I watched the PGA Golf championship this year. Like many, I am impressed with the distance the golfers can drive the ball. It seems that everyone can drive the ball over 300 yards, even the smaller players. For example, Justin Thomas is a medium size guy at 5’10” and 160 pounds but he regularly drives the ball right there with the other players. Sure, Justin has the best equipment but he has a beautiful swing, designed to transfer momentum from the ground to the club. He has a great kinetic chain. We see the kinetic chain utilized in many activities such as overhand throwing, tennis serving, extra point kicking, soccer penalty kicks, and slap shots in hockey.
The kinetic chain is the sequential transfer of kinetic energy from the ground to the hand or foot. For the right handed person this involves pushing with the left foot through the leg to the pelvis that twists to the left followed by a higher speed twist of the trunk to the shoulder, arm, forearm, and wrist. Each movement is faster than the previous transferring energy from the ground to the hand. The kinetic chain is like a whip, each part increasing in velocity until the final release. When done properly the result is like magic, a 100 mph fastball, a 60 yd field goal, but when there is a flaw in the movement, the end result is weakened, slower.
Besides performance, one attribute of the kinetic chain is that it reduces stress on each individual segment of the sequence, thereby reducing injury. Baseball is one of the most popular sports in the world and the overhead pitch in baseball is probably the best example of the chain. Injuries to baseball pitchers is the bane of the sport, often related to overuse but also to improper mechanics, a poor kinetic chain. Nolan Ryan’s overhead pitch was a marvel of the chain. It seemed that his throw was effortless yet he made his living over four decades as the greatest fastball pitcher in history, striking out more batters than anyone in history. He was rarely hurt.
The kinetic chain is natural, a movement that is developed and honed not in the laboratory but in the backyard and the playing grounds. When young children first try to throw, they naturally step forward with the same leg as their throwing arm. Correcting this does not help. As they grow, most start to step forward with the opposite foot. This is the beginning of the chain. Developing the chain is one of the most important skills for any youngster involved in sport. We use the chain in many sports but if you cannot throw, you cannot hit a tennis serve, spike a volleyball, or play badminton.
Children develop the chain by participation in activities that require the chain. Obviously, throwing is of utmost importance, but how does a child learn to throw? Sport skills are only learned by doing, not watching. Get outside. Children naturally develop the chain by participation. Playing catch with your child helps but a few days of catch is not enough. One problem with playing catch is that the emphasis is often made on accuracy. When children throw for accuracy they do not develop the chain. Only by trying to throw for velocity is the chain developed. Hanging a tire from a tree may seem like a good idea, but trying to throw through the hole will cause the child to slow down, just the opposite of the chain. Velocity first is one key for all sports that use the chain.
Provide situations where accuracy is not required. Stand next to a lake or river and throw rocks; you can’t miss. Throw tennis balls against a backboard. Not only can you throw for velocity, you learn to catch as well. Throw balls from the outfield, letting it bounce. Above all, you need to be patient. Accuracy comes later. I am against using radar guns to measure velocity. You want children to throw freely, but measuring velocity early on disrupts. Allow the child to develop naturally.
Kinetic chain activities are whole body activities. This means strengthening the whole body from the legs, to the core, to the shoulder, and to the arm. This means maintaining the flexibility of the whole body. Avoid injury by playing seasonally. Early specialization does not work, often leading to injury and burnout. Don’t overuse. Be wary of so-called throwing experts.
Jim Johnson is a retired professor of exercise and sport science after teaching 52 years at Smith College and Washington University in St. Louis. He comments about sport, exercise, and sports medicine. He can be reached at jjohnson@smith.edu.