mass of the car in motion . You come to a traffic light and it is red . You put your foot on the brake pedal , the tires push back against the pavement , and you come to a stop before entering the intersection . The car ’ s momentum has ended .
In the same way , when a player makes a volley their feet push against the court surface to put their body in motion , generating momentum that moves the body toward the NVZ . For example , a player is standing at midcourt when the opponent pops the ball up . The player steps forward toward the NVZ , strikes the volley , and takes another step . This is a body in motion and therefore has momentum . How do they dissipate their momentum ? There are actually two ways . First , the player transfers some of their momentum to the ball when they strike it , much like a billiard ball striking another ball , except in this case the mass of the player is much greater than the mass of the pickleball , so they probably still have momentum . That remaining momentum must be transferred back through their feet to the court surface , similar to the tires on the car transferring its momentum to the road .
The momentum of the player moving across the court is called linear momentum . There is a second type of momentum in play during volleying , called rotational momentum . Imagine a player standing flat-footed just behind the NVZ and striking a volley . Their paddle , arm , and upper body rotate around their center of gravity , generating momentum . After striking the ball they are leaning forward with their weight on their toes , windmilling their arms as they fight the momentum of their swing . If they are not able to dissipate their momentum through the strike of the ball and their feet pushing against the court , their rotational momentum will become linear momentum and they will take a step forward into the NVZ , committing a fault .
This is similar to gymnasts
MOMENTUM DEFINITION
3 . A . 20 . Momentum – Momentum is a property of a body in motion , such as a player executing a volley , that causes the player to continue in motion after contacting the ball . The act of volleying produces momentum that ends when the player regains balance and control of their motion or stops moving toward the non-volley zone . performing a vault . They sprint down the runway , gaining speed and creating linear momentum , hit the springboard and fly up into the air . They flip , turn and twist , converting the linear momentum of their run into rotational momentum . They then land with both feet together on a soft mat , which absorbs their momentum . If they “ stick ” their landing , they stand up straight with both arms raised in triumph to show that they have regained their balance and are in control of their motion , giving a big smile to the judges and spectators . If they don ’ t stick their landing , you see them take a step forward as their rotational momentum is converted back into linear momentum . For the vaulter , that step is a mandatory deduction . In the same way , if our flat-footed volleying player is not able to absorb their rotational momentum with their feet , their step forward creates the NVZ fault .
A similar dynamic occurs with our car example . When you press on the brake , as the car decelerates it leans forward slightly with more weight on its front wheels . When it comes to a complete stop , the car settles back with its weight more evenly distributed on both front and back tires . Both the linear and the rotational momentum of the car have ended . The car is in balance and under control .
In both our car example and our gymnastics example , we see the elements that demonstrate the end of momentum in the act of volleying — balance and control , or a stopping of motion — that are part of the new definition of the end of momentum in Rule 3 . A . 20 .
When a volleying player “ regains balance ,” their weight is evenly distributed on their feet from front to rear and side to side . When they are in “ control of their motion ,” they are not being impelled or compelled to continue to move ; their subsequent movements are volitional .
When a player “ stops moving toward the non-volley zone ,” that can occur in two ways . Either they can “ stick their landing ,” coming to a complete stop , or they can change the direction of their movement so as not to be headed toward the NVZ . For example , a player hits a volley , steps toward the NVZ , then pivots so they are moving parallel to the NVZ line and not stepping into the NVZ . Their momentum toward the NVZ has ended .
Judging the end of momentum from a volley requires just that , judgment . Judgment calls are a necessity in applying many of the rules of pickleball , such as line calls , hinders , and most fault calls . The elements of the new definition of momentum provide specific criteria upon which judgment calls can be made on NVZ momentum calls : balance and control , or a stopping of motion . •
Dick Osman is a USA Pickleball Certified Referee and District Ambassador in Charlotte , N . C . He participated in the committee that drafted the definition of “ Momentum ” for the 2021 Rulebook , along with fellow CRs Matthew Cross and Ken Purvis .
MARCH / APRIL 2021 | MAGAZINE 57