Longboard Dynamics: Carving vs Surfskating vs Long Distance Pumping (LDP)

The Physics of Flow: How Longboard Skaters Generate Thrust

Revised May 15, 2025

Longboard skaters harness the laws of physics to generate flow. While riders might not always know the exact principles at play, they can feel those equations pushing and pulling them forward as they carve through S-curves.

From an engineering perspective, this is a dynamics problem best explained with force vector diagrams. Here, we simplify the dynamics problem into a statics (stationary) "snapshot" at just the right part of the riders path, to illustrate the mechanism.  The engineers may roll their eyes at this, but it's not a terrible assumption and quasi-static illustrations are a lot easier for most people to get their heads around.  A deep understanding of rider technique combined with longboard truck setup leads to a simple explanation.

Featured in this blog are the interesting attributes of Hamboards HST Truck system providing exemplary illustrations.  Any carving truck system can be set up to for forward force creation without foot pushing, so long as the angles provide for the preferred riding style.  

Surfskating is mentioned in this blog, but HST Trucks are not surfskate trucks, they are Carving trucks.  The authors distinguish between Back Foot Carving and Surfskating set-up's in the terminology section.  

Bottom Line Up Front

Through successive S-turns, the front of the board can "pull" and the rear can "push" the rider forward simultaneously on any kind of longboard. Minimizing drag while optimizing thrust depends heavily on the longboard's steering geometry and the rider's technique, all of which are explained below.

Key Terminology

Longboards are specialized skateboards that the rider can turn by leaning, without the need to lift the front wheels off the ground, like with regular skateboards. They are considered counter phase turning mechanisms. They don't need to be peculiarly "long" to be longboards, but they can be. For example, the Hamboards® Classic longboard towers at 74 inches while the Hamboards Twisted Fin longboard is 26 inches. What they share in longboard DNA is the Hamboards HST® Truck System.

We categorize longboards into three "center of turning" types:

• Centered
• Back Foot
• Rear Axle

We also refer to three primary riding styles:

• Carving (Centered and Backfoot)
• Surfskating
• Pumping

By analyzing force vector diagrams, we can explain how riders create forward force without foot pushing. Forward force vectors are known as thrust, while backward force vectors are called drag. Understanding why the center of turning is critical for different riding styles is essential.

With proper technique, skilled riders can generate forward thrust (pump) on any type of longboard, though certain setups work better for different riding styles.

Longboard Types by Center of Turning

• Centered Longboards have equal turning in the front and rear, with the center of turning located at the center of the wheelbase.
• Back Foot Longboards have more turn in the front than the rear, with the center of turning located near the rear foot.
• Rear Axle Longboards have all the turning in the front, while the center of turning is located at the rear axle.

 

Riding Styles Explained

Carving, a term borrowed from surfing, is the original means of propulsion, without foot pushing, in longboarding.

Centered Carving

Mechanics: Equal front/rear turning with trucks rotating about an angled pivot that coordinates lean and turn together.  Center of turning at the midpoint.  During S-turns, the front and rear axles follow identical paths
Stability: Most stable of the four styles, excellent for hills and moderate to high speeds
Technique: Rider stands centered over the board making flowing S-turns
Feel: Snowboard-like carving sensation with smooth, predictable turns

World Champion Surfer Cory Lopez demonstrates longboard carving on a Hamboards Twisted Fin with HST 40/40 trucks, creating forward thrust powerful enough to climb uphill. Notice how his front hand stays over his front hip, allowing him to twist his body core and create lateral force with both feet through powerful S-curves. Cory generates roughly equal forward thrust vectors with both front and rear wheels—an aerobic method requiring high skill and fitness.

Cory powers his rear foot opposite to his front foot, causing him to feel front pull and rear push equally and simultaneously. He uses this same technique on his shortboard surfboard to generate thrust and gain speed on a wave. 

Here's a magical full video with Cory Lopez and his kids.  

Back Foot Carving

Mechanics: Trucks rotate about one angled pivot which coordinates lean and turn together; center of turning under the back foot.  During S-turns, the front axel travels a wider path than rear axle.  
Stability: Gains stability with speed like actual surfing; suitable for modest hills and distance riding
Technique: Requires keeping center of gravity perpendicular to the angled deck; cannot be "cheated" with arm movements
Feel: Authentic longboard surfing sensation with powerful flow, speed and grace; creates a connected flow state between rider and board

Hunter Joslin, the iconic surfer and founder of IndoBoard, demonstrates surfskating on a Hamboards Burst with HST 40/20 trucks, accelerating along a flat surface. His front hand stays over his front knee, enabling him to twist his body core and create lateral force with both feet through powerful S-curves—a technique requiring substantial power, skill, and fitness.

Hunter primarily steers with his front foot while powerfully driving his rear foot in the opposite direction at precisely the right moment. Though he generates a much larger front force vector (pull) by moving his front foot, Hunter pushes hard with his back foot too, resulting in a combination of front pull and rear push.

Here's an amazing full conversation with Hunter Joslin teaching us all about balance and flow.  

Pumping (Long Distance Pumping or LDP)

Mechanics: All turning from the front with center of turning at the rear axle; front axle travels wider path while rear travels minimal path
Stability: Moderate stability focused on maximizing propulsion efficiency
Technique: Rider stands over front of deck making rapid sequential S-turns
Feel: Specialized motion optimized for distance travel with maximum forward force generation

World-class Long Distance Pumping athlete Landy Cook demonstrates longboard pumping on a prototype 60-inch carbon fiber reinforced, foam core board with HST 55/ZR0 trucks, efficiently accelerating on a flat surface. Both his feet are positioned near the front truck, allowing him to swing his lower body like a pendulum and drive the front wheels in the turning-direction through powerful S-curves. Landy creates only front thrust (pull) with zero rear thrust (push)—a powerful, highly efficient technique that can be mastered with good rhythm.

Landy feels only front pull, making this very efficient. Pumping has become an essential skill for endurance distance skating.

Surfskating 

Mechanics: A dual pivot system, commonly swivel front trucks for turning with separate leaning mechanism; which creates extreme front turning angles; center of turning under the back foot.  During S-turns, the front axel travels much further than the rear axel.   
Stability: Decreases with higher speed (unlike actual surfing); and somewhat unsafe on hills
Technique: Can turn without significant leaning; easier for beginners to generate initial movement but harder to master
Feel: Mimics aggressive short board surfing maneuvers rather than longboard surfing; prioritizes radical turning over flow.  

Hamboards are NOT surfskates.  HST Trucks have one pivot axis that coordinates lean and turn and can be used for Centered Carving, Back Foot Carving and Pumping.  It features interchangeable components, allowing any deck to be configured for different riding styles. Four different kingpin pivot angles (0°, 20°, 40°, and 55°) can be combined to match any of these riding styles.

The Mechanics of Forward Thrust

The illustrations show the precise moment when the rider pushes the front in the direction of the front wheels' path and pushes the rear in the direction of the rear wheels' path to create forward thrust. It's a kind of twisting or "scissoring" motion. Forward thrust comes in pulses, propelling the board forward at just the right point during sequential S-curves with synchronization and rhythm.

When riding through S-curves, there is one force vector for both the front and rear legs (feet). When the rider pushes in opposite directions with the front and rear feet, they create forward thrust: pull from the front and push from the rear.

Technique Adjustments by Riding Style

For Rear Foot Carving and Surfskating: The big idea here is to push the front truck, in the direction it's heading at the edges of S Curves.  Riders should push much harder on their rear foot because they have less "rear turn" to work with, as the center of turning is already under the rear foot. And the consequence of this hard rear foot push is to allow the equal and opposite reaction from the front foot.  This could be why many surfskating coaches encourage riders to push harder with their rear foot.

For Centered Carving: The big idea here is to push the front truck in the direction it's heading while simultaneously pushing the rear truck in the direction it is heading.  Riders should push equally on front and rear feet in opposite directions. 

The illustration above shows how any longboard with adequate steering can be ridden to create forward thrust.  

For carving (diagram above), the rider is advised to push equally on front and rear feet, in opposite directions. If they push with both feet in the same direction the rear thrust vector is "canceled out" by a front drag vector.  But when the rider pushes in the opposite direction with their front foot, they get two forward thrust vectors.  

How much forward thrust can a rider create? 

With a bunch of assumptions we can calculate a guess.  

Assuming that Ff + Fr = 0, Sf + Ff = 0 and Sr + Fr =0,

then Tf + Tr = Forward Thrust

Tf = Rf sin 𝜃f, where Rf = Ff tan𝜃f, so Tf = Ff * sin 𝜃f * tan𝜃f

Tr = Rr sin 𝜃r, where Rr = Fr tan 𝜃r, so Tr = Fr * sin 𝜃r * tan𝜃r

So, in the 55/20 example illustrated above, If a rider pushes 10 lbf with both feet in opposite directions, they can create up to 3.7 lbf forward thrust.  The rider is pulled forward by 3.3 lbf front thrust and pushed forward by a much smaller 0.4 lbf rear thrust.  In this 55/20 configuration it’s ~ 90% pull and 10% push.  

NOTE: The more front turn your board has, the stronger these relationships become, so swivel type surfskates are highly efficient for creating forward thrust.  

The Hamboards HST Truck System

When Peter Hamborg and his kids invited me to help with Hamboards, they wanted a big skateboard that feels just like surfing. It took time to understand what they wanted, but we eventually developed the HST truck system that delivers the feel they were looking for.

Unlike most "surf skate trucks" that swivel or have two axes in the front, the HST truck system leans and turns in a coordinated manner, but does not swivel. Riders can't "cheat" the HST Trucks—they must synchronize their entire body with the board. Riders need balance, rhythm, and coordination of their center of gravity with the board to achieve flow.

As Hunter Joslin notes, "There's no better surf training in the world than a good skateboard." Mastering the Hamboards Burst with HST 40/20 or 55/20 trucks, combined with balance training on Indoboard, will advance skills and create muscle memory that benefits riders when they surf, snowboard, or slalom ski.

Referring to the image above, the HST system can be applied to any longboard for many different riding styles.  Since these are all counter phase steering, the turning radius is defined by Pythagorean theorem.  If the rider wants a shorter turning radius, they'll need to choose a set-up that works best for themselves.  Many team riders have settled on a "goldilocks" combination of a turning radius ~ equal to the wheelbase length with a back foot configuration and ~ 25° of board lean.  The HST 55/20 (back foot) and the HST 40/40 (centered) are favorite set-ups.  The former is relatively new but the latter has been the long time standard for Hamboards®.  

Conclusions

With proper technique, skilled riders can create forward thrust (pump) with any type of longboard skateboard that has a high degree of turning. It comes down to twisting or swinging the lower body at just the right moment. The longboard's center of turning location is critical, and the riding style needs to match the setup.

Centered Longboards can be pumped to maximize forward thrust, pulling from the front and pushing from the rear, though this requires significant energy and skill. Most traditional Hamboards are Centered Longboards.

Back Foot Longboards offer a comfortable combination of carving and pumping with proper technique. Most surfskates are variations of Back Foot Longboards and are generally easier to learn to pump. All Hamboards decks can be converted to Back Foot Longboards.

Rear Axle Longboards are the most efficient for optimizing forward thrust through pumping. Optimizing the front turning angle and using a longer deck yield the best forward thrust vectors, though the turning diameter can be quite large. All Hamboards decks can be converted to Rear Axle Longboards.

Hamboards HST Trucks are interchangeable and modular. They can be set up for Centered, Back Foot, and Rear Axle longboards with minimal effort, allowing riders to adapt their boards to their preferred riding style.  

NOTE: This is not an engineering or design report.  It's illustrations are basic and the copy is intended for readability.  The hope is to get the main points across in a relatively simple and concise manner.  For more rigorous reviews of skateboard technology and culture, please refer to this website which is a carefully curated reference for anyone who seeks a deeper understanding.  

Author: Don Sandusky, PhD - Hamboards and SUPSkate
Contributors:
Steve Ng - Hamboards and SUPSkate
Abraham Paskowitz - Hamboards and "first family of surfing"
Mark French, PhD - Purdue University
Scott Imbrie - Founder Original Longboards
Leonard Leffler - Champion Ultraskate Athlete and Skate Poling Pioneer
Andy Andras - World Record LDP Athlete and owner of Miami Ultraskate
Cory Lopez - World Champion Professional Surfer
Hunter Joslin - Iconic Champion Surfer and Owner of Indoboard
Landy Cook - World Class Skate Poling Athlete
Bob Foster - Philadelphia Skating Legend, PA
Earl Stout - Philadelphia Longboard Legend, PA
Bill Fitzhugh - Satorial Distribution, UK
Josh King - Team Rider - Mid Atlantic USA
Mark Harris - Team Rider - Florida
Tarzan - Team Rider - Huntington Beach CA
Chris Slaughter - Longboard Aficionado - Florida
Connor Baxter - Fastest stand up paddler in the world, Maui HI
Leighton Nakamoto - PE Teacher, Maui, HI
Auguste Elder - Artist/Teacher, Forrest Hills, NY
... and many more ...