A warm bath before sleep works similarly. Remove the heating pad once sleep begins.
Daytime stretching of the leg muscles, particularly the quadriceps and calves, can reduce the frequency of nighttime episodes. Holding each stretch for 20 to 30 seconds and repeating it a few times targets the tightness that builds as bones outpace the soft tissue around them. For nights when the pain is strong enough to wake a child, ibuprofen or acetaminophen can help, though aspirin should be avoided in children due to the risk of a rare but serious condition called Reye’s syndrome.