Doing what is best for children

CrossFit Kids was founded in 2004 by Jeff and Mikki Martin and is a method for teaching Greg Glassman’s CrossFit to children, ages 3-18. Based on the principle of Mechanics => Consistency => Intensity, CrossFit Kids emphasizes good movement throughout childhood and adolescence. Consistently good mechanics translates to physical literacy, enhanced sports performance, and fewer sports injuries for kids. Not only that, a vast body of research indicates that exercise is beneficial to cognitive function, which means that consistent adherence to the program can have a positive impact on children’s academic achievement.

CrossFit Kids is meant to be BIG fun for all ages. Broad-Inclusive-General fun. Fun means we provide an active alternative to sedentary pursuits, which means less childhood obesity and all-around better health for our children. Further, the needs of second graders and high school varsity wrestlers differ by degree and not kind; the program is scalable for any age or experience level and accounts for the varied maturation status one can find in a class full of kids. CrossFit Kids is designed to be minimalist; it is inexpensive and often requires little or no equipment, allowing a wide array of socioeconomic groups an opportunity to be physically fit and physically active throughout their lives.

CrossFit Kids programs can be found in over 1,800 gyms and more than 1,000 schools worldwide.

According to Merriam-Webster’s Collegiate Dictionary, Eleventh Edition, accuracy means “freedom from mistake or error.” In sports, as in most things, that is an ideal only, but it is a constant athletic pursuit. To be accurate in sports requires excellent kinesthetic awareness and proprioception, that is, body control. Accuracy, like its neurologically based counterparts agility, balance, and coordination, allows us to control our bodies to accomplish specific tasks under working conditions, that is, on the field of play, on the job, under load, or in other kinetic situations.

CrossFit Kids’ focus on mechanics first ensures that the skill of accuracy is trained all of the time in fundamental ways. In more direct terms, accuracy is practiced through a variety of exercises:

Basic dot drill
Balance beam traverses
Hurdle hops
Precision jumps
Vertical jumps with two-hand touches of a target
Wall ball shots to a target

Agility is considered by many to be essential to athleticism. It is a complex and fascinating skill comprising cognitive, perceptual, and physical components influenced by a slew of variables. It also relies on accuracy, balance, and coordination. Agility can be viewed as the ability to quickly change direction, speed, and movement patterns as well as to stop and start quickly in response to environmental stimuli or in a predetermined manner. Although mobility and posture, that is, flexibility, are important components, equally important is strength And by strength, we mean muscular strength and local muscular endurance, particularly in the posterior chain, and midline stability.

CrossFit Kids sees agility as the real-world application of force in the face of counter forces unexpected or expected, and we approach it from a fundamental standpoint. Our goal is to provide kids with the most basic ingredients on which to build not only sports-specific skill but the capacity to move through a physical world that daily confronts them with obstacles and pitfalls, invited or unforeseen.

CrossFit Kids looks to improve agility through activities that require it:

Basic dot drills
Cone drills
One- and two-legged jumping/hopping
Speed ladders

In this manner, we are practicing agility. However, as far as CrossFit Kids is concerned important groundwork for the development of sport-specific agility is laid in the form of mobility exercises and midline stabilization auxiliary movements:

Handstand holds and walks
Ice cream makers
Plank holds
Wall walks and walk-ups

But the real work is done in the WODs. CrossFit Kids is a strength-and-conditioning program. We are constantly building kids’ strength in developmentally appropriate ways. Long-time CrossFit Kids exposure yields a deeply rooted ability to apply productive force wed to good movement. The result? Improved agility and more generally improved athleticism in terms of sports performance and injury prevention.

Balance, or postural control, is the ability to maintain the body’s center of gravity over the base of its support. Learning this complex motor skill is rooted in perceiving the difference between being in and out of balance in conjunction with the ability to correct oneself when out of balance. This requires the body to be in a constant state of automatic movement and relies on the coordinated activity of visual, vestibular, and somatosensory (which includes touch and proprioception) systems as well as movements of the ankle, knee, and hip joints. Balance can be characterized as static or dynamic and as with eyes open or closed. Coordination, flexibility , and even strength play a role in balance, as do body weight and height.

CrossFit Kids offers children various opportunities to practice balance during class. Here are just three examples of activities kids might perform as part of a dynamic warm-up:

Balance beam traverses
One-legged hops
Precision jumps

Meanwhile, the building of strength occurs during workouts. However, CrossFit Kids has long held a keen interest in the vestibular system as its proper function is important not only to balance but to cognitive and emotional well-being. CrossFit Kids stimulates the vestibular system in every class in the following ways:

Bar roll-overs
Forward rolls
Handstand holds against the wall
Log rolls
Wall walks and walk-ups

More advanced work includes

Back flips
Free-standing handstands
Handstand push-ups
Handstand walking
Ring handstands
Ring handstand push-ups

On a final note, CrossFit Kids’ focus on proper nutrition will help blunt the impact  of childhood obesity on not just balance but so many other things critical to a child’s mental and physical well-being.

Coordination is the ability to execute complex interlimb tasks as a result of mastering the multiple degrees of freedom related to movements. As with accuracy, agility, and balance there is a large neurological component to coordination, which like those other skills can be improved with practice. Athletic kids are often seen as having “good coordination,” which might even be looked at as shorthand for saying they possess good balance, accuracy, and agility, as these four skills are interrelated.

Because coordination is required in the most basic of everyday things that people do, CrossFit Kids addresses it with nearly every exercise that shows up in class. Here are just a few:

Basic dot drill
Box jumps
Handstand walking
Monkey bars
Olympic weightlifting
Speed ladder
Wall ball shots

Cardiovascular and respiratory endurance refers to the ability of the heart, blood vessels, and lungs to take in and deliver oxygen to working tissues and muscles and to the ability of those tissues and muscles to use that oxygen in a sustained manner. This trainable skill also depends on the efficient function of the three metabolic pathways—the phosphagen, glycolytic, and oxidative pathways. Although we can directly impact our cardiovascular and respiratory endurance by engaging in aerobic activities such as long-distance running, biking, and swimming, anaerobic activities such as sprint intervals, Olympic weightlifting, and powerlifting have been shown to have a beneficial impact on cardiovascular and respiratory fitness.

CrossFit Kids trains cardiovascular and respiratory endurance nearly every class via workouts requiring constant movement through couplets, triplets, and other sequences of movements performed in relatively short time domains. Bear in mind that the intensity of these workouts is relative for children and typically increases as they mature and are, at any rate, dependent on each child’s ability to perform the movements safely as determined by the CrossFit Kids trainer.

Simply put, flexibility can be considered the ability to elongate muscles; it can also be considered a measure of the range of motion at a joint. This skill might also be looked at as the ability to achieve positions required to perform an activity. Some suggest that without this ability, we are unable to fully express our athleticism, but it is not a—ahem—stretch to say that our daily activities can be hampered as well.

CrossFit Kids thinks in terms of the broader concept of mobility, which involves muscles, connective tissues, and joints and the degree of freedom of movement these elements allow. Good mobility has implications for not only sports performance but more importantly injury prevention. CrossFit Kids starts directly addressing flexibility/mobility when children enter the preteen class and it becomes a central part of programming in the teen class as well as in teen strength training.  A variety of dynamic and static stretching, including proprioceptive neuromuscular facilitation ( PNF), and forms of myofascial release are prescribed.

Power, along with speed, is an adaptation derived from training and practice. Mathematically, power can be expressed as

Power = Force x Distance/Time

Power, then, is the “time rate of doing work,” where work is force exerted on an object and the distance that object moves. That object might be an athlete’s own body. Really, we are talking about our ability to perform work in minimal possible time.

As with strength, CrossFit Kids uses developmentally appropriate methods to build power in children, drawing on, among other areas, gymnastics, plyometrics, and Olympic weightlifting. For example, children with the strength to do strict pull-ups can be taught a gymnastics kip, allowing them to do more pull-ups in less time. That means more work is done, which means more power produced.

Some ballistic and explosive exercises for developing power include the following:

Box jump
Broad jump
Kettlebell swing
Kipping pull-up
Power clean
Power snatch
Push Press
Wall ball shots

It is important to keep in mind that strength is the basis of power and that exercises that develop strength will also develop power alongside ballistic and explosive movements.

Speed is one of two general skills, along with power, that develops as a result of practice and training. Speed can be considered as the time it takes to cover a fixed distance. It might also be looked at as the ability to achieve a high velocity through a range of motion.

In terms of functional movement, speed is an expression of strength, which we understand to be the application of force. This force can be characterized as the expression of both impulse—a change in momentum resulting from a force—and power.

CrossFit Kids addresses speed in a manner similar to its approach to power. That is, through explosive and ballistic movements including the following:

Box jump
Broad jump
Kettlebell swing
Power clean
Power snatch
Push Press

CrossFit Kids takes a focused view on stamina and considers local muscular endurance, which is tied to strength and how efficiently the metabolic path ways process and deliver energy. It should be noted, however, that stamina is often closely tied to cardiovascular and respiratory endurance and refers to the body’s ability to continue working under sustained high-intensity activity. This work might be more broadly characterized in terms of how efficiently the cardiovascular, respiratory, nervous, and musculoskeletal systems function while under load.

CrossFit Kids hits this trainable skill in the context of the WOD. In fact, nearly everything an athlete performs in CrossFit Kids class will address stamina in its global and local context.

  • Strength is the one skill that is actually identified in the shorthand description of CrossFit Kids: astrength-and-conditioning program. So it should come as no surprise that CrossFit Kids sees strength as a vital component of our ability to perform activities of daily living throughout the life course. Strength is the maximal force that a muscle or muscle group can generate at a specific velocity. In athletics, as in life more generally, we want this force applied productively, which means that strength must function in the presence of other physical skills. Given how highly that CrossFit Kids values strength, we provide developmentally appropriate resistance training for all age groups.

    Strictly performed body weight exercises require strength:

    Dips – bar and ring
    Handstand push-ups
    And of course CrossFit Kids trains strength with external objects such as barbells, dumbbells, kettlebells, medicine balls, and sandbags:

    Farmer’ and other weighted carries and walks
    Prowler and sled work
    Squats – back, front, and overhead
    Proficiency in many of these movements means we can explore one-sided versions of some of them as well as other exercises, which as auxiliary work, yields agility, balance, and strength gains particularly important for injury prevention:

    Box step-ups
    Bulgarian squats
    One-legged deadlifts
    One-legged hops and jumps
    Russian squats
    It is important to note that preschool-level resistance training is always done UNLOADED while good movers at the elementary level will work with extremely light loads. Preteens begin using more weight, but it is not until the teen level that the technically proficient athletes begin exploring maximal loads.

Baechle TR and Earle RW, eds. Essentials of Strength and Conditioning, 3rd ed. Champaign, Ill: Human Kinetics. 2008. https://www.amazon.com/Essentials-Strength-Training-Conditioning-3rd/dp/0736058036/ref=sr_1_1?s=books&ie=UTF8&qid=1366114837&sr=1-1&keywords=essentials+of+strength+training+and+conditioning

Balamurugan D. Effect of nine weeks resistance training program on physical fitness variables—A study.Asian Journal of Physical Education and Computer Science in Sports 7(1): 22-25, July-December 2012.https://www.ifcss.in/JournalNo.7/Asian%20Journal%207.pdf#page=26

Baye D. High intensity strength training for cardiovascular conditioning and fat loss. Drew Baye’s High Intensity Training. April 26, 1998. Available at https://baye.com/high-intensity-strength-training-for-cardiovascular-conditioning-and-fat-loss/. Accessed April 8, 2013.

Bernier JN and Perrin DH. Effect of coordination training on proprioception of the functionally unstable ankle.  Journal of Orthopaedic and Sports Physical Therapy 27: 264-275, 1998.https://libres.uncg.edu/ir/uncg/f/d_perrin_effect_1998.pdf


Bernstein NA. The Co-Ordination and Regulation of Movements. Oxford : Pergamon Press, 1967.https://books.google.com/books/about/The_co_ordination_and_regulation_of_move.html?id=kX5OAQAAIAAJ

Burton L and Brigham H. Propioceptive neuromuscular facilitation: The foundation of functional training. FMS. September 22, 2010. Available athttps://www.functionalmovement.com/articles/Screening/2010-09-22_proprioceptive_neuromuscular_facilitation_the_foundation_of_functional_training. Accessed June 8, 2013.

Cook G. Athletic Body in Balance. Champaign, Ill: Human Kinetics. 2003.https://www.amazon.com/Athletic-Body-Balance-Book-Package/dp/0736064125/ref=sr_1_1?ie=UTF8&qid=1366114752&sr=8-1&keywords=athletic+body+in+balance


Cortis C, Tessitore A, Lupo C et al. Inter-limb coordination, strength, jump, and sprint performances following a youth men’s basketball game. Journal of Strength and Conditioning Research 25(1): 135-142, January 2011. https://www.ncbi.nlm.nih.gov/pubmed/20885333

Cortis C, Tessitore A, Perroni F et al. Interlimb Coordination, strength, and power in soccer players across the lifespan. Journal of Strength and Conditioning Research 23(9): 2458-2466, December 2009.https://www.ncbi.nlm.nih.gov/pubmed/19910829

Čular D, Miletić A, and Miletić Đ. Unicycling and balance improvement. Acta Kinesiologica 4(1): 75-81, 2010. https://www.sposci.com/actakin.com/PDFS/BR0401/SVEE/04%20CL%2013%20DC.pdf


DeForche BI et al. Balance and postural skills in normal weight and overweight prepubertal boys.Pediatric Obesity 4(3): 175-182, 2009.https://onlinelibrary.wiley.com/doi/10.1080/17477160802468470/abstract


Ganfield L. Myofascial release therapy. Spine-Health. Available at https://www.spine-health.com/treatment/physical-therapy/myofascial-release-therapy. Accessed June 10, 2013.

Glazer NL et al. Sustained and shorter bouts of physical activity are related to cardiovascular health.Medicine & Science in Sports & Exercise 45(1): 109-115, January 2013.https://www.ncbi.nlm.nih.gov/pubmed/22895372

Guskiewicz KM and Perrin DH. Research and clinical applications of assessing balance. Journal of Sport Rehabilitation  5: 45-63, 1996. https://blog.aokhealth.com/wp-content/uploads/2009/12/Assessing-Balance-D_Perrin_Research_1996.pdf


Laukkanen JA et al. Cardiovascular fitness as a predictor or mortality in men. Archives of Internal Medicine 161: 825-831, 2001. https://archinte.jamanetwork.com/article.aspx?articleid=647696


Lloyd RS et al. Considerations for the development of agility during childhood and adolescence.Strength and Conditioning Journal Published ahead of print, 2013. https://journals.lww.com/nsca-scj/Abstract/publishahead/Considerations_for_the_Development_of_Agility.99660.aspx


Kinesthetic awareness & proprioception. Eat Big, Lift Big. December 15, 2011. Available athttps://www.liftbigeatbig.com/2011/12/kinesthetic-awareness-proprioception.html. Accessed June 11, 2013.


Merriam-Webster’s Collegiate Dictionary, 11th ed., s.v. “accuracy.”