The Science behind the Swing

Although this page is developed with the golf swing in mind, the same exact principles and philosophies apply to the baseball swing.

At Fourteen23 Fitness, our mission isn’t just to tell you what to do — we want to show you why it matters. This isn’t a generic list of drills or a one-size-fits-all training plan. This is the science behind the swing, broken down with transparency, intent, and real-world application. Every recommendation we make is rooted in biomechanics, physiology, and proven performance principles — so you’re not just following instructions, you’re understanding the logic behind them. We believe athletes perform better when they know the why behind their work—and this page is built to give you exactly that.

Here, we’ll dissect the origins of rotational power and movement efficiency. You’ll learn where energy is generated in the swing, how it builds through the kinetic chain, and where it can leak or amplify. We highlight the key physical checkpoints that matter most — lower body force production, rotational sequencing, spinal leverage, and fast-twitch muscle recruitment — and explain how each contributes to speed and power. Most importantly, we’ll show you how to target these areas directly in your training so you’re not just swinging harder, you’re swinging smarter.

Kinematic Sequence

The golf swing is a dynamic, full-body movement that relies on the efficient transfer of energy from the ground up. This energy travels through the kinetic chain—from the feet and legs, into the hips, through the torso and shoulders, down the arms, and finally into the club. To maximize clubhead speed and strike efficiency, each segment of the body must rotate in a precise sequence. This concept is called the kinematic sequence: the pelvis leads the downswing, followed by the torso, then the lead arm, and finally the club. When timed correctly, this creates a whip-like effect that allows even average-sized golfers to generate elite-level speed without forcing it.

  • Power starts from the ground, and so does the proper kinematic sequence.
  • Following the rotation of the hips, the torso builds on this rotation and adds to it.
    • The absolute angular velocity of the torso is the absolute angular velocity of the hips + the angular velocity of the torso relative to the hips.
  • After the torso has began rotating, the lead arm begins and adds onto the angular velocity of the torso.
    • The absolute angular velocity of the lead arm is the absolute angular velocity of the torso + the angular velocity of the lead arm relative to the torso.
  • The last piece of the kinetic chain, the bat/club fires last and adds on to the angular velocity of the lead arm.
    • The absolute angular velocity of the bat/club is the absolute angular velocity of the lead arm + the angular velocity of the bat/club relative to the lead arm.

In rotational sports, absolute velocity is the total speed of a segment relative to the ground—while relative velocity is how fast that segment is moving compared to the part below it. Each joint or segment in the kinetic chain builds on the speed generated by the one before it. The faster and more efficiently a lower segment rotates, the more potential the next segment has to generate even greater absolute velocity. That’s why sequencing matters: power isn’t just about how fast one part moves, but how well that speed stacks through the chain.

Ground Reaction Forces

Ground reaction forces (GRFs) are the engine behind rotational power in the golf swing. Every efficient and powerful swing starts from the ground up. As you coil into the backswing, initiate the downswing, and rotate through impact, your body is constantly pushing into the ground—and the ground is pushing back. This exchange of force is what allows you to stabilize, create torque, and accelerate the club with speed and control. GRFs come in three key directions—horizontal, torque (rotational), and vertical—and mastering their sequence is essential for generating effortless power.

Horizontal ground forces initiate during the backswing, especially in the loading of the trail leg. As the golfer shifts pressure into the trail foot and coils the hips, a subtle horizontal push into the ground helps establish a stable base. This bracing action creates resistance and allows the upper body to rotate over a loaded lower body, building potential energy in the backswing. Without proper horizontal loading, the backswing can become disconnected, rushed, or overly lateral.

Torque (rotational) ground forces occur during the transition—when the lower body begins to rotate before the upper body unwinds. Here, the lead and trail feet apply shearing forces in opposite directions, creating rotational tension through the pelvis. This separation between hips and shoulders is what creates coil and stretch through the core, fueling a powerful and properly sequenced downswing. Torque forces are a major contributor to clubhead speed without adding effort.

Vertical ground forces come into play as the golfer moves into and through impact. As pressure shifts to the lead foot, the body begins to push upward into the ground. This upward force helps clear the lead side, stabilize the swing arc, and accelerate the clubhead through the ball with maximum efficiency. Vertical force is often the missing link in players who have good mechanics but lack explosiveness—it’s the final expression of everything stored during the swing.

Muscle Fiber Types & Their Role

Slow-Twitch (Type I) Muscle Fibers

The Foundation of Stability, Control & Endurance.

Slow-twitch fibers are the workhorses of control and consistency. They contract at a slower rate than fast-twitch fibers but are highly resistant to fatigue, making them essential for movements that require postural stability, fine motor control, and sustained output over time. In rotational sports like baseball and golf, they help anchor your body during load and transition phases, providing the stable platform needed for efficient sequencing.

Whether you're holding your posture through the stride phase of a swing or maintaining form during a long round or game, your Type I fibers are doing the behind-the-scenes work—quietly keeping your body aligned, balanced, and ready to transfer energy. These fibers are critical for making your explosive movements repeatable, consistent, and clean.

Training for Slow-Twitch Development:

  • Tempo-Based Strength Work – Slower eccentrics (3–5 seconds down) and controlled concentrics build control under load.
  • Isometric Holds – Pauses at key positions (like the bottom of a split squat or RDL) strengthen positional endurance.
  • Higher-Rep, Submaximal Controlled Sets – Loads around 50–70% of max for 10–20 reps target muscular endurance and control.

Benefits for Rotational Athletes:

  • Enhances balance and posture under fatigue
  • Improves control during load-stride-sequence phases
  • Builds the platform for efficient energy transfer
  • Supports endurance through high-volume swings or extended play

Fast-Twitch (Type II) Muscle Fibers

The Engine of Explosive Speed & Rotational Power

Fast-twitch fibers are your body’s power generators. These fibers contract rapidly and with force, allowing you to accelerate the bat or club, rotate explosively through the hips and torso, and generate elite-level velocity at impact. They are essential for single, high-intensity movements—like a swing, sprint, or throw—and are the key to maximizing your rate of force development (RFD).

Fast-twitch development isn’t just about going heavy—it’s about moving with intent and explosiveness. These fibers respond best to high neural demand, meaning your nervous system must be primed to fire them fast and efficiently. That’s why fast-twitch training often looks like a mix of maximal strength work and explosive plyometrics or med ball throws.


Training for Fast-Twitch Development:

  • Heavy Compound Lifts – Low-rep deadlifts, squats, and presses (85–95% 1RM) increase overall force potential.
  • Dynamic Effort Lifts <– Lighter loads moved with speed teach the nervous system to recruit fast-twitch units quickly./li>
  • Explosive Movements – Jumps, sprints, slams, and rotational throws develop speed, power, and sequencing under velocity.

Benefits for Rotational Athletes:

  • Drives bat speed or clubhead velocity through fast rotation
  • Improves explosiveness out of the load and through impact
  • Enhances ability to create force in short time windows (critical in reactive sports)
  • Sharpens neuromuscular coordination and intent

Not Just Strong, but Mobile


Raw strength isn’t what drives clubhead speed—mobility is what allows your body to create and express that strength through efficient movement. In golf, the swing is a complex, full-body sequence of motion, and every joint in that chain needs to move well for power to be produced and transferred effectively. Without functional mobility, you’re forced into compensations that limit distance, disrupt sequencing, and increase injury risk.

Critical joints like the ankles, hips, thoracic spine, and shoulders play specific roles in setting up and executing the swing. For example, the trail hip must internally rotate during the backswing to allow a full coil, while the lead hip must externally rotate to clear through impact. The thoracic spine must rotate independently of the pelvis to create separation, and the wrists must hinge and release with precision. When these joints are restricted, you lose the ability to load effectively and rotate cleanly, reducing both speed and control.

Mobility isn’t just about being loose—it’s about owning usable, strong ranges of motion. You need to be able to rotate, hinge, and separate under tension and with control. Golfers with true mobility can stay in posture longer, maintain a stable base, and generate clubhead speed without relying on excessive effort or forcing motion from the wrong places.

Strength training helps build the engine, but mobility is what lets that engine perform at full capacity. If you want to maximize power, consistency, and longevity in your swing, mobility needs to be a cornerstone of your training. When your joints move the way they’re supposed to, your swing becomes more powerful, more fluid, and more repeatable.

Loading the Back Leg

Proper ankle & hip mobility required to effectively load the back leg without swaying.

Backswing & Transition

To get into an effective transition position, sufficient mobility is required in the ankles, hips, torso, shoulders, elbows, wrist, neck, etc

Impact

Even at impact, the proper mobility is required to get into position including but not limted to in the shoulders, elbows, hips, ankles, etc.

At F23 Torque, We Train for P.E.A.K Performance