light bullpen / 50-75% effort


To allow a pitcher to work off the mound at a lower intensity.  

Low-Intensity Bullpens vs. High-Intensity Bullpens

High-intensity bullpens will always serve as a Performance Day and must NEVER be thrown on back to back days, whereas low- intensity bullpens can be throw much more frequently, and commonly on back to back days.


All low intensity bullpens should be performed at the pitcher's specific mound distance and should be completed at no more than 75% intensity.  Low intensity bullpens prove to be extremely vital to the proper sequence of a pitcher's mechanics off of a slope. Because of the lower intensity, a pitcher should utilize Training Phase 4A as a way to work on the repeatability of their mechanics. The USPBL Throwing Program advocates frequent low intensity bullpens as long as the thrower is adhering to the Soreness Protocols. 

Depending on a player's Throwing ScheduleTraining Phase 4A can serve a variety of roles for the proper development of a pitcher.  Commonly, Training Phase 4A will be used to work a pitcher's ability to repeat their delivery and develop the accuracy and effectiveness of their pitches at a lower intensity level.  Scenarios for implementation include, but are not limited to:

Pre-Game Throwing Routine for Starting Pitchers

Training Phase 4A can serve as a progression for starting pitchers to follow as they prepare the arm and body before the game. The starting pitcher will follow the exact progression of phases above, but add an additional 10-15 max intensity throws to conclude their bullpen prior to the game.

Light Bullpen Between Games / Starts

Starting pitchers can use Training Phase 4A for use as a light bullpen between starts.  The number of times a starting pitcher can use Training Phase 4A within their Throwing Schedule will depend on their specific Soreness Protocols and The 48-Hour Rule

In most cases, a starting pitcher will throw one light/moderate intensity bullpen between starts.  The USPBL Throwing program allows for multiple light bullpens to be thrown between starts assuming the pitcher is abiding by proper Soreness Protocols. This can be particularly important for a pitcher who is making an adjustment in his mechanics or developing a new pitch.


In order to get to Training Phase 4A, a specific progression must be followed to allow the arm and body to warm-up appropriately. This is outlined in the table below: