There is a tendency within the less logical physical conditioning community to select heavy medicine balls for various exercise assignments.
They do this because they equate weight with strength and assume that if a 6 lb ball is good for an assignment then 18 lbs must be 3 times more
effective. We must be aware that the primary benefit of medicine ball training is not strength proper but multijoint power through the summation of ballistic body segment forces of which strength is only one of the general physical skill components. Agility, coordination, speed, dynamic flexibility, balance and accuracy are also in play when measuring the total horsepower generated in any ballistic movement. We must always be aware of this basic kinesiology principle. MAXIMUM HORSEPOWER IS GENERATED AT 1/3 TORQUE. The principle applies to singular or multiple joint movements. This principle tells us that more is not always better when the training intent is POWER. We must also be aware that the OVERLOAD
PRINCIPLE OF EXERCISE can be met with either velocity of movement or weight or a combination of the two. All three overload mechanisms can be used to summon the desired number of motor units to perform the task with each mechanism having a different intent. With medicine ball, velocity or combination of velocity and weight should always be the mechanism of choice. This is the same mechanism of choice of the Olympic lifts and their variations. Horsepower generation through the bilateral summation of forces from ankle, knee, hip, posterior spine, shoulder and elbow through O lifting is unmatched as all of the joints are working ballistically in the proper sequence and direction at precisely the proper time. Medicine ball assignments if the weight overload is not too great can be horsepower training using many more combinations of force summation. When this is the intent, lighter balls should always be used. Where strength proper through less complicated movement is the only intent, heavier
balls can be used as a strength-training implement but never will it be as effective as other.

More Discussion

Coaches trainers and physical educators are often time baffled when an individuals performance of a physical task has no or little relationship with the measured strength levels of the body segments involved in the task. Failing to recognize the reason for the discrepancy they continue
along the same training path of more strength proper development. Though psychological and other complicated physical factors may partially account for the performance short fall the cause is primarily the insufficient generation of power through the summation of the forces involved.
The ability of an individual to capture the full sum of potential power of all the joints involved in the proper sequence and direction at precisely the proper time is related to their command of the other general physical skills involved. The more ways an individual can display these general
physical skills the easier it becomes to transfer them to new tasks. Good summation explains why a welter weight boxer who can bench press only his body weight can deliver a knock-out punch or why a pitcher who can do only 5 bodyweight pull-ups can throw a 100 mph fast ball.
Poor summation explains why a 450 lb bench presser can throw the shot putt only 45 feet. When these discrepancies are discovered, the first 2 examples should go into the weight room and begin a strength training cycle that includes medicine ball assignments to incorporate the new
strength as it develops. The shot putter on the other hand should terminate his strength training immediately and begin incorporating multi-joint high velocity medicine ball assignments. The weight of the ball needs to be heavy enough to visibly slow the intended motion but not so
heavy that it distorts it or diminishes the prescribed volume of repetition

More drill- less instruction

A good coach knows that a specific athletic skill is learned (discovered) and not taught. The coach's time and attention is spent on directing sufficient drill and repetition activity that allows the athlete to discover the aspects of the skill experientially. They may from time to
time point out glaring errors in movement but for all practical purposes the fine balance, agility, reflex transition points and coordination is discovered and incorporated through directed repetitive activity. The right light weight medicine ball is a perfect tool for drill construction.
Light and the drills can be practice and training. Heavy and it becomes strength proper training only.

Weight - Velocity - Volume

To clarify the relationship between weight, volume and velocity of work go to Click on the Dynamax video of trainer to trainee doing the 5 stroke big wheel, a series of high velocity core shoulder girdle movements where the movement changes every 5 strokes.
The medley of movements is designed to work the anterior trunk and shoulder girdle at all angles at high velocity and quick transition time with movement change. The weight being used in the video is a 6 lb ball. The 4 or 6 lb ball is ideal. A larger stronger trainee will move the ball at a
higher velocity, benefiting the same through the velocity/weight overload mechanism as the less strong trainee. A heavy ball, 12 to 20 lb would diminish velocity, volume and distort the intended motions. The super wheel can be done in 3, 5, or 8 strokes depending on the dosage the
trainee can handle without distorting.


When we say distortion we are talking about the structure, rhythm, direction and intensity of the portions or the whole of a movement or repetitive cycles of movement. The KINEMATICS. To a large extent kinematics is as individual as fingerprints but within fundamental parameters. When weight overload is added to a cycle of repeated movements, the last cycle should look substantially the same as the first.


With any assignment utilizing the medicine ball as weight and joint and stroke velocity as the mechanism of overload, the weight selected should be light enough so that the assigned stroke volume can be completed at the highest stroke velocity without substantially altering the kinematics of the assigned motion. If you error on the side of light weight, velocity increase will insure the practice- training effect. To error on the side of heavy weight, you fail in velocity, volume and integrity of the assigned movement leaving you with only a strength training set.