Published averages for a 12-year-old’s vertical jump vary widely, typically falling somewhere between roughly 12 and 16 inches for untrained kids, with athletic 12-year-olds clearing more. But that range obscures a messier reality: the number you get depends heavily on how the jump is measured, whether the child plays a sport, their body composition, and whether they have begun puberty. Research on youth jumping performance reveals that age 12 sits at a fascinating crossroads where some of these factors are just beginning to diverge.
Why a Clean Average Is Hard to Pin Down
If you search for “average vertical jump for a 12-year-old,” you’ll find various numbers floating around coaching sites and fitness forums. The trouble is that most of those figures are either self-reported, drawn from a single school or athletic program, or measured using different equipment than what a laboratory would use. Even peer-reviewed studies that collect normative jump data on schoolchildren end up with results that don’t line up perfectly with each other, because they use different jump protocols, recruit from different populations, and test on different devices.
One large study of English schoolchildren aged 10 to 15 collected normative vertical jump and peak power data, finding that boys produced significantly higher jump heights and peak power than girls beginning around age 11 and 12, respectively.1Journal of Sports Sciences. Vertical jumping and leg power normative data for English school children aged 10-15 years The actual mean values in that study, though, reflect one specific population of British children, and the numbers would shift for children in a different country, at a different fitness level, or tested on different equipment. That is the core challenge: there is no universal benchmark for 12-year-olds because the variable space is enormous.
How Measurement Method Changes the Number
This is something most parents and young athletes never think about, but it probably explains more of the variation in reported averages than any biological factor. The device used to measure a vertical jump can change the result by several inches. A study comparing a popular contact mat, a Vertec reach device, and a laboratory force plate found striking differences: the contact mat reported an average jump height of about 50 centimeters (roughly 20 inches), while the force plate measured the same jumps at about 34 centimeters (roughly 13 inches).2PubMed. Accuracy of a vertical jump contact mat for determining jump height and flight time That gap exists because each device calculates jump height differently. Contact mats rely on flight time, which can be inflated if the jumper tucks their feet up during the airborne phase. Force plates derive height from the impulse the jumper produces against the ground, which tends to give a more conservative and biomechanically rigorous number.
The Vertec, which measures how high you can touch a set of plastic vanes mounted on a pole, came in close to the contact mat’s values in that same study. The Vertec is the device most commonly used in gym class and youth sport tryouts, so the “vertical jump” number a 12-year-old brings home from school is more likely to resemble the contact-mat reading than the force-plate reading. This matters if you’re comparing your child’s score against a number from a research paper that used a force plate. An apparent gap of four or five inches might be entirely explained by equipment, not talent.
The Sex Difference at Age 12
Before puberty, boys and girls jump at roughly similar heights. The divergence starts to appear right around 11 to 12 years of age, and it accelerates through the mid-teens. That English normative study found boys jumping significantly higher than girls from about age 11 onward.1Journal of Sports Sciences. Vertical jumping and leg power normative data for English school children aged 10-15 years A separate study looking at age- and gender-related differences in explosive leg function found that reactive strength differences between boys and girls showed up from ages 11 to 12, while differences in countermovement jump height didn’t reach significance until around 15 to 16.3PubMed Central. Age- and gender-related differences in explosive leg muscle function with respect to jump tests used: a comparative study – Section: RESULTS
What this means practically: at age 12, the gap between boys and girls is real but relatively small compared to what it becomes by age 15 or 16. A girl who jumps as high as the average boy at 12 is not unusual. By 15 or 16, the hormonal changes of puberty have widened the gap enough that the distributions barely overlap at the top end. So if you’re a 12-year-old girl comparing yourself to a boy the same age, the playing field is more level right now than it will be in a couple of years.
Why Puberty Timing Matters More Than Age
Two 12-year-olds can be separated by years in biological maturity. One might be pre-pubertal and the other already well into a growth spurt. Since vertical jump performance depends on muscle force, tendon stiffness, and neuromuscular coordination, children who are further along in puberty tend to jump higher regardless of their calendar age. Research on adolescent male soccer players examined landing force and jump performance across different maturity levels and found that maturity status influenced jump outcomes, though the relationship isn’t always straightforward in terms of landing forces.4PubMed Central. Association Between Maturity Status, Landing Force, and Jump Performance in Adolescent Male Soccer Players – Section: Results
This is why comparing a 12-year-old’s vertical against a single average can be misleading. An early-maturing 12-year-old boy who has already gained significant muscle mass might jump 18 or 19 inches, while a late-maturing boy the same age might struggle to clear 10. Both are normal. Maturity offset, which is the estimated distance in years from peak height velocity, is a better predictor of explosive performance than chronological age alone during this window.
Athletic Kids vs. Non-Athletes
Sport participation creates a visible split in jumping ability by age 12. A study tracking young athletes in volleyball, basketball, and soccer alongside non-athletic peers found that squat jump and countermovement jump heights were already significantly higher in volleyball players compared to non-athletes at age 12.5PubMed Central. Can sport-specific training affect vertical jumping ability during puberty? By age 13, 14, and 15, all sport groups pulled ahead of the non-athletes. Volleyball players, who spend the most time jumping during practice and competition, showed the earliest and most pronounced advantage.
Part of this is self-selection: kids who can jump well are drawn to sports that reward jumping. But training also reshapes the neuromuscular system. A study of preadolescent athletes found that long-term athletic training was associated with greater tendon stiffness, and that tendon stiffness was the strongest predictor of jump height in trained children, while raw muscle strength was the better predictor in untrained children.6PubMed Central. Effects of long-term athletic training on muscle morphology and tendon stiffness in preadolescence: association with jump performance – Section: RESULTS In plain terms, training teaches the tendons to store and release energy like a spring, and that elastic contribution becomes the dominant driver of jump height in kids who train regularly. Untrained kids rely more on brute muscle force.
Body Composition and Jump Performance
Carrying extra body fat drags down vertical jump scores at every age. This is intuitive enough: jumping is essentially launching your own bodyweight against gravity, so the more of that weight is non-contributing mass, the lower you go. Research on preschool-age children found that those who were overweight or obese had shorter flight times, lower flight heights, and less power relative to body mass compared to normal-weight peers.7PubMed Central. Associations between nutritional status and jumping performance in pre-school children – Section: Results The pattern persists into adolescence.
An interesting nuance is that BMI alone doesn’t predict jumping performance well. A study of youth soccer players found that body fat percentage was strongly associated with vertical jump scores, but BMI was not significantly associated with any performance measure.8PubMed Central. Field-Based Performance Tests Are Related to Body Fat Percentage and Fat-Free Mass, But Not Body Mass Index, in Youth Soccer Players The reason: BMI cannot distinguish between a muscular kid and a kid carrying excess fat. A 12-year-old who is “heavy” because they have well-developed leg muscles may actually jump quite well, while a lighter child with a higher proportion of body fat may jump poorly. If your child’s BMI looks high but they’re clearly athletic and muscular, their vertical jump potential may be better than the BMI number would suggest.
Can a 12-Year-Old Improve Their Vertical?
Yes, and the research is encouraging on this point. Plyometric training, which involves repeated jumping, bounding, and hopping drills, has consistently been shown to improve explosive performance in children. A study of school-age children found that just four weeks of plyometric training produced large improvements in performance measures compared to a control group, with the gains appearing on both hard surfaces and softer training surfaces.9PubMed Central. Effects of Four Weeks of Plyometric Training Performed in Different Training Surfaces on Physical Performances in School Children: Age and Sex Comparisons That same study noted that age and sex influenced the magnitude of improvement, which makes sense given everything discussed above about maturation.
For older adolescents and adults, combining plyometric work with resistance training appears to be the most effective strategy for boosting vertical jump. Plyometrics improve the speed of muscle contraction and the ability to store and release elastic energy, while resistance training builds raw force capacity.10PubMed. Training methods to improve vertical jump performance For a 12-year-old, though, heavy weight training is usually not recommended or necessary. Simple plyometric progressions, bodyweight squats, single-leg hops, and general sport participation tend to produce meaningful gains. The nervous system at this age is highly responsive to new movement challenges, so even playing a jumping-heavy sport like basketball or volleyball a few times a week will likely shift the needle.
One thing to keep in mind: children who are physically active in general tend to jump higher, even outside of formal training programs. Research on 6- to 10-year-olds found that both self-reported and objectively measured physical activity levels were positively associated with vertical jump performance.11PubMed Central. Associations between physical activity, screen time, and fitness among 6- to 10-year-old children living in Edmonton, Canada The direction of causality is a bit chicken-and-egg, but the association is clear: more movement, better jumping. If your 12-year-old is mostly sedentary, getting them moving regularly may be the single biggest lever you can pull.
Countermovement Jump vs. Squat Jump
If you dig into youth fitness testing literature, you’ll see two jump types come up repeatedly. The countermovement jump starts from a standing position: the jumper dips down quickly and immediately explodes upward. The squat jump starts from a held squat position with no preliminary dip. Almost everyone jumps higher on the countermovement version, because that quick downward dip stretches the muscles and tendons, allowing them to snap back and contribute extra force. This is called the stretch-shortening cycle.
For years, coaches assumed that a big difference between countermovement and squat jump heights was a good thing, because it meant the athlete was effectively using elastic energy. More recent research has pushed back on that interpretation. A study of over 770 athletes found that a large gap between the two jump types might reflect poor ability to produce force rapidly, or excessive slack in the muscle-tendon unit, rather than superior elastic rebound.12PubMed. The difference between squat jump and countermovement jump in 770 male and female participants from different sports For a 12-year-old, this is mainly useful context if a coach is testing both types: a low squat jump relative to the countermovement jump isn’t necessarily a problem, but it isn’t necessarily a sign of great elasticity either. It’s just one data point that needs to be interpreted carefully.
How Boys and Girls Produce Force Differently During Adolescence
Beyond simply jumping higher or lower, male and female adolescents appear to use distinct neuromuscular strategies to generate vertical force. Research on plantar flexor activity and Achilles tendon stiffness during jumping found that adolescent males tend to show higher activation of the primary jumping muscles and lower activation of opposing muscles, leading to greater force production and better use of elastic energy from their tendons. Adolescent females, by contrast, show greater co-contraction of opposing muscle groups, which stiffens the joint through a different mechanism.13PubMed Central. Effects of Maturation on Plantar Flexor Activity and Achilles Tendon Stiffness in Vertical Jumping: Sex Differences – Section: Discussion
Neither strategy is inherently “wrong.” The female pattern of co-contraction provides joint stability and may serve a protective function, even if it costs some jump height. The male pattern maximizes force output but relies more heavily on tendon compliance. These differences become more pronounced through puberty, so at age 12 they may only be beginning to appear. Understanding them can help coaches design training that matches how a young athlete’s body is actually producing force, rather than assuming all kids should train the same way.
Landing Forces and Injury Awareness
Parents sometimes worry about whether jump training is safe for a 12-year-old whose body is still growing. The concern is understandable: growth plates in the knees and ankles are still open, and the repetitive impact of landing could theoretically cause problems. The evidence, however, suggests that supervised plyometric training is well-tolerated by youth when progressions are sensible. A study that collected normative landing-force data on adolescents (mean age 16, a bit older than 12 but the closest available reference) found that the average peak vertical ground-reaction force during a drop landing was about 4.5 times body weight, with no significant differences across sex, activity level, or sport type.14Journal of Science and Medicine in Sport. Normative data of vertical ground reaction forces during landing from a jump
That 4.5-times-bodyweight number gives you a sense of scale: a 90-pound 12-year-old lands with roughly 400 pounds of force on every jump. The body is designed to absorb this, but technique matters. Teaching kids to land softly with bent knees, to absorb force through the hips and ankles rather than landing stiff-legged, and to build up jump volume gradually is more important than worrying about whether they should be jumping at all. Most youth sport injuries come from overuse and poor recovery, not from the act of jumping itself.
What to Do With a Vertical Jump Score
If your 12-year-old just got tested and you’re trying to figure out if their score is “good,” the most useful comparison is against kids in similar circumstances: same sex, same sport background, similar maturity level. A non-athletic 12-year-old boy jumping 13 inches on a Vertec is perfectly normal. An athletic 12-year-old girl in volleyball clearing 15 inches is also normal for her context. The number in isolation doesn’t mean much without knowing the measurement device, the jump protocol (countermovement vs. squat, arm swing allowed vs. hands on hips), and the child’s training history.
Where vertical jump testing gets more useful is in tracking change over time within the same child, using the same equipment and protocol. If your 12-year-old’s vertical goes from 12 inches in September to 15 inches in March, you know their training is working, regardless of where those numbers sit relative to some national average. That individual trajectory is what coaches and sport scientists actually care about, not how a child stacks up against a single population mean. Given all the sources of variation described above, chasing a benchmark number is far less productive than focusing on steady improvement.