The present disclosure provides for various objects (weights, playing apparatuses, balls, clothing, etc.) that have liquid disposed in them to assist in building and strengthening small muscle fibers and/or nerves. The various objects can include weights, playing apparatuses such as objects that can be swung in sports, balls, and clothing or other objects that can be worn by humans or other animals. The objects include fluid paths and re¬directions walls disposed within the fluid paths to direct fluid flow to particular areas within the objects. The designated areas to where fluid flow is directed aid in development of small muscle fibers and/or nerves due to the fluid sloshing around at those particular locations. Methods of making and using the various objects disclosed are also provided.

A tennis ball including a non-foamed thermoplastic core defining an internal volume. The core includes a thermoplastic material having a specific gravity of 0.86 to 1.38, a flexural modulus of 2.0 to 50.0 MPa, and a Shore D hardness of 10 to 70. A thickness of the thermoplastic material is between 3.0 and 8.0 mm. The thickness of the thermoplastic material is configured to maintain dimensional stability at internal pressures of between zero and 15 psi.

A tennis ball including a non-foamed thermoplastic core defining an internal volume. The core includes a thermoplastic material having a specific gravity of 0.86 to 1.38, a flexural modulus of 2.0 to 50.0 MPa, and a Shore D hardness of 10 to 70. A thickness of the thermoplastic material is between 3.0 and 8.0 mm. The thickness of the thermoplastic material is configured to maintain dimensional stability at internal pressures of between zero and 15 psi.

A rubber composition for a tennis ball includes a base rubber and a high-flatness filler. The high-flatness filler has an average particle diameter D.sub.50 of not less than 1 μm and not greater than 50 μm. A degree of flatness DL is not less than 40 and not greater than 200. An amount of the high-flatness filler per 100 parts by weight of the base rubber is not less than 5 parts by weight and not greater than 100 parts by weight. A ratio (E2/E1) of a tensile elastic modulus E2 in a tensile strain range from 70% to 100% to a tensile elastic modulus E1 in a tensile strain range from 10% to 30%, of a vulcanized rubber obtained by vulcanizing the rubber composition, is not less than 0.60 and less than 1.00. The tennis ball includes a hollow core formed from the rubber composition.

A punching ball is spherical and specifically designed for striking against a wall for power and precision training. The punching ball can have varied weight, size, rebound characteristics and density parameters while maintaining a multilayer configuration in which there are two layers of foam around a dense core. The outer-most foam layer is covered by an outer shell material. By using different densities in the foam layers and for the core, the punching ball can deform around the fist of a person punching the punching ball. As such, the punching ball can be directed to a desired location during a punch. This provides a method of training in power and precision, as the punching ball can be repeatably punched towards a wall, the person training having to follow-through on every rebound.

A punching ball is spherical and specifically designed for striking against a wall for power and precision training. The punching ball can have varied weight, size, rebound characteristics and density parameters while maintaining a multilayer configuration in which there are two layers of foam around a dense core. The outer-most foam layer is covered by an outer shell material. By using different densities in the foam layers and for the core, the punching ball can deform around the fist of a person punching the punching ball. As such, the punching ball can be directed to a desired location during a punch. This provides a method of training in power and precision, as the punching ball can be repeatably punched towards a wall, the person training having to follow-through on every rebound.

A strip subassembly (2) which may be used to form a takraw ball or a similar woven ball, includes a backbone strut (4) and one or more pads (6) attached to the backbone strut (4). In the woven ball, the pads (6) form an even surface which is comfortable for the player.

A tennis ball including a spherical hollow elastomeric core having a specific gravity of less than 1 and a thickness of at least 4.5 mm, and a textile layer covering the spherical elastomeric hollow core. The spherical hollow core has an initial internal pressure of no greater than 5 psi. The tennis ball has a first tennis ball rebound height when measured at a first time when the tennis ball is unused and a second tennis ball rebound height measured after the tennis ball is exposed to atmospheric pressure for four months following the first time and is unused. The second tennis ball rebound height being at least 96% of the first tennis ball rebound height.

Biodegradable tennis balls are described. A biodegradable tennis ball includes a core forming a hollow interior chamber, the core made of a blend of a rubber based material, a first petroleum based material, and a first biodegradable additive. The biodegradable tennis ball also includes a felt layer overlaying a surface of the core, the felt layer made of a second blend of a second petroleum based material and a second biodegradable additive. In some cases, the biodegradable tennis ball may include an adhesive layer adhering the felt layer to the core. In some cases, the felt layer may further include wool.

Biodegradable tennis balls are described. A biodegradable tennis ball includes a core forming a hollow interior chamber, the core made of a blend of a rubber based material, a first petroleum based material, and a first biodegradable additive. The biodegradable tennis ball also includes a felt layer overlaying a surface of the core, the felt layer made of a second blend of a second petroleum based material and a second biodegradable additive. In some cases, the biodegradable tennis ball may include an adhesive layer adhering the felt layer to the core. In some cases, the felt layer may further include wool.