Technical and Anatomical Analysis of Reilly Opelka's Serve

Reilly Opelka: one of the tallest servers in tennis with one of the biggest serves.

Reilly Opelka is one of the biggest servers on the ATP Tour--and he is also one of the biggest players, standing at 6' 11'' tall. I have followed his career closely since he was a junior and spent a week closely observing his game a few years back at a USTA training camp.

The tennis serve is a complex biomechanical movement utilizing both the upper and lower body. In this article, I will analyze the serve movements during three main phases of the motion: Start to Power Position (Setup), Power Position to Contact (Acceleration), and Contact to Landing (Deceleration).

These stages build on the research of Mark Kovacs and Todd Ellenbecker and their excellent study on the 8 Stage (3 Phase) Serve Model. I highly recommend this study for those who want to brush up on their serve biomechanics.

And you can see more high speed footage of Reilly from an amazing overhead view in the High Speed Archive. (Click Here.)

I will analyze the motion from both a technical perspective and—for those diehard biomechanics nerds out there—an anatomical point of view. Recently I took a course on anatomy so I am sharing what I learned. If the anatomy doesn't interest you just skip to the next section!

An extreme starting position and delayed right arm movement.

Reilly has a very interesting extreme starting position with the right foot staggered far behind the left foot, similar to John Isner. Like Isner, Reilly utilizes the pinpoint style of serving, which is common—-and some argue, more effective— for tall players, although I'm not sure I agree with this opinion.

Reilly has a nice rhythm of the arms with the left arm leading and tossing the ball up and combined with a delayed right arm movement. This delayed racquet arm sequence was popularized by the great Pete Sampras.

Reilly has a slightly abbreviated backswing, which is common on tour these days. He doesn't lift the racquet straight up like Monfils, nor does he have the full classical wind up.

One of the most interesting aspects of Reilly'a delivery is his unique pinpoint setup. After tossing, he slides his right foot up to the left foot, but instead of tucking the feet together, Reilly positions his right foot behind his left—so far behind that his right toes point to his left heel.

Reilly's unique pinpoint stance.

In all my years of studying biomechanics, I have never seen another elite pinpoint server do this. It's one-of-a-kind, and it could be a new trend that will filter down to young juniors and other pros coming up.

That extreme step up position helps to force Reilly's hips more closed during the pinpoint action, and allows him to store more energy. A common error among pinpoint servers is to step up to the right or the lead foot, causing the hips to open prematurely and release energy too soon.

Reilly fights against this kind of biomechanical inefficiency to accentuate the hip coil and the energy loading concomitant to that closed hip position. Reilly achieves a very deep right leg drive combined with this extreme coiled right hip position—a great shot put setup to deliver max power later.

While Reilly hits that deep coiled position with his lower body, his upper body achieves a beautiful trophy or power position with an excellent degree of separation between his shoulder line and hip line in both the longitudinal or sagittal plane and the frontal plane, a great right angle power position, resulting in a perfect archer pose.

The toss the move to the power position.

Reilly tosses the tennis ball upwards by elevating the left arm by flexing the shoulder. The shoulder is flexed at the glenohumeral joint, which is the ball and socket synovial joint. The movement takes place in the sagittal plane and the primary agonist—the muscle whose contraction moves a part of the body directly--is the anterior deltoid (with assistance from the coracobrachialis) while the primary antagonist --the muscle that is relaxing or lengthening --is the posterior deltoid with some assistance from the latissimus dorsi, and teres major.

Reilly abducts the racquet arm away from the body, lifting the racquet towards the power position, which is sometimes referred to as the "trophy position". This abduction takes place at the glenohumeral joint, which is a ball and socket synovial joint. The movement takes place in the frontal plane and the primary agonists are the supraspinatus, medial deltoid, and trapezius, while the antagonists are the pectoralis major and latissimus dorsi.

Additionally, Opelka flexes his right elbow of the racquet arm to approximately 90 degrees to achieve the power position. This flexion takes place at the humeroulnar and humeroradial joint or elbow, which is a hinge type synovial joint. The flexion takes place in the sagittal plane and the biceps brachii is the primary agonist in flexion of the elbow joint, while the primary antagonist is the triceps brachii.

Reilly's great, deep knee bend.

As Opelka looks upward to spot the ball, he extends his neck—the vertebral column. The vertebral column is comprised of cartilaginous joints and extends in the sagittal plane.

The primary agonists of cervical spine extension are trapezius and longissimus capitis, while the primary antagonists are the sternocleidomastoids and scalenes. The muscles of the neck that support spinal column extension can often become inflamed causing pain.

Opelka makes a deep knee bend to load energy in his legs. He flexes his knees at the patellofemoral joint, a synovial hinge joint. This flexion takes place in the sagittal plane and the primary agonist is the hamstring group (biceps femoris, semitendinosus, semimembranosus) while the primary antagonist is the quadriceps group (vastus lateralis, vastus medialis, rectus femoris, and vastus intermedius).

Reilly's racquet moves very slowly up to the power position, then the legs begin to fire, and the racquet “chases" the leg drive, reaching into a deep racket drop and the maximum point of external shoulder rotation. Next, Opelka seemlessly extend upward to the ball with maximum acceleration as his shoulder moves from external rotation to internal rotation.

Slow movement to power postion—then the legs uncoil helping create a deep drop with additional external shoulder rotation.

It's important to note the rhythm during this phase: Really has a delayed buildup in which the racquet moves relatively slowly up into the power position, then the legs fire creating a deep drop, and then accelerating the racquet upwards following the leg drive. The upward push of the legs actually helps to drive the racquet deeper into the drop position, maximizing the racquet drop and the range of motion in terms of external shoulder rotation.

So many players, both junior and adult, and recreational players—and even many pro players, especially on the women's side--struggle to get this sequencing right. Typically, players will drop the racquet too early and the legs will fire late in the sequence. It's critical to remember that the legs trigger the racquet drop and the acceleration phase of the arm—not the other way around. (Click Here for John Yandell's discussion of this in his article this month.)

Many players and coaches believe mistakenly that the acceleration phase begins essentially at the ball toss. Kovacs and others have argued that acceleration really does not begin until the racquet hits the deepest drop point and fires upwards to the ball. The movements that take place before this phase are a setup. They are not contributing much to acceleration.

The majority of racket acceleration is in the fraction of a second between the drop and the contact.

In a study of the Sampras serve Brian Gordon and John Yandell found that the overwhelming majority of racket acceleration occurs in the 1/10 of a second between the drop and the contact. (Click Here.)

For a big guy, Reilly does a fantastic job getting a strong knee bend and really loading his lower body well before exploding up into the ball with a good jump. He knees reach an approximate angle of 90 degree bend and he goes down and up fluidly, never getting stuck with a hitch in the knee bend.

As he explodes off the court, his body reaches full extension at impact maximizing his reach and angle of approach for the ball down into the opposite court. Opelka does a great job stretching his frame upwards, extending his legs and keeping his head up through impact.

Reilly begins to accelerate the arm by dropping the racquet behind his back, reaching the point of maximal external rotation at the lowest point in the drop. The shoulder is externally rotated at the glenohumeral joint, which is a ball and socket synovial joint. The movement takes place in the transverse plane and the primary agonists are the infraspinatus and teres minor while the primary antagonists are the subscapularis and teres major, and latissimus dorsi.

Another view of the external rotation to the contact.

Opelka reaches up to strike the ball and extends his arm at the elbow (humeroulnar and humeroradial joints), which is a synovial hinge joint. The movement takes place in the sagittal plane and the primary agonist is the triceps brachii, while the primary antagonist is the biceps brachii.

During this phase, Reilly is also reaching upwards towards the ball by upwardly rotating his scapula at the scapulothoracic joint. The scapulothoracic joint is not a true synovial joint. Rather, the scapulothoracic articulation is formed by the convex surface of the posterior thoracic cage and the concave surface of the anterior scapula. The scapula is a flat bone, with the gliding surfaces formed by the subscapularis and the serratus anterior.

This rotation takes place in the frontal plane, while the primary agonists of this rotation are the trapezius and serratus anterior muscles and the primary antagonists are the rhomboids and latissimus dorsii.

A big source of power on the serve for Reilly is his shoulder internal rotation that occurs as he accelerates the racquet upwards to the ball. The shoulder is internally (medially) rotated at the glenohumeral joint, which is a ball and socket synovial joint.

The explosion of the lower body.

The movement takes place in the transverse plane and the primary agonists are the subscapularis and teres major, and latissimus dorsi while the primary antagonists are the infraspinatus and teres minor.

During this phase, the lower body is exploding: There is significant plantar flexion at the ankle (talocrural) joints--hinged synovial joints--as Reilly jumps upwards to the ball. This plantarflexion takes place in the sagittal plane and the primary agonists are the gastrocnemius and soleus, while the primary antagonists are tibialis anterior, extensor digitorum longus, and extensor hallucis longus.

There is also forceful extension at the patellofemoral joint, which is a synovial hinge joint. This extension takes place in the sagittal plane and the primary agonist is the quadriceps group (vastus lateralis, vastus medialis, rectus femoris, and vastus intermedius), while the hamstring group (biceps femoris, semitendinosus, semimembranosus) is the primary antagonist.

From contact to landing, Opelka demonstrates a couple of idiosyncrasies. For example, when he jumps, sometimes his left foot flexes to an unusual degree of angle. This means he lifts his toes up midair.

But sometimes Opelka has an awkward heel landing—not recommended.

He doesn't do this all the time, but in my video analysis, he does from time to time and this creates an awkward heel dominant landing. Typically the foot should remain at a lesser angle after in the explosion of the lower legs up to the ball. Because his ankle is flexed to such a degree, Opelka sometimes lands awkwardly on his heel rather than his normal midfoot or front foot strike landing, which is more typically of all professionals.

Opelka continues with a strong internal rotation of the shoulder driving the upper arm post-impact during the deceleration phase. His body posture during this phase is incredibly erect—very upright.

Another idiosyncrasy for Opelka, in addition to an intermittent heel strike landing, he sometimes looks like he is almost walking through the landing rather than getting that high kickback of the right leg, which is very common among professional players.

Sometimes Opelka get a big kickback on landing, and other times he simply landing and almost walks forward! Very unusual. In addition, sometimes he keeps his legs close together post-impact rather than getting that big leg separation which is de rigueur on the tour tor male servers.

During this deceleration phase, Reilly continues to rotate the radiocarpal (wrist) joint, now more as a decelerative function. The radiocarpal joint is an ellipsoidal (condyloid) type synovial joint. This takes place in the transverse plane and the primary agonist is the pronator teres, while the primary antagonist is the supinator.

The racquet comes down and finishes across the body.

In addition, Reilly lowers his racquet arm demonstrating extension at the glenohumeral joint, a ball and socket synovial joint. The primary agonists are the posterior deltoid, latissimus dorsi, and teres major while the primary antagonists are the anterior deltoid and coracobrachialis.

Reilly brings the racquet arm down across his body by horizontally adducting his shoulder at the glenohumeral joint, a ball and socket synovial joint. The primary agonist is the pectoralis major with assistance from the anterior deltoid while the primary antagonist is the posterior deltoid with help from infraspinatus, among others, and the horizontal adduction is occuring in the transverse plane.

At the finish of the swing, Reilly's racquet arm fully crosses his body, medially (internally) rotating at the glenohumeral joint, a synovial ball and socket joint. The rotation takes place in the transverse plane and the primary agonists are the subscapularis and teres major, and latissimus dorsi while the primary antagonists are the infraspinatus and teres minor.

As Reilly prepares to land, he dorsiflexes his left ankle at the talocrural joint, which is a hinged synovial joint. As mentioned, sometimes his ankle is put into extreme dorsiflexion, which is unnecessary. The primary agonists are tibialis anterior, extensor digitorum longus, and extensor hallucis longus while the primary antagonists are the gastrocnemius and soleus. The dorsiflexion occurs in the sagittal plane.

Opelka lands with his torso upright and the rear leg kicking back.

On landing, as with all top professional servers, Opelka usually extends his right hip at the coxal joint, which is a ball and socket synovial joint. This hip extension drives the right leg backward as a counterbalance. Hip extension takes place in the sagittal plane and is primarily driven by the gluteus maximus as agonist while the primary antagonist is the iliopsoas.

As Opelka lands, he straightens his back—again the vertebral column--and maintains good posture to assist his balance and preparation for the returning shot. Opelka is straightening his vertebral column, which consists of cartilaginous joints and extends in the sagittal plane. The primary agonists of spinal extension are the erector spinae (spinalis, longissimus, and iliocostalis), while the primary antagonist is the rectus abdominis.

As he lands, Reilly flexes his cervical spinal column to level out his head and look down the court at his opponent. The vertebral column is comprised of cartilaginous joints and flexes in the sagittal plane. The primary agonists of cervical spine flexion are the sternocleidomastoids and scalenes while the primary antagonists are the trapezius and longissimus capitis. The muscles of the neck that support spinal column flexion can often become inflamed causing pain.

I hope you enjoyed and learned from this technical and anatomical review. It's important to appreciate some of the unique aspects of Reilly's motion. Some parts, like the extreme pinpoint stance might be worth copying, other parts, such as the heel striking and lack of hip extension, should be disregarded. I've included a thorough anatomical discussion for those who would like to dive into anatomy and physiology. If you have any technical questions, post them in the message boards or email me directly at chris@chrislewit.com

Technical and Anatomical Analysis of Reilly Opelka's Serve

Chris Lewit