Given that there seems to be sufficient interest in the fast low bouncing low net clearance version of my first serve, I am going ahead and starting a thread to discuss it. I use it occasionally say 1 in 15 times at the beginning of a playing session and use it much more frequently (say 1 in 4 times) towards the end of a 2-3 hour playing session when the explosive leg drive needed for the for traditional serves is harder to come by. I am able to execute it with about 50% success rate in match play. I think the actual rate is likely slightly higher because opponents usually give themselves the benefit of the doubt on line calls and serve targets an area close to the service line. I can serve in the low teens with this motion. Can crank it up to 120s at the cost of accuracy (mostly hitting long, directional accuracy is still present). I think it would be a good option as a change up for a taller player who has played a pitching sport before and is in need of a fast easy action resting serve that does not require the more elaborate energy sapping service motion of a traditional serve. Or as a cranked up change up low bouncing slider if used as an attacking option. Here are three videos that show the serve from all three angles (from behind, from the right side and the left side). Now I will explain how the surprisingly large amount of racquet head speed is generated using this serve. Below are the three important frames that describe the loading phase. The first is the power position before the start of the trunk rotation, second is the maximal elbow raise as the cartwheel occurs, the third is the maximum shoulder raise position right before the start of butt cap drive towards the ball and extension of the the forearm. I used to be genuine fast bowler in cricket in my youth capable generating over 85 mph bowling speeds. In cricket pace bowling much of the speed is developed by planting a straight extended front foot at the bowling crease and transferring the resulting ground force impulse to the ball. A larger horizontal (braking) impulse is associated with a faster ball speed and a larger plant angle of the front leg (measured from the vertical) at front foot contact is associated with a larger horizontal impulse. One of the key determinants of ball speed in cricket (and baseball) is the horizontal impulse generated at the ground over the period from front foot contact until ball release. A fast bowler with a full run up can generate peaks of 15 times their body weight of ground impulse at ball release. Baseball players generate over 2 times body weight of ground impulse at release. The ground force impulse in cricket bowling is powerful enough to explode shoes like in this incident https://vine.co/v/O9m2qqKA1aY I had a few pairs explode on me like that in my youth. As you can see in frame one above I have a large plant angle and from the first video you can see my front foot, shuffling, planting and forcefully pushing down and generating a large ground force impulse in the time period between maximal elbow raise in frame 2 and maximum ISR stretch in frame 3. The only pro player that I have seen use a similar front foot shuffle and push off but with different timing is Mikhail Youzhny In a very short period of time between these two positions (elbow raise to shoulder raise) I have converted the rotation of the truck and the ground force impulse into a pretty significant ISR stretch by the time I reach the position in frame 3 when the forearm drive to the ball starts. The timing of this lower body drive is very different than a regular serve where it happens much earlier (right after power position). So my SSC is much more shortened than the traditional serve SSC and hence I believe more powerful. The only other server who uses this delayed leg push timing that I found was Rosco Tanner. As you can see from his sequence below he pushes down on his legs and barely gets off the ground in the frames between traditional racquet drop and maximal shoulder stretch. Roscoe is known to have generated 2 times body weight or more of ground force reaction. Another similarity that I share with Roscoe is the quick mostly horizontal swing loop. The closest analogue among the current pros is Bernie Tomic (don't know why folks with unsavory personal lives seem to have such novel and interesting service motions). When I really go for it while executing this serve, I generate significant ground force impulse. In the first year of taking tennis I bought toe box reinforced adidas barricade shoes. The ground force impulse being generated by my hard serves while wearing these reinforced shoes crushed my left big toe and caused the toe nail to turn blue and fall off. I had to return those and go to softer shoes. I also had to resort to cutting a hole in the toe and keep that pair handy like I used to do in my cricketing days to avoid the same situation. https://www.quora.com/Why-do-fast-bowlers-tear-the-front-part-of-their-shoes I went to graduate school at UW-Madison. While there I played intramural baseball and ice-hockey. Picked up pitching pretty easily given my pace bowling background. Took a winter to learn to skate well and the next winter I learned how to hit the slap shot. Loved that stroke. I came to this forum to get advise on this serve about a year ago and got some encouragement and a fair share of ridicule. It wasn’t until the middle of last year that it all clicked for me when I saw Roscoe’s serve. I studied my service motion in greater detail and researched the biomechanics of cricket, baseball and ice hockey. Only then was I able to understand what was going on and why my body was producing the serve the way it did. My serve has a horizontal tennis swing loop with elements of the cricket bowling action (plant angle, front foot plant, ground force impulse ..), mixed with a baseball pitching action (use of bent elbow not allowed in cricket, shoulder loading and ESR-ISR SSC) and with a ice hockey slap shot tacked in the end (the dominant hand portion). They were well tied together, nicely timed and the resultant action generates easy, controlled and effortless pace that I can keep up for hours. It was discouraging earlier when people called it wild and uncontrolled on this forum. It was no worse in its misses (people with far weaker serves hit longer and wider than me and there are plenty of kick serve wielders that I encounter who serve into the next court at least once or twice a session) than even the highest level peers I played with. The percentages were not bad either (I have yet to encounter at the rec level a player with a first serve that is above the 50% level who has a non-attackable first serve) and it suits the first strike tennis that I play. Anyways people who play me regularly are used to it now and have changed their perceptions. Most seem to enjoy the challenge of returning it and the easy power they can harness even with just a continental grip bunt back. Anyways I am fond of this stroke. I think it is nice looking and it does what it supposed to, get the ball to whiz past returners or throw up easy sitters to put away.