The Updated Biomechanics of the Volleyball Arm Swing

 

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A long, long time ago, in a website no longer working, resides a series of blogs about the biomechanics of volleyball. This is a long-awaited follow-up to the arm swing post from 2012. The original has disappeared and I cannot find the link to the most popular one (Update- I apparently looked for it the week that it did not exist...the link is here scroll down. Not all are tagged volleyball). Oops, :-). These posts circulated far beyond my expectations. I thank you to those who enjoyed and shared my last post. I can only hope the same comes for this one. Thank you also for your patience as this has been a back burner project for some time. After nearly a two month break from all things social media, I have a renewed drive for sharing what I believe about volleyball and the athletic life.

Over the last few years, I have deepened my understanding of the swing (and other volleyball skills of course). This post has been written, edited, and rewritten several times throughout this last year. I must precede this analysis with a few key points. There’s no right or wrong. That is too rigid, too reductionist, too binary. Rather, we should consider the spectrums of:

  1. Better vs. Worse: This is a continual process and if we are not getting better, then we are getting worse. If you’re not trying to get better, why are you here? Close this tab, seriously. I did not write this for you.
  2. Sustainable vs. Unsustainable: Maybe your arm swing works now, but will it be as effective or better in 6 months? A year?
  3. Creating Legends through maximized potential: Here are a few examples. Everyone knows Usain Bolt does not have the best start in his 100m dash. He is still the fastest man in the world and holds the world record. But how long will he own that record? Will it last 5 years? or 80? Kerri Walsh-Jennings, she’s had five shoulder surgeries now. Or is it six? I don’t know, I’ve lost count. Could she have earned another medal in Rio this year if she didn’t have two dislocations and another surgery within the year prior to Rio? My passion and day dreaming gravitates towards legendary stories that last for lifetimes. Helping people create stories that last and are fabled like Babe Ruth’s home run record. 

I love to ask questions of where can potential be cultivated within an athlete’s life. These are visions I have every one of my athletes. As the great John Lennon said, “You may say I'm a dreamer. But I'm not the only one. I hope someday you'll join us.” I am not writing this to keep people mediocre. While I am satisfied with wherever the athlete is during this moment, I am passionately driven towards the questions of “what’s next?” and "what's possible?"

My aim with this post is to satisfy the layman, the coach, and the sports scientist. The prior post contrasted the high elbow versus the low elbow and the professional volleyball players that utilized each. It summed up that those who started with a low elbow did not have any shoulder injuries, that I could find. Those who drew their arm back into a high elbow position did have injuries. I compared it to the much more well researched baseball pitching mechanics, which are not much different in my eyes. The main target for my argument against the high elbow is Kerri Walsh-Jennings. Who has continued to have shoulder injuries since the writing of my first article. This is just what I think is best as of today (2/9/17), but it may change. Strong opinions I have. Weakly held, they are...hmmmm. (Huge Star Wars fan, couldn't help it. #Yoda)

  1. Outline of new post
    1. I aim for this post to be much more comprehensive. I will discuss some of the mental attributes as well as all the physical ones. I want to outline an attack that will allow any player to have a long and storied career without a shoulder injury. Will you join me in this dream? 
    2. I will introduce my three main phases of the entire process of making ball contact. The further the indent of the bullet point, the further in detail I go. If you want to keep it simple, just stay left. All examples will be for a right handed hitter. A key learning point for me is that I believe there should be two two variations of the step close. Footwork for attacking at the net. And footwork that allows for an efficient broad jump for the jump serve and back row attack. I will have media from several different volleyball players, myself included: :-)
      1. If you would like more pictures and video examples, simply ask. This post can grow and evolve as needed.
    3. These phases will be: 
      1. Phase 1: Footwork: Timing & Loading 
      2. Phase 2: Flight Time
      3. Phase 3: Deceleration and Landing. 
      4. All of these phases depend on the quality of the preceding phase’s execution.

Phase 1: Footwork, Timing & Loading

  • First Step
    • Timing & Coordination:
      • First, the athlete must read the scenario in order to anticipate where the ball will be. The faster and more accurately this is processed the better the outcome of the play. 
        • Athletes who succeed in this area typically have a larger training age or more diverse history of random play. Regardless of the sport, the ability to anticipate a ball’s or person’s trajectory is a skill learned over years of play. 
        • For the attacker, once the anticipated location of the ball has been acquired, the athlete will progress towards the net. I will only discuss the last three steps. I do not care if the athlete uses a three, four, or five step approach. The last three are the most important to me. The first step should be the left foot pointing towards the anticipated jump location. 
          • Based upon how fast the athlete needs to accelerate forward lean angle of the spine will vary. The faster the athlete needs to move, the further forward they need to lean. The athlete’s forward lean would be limited to 45 degrees. 
            • Regardless of body angle, the left ankle should be dorsiflexed (think toes up) to around 90 degrees. This is the most stable and most powerful position of the ankle. If they really need to accelerate, their forward lean will increase and their heel will come off the ground, maintaining ankle dorsiflexion.
            • This is a very important principle - The further the foot is from the center of mass/midline the more time will be wasted. If this inefficiency occurs, the athlete must wait for the center of mass to travel forward over the center of pressure (where the foot is pressing on the ground) to accelerate.
              • Occasionally some athletes will unconsciously do this as a timing step to slow themselves down. This timing is inappropriately placed too late in the approach. It should be done before this left legged step initiates.
              • The arms swing forward in a very relaxed manner in preparation for a big extension when pushing off the left leg.  and up as the left foot goes forward. The timing of the becomes crucial later on for optimal coordination and timing and maximizing jump height.
          • The athlete’s torso is square to the direction of their foot. I see many athletes do a funky wind-up, where they face the opposite direction and swing back to have their left shoulder closer to the net.  
      • This is where things diverge into two movement solutions to the problem of optimal attack. Two variations of the Step-Close

At The Net

  • Reciprocal limb motion: As the right leg starts to swing forward,  the left leg pushes the center of mass forward. The further the right knee moves forward and up, the more the left leg will push. But remember, the further the right leg reaches forward, the more it will also act as a deceleration step. This can be a benefit if rapid deceleration is needed and can also work against you if you are trying to maintain speed in a broad jump. 
    • As the left hip extends, the arms come back at the same time. When the right heel makes contact, the arms should stop moving and be prepared to start coming upwards. Shoulder extension varies from athlete to athlete, but the further the arms go the harder it is going to be to time it with the jump. 
    • During the swing phase of the right leg, it should begin to turn outwards in preparation for landing. 
      • The foot should point 30-45 degrees to the right. Ideally, the knee follows with the foot as closely as possible. But forward momentum makes this a goal typically unattainable. Nonetheless, the intent of movement should not change. 
      • For right side attackers, we can aim for 15-30 degrees of external rotation of the leg. I battled with this internally for a while but the ball works too much as an attractor (dynamic systems theory)  to pull the athlete’s body to rotate more towards the net. 
      • For middle blockers approaching the setter from the right side of the court. It will be extremely difficult to get the feet turned right. For this reason, the range of preferred external rotation of the right foot is more dynamic. The feet can point straight forward or the full 30-45 degrees if possible.
  • To repeat myself because this concept is important to understand - The more the athlete needs to decelerate, the further forward the foot should be from the center of mass. However, the further forward the foot reaches, the greater amount of stress is placed on the body as well as an exponentially increased demand of knee stability, dynamic hip mobility, and core stability. I based upon the athletes’ capabilities, that will determine the appropriate distance allowed between left and right foot contact. If a large step is executed, there should be proper training done off the court to mitigate the accrued stress of these mechanics. 
  • An extremely common error here, the right foot and knee not pointing the same direction. Most commonly the foot points out to the side, while the knee continues to point forward. This will not help decelerate the body. It will force the left foot to plant nearly parallel with the net to “block” the momentum and jump straight up. This is an extremely dangerous position for both knees and extremely inefficient jumping mechanics. Furthermore, because the right hip is still relatively pointed forward, the torso is at a disadvantage to open up the chest and arm in preparation for attack. (Max Holt - https://youtu.be/oN_K5D510LQ?t=1m3s)
    • This leads to many shoulder injuries, aches/pains.
  • Upon right heel contact, the arms should start to aggressively swing forward and up.
Max Holt showing some room for improvement. 

Max Holt showing some room for improvement. 

  • Once the right leg is completely planted, the pelvis should continue to rotate around a stable right leg. 
  • The left leg should plant roughly shoulder width apart with feet parallel. However the right foot plants, the left foot must plant parallel
    • There MUST be sopace between the knees for the center of mass to descend, and create a stretch-shortening cycle for the hips. If the hips cannot do this, there is a cascade of events that happen up and down the body. Ultimately leading to a worsened arm swing.
      • Consider the joint-by-joint approach, or dynamic systems theory for this idea. If the hip is rigid, the lumbar spine becomes more mobile, stiffening the thoracic spine (preventing rotation), providing a poor foundation for the shoulder. It is no wonder why nearly every athlete who jumps like this extends their back rather and rotates it, finishing with a pike instead of rotating. Sadly, this example (below) is from an AVCA Tip of the Week, praising these mechanics.
  • Here’s an example (below) of backward rotation that I believe to be stemming from improper footwork. Taylor Sander rarely rotates to hit the ball. I don’t think he is able to because of how he takes his approach. If you watch closely, he actually rotates backward away from the ball in this attack. This is a common occurrence as he never rotates through the ball. From the back row, he has more space to rotate and sets up better, however his neuromuscular system does not know how. Thus resulting in this pike position. I believe his youth is saving his shoulder right now, but if a knee or back injury doesn’t sideline him a shoulder injury might in the coming years.

Phase 1: Backrow attack & Jump Serving

  • Over the last year, this is where I have done most of my critical thinking. Those who have seen me on the volleyball court have seen me often looking like this emoji 🤔. I have decided that there should be two different approaches based upon differing situations. 
  • When attacking from the back row or service line, it is an extreme advantage to be able to broad jump and attack the ball from a closer point to the net. Often times this goal leads to the terrible mechanics stated above with the left leg “blocking” the momentum the right leg was unable to decelerate.
  • In this scenario, I want to optimize rotation with broad jumping ability. In order to do that we must change the details of the step-close. Instead of the right foot turning outwards, it should point forward to the net. The knee must follow the trajectory of the foot. I should mention that this is something I only recently realized I did occasionally in college. Hence me using images of myself as examples. I must clarify that this is not a confirmation bias of my own mechanics.
    • What the pelvis and left leg do here is paramount. The left foot and knee must be pointing in the same direction of the right leg. With the left foot in front of the right, this should still open up the pelvis slightly in preparation for ball contact. 
    • The pelvis will rotate over the right leg and then plant the left leg, also with the foot pointing towards the net. The athlete will then jump in a staggered stance. This staggered stance still allows the pelvis to rotate and open somewhat while preserving the integrity of the knees. We are sacrificing total rotational power for a closer attacking point to the net.
    • As the body travels forward, the right ankle should continue to stay dorsiflexed (bent) as the heel lifts and weight is transferred to the ball of the big toe.
  • The left leg spends nearly no time eccentrically contracting (descending). The right leg is much more like a spring compressed, then the compression is maintained, then released. I’ve done some crude measurements of the timing of these steps and the right leg is approximately on the ground 166%-200% longer than the left.

Broad Jump Footwork In Motion

Austin Einhorn Displaying Broad Jump Footwork

Austin Einhorn Displaying Broad Jump Footwork

  • On a training stand-point, I would want to ensure that the right leg was trained slightly differently than the left. It must have more strength and structural integrity to deal with the change of direction and increased ground contact time. Ideally, the right leg should spend about .35 seconds on the ground. While the left leg can range between .15 and .20 seconds. 
  • Furthermore, I would train with the pelvis rotated over the left leg more frequently to change the length-tension relationship at the pelvis and hips. My goal here is to continue to train for a balanced body. 
  • This increased demand on the right leg, and the rotational forces exerted during the step-close, I believe to be some of the factors that contribute toward the vast amount of right handed volleyball players having right knee pain. Though, many other factors are at play. 

Phase 1: The Arms

  • The timing of the arms here is imperative to reach maximal jump height. The arms should come along with the left leg and reach maximum shoulder flexion at the same time as the legs straightening to maximize vertical jump. 
    • Many athletes who jump with their knees inwards, or do not use their hips well will throw their arms up early as compensation. This results in them never having time to generate whole body rotation and typically swing with just their arm. 
    • As the left arm comes up, it does not get straight overhead as many think. It actually should stop around 45-60 degrees beyond parallel to the ground. The left elbow should remain bent and the left hand should be facing the target or the net. The left hand/wrist position is critical to set up certain neuromuscular rotational patterns. The right arm ideally begins to get pulled back right as the athlete is leaving the ground. This may cause lots of controversy in the “bow and arrow” community. Look at most powerful hitters and their right arm starts to get drawn back as they leave the ground. 

 

    • I still maintain that the bow-and-arrow contributes towards many shoulder injuries. Especially when the elbow is higher than the shoulder. Kerri Walsh-Jennings is the case study here. By drawing her elbow up and back puts a high demand on the rotator cuff to keep the ball of her humerus in the socket. The main job of the rotator cuff is to keep the ball in the socket throughout a wider range of activities, more than to actually rotate the arm. It’s poorly named. No wonder she had two recent dislocations and two rotator cuff tears. The amount of (p)rehabilitation she may or may not have done simply was not enough to counteract the innumerable amount of swings she has taken.

Phase 2: Flight Time

Phase 2: Part 1 - Cocking of the arm

  • This is when the arm begins to come backward. It must come backward as relaxed as possible. This can be maximized if the arm isn’t drawn back at all. The rib cage should be the vessel that brings the arm backward. I must vent with you momentarily - people’s thoracic spines are disasters today. It has become a large focus in my training. 
  • The left arm will continue to come downwards to seek artificial stability (real stability would be if it were to grab onto a pole or the ground) in order to serve as a stable hinge for the right side of the body to rotate around.
  • Simply put, imagine there should be little to no wrinkles in the back of the shirt at the right shoulder.
Screen Shot 2017-02-08 at 8.06.25 AM.png
  • The left arm will continue to come downwards to seek artificial stability (real stability would be if it were to grab onto a pole or the ground) in order to serve as a stable hinge for the right side of the body to rotate around.
    • The right forearm should be parallel to the ground with hand also facing the ground. 
    • During this phase and the rest of the arm swing, the swing arm should be as relaxed as possible. Again, the more relaxed the arm the better everything will be. The arm does not generate power, it transfers it. The hips generate the power. 
      • Increasing tension in the right arm robs healthy tension from the core and hips. Leave it alone, don’t try to hit hard with an effortful arm.

Flight Time Part 2 - Rotation

  • This is when the magic starts to happen. The hips begin to rotate forward. This then creates an inertial moment at the relaxed hand. To elaborate, as the hips start to come forward the hand stays at rest (because it is relaxed, have I mentioned that yet?). An object at rest stays at rest unless acted upon. The hand will relatively stay where it is as the body starts to pull away from it. This is what creates the whip or rubber band effect.
    • Legs may begin to straighten or come forward if the feet are still behind the hips. The left arm will continue to try and find stability by rotating downwards and backward. The arm may come down to the side, or in front of the athlete. Both are acceptable. I prefer the elbow to be bent so there is more co-contraction of all the muscles in the arm.  To clarify, just because the left arm comes backward does not mean it should be forcefully drawn back. The emphasis should be on a relaxed right arm and whole body rotation.
Ashton Eaton - Decathlon. Winner of my "Best Athlete in the World Award"

Ashton Eaton - Decathlon. Winner of my "Best Athlete in the World Award"

  • Throughout Phase 2, the shoulders and hips should be near parallel to one another. What we want it segmental rotation at the thoracic spine, with slight segmental back extension. Ashton Eaton (Decathlon), demonstrates this beautifully with his javelin throw. He is allowed to have his shoulders not parallel to his hips because his task is different. He is trying to throw upwards on the object. We are trying to hit downwards or at least flat on a ball. This is where it gets complicated for children. They play on too high of a net, with too heavy of a ball, on too big of a court. Soccer, baseball, tennis, hockey, all shrink the game for the child. We do not do this enough. 
    • The hips should continue to rotate as the shoulders now catch up. This leaves the hand very far behind as the elbow comes up and forward. If you are looking at the athlete from behind, we are aiming for the arm to be at 1-2 o’clock range. NOT 12 o’clock. Yes, you get a tiny bit higher of a reach, but you sacrifice shoulder integrity and power.

Flight Time Part 3 - Acceleration of the arm & ball contact

  • Now all the potential energy built up will be released through an explosive elbow extension and shoulder internal rotation. 
    • This is also when the left leg may come forward. The left leg comes forward because there is no ground for the foot to stabilize on. Thus the left leg comes forward to simulate the torso rotating over the left leg, like a baseball pitcher. The ground helps the pitcher bend and rotate over a bent left leg. This is something that is unconscious and is a byproduct of good patterning. One should not be trying to flex their left hip before impact. Again, the foci are whole body rotation and a relaxed arm. These two choices will result in lots of good patterning. 
  • Contact - If the athlete was able to anticipate and read the opponent enough to make a strategical decision of attack location, not much should change within the body between each contact. I believe the arm trajectory is similar to that of a golf swing. One’s golf swing typically does not change drastically based on the situation, rather the club head is angled differently. Club head = hand. The same is true for the volleyball attack. More straight down swings should have a later contact point with the hand on top of the ball. While deeper swings are more behind the ball. Balls hit to the left or right should be manipulated by the hand. 
    • Balls hit left should be due to the wrist going into ulnar deviation (think pinky finger pointing to 3 o’clock). As well as slight supination of the wrist (think thumb turns towards head). Balls hit to the right should be as a result of the thumb going towards 7 o’clock, and slight pronation of the wrist. Think thumb pointing towards the ground

Flight Time Part 4 - Deceleration & Landing

  • Deceleration, I really did not want to have to talk about this. After much of what I have seen about “wrist snap”, or how the arm needs to finish by your side, or any strict spot I must discuss this. Again, the arm is as relaxed as possible. The more relaxed it is the faster it will be able to whip behind your hip’s rotation. That means the arm should fall somewhere near mid-line. But occasionally it will fall at one’s side when the strategy of the attack dictates that kind of follow through. The main thing is the arm is relaxed and has free reign to move wherever the preceding attack places it. A majority of the time it should fall towards mid-line, but it has the freedom to finish in other places as well.
  • Landing: The landing is just as important as the jump. It is quite difficult to do correctly at times with the net impeding forward movement. However, I still want the athlete to land on nearly a flat foot so they absorb forces through their entire leg, and NOT their calf and quads.
    • In my findings when athletes land on their toes, it increased the work-load of the calf and quadriceps and decreases everything else. Not to mention we already know that landing on your toes is extremely unstable.
    • If the athlete rotates enough, they will land with their feet pointing left and reducing the forward shearing stress at the knee.
  • The right foot should land in front of the left, at any distance That should be a marker of whether or not the athlete rotated.

Conclusion

  • Lateralize to other sport. We must not be so arrogant to think our swing is so wonderfully unique. It’s just rotation. 
    • The arm swing is way more than just the arm. It starts on the ground and the ability to time and relax the arm appropriately. This can appropriately develop through a variety of diverse, adverse, and active life experiences. Children these days lack the necessary lifestyle components to combat specialization. As I said in a previous blog post on specialization, specialization is not the actual danger for our sport and our youth. What is attributing to this injury epidemic is the failure avoidance, lack of random play, lack of labor and adversity. 
  • The fortunate truth is that even though innumerable factors contribute towards these problems, the solution is quite simple. Almost too simple. 
  1. Move. 
  2. Prioritize Sleep (For recommended sleep routine products that I use click here)
  3. Breathe, gain a deep understanding of the breath.
  4. Play.
  5. Fail.
  6. Succeed.
  7. Learn. 

Do 1-7 outside as much as possible.

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- Austin Einhorn