The document analyzes the author's tennis serve technique. It identifies key joints, muscles, and phases involved in the serve. The author conducted qualitative assessments of their hip height, elbow angle at contact, and ball projection angle. Areas for improvement include increasing compactness in the prepatory phase to allow for greater extension, and working on transverse shoulder rotation for a more advanced serving motion.

1. Christopher Johnston
Tennis Serve Analysis
Introduction
I started playing tennis in high school. I tried out for the varsity team with no
experience and as expected, I did not make the cut to play in any actual games. This did
not make me lose my hopes of learning the sport and I have continued to play ever since.
Over my last three semesters in college I have taken tennis for my required sports classes.
I have continued to play tennis outside of class and can now play at a rather average level
consistently. My ambitions for this activity are to make it a lifelong sport that I participate
in. I plan on playing for the rest of my life whether it is recreationally or competitively.
Skill wise I hope to be able to improve all aspects of my game. I currently have been
working on my serve so I thought that this project would be the perfect opportunity to
help with the learning process. My long term skill goals are to be able to play the game
with all different styles; whether it is a strong forehand game, strong serve, or the ability
to make the opponent run around the court. In order to perfect the different aspects of
the game I need to hone in on many aspects of the game.
A powerful shot can blow the opponent out of the water, but accuracy is the key
to winning a match when it comes to tennis. It doesn’t matter if your shot is powerful if
you can’t place a shot in the court or away from your opponent. A well placed drop shot
can leave your opponent stunned with nowhere to go. The major force that determines if
a shot is a top spin shot or the previously mention drop shot, is lift force. Due to the
magnus effect a top spin shot will drop faster and a backspin shot will make the ball be in

2. the air for a longer time. These two spin shots are a key to success when facing an
opponent in tennis
Prepatory Phase
For my prepatory phase I think that the shoulder, shoulder girdle, elbow and radio
– ulnar, knee, and hip joint are the most important. Without strength and mobility in the
shoulder girdle the prepatory phase would be almost nonexistent and a powerful serve
cannot be had. Extension at the elbow and radio-ulnar join is crucial during the prepatory
phase because it readies the player to extend their elbow to hit the ball during the
propulsive phase. Knee and hip join flexion are important because it preps the player for
triple extension during the propulsion phase. The following table shows the joints,
actions, and muscles used in the prepatory phase.
Table 1. Joints, actions, and muscles used during the prepatory phase of the tennis serve
Propulsion Phase
The most important joints in the propulsion phase are the same as the prepatory
phase: shoulder, shoulder girdle, elbow and radio – ulnar, knee, and hip joint. The same
joints are being used but they are doing completely opposite actions than in the
prepatory phase. Thanks to the prepatory phase, these joints primed to extend and hit the
ball with great speed. The more mobile the shoulder girdle and shoulder joint are the
better extension at contact can be had which would increase the speed at which the
Prepatory Phase
Joints Action Muscles
Shoulder Joint Extension Deltoid, Posterior | Pectoralis major, sternal | Latissimus dorsi | Teres major | Triceps, long head
Shoulder girdle Downward rotation and Retraction Pectoralis minor | Rhomboid | Trapezius II,III,IV
Elbow/radio-ulnar joint Flexion Biceps brachii | Brachialis | Brachioradialis | Pronator teres
Knee joint Flexion Semitendinosus | Semimembranosus | Biceps femoris | Sartorius | Gracilis | Gastrocnemius
Hip Joint Flexion Iliopsoas | Sartorius | Rectus Femoris | Pectineus | Tensor fasciae latae

3. projectile is hit. The transverse movement in the shoulder and shoulder girdle is seen in
more skilled players.The radio-ulnar join extension is needed in order to increase the
extension at contact of the projectile. The triple extension used to generate power during
the propulsive phase includes the knee, hip, and ankle joint. The ankle joint was not
included because I believe that the other joints are more important during this phase.
The following table shows the joints, actions, and muscles used in the propulsion phase.
Table 2. Joints, actions, and muscles used during the propulsion phase of the tennis serve
Post-Propulsion Phase
The post propulsion phase is important because it allows the player do get ready
for the next shot if they execute it well. When I serve I tend to rotate my whole body to
the left. My right leg swings over the left. Unfortunately this is not the best form because
I may cross my feet up and trip on them. The joints I chose for this phase are the
shoulder, shoulder girdle, thoracic and lumbar spine, ankle, and hip. I chose the shoulder
girdle and shoulder because a follow through must be executed in order to not put too
much eccentric muscle strain on the shoulder. The thoracic and lumbar spine and the hip
must move almost simultaneously in order to reduce stress between the two systems. If
the ankle does not dorsiflex on landing then the server will land on their toes and have a
small base of support which could cause them to fall. The following table shows the
joints, actions, and muscles used in the post-propulsive phase.
Propulsive Phase
Joints Action Muscles
Shoulder Joint Transverse Adduction Deltoid Anterior | Pectoralis Major Clavicular | Pectoralis major, sternal | Coracobrachialis | Biceps, short head
Shoulder Girdle Protraction Pectoralis Minor | Serratus Anterior
Elbow/radio-ulnar joint Extension Triceps brachii | Anconeus
Knee Joint Extension Rectus Femoris | Vastus group
Hip Joint Extension Gluteus maximus | Biceps femoris | Semitendinosus | Semimembranosus

4. Figure 3. Joints, actions, and muscles used during the post-propulsion phase of the tennis
serve
Important Muscles
Some of the primary muscles used during these three phases are the deltoid
anterior, biceps femoris, tibialis anterior, semitendinosus, and the triceps brachii. I chose
these muscles because a lot of them are used in multiple actions.
The semitendinosus is used at the hip joint during medial rotation and extension,
and at the knee joint during extension. To improve functional strength in the
semitendinosus, medial rotation and extension exercises must be done. One exercise that
can be done for both extensions at the hip at the knee join is a standard squat. The squat
is a perfect exercise for a tennis player because it mimics both the prepatory phase and
propulsion phase. The squat should be done at a low weight and high volume in order to
be specific to the needs of a tennis player. The tennis player is moving their legs fast in a
match so there is no need to max out weight while performing squatting. The low amount
of weight and high amount of reps will be sport specific for the tennis player. There is
going to be a little amount of weight on the bar which means that the repetitions are
going to be high. Safety concerns come into play with a high amount of repetitions
because form can break down. If the athlete’s form breaks down and he/she cannot safely
Post Propulsive Phase
Joints Action Muscles
Shoulder Joint Transverse Adduction Deltoid Anterior | Pectoralis Major Clavicular | Pectoralis major, sternal | Coracobrachialis | Biceps, short head
Shoulder Girdle Protraction Pectoralis Minor | Serratus Anterior
Thoracic and Lumbar Spine Rot. to L. R. External Oblique | L. Internal Oblique | L. Erector Spinae
Ankle Joint Dorsiflexion Tibialis anterior | Extensor digitorumlongus | Peroneus tertius
Hip Joint Medial Rot. Tensor fasciae latae | Gluteus Maximus |Semitendinosus | Semimembranosus | Gracilis

5. perform a free weight squat then I think it would be a good idea to make them use a
squat machine. An exercise that could be used for semitendinosus medial rotation is a
static band hold. The athlete would lie on their stomach with a band around their ankles,
flex their knees, and then medially rotate their hips and hold it. This exercise is rather
safe because they can control the resistance and it is easy to release the tension once the
exercise is over. To improve the functional length of the semitendinosus I would tell my
athlete to foam roll. Foam rolling is easy because it can be done on the ground. Another
reason I think foam rolling would be a good idea is because when foam rolling it is easy to
not contract the hamstring while the athlete is doing it. I believe that when doing a
stretch such as a hip hinge it is easy for the athlete to contract their hamstring. The
muscle that is being stretched should not be contracted.
The next muscle I chose is the biceps femoris because of its involvement in knee
flexion in the prepatory phase and hip extension in the propulsive phase. The squat is also
good for strengthening the biceps femoris. Light weight and high reps should be used
when performing the squat because tennis is not a maximal effort sport. If form starts to
break down then the athlete should use a squat machine in order to be safe and not hurt
themselves. A good exercise to lengthen the biceps femoris is to foam roll it.
The last muscle in the legs that I chose is the tibialis anterior because it is needed
to land properly in the post-propulsion phase. The tibialis anterior is activated during
dorsiflexion. One exercise that can be done to strengthen it is to sit down on a chair and
just dorsiflex the ankle. This should be done with minimal to no weight due to the natural
strength of the tibialis anterior being weak. The only safety concern I have is that athletes

6. sometimes feel the need to use a lot of weight when doing an exercise. It would be easy to
overload the tibialis anterior and injure it due to in not being a strong muscle. A good
way to stretch the tibialis anterior would be to foam roll it. The athlete could place their
shins on the foam roller and then sit on their ankles and then roll out the tender spots.
I talked a lot about the squat for all three muscles because I think that it is the best
exercise for all three. The serve is essentially a squat so the best way to improve this
movement is to do it over and over again. This is the meaning behind sports specific
training. I mentioned foam rolling a lot because I think it is one of the safest stretch
lengthening exercises for the legs. It does not require the athlete to curve their spine in
order to stretch their legs like a hang stretch would. This allows people with immobile
spins to stretch their hamstring. Foam rolling also allows the athlete to pin point tender
spots and apply pressure to them in order for pain relief.
The first muscle in the upper body that I think is important is the triceps brachii.
The triceps brachii is activated when the elbow and radio-ulnar joint extends. This is
important when the athlete is trying to hit the ball at its apex during the serve. A good
exercise to increase triceps brachii strength is tricep extension. This would be done with
low weight and at a fast speed in order to develop power. In theory this power should
transfer to the serve since it is a sports specific exercise. In order to perform the exercise
safely the athlete needs to makes sure the weight is far enough away from their head so
they do no accidentally hit it on their way down or on the way up. If the user is unable to
do this exercise safely with free weights then they could do tricep extension exercises with

7. cables. A good lengthening exercise for the tricep is to put it behind your head by placing
the same side hand on the same side scapula and hold this position for sixty seconds.
One of the most important muscles for the tennis serve is the deltoid anterior. It is
involved in the transverse adduction of the arm during the propulsion and post-
propulsion phase. A good exercise for increasing deltoid anterior strength is a cable cross
over. The athlete stands next to the cable machine, grips it at about elbow height, and
then pulls it across their body. This would be at a light weight and high reps in order to
replicate the intensity of a tennis serve. I can see no danger in doing this exercise besides
adding too much weight to the machine which could result in a shoulder injury. A good
lengthening stretch for deltoid anterior would be to cross the shoulder over the arm and
hold it. This would be a good way to static stretch the deltoid anterior.
POSSUM Scale
The tennis serve is light and fast so I am going to want a large back swing and my
swing should be sequential. The effort of intensity is maximum so I am going to want to
increase my number of segments, increase my transverse action, increase compactness,
have a large extension at contact, and have max speed and rage of motion. I will want to
be rather mobile during the serve so my line of gravity will be outside of my base of
support. I want the ball to go in a downward path which means I want to hit it at an angle
below the horizon. I have a power serve so I am going to want to have maximum
translation by hitting the ball through the center of gravity.

8. Quantitative Assessment
My first qualitative assessment was hip height during the start of the start of the
prepatory, end of the prepatory/start of the propulsion phase, and end of the propulsion
phase. I used hip height to relatively judge my waist center of gravity to my shank and
thigh center of gravity. In general, the close these three centers of gravities are to each
other the more compact I am. I included the prepatory phase because compactness
during this phase determines the amount of extension at the hips and knee joints during
the propulsive phase. Between the start of the prep and the end of the prepatory phase I
squatted down 4.86 inches. From the beginning of the propulsive phase I rose 10.58
inches. These calculations can be seen in figures 1 through 4. I believe that if I was more
compact during the prepatory phase it would all me to extend more during the propulsive
phase and hit the ball at a greater speed.
My next qualitative assessment was taken at the end of the propulsion phase. I
assessed the angle my elbow was at during contact in order to determine the extent of my
extension at release. I determined that my elbow was at a 160 degree angle when it came
in contact with the ball. During this assessment I also noticed that more forearm was out
of line with my spine because I was reaching out in order to make contact with the ball.
This qualitative assessment can been seen in figure 4.
The last qualitative assessment I took was the path of projection. In order to do
this I translated the location of the ball at the start of the post-propulsive phase onto the
picture at the end of the propulsion phase. I found that my path of projection was at
about 6 degrees below the horizon. I believe that this serve is the only one that made it

9. on to the other side of the court. My other shots had a greater angle which made it hit the
net and not go over. This qualitative assessment can be seen in figures 4-5.
Core Concept Performance
One core concept I feel that I have almost perfected with the tennis serve is the
number if segments. I am using my ankles, knees, and hips to explode out of the squat
position and up towards the ball, while almost simultaneously I am extending my
shoulder and elbow to make contact with the ball. I believe that this core concept is
advanced enough that an expert level me would not be able to tweak anything without
further evaluation. However, my nature of these segments could use a little work. My
trunk and shoulder do go through the transverse plane but not to the extent that they
should. I believe that an expert version of me would finish with the racquet across the
body instead of the same said that it started at. Naturally my spine would follow this
shoulder rotation because it is influence by shoulder girdle rotation; this would cause my
trunk to have more transverse rotation.
The next core concept I want to address is extension at contact. A tennis serve is a
max intensity effort so my extension at contact should be as long as possible. My
extension at contact was not as long as it could be because when I throw the ball out too
far in front of me it forces me to reach out for it. Since I have to translate my arm forward
I am not able to extend it vertically as much as needed. An expert version of me would
throw the ball closer to myself so I would not have to reach out for the ball and I could
have max extension at contact.

10. Compactness during the prepatory phase is essential because it allows for fast
movement up toward the ball during the propulsion phase. At the start of my propulsion
phase my knee angle is rather large which means I am not compact so I will have
decreased speed towards the ball. I believe that an expert version of me would be more
compact and squat lower during the prepatory phase in order to allow them to be faster
at the start of the propulsive phase.
The purpose of the serve is to have the ball’s initial path to be downward. The
tricky part here is that the angle cannot be too sharp or else the ball will hit the net. The
path of the ball that I hit was six degrees. I believe that this angle is decent but nowhere
near an expert level. I believe I was able to have a successful serve with such a small angle
because I hit the ball too late and it was rather low when I struck it. I believe that an
expert version of me would hit the ball with a higher degree below the horizontal. They
would hit the ball when it is higher in the air which would allow them to make a
successful serve with the increased angle.
Approach to Improvement
My approach to improvement would be to address compactness. I would first
address compactness because I believe that it has a large effect on other core concepts as
well. Currently I am not compact enough during my serve and I do not get that low in the
prepatory phase. I believe that being more compact and increasing my speed during the
start of propulsion phase will make my nature of segments more transverse. The high
speed at which im starting the serve will force my trunk and shoulder to move through
the transverse plane in order to slow them down without too much eccentric muscle

11. strain. A good sports specific exercise to prescribe to this athlete would be to toss the ball
up while getting into a compact squat position and then stop the exercise there. This
exercise would be repeated until the athlete is comfortable with getting into a compact
position during the prepatory phase. Once the athlete is comfortable with the first phase
of the serve then they can spring back up an actually hit the ball.
Modification of movement
The easiest modification that I could make is to throw the ball closer to me during
the prepatory phase. This would make it so I have less horizontal translation when hitting
the ball. I would not have to extend my arm forward as much and I can have more vertical
extension of my arm at time of contact with the ball. My prepatory phase needs to be
more compact in order for me to generate more speed at the start of the propulsive phase.
This greater speed will lead to a more transverse movement which is essential for speed. I
believe that I need to work on my shoulder mobility so I can have a greater range of
motion throughout the whole movement and it will also make it easier for me to have a
long extension at contact. If my changes work I will practice doing “perfect” form on a
consistent basis. Once you get form down that does not mean the work stops. The next
step is to be consistent and gain strength so form does not break down over time in a
game.
Commercial for Myself
I didn’t have perfect attendance but I did only miss one day of lecture and I still
find that rather impressive. I often came to open lab hours to not only get help with
assignments but on a couple occasions I came to talk about career options within

12. biomechanics and outside of biomechanics. When I first saw that I had to take
biomechanics I had no interest in it and was nervous about taking it because I heard it
was hard. I’m glad that I took it and actively participated in this class. This class had made
me question my daily activities and I even sometimes evaluate others. Just the other day I
informed my roommates that if they have to do the walking test with a cop that they
should do it fast in order to have better balance. This class has allowed me to explore an
area of interest that I thought never existed and I think that is what college is all about.

13. Figure 1. Start of Prepatory Phase

14. Figure 2. End of Prepatory Phase

15. Figure 3. Start of Figure 3. EnP Propulsive Phase

16. Figure 4. End of Propulsive Phase

17. Figure 5. Start of Post-Propulsive Phase

18. Figure 6. End of Post-Propulsive Phase