Fast Swing Rate

Fast swing rate is the percentage of a hitter's swings that meet or exceed the MLB threshold for "fast" bat speed, currently defined using the median MLB bat speed as the cutoff. It measures how often a hitter is swinging at or near maximum effort versus taking a more controlled or shortened swing.

How It Is Measured

MLB's Statcast system measures bat speed on every swing. Fast swing rate counts the percentage of those swings that are above the "fast" threshold. The threshold is set at the MLB median bat speed so that roughly half of all major league swings qualify as "fast" for the average player.

A hitter's fast swing rate can vary significantly based on:

• Count (hitters often swing harder in favorable counts)
• Pitch type (fastballs tend to generate more effort than off-speed)
• Pitch location (pitches in the hitter's zone tend to produce more committed swings)

What It Tells You

Fast swing rate, on its own, is not a quality metric. Swinging hard at a bad pitch is not valuable. But combined with other metrics, it tells a useful story:

• High fast swing rate + high blast rate = a hitter who swings hard and makes good contact when they do. This is the ideal profile.
• High fast swing rate + low squared-up rate = a hitter who goes after it but doesn't find the barrel consistently.
• Low fast swing rate + high squared-up rate = a contact hitter who rarely lets it all the way go. May have untapped power potential.

Coaching Application

At the youth level, coaches can observe the same concept without Statcast data. Does the hitter commit fully when they decide to swing? Or are they "arms-only" swings, holding back, or half-committed? A hitter who regularly takes half-swings is leaving power on the table. Teaching them to either take the pitch entirely or commit fully is one of the most practical applications of what fast swing rate measures.