1. Tennis Rackets
Readings: Ch 7, Websites: Welcome to RacquetTECH.com,
Materials
Wood -not used much anymore. Why?
Metal - Aluminum is stiffer, more control, lighter . Steel - heavier, less control.
Composite - combine fiberglass with aluminum, Graphite, Kevlar, ceramic. (I-Beam Construction - Fig 7.3)
Construction
Sizes - maximum size is 32 inches long, head 15.5X11.5 in (178 sq in) (Fig 7.4)
Traditional - up to 80 sq in
Midsize sq in
Super midsize sq in
Oversize sq in
Super oversize sq in and above
Wide-Body rackets and shapes
Frame has aerodynamic design (Fig 7.5)
Head frame is wider when viewed from the side
Increased stiffness
Vibration-free innovations

2. I-beam construction:
Sizes:

3. Throat Shapes

4. Frame Designs

5. Playing and String Characteristics
Playing characteristics
Stiffness and flexibility (ground strokers want flexibility)
Weight and balance - handle-loaded for lower MOI about the hands and greater MOI about the COM (less impact recoil effect)
New trends and gimmicks
Curved handle – did not catch on
String dampeners
Mass on frame edges
“Shock absorbing” handles
String characteristics (Fig 7.9, 7.10)
Gut vs synthetic
Gut is expensive and is not durable
Elasticity of synthetics degrades at high tensions
Thickness - thicker strings increase control
Tension - higher tension for more control, lower for more power
Suggested appropriate tensions on next slide

6. Strings: Types, Shapes, Tension

7. Swing Weights (From Racquet Tech Sept, 1999)

8. Summary of “The modern tennis racquet” by Howard Brody (1996)
Introduction
Wood no longer used because of limited strength/wt ratio
Modern racquets are lighter, stiffer, longer, thicker, wider, and have a bigger head
Rules limit length of racket and size of head
New rules are made when some innovations come along
Strings
String deformation is more relevant than string tension
For a given racquet, strings are more efficient in returning energy than the ball, so looser strings give more post-impact ball velocity
Most players now use synthetic strings
Website for racquet stringers: Welcome to RacquetTECH.com

9. Brody article, cont’d
Sweet spots of the racket – place where impact feels good
Center of percussion – no reaction force at hand
Reaction force of a non-central hit can be minized by increasing MOI about COP
Node of fundamental mode of vibration ( Hz)
Vibration dampening helps minimize vibrations when impact is not on the node
Node and COP are usually close together
Power spot – point of maximum COR
Location depends on both swing mechanics and racquet design
Design objective is to make power spot coincide with COP, & node – at the racquet face center.

10. Brody article, cont’d Racket width and stability
Impacts off the longitudinal axis of racquet produce twist
Twist effect can be minimized by maximizing MOI about longitudinal axis
Make racquet face larger, or load around perimeter of racquet
Why does using a larger grip size help with twist effect?
Racket length
Traditional standard length is 27 inches
Maximum is 32 inches, but ATP uses 29 in max
Which length is best?
Conclusion – modern racquet is better due to
More power, less effort, more forgiving, more durable

11. Prince
Racquet
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