Yonex RDX 500 HD Midplus

Head size (also known as the “string bed” or “oval”) is one of the most important characteristics of a tennis racket, as it directly affects power, control, forgiveness, and comfort.

🎾 What is head size?

It’s the area of the frame where the strings are interlaced, measured in square inches (in²) or square centimeters (cm²). The most common sizes range from around 85 in² (550 cm²) to 135 in² (870 cm²).

📏 Main categories

⚙️ Impact on gameplay

• Small head sizes: offer more control, but less forgiveness. Ideal for advanced and technical players.
• Midplus head sizes: balanced mix of control and power, suitable for a wide range of players.
• Large head sizes (Oversize): generate more power and a bigger sweetspot. Easier to play with, especially for shorter swings or less frequent players.

🎯 In practical terms

A larger head size means a larger sweetspot, making the racket more forgiving on off-center shots.

A smaller head size offers greater precision and responsiveness, but demands better technique and clean contact.

🔺 Isometric head shapes

Some manufacturers use a head shape called isometric, which differs from the traditional oval design. The isometric head has a more squared profile, with the upper and lateral parts slightly expanded, which helps increase the sweetspot.

At the same total surface area, an isometric racket offers more effective hitting area compared to a standard oval shape, improving forgiveness and consistency on off-center hits. This design is especially appreciated by players seeking a blend of precision, power, and comfort without increasing overall head size.

String pattern is a key technical parameter that affects control, spin, string durability, and impact feel.

🎾 What Is String Pattern?

It’s the arrangement of vertical (main) and horizontal (cross) strings in the racquet’s head.

📏 Common String Patterns

⚙️ Effects on Play

• Open patterns (e.g., 16x19, 14x18): more string movement → more spin and power → shorter string life.
• Dense patterns (e.g., 18x20): more stability and control → less string deformation → greater durability and precision.

🎯 In Practice

If you're a spin player or want more power and effect, go with an open pattern. If you prefer precision and consistency from the baseline, a denser pattern is often better suited.

The racquet beam profile is one of the key factors affecting how a racquet performs on court. In addition to thickness, the shape of the frame — boxed, tapered (aerodynamic), or hybrid — plays a fundamental role in control, power, and feel at impact.

🎾 What is the beam profile?

The profile refers to the side thickness of the frame, measured in millimeters. The thicker it is, the stiffer and more powerful the racquet tends to be.

📏 Beam thickness types

🔷 Frame section types

⚙️ On-court effects

• Thin + boxed beam: maximum feel, control, and flex. Requires more skill.
• Thick + profiled beam: high power and easy play. Less sensitivity on contact.
• Hybrid beam: ideal balance for versatile performance.

🎯 In practice

Beam profile affects frame stiffness, energy return, and the feel on ball impact. Considering both thickness and shape is essential to find a racquet that fits your playing style.

The weight of the racquet is one of the most important aspects that affects on-court performance. The ideal weight choice depends on personal preference and playing style, as it influences power, control, maneuverability, and comfort.

🎾 What is the weight of the racquet?

The weight of the racquet is its overall mass, typically measured in grams (g) or ounces (oz). Lighter racquets are more maneuverable, while heavier ones offer greater stability and power.

⚖️ Types of racquet weights

⚙️ Effects on play

• Light racquets: easier to maneuver, ideal for quick responses and speed, but less power and control.
• Medium racquets: excellent balance between power and control, versatile for players of various levels.
• Heavy racquets: more stability and power, ideal for solid shots and precision, but require more strength and can be tiring to maneuver.

🎯 In practice

If you're looking for maneuverability and speed, a lighter racquet is ideal. If you prefer a balance between control and power, opt for a medium-weight racquet. For advanced players seeking maximum power and stability, a heavier racquet is the best choice.

The balance of the racquet is a key parameter that directly influences the feel of the racquet in your hand, as well as its performance on the court. It refers to the distribution of weight along the frame and determines how the racquet reacts during play. A correct balance is essential for getting the most out of every shot.

🎾 What is racquet balance?

The balance of the racquet is the position where the weight of the racquet is distributed. It is usually measured in centimeters (cm) from the base of the handle, along the frame. The balance point is where the racquet is "neutral," meaning if you rest it on a finger, it will not tilt toward the head or the handle.

📏 Types of balance

⚙️ Effects on the game

• Head-heavy balance: Greater power on groundstrokes, particularly useful for players who hit powerful, heavy shots. Less maneuverable, so it can become tiring after long matches.
• Head-light balance: Greater maneuverability and speed for quick shots, ideal for net play or fast shots. Less power compared to a head-heavy racquet, so it may require more strength on groundstrokes.
• Even balance: Provides a good combination of power and control without overly favoring one aspect. Suitable for intermediate players looking for a versatile racquet.

🎯 In practice

The choice of balance depends a lot on your playing style and personal preferences. If you’re looking for a racquet that helps generate power, a head-heavy balance might be the right choice. If you prefer control and speed in your shots, a head-light racquet will give you an advantage. If you’re unsure, an even balance provides a good middle ground for all levels of play.

The stiffness of the racquet is a crucial parameter that affects the playing feel, power, and comfort. It refers to the resistance of the racquet frame to deformation upon impact with the ball. The stiffer the frame, the less deformation there will be, and the more energy will be transferred to the ball, generating more power. However, greater stiffness can reduce the comfort feel, especially if the ball doesn't hit perfectly in the sweet spot. Conversely, a more flexible frame offers more control and a softer feel at impact but may sacrifice some power.

🎾 What is racquet stiffness?

Stiffness is the ability of the frame to resist bending when the ball strikes the strings. It is measured in a value called RA (Racquet Stiffness Rating), with higher values indicating greater stiffness.

📏 Types of stiffness:

⚙️ Effects on gameplay

• High stiffness: more power, less control, greater stress on the arm and elbow. Ideal for players with good technique who seek immediate power.
• Medium stiffness: good balance between power and control, suitable for most players.
• Low stiffness: more control and comfort, but requires more effort to generate power. Ideal for players who seek a soft feel and prefer control over spin.

🎯 In practice

The choice of stiffness depends on your personal needs and playing style. If you seek power and a quicker response, a stiffer racquet might be the right choice. If, on the other hand, you prioritize control, comfort, and a softer feel at impact, a racquet with lower stiffness might suit you better.

The "polar index" of a tennis racket is not a universally recognized term among all manufacturers, but it is used by some brands or specialized apps to describe a specific aspect of the racket’s weight distribution.

🎾 What is the Polar Index of a racket?

The Polar Index is an indicator of how polarized the racket's weight is—in other words, how much the weight is concentrated toward the head and handle rather than the center of the frame.

📐 How it works:

• The higher the Polar Index, the more the weight is distributed toward the racket’s extremes (typically the head and handle).
• The lower the Polar Index, the more mass is concentrated in the center of the frame.

• Players who customize rackets by adding lead tape, silicone, etc.
• Advanced players looking to fine-tune swingweight, maneuverability, and power.

📊 Practical effects:

🎯 In practice

• Players who customize their rackets.
• Coaches and technicians optimizing maneuverability, spin, and control.
• Anyone who wants to understand why a racket swings or hits in a certain way.

Dynamic stiffness of a tennis racket is an advanced parameter that describes how much the racket resists deformation during real impact with the ball.

🎾 What is dynamic stiffness?

Unlike static stiffness (RA index), which is measured on a static frame, dynamic stiffness takes into account the real-world behavior of the racket during use, including:

• The interaction between strings, frame, and ball
• The speed of the impact
• The contact point on the stringbed

🔍 Key differences

📐 Practical example

A racket with a RA of 60 may appear flexible, but if it has tight strings and a small head size, it may actually have a high dynamic stiffness. On the other hand, a racket with an RA of 70 may feel softer when strung at low tension with elastic strings.

📊 Why is it important?

• Arm comfort: less vibration → more comfort
• Ball control: more deformation = longer dwell time
• Power and speed: less deformation = more energy transfer

🎯 In Practice

• RA (static): useful for comparing frames
• Dynamic stiffness: more useful for understanding how a racket actually plays
• Depends on: strings, tension, contact point, materials, frame design

Swingweight is a fundamental parameter that measures how "heavy" a racket feels during a swing, i.e., during the motion of a stroke. It differs from static weight: two rackets can weigh the same in hand but feel very different during play.

🎾 What is Swingweight in a tennis racket?

Swingweight represents the resistance to rotation of the racket around the hand’s pivot point (typically 10 cm from the butt of the handle). It is expressed in kg·cm² and measured using tools like the Babolat RDC or Wilson Diagnostic Machine.

📊 Typical values

🧠 What affects Swingweight?

• Balance point: the more weight in the head, the higher the swingweight
• Total mass: more weight generally increases swingweight (but not always linearly)
• Weight distribution: more polarized rackets have higher swingweight

🪄 On-court effects

🔧 Can I modify it?

• Adding lead at 12 o’clock → significantly increases swingweight
• Lead at 3 and 9 o’clock → moderate increase, improves lateral stability
• Silicone in the handle → little effect on swingweight, alters balance point

Spinweight is a parameter that measures how easy it is to generate spin on the ball during play. It differs from swingweight, as it focuses on the racquet's ability to produce spin rather than its resistance to rotation.

🎾 What is Spinweight?

Spinweight represents the ease with which the racquet generates rotation on the ball, and is influenced by the weight distribution of the frame and the strings. It is measured in kg·cm² and reflects how quickly the racquet head moves during impact with the ball.

🧠 What Affects Spinweight

• Balance: A head-heavy racquet increases spinweight, favoring faster movement of the racquet head
• Total weight: A heavier racquet tends to generate more spin but reduces maneuverability
• String pattern: An open string pattern (e.g., 16x19) increases spin potential, while a closed pattern (e.g., 18x20) provides more control

🪄 Effects on Court

🔧 Can I Modify It?

• Adding lead tape at 12 o'clock → increases spinweight, favoring faster movement of the racquet head
• Lead tape at 3 and 9 o'clock → smaller increase, enhances lateral stability and spin on lateral shots

Twistweight is a parameter that measures the racquet's resistance to twisting during impact with the ball, especially when hitting off-center. It’s an important measure for players who want to understand how stable the racquet will be on off-center hits or when striking with a lot of spin.

🎾 What is Twistweight?

Twistweight represents the resistance to torsion of the racquet around the axis of the handle when the ball strikes the racquet off-center. It is measured in kg·cm², and a higher twistweight indicates a racquet that resists twisting during impact with the ball.

🧠 What Affects Twistweight

• Racquet Design: A stiffer and wider frame tends to have a higher twistweight
• Balance: A head-heavy racquet will have a higher twistweight
• String Pattern: An open string pattern reduces twistweight, while a denser pattern increases it

🪄 Effects on Court

🔧 Can I Modify It?

• Adding lead tape at 3 and 9 o'clock → increases twistweight, improving lateral stability
• Adding lead tape at 12 o'clock → increases resistance to torsion by adding weight to the racquet head
• Higher string tension → can increase twistweight by making the frame stiffer

Recoilweight is a parameter that measures the racquet's resistance to returning to its original position after impact with the ball. A higher recoilweight means the racquet is slower to return to position, while a lower recoilweight indicates the racquet recovers more quickly after the shot.

🎾 What is Recoilweight?

Recoilweight represents the resistance to the racquet's return after impact with the ball. It measures how quickly the racquet returns to its original position after each shot, and it is influenced by factors like weight, balance, and frame stiffness. It is measured in kg·cm².

🧠 What Affects Recoilweight

• Weight: A heavier racquet generally has a higher recoilweight, as it takes longer to return after impact
• Balance: A head-heavy racquet will have a higher recoilweight
• Frame Stiffness: A stiffer frame will return more quickly, resulting in a lower recoilweight

🪄 Effects on Court

🔧 Can I Modify It?

• Adding lead tape at 12 o'clock → increases recoilweight, improving stability
• Lead tape at 3 and 9 o'clock → reduces recoilweight, increasing recovery speed
• Stiffer strings → decrease recoilweight and accelerate racquet return

The length of a tennis racket is a key factor that directly influences maneuverability, leverage, and overall control during play. Different racket lengths suit different ages, skill levels, and playing styles.

📏 How long is a tennis racket?

Standard adult tennis rackets are typically 27 inches (68.6 cm) long, though they can vary slightly. Longer rackets provide more reach and power, while shorter ones are easier to maneuver and control. Junior racket lengths vary depending on the child’s age and height.

🎯 Racket length by age and skill level

⚙️ How length affects gameplay

• Longer rackets: provide more power and reach thanks to greater leverage, but can be harder to maneuver, especially for beginners.
• Shorter rackets: offer better control and quicker reactions, ideal for kids or players who prefer agility.
• Standard length (27”): offers a good balance of control and power, suitable for most adult players.

🧠 Practical tip

If you're a beginner or buying for a young player, choose a racket length based on the player’s height and strength. Intermediate or advanced adult players typically do well with the standard length, though the ideal size depends on your playing style.

Frame torsion refers to the racquet's resistance to twisting during off-center impacts. When the ball is not struck directly on the sweet spot, torsional stiffness helps maintain shot stability and reduces vibration.

🔄 What is torsion?

During an off-center hit, the racquet tends to rotate or twist sideways. This movement is called torsion. A racquet with high torsional resistance stays more stable, helping to control the shot and reduce unwanted feedback.

📊 Impact of Torsion on Performance

🧠 Summary

A racquet with high torsional stiffness is ideal for powerful players who need stability on imperfect shots. Players who prefer a softer feel might choose a more flexible frame, accepting some compromise in shot stability.

Vertical flex refers to how much the racquet frame bends backward (toward the player) during ball impact and is often represented by a measurement called RA (Stiffness Rating). This value indicates how resistant the frame is to bending under force: the higher the RA, the stiffer the racquet. This flex influences the feel, dwell time, and energy transfer during the shot.

🔧 What does vertical flex mean?

When striking the ball, the frame deforms slightly in the vertical direction. A racquet with higher vertical flex absorbs impact better, offering greater comfort and control, but with less explosive power. A stiffer frame, instead, transfers energy more quickly to the ball.

📊 Effects of Vertical Flex on Performance

🧠 Summary

Vertical flex is a key characteristic to match with your playing style. Players who value control and feel may prefer more flex, while those who rely on powerful strokes may choose stiffer frames.