The invention relates to the new structure of the fin or the fin's blade (2). The blade (2) is made of segments (S) and transitions (T), wherein a segment with a positive incline and a segment with a negative incline alternate along the blade (2). For example, two neighbouring segments (S) with a transition (T) can form the shape of a wave, a triangle, a trapezium or a tooth. Individual segments (S) can be flat, mainly flat or curved. The lengths of two neighbouring segments (S) with a transition (T) define total length (L). Heights (H) of segments (S), total length (L) and transition (T) length can be equal, they can increase or decrease linearly, progressively or regressively. Random combinations of changing shapes, heights (H), segments (S), total lengths (L) and transitions (T) along the blade (2) are possible. Segments can follow each other across the entire width of the blade's (2) surface or optionally in one part of the fin. Preferably, segments (S) are produced in the shape of waves with connective transitions, thus in the shape of a sinusoid. Preferably, the height (H1) of the segment is the highest at the root (7) of the blade (2), where the foot pocket (1) is installed, and decreases towards the ending (8) of the blade (2) until the transition to the flat part (10). Preferably, total lengths (L) are equal or increasing from the root (7) towards the ending (8) of the blade (2).

A mono-fin for swim training is disclosed. The mono-fin has two separated boot structures that from two separate foot cavities for holding feet with toes positioned in front regions of each of the boot structures and heels positioned at back regions of each of the boot structures. The mono-fin has a mono-fin structure with blades portions connecting the boot structure through the front regions of each of the boot structures. In a middle region of the mono-fin structure and between the blade portions, there is flex region. The flex region allows angles between the boot structures, distances between the back regions of the boot structures and angles between the blade portions to be changed simultaneously by a swimmer while swim training in an aquatic environment.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A resistance kickboard attachment is disclosed. When attached to a kickboard, the resistance kickboard attachment adds resistance while swimming with the kickboard. The resistance kickboard attachment includes a resistance pocket, with variable resistance provided by an adjustment of a rear aperture of the resistance pocket. The resistance kickboard attachment attaches to the kickboard with a transverse and a longitudinal strap. The transverse strap includes an adjustment on either side of the longitudinal strap which allows the longitudinal strap to be centered on the kickboard.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A method for providing a swim fin includes providing a foot attachment member and a blade member having a predetermined blade length. The blade member has a soft portion made with a relatively soft thermoplastic material. The method includes providing a relatively harder portion and the relatively soft thermoplastic portion that is molded to the relatively harder thermoplastic portion. The method includes providing an orthogonally spaced portion of the relatively harder portion that is arranged a predetermined orthogonal direction while said swim fin is in state of rest. The method includes providing the blade member with a predetermined biasing force portion that is arranged to urge the orthogonally spaced portion while the swim fin is in a state of rest. The method includes arranging a significant portion of the blade length to experience pivotal motion a lengthwise angle of attack during use.

A wetsuit for aquatic activities may include a wetsuit material having a first surface and an opposite second surface. The wetsuit has a portion comprising one or more paddling assist members that may be configured to lay flat while inserting the portion into water and extend outward from the surface of the wetsuit when the portion is drawn backward during a paddling stroke movement to provide greater resistance to the movement, increasing thrust provided by the movement.

Swim training devices and methods for portable swim training that assists swimmers in proper swimming alignment. Devices and methods include a leg stroke training system. Devices and methods also include an upper body training system. Such training methods, devices and systems can be used separately or in combination.