Blast Connect | Metrics

What is Body Rotation?

In a baseball swing, the resultant Bat Speed is a combination of both body and bat rotations. Blast uses an advanced algorithm model that allows us to measure the contributions of both body and bat rotations from the sensor attached to the bat. This allows the ability to analyze connection in the swing by comparing the contributions of both body and bat rotations once the hitter has committed to the swing by unhinging their wrists. The Body Rotation is expressed as the ratio of Body Rotation to total rotation during this time.

Why is Body Rotation important?

The Body Rotation ratio provides an objective swing metric that provides advanced insights into the hitter's rotational movement patterns. An efficient swing has connection between the body and bat rotational movement patterns. The ability to assess disconnection in the swing is very important from a player development and training standpoint. Disconnection occurs when there is either too much Body Rotation or too much bat rotation. A swing that has the appropriate relative contributions of body and bat rotations is an efficient and Powerful swing that maintains proper sequencing. An efficient baseball swing is one in which the body creates the initial movements, which is then transferred to the arms and out to the bat, thereby maximizing Bat Speed through this proximal-to-distal kinematic sequencing movement pattern.

What should Body Rotation be?

Most players should have an average Body Rotation ratio of 45%, with a typical dynamic range of 40%-50%. A value that is consistently outside this range typically indicates a deficiency in the hitter's kinematic sequencing pattern. Variation in Body Rotation ratio from the efficient average of 45% and outside of the typical dynamic range of 40%-50% can result from extreme pitch locations. Pitch locations such as low and inside or high and outside require more adjustability in the swing. The more disconnection that is found in the hitter's swing between the body and bat rotational patterns, the more variation that will be observed in the Body Rotation ratio.

How do I improve Body Rotation?

All players should understand what their typical Body Rotation ratio is for a middle-middle (mid-height and middle of plate) pitch. The best way to accomplish this is with tee work with the tee setup in the middle of the plate at an approximate height near the hitter's belt line. In this use case, the hitter should focus on achieving an average efficient Body Rotation ratio of 45%, with consistent Body Rotation ratios between 40%-50%. Once the hitter is able to achieve consistency with this constrained task, they should then focus on adjustability in the swing by hitting different tee locations, such as high and outside and low and inside. Monitoring of the Body Rotation ratio for these tasks will demonstrate how well they maintain connection in their swing for these different pitch locations. Using the Body Rotation ratio metric in batting cage practice and live pitch practice is a further extension of training which demonstrates the level of consistency in the hitter's rotational movement patterns on a pitch to pitch basis. If the hitter is consistently achieving Body Rotation ratios that are < 40%, this typically indicates that they have a disconnection in their swing as there is not enough Body Rotation and they are too hand dependent as they are unhinging their wrists and committing to the swing too early. Connection drills should be used to achieve a more effective Body Rotation ratio. If the hitter is consistently achieving Body Rotation ratios that are > 50%, this typically indicates that they have a disconnection in their swing as there is not enough bat rotation during the latter half of the swing as they are not fully unhinging their wrists into impact. This indicates that they are not maintaining their wrist hinge angle late in the swing. Hinge angle drills that maintain the angle between the bat and forearm should be used to achieve a more effective Body Rotation ratio.