Joint Rotational Exercise and Stretching Tool

The present invention relates generally to exercise and rehabilitation equipment, and more particularly to tools for strengthening and mobilizing joints using isolated rotational resistance.

Many shoulder injuries and movement impairments are caused by weakness, tightness and imbalance in the muscles responsible for internal and external rotation of the shoulder joint. These muscles often lack sufficient strength due to inadequate training stimulus and are commonly tight from prolonged static postures, such as sitting with forward shoulder posture.

Current rehabilitation and training approaches for these muscles typically include elastic bands, light dumbbells, and manually guided stretches. However, these tools provide linear resistance, not rotational torque, which limits their effectiveness for strengthening joint rotation directly.

For example, when using a weight for shoulder external rotation with the a person standing with their upper arm horizontal and the forearm perpendicular to the upper arm, the resistance is greatest when the forearm is horizontal and decreases as the forearm moves vertically—leaving the initial and final portions of the rotation underloaded. Elastic bands exhibit a similar issue: their resistance varies based on the angle of stretch, with effective torque applied only through a limited arc of movement.

Similar limitations are found in rehabilitation of the elbow and wrist joints, particularly in addressing conditions such as golfer's elbow and tennis elbow. These injuries often result from muscular imbalance or insufficient strength in the muscles and connective tissues surrounding the elbow. Common corrective exercises include wrist curls performed in a pronated or supinated position using light dumbbells, but these, too, rely on linear resistance that does not align well with the natural arc of wrist rotation.

Another tool used in wrist and forearm rehabilitation is an elastomeric cylinder, roughly the length of the forearm, which the user twists in complex patterns to apply rotational loading. While effective in some cases, these devices require coordinated motion that may be difficult for the average user to perform correctly or consistently, often resulting in frustration and poor adherence to exercise programs.

In clinical and performance settings, specialized machines exist that provide rotational resistance to target shoulder and elbow movement. These typically include a seat, arm support, and lever-based resistance system. However, such machines are often large, expensive, and not suitable for home use.

There remains a need for a tool that enables isolated joint rotation with consistent resistive torque at the shoulder, elbow, and wrist joints, in a compact, user-friendly, and versatile format suitable for both rehabilitation and performance applications.

The present invention provides a rotational exercise and stretching tool that enables targeted strengthening and mobilization of joints such as the shoulder, elbow, and wrist without the need for large machines. The device allows for controlled, joint-specific rotational resistance through a variety of user positions and angles, supporting both concentric and eccentric muscle loading as well as isometric holds and passive stretching.

While traditional rehabilitation exercises for joints like the glenohumeral joint, elbow, or wrist often use dumbbells, elastic bands, or improvised tools, these typically rely on linear resistance and do not consistently provide torque aligned with the rotational axis of the joint. This invention overcomes those limitations by providing consistent resistive torque throughout the intended arc of motion, reducing the complexity and variability seen in conventional tools.

In some embodiments, the invention comprises a secure mount that may be affixed to gym equipment (such as a squat rack), to structural features (such as a wall, post, door, or doorframe), or to a wearable harness or purpose-built frame. A torque-generating mechanism is operably coupled to the mount and provides rotational resistance—typically bidirectional and variable—to accommodate different users and exercise needs.

An ergonomic lever arm is operably connected to the torque unit and includes one or more alignment features configured to position the user's limb in alignment with the axis of rotation. The lever arm may be adjustable in length, interchangeable, or extendable, and may incorporate a grip geometry or cuff to support various joint configurations and exercises.

In use, the tool is positioned and adjusted so that the user's selected joint—such as the wrist, elbow, or shoulder—is aligned with the axis of rotation. The user may then apply muscular force to rotate the lever arm concentrically or eccentrically against resistance, or may hold the arm in a fixed position for isometric loading. In some cases, the tool may also be used passively, with the arm moved by a second limb, another person, or external force to facilitate stretching or joint mobilization. These exercises may be performed in standing, seated, or lying positions, depending on the mounting location and desired movement.

The Rotational Exercise and Stretching Tool is designed for strengthening and mobilizing muscles and connective tissues surrounding joints of the human body. The tool comprises:

The lever arm may be of adjustable or interchangeable length and is designed to accommodate both limb alignment and targeted resistance application. In some embodiments, forearm rests, elbow cups, cuffs, or other ergonomic contact geometries are provided to facilitate consistent limb positioning. The torque unit may employ any of a variety of mechanisms including but not limited to torsion springs, elastomers, weights, pneumatic pistons, electric actuators, or other mechanisms to generate rotational resistance, typically bidirectional and adjustable in intensity.

The mount may be affixed to a variety of surfaces including but not limited to gym equipment, vertical posts, doors, door frames, or structural walls. In some embodiments, the mount supports rotation axes that are horizontal, vertical, or angled (e.g., 45 degrees), enabling use across a variety of anatomical planes.

Depending on how the tool is mounted and configured, it may be used to facilitate joint-specific exercises for the shoulder, elbow, wrist, hip, or other articulations. Exercises may include rotational strengthening, isometric holds, eccentric control, or passive stretching. A detailed description of these use scenarios is provided in the Methods of Use section.

The following descriptions refer to illustrated embodiments of the invention and are provided to enable understanding of its structure, function, and various configurations. These embodiments are exemplary in nature and do not limit the scope of the invention, which is defined by the claims.

Unless otherwise specified, the terminology used in this description should be interpreted according to the following principles:

While the figures illustrate specific structures, shapes, and mechanical arrangements, it should be understood that alternative materials, geometries, fastening systems, and configurations may be used to achieve equivalent function. Accordingly, components shown or described in one embodiment may be substituted, repositioned, or omitted in other embodiments within the scope of the invention. Dashed lines in the figures are used to indicate groupings of components functionally associated as a system or assembly, without implying structural enclosure.

Reference numerals are used consistently across figures unless otherwise specified, and similar numbers refer to similar or functionally equivalent components.

This embodiment includes a mount system, comprising:

The rotational resistance is generated by a torque unit, which comprises:

Fixed elements (axially-proximal fixed pieceand axially-distal fixed piece), each with square holes that keep them rotationally fixed to the axial shaft.

Mobile elements (axially-proximal mobile pieceand axially-distal mobile piece), each with round holes allowing rotation about the axis.

A torsion spring, with a proximal spring legand distal spring leg, configured to apply torque as the mobile pieces rotate relative to the fixed pieces.

Hardwareconnects the two mobile piecesand, ensuring they rotate together.

Hardwareconnects the two fixed piecesand, ensuring they remain stationary with respect to one another and to the mount.

The lever arm systemis connected to the torque unitand includes:

An axial shaft, which transmits torque from the torque unitto the mount system. The shaft remains rotationally fixed relative to the mount but allows transfer of reactive torque from the tool back into the mount.

A lever arm, received within a lever-arm mount, which includes a series of holes allowing the effective length of the lever arm to be adjusted.

A spring pinis used to secure the lever arm at a selected length.

A lever-arm handleis located at the radially-distal end and may be oriented either parallel or perpendicular to the circumferential direction of rotation, enabling the user to adopt a supinated, neutral or pronated grip.

Hardwaresecures the lever-arm mountto the torque unit, such that the lever armrotates in unison with the mobile elementsand.

A contact geometryfor the forearm is located at the radially-proximal end of the lever arm. In this embodiment, it is a shaped post oriented approximately perpendicular to the lever arm and approximately parallel to the axis of rotation, configured to contact the user's forearm near the elbow, particularly for shoulder rotation exercises performed with the elbow bent at a right angle.

In this embodiment, the torsion springprovides substantially equal torque in both clockwise and counterclockwise directions. When the lever arm systemis in a neutral position (as shown in), both spring legsandare in contact with the mobile and fixed pieces.

As the lever arm system is rotated clockwise (), the distal spring legmoves with the mobile pieces while the proximal legremains engaged with the fixed pieces. When rotated counterclockwise (), the roles reverse: the proximal spring legmoves with the mobile pieces, while the distal legremains engaged with the fixed elements. In either direction, the spring winds tighter, creating resistive torque.

As illustrated in, this embodiment may also incorporate two torque unitsmounted along the same axial shaft, or along aligned but separate shafts. The fixed components of both torque units remain rotationally fixed to the mount via the shaft(s), while the mobile components are secured to one another and to the lever arm via hardware(or equivalent structural features), thereby increasing the total resistance.

It will be understood by those skilled in the art that additional torque units could be mechanically linked via gears, pulleys, or other means to increase total torque output without physically stacking them along the same axis.

illustrate an alternative embodiment of the invention in which the torque-generating mechanism consists of a drum-and-strap system, rather than the torsion spring-based torque unit described in the previous embodiment.

In this embodiment, a drumis rotatably mounted about a circular axial shaft. A flexible strapis affixed around the drum and extends to an attachment point, which is configured to connect to a source of linear resistance. As the lever arm systemis rotated by the user, the drumrotates via a connecting member, thereby winding or unwinding the strap and raising or lowering the attachment point.

A resistance element—such as a tension spring, weight stack, or elastomeric band—is secured to the opposite end of the strap. As the strap is displaced due to drum rotation, the linear resistance is effectively converted into rotational resistance (torque) experienced at the lever arm.

To permit mounting in a vertical-axis configuration, the front face of the drum may be fitted with crown gear teeth, which engage with a corresponding set of crown gear teethon a vertical rotation wheel. The lever arm systemmay be operably connected to the vertical rotation wheel via the same or an alternate connecting member, such that movement of the lever arm results in synchronized rotation of the vertical wheel and thus the drum.

This arrangement enables the use of the same linear-to-rotational resistance conversion mechanism when the tool is oriented for rotation about a vertical axis, broadening the versatility of the tool for multiple joint configurations.

While the drumis illustrated as circular, it should be understood that drums of non-uniform or variable radius may be used to produce torque curves that vary across the range of motion. For example, an eccentric or cam-shaped drum may be used to increase or decrease resistance as the lever arm rotates.

Similarly, the strapmay be any flexible tension member capable of transmitting force, including but not limited to a rope, cord, chain, or fabric band. The system may also be used with a unibody elastomeric element, wherein the strap and resistance element are integrated into a single component.

Further, while only horizontal and vertical axis configurations are illustrated in the figures, it will be understood that the rotational axis of the tool may be positioned at any oblique angle. The angular conversion mechanism shown in this embodiment utilizes a crown gear arrangement for illustrative purposes; however, other suitable mechanical linkages may be employed to achieve a similar function. These may include, but are not limited to, bevel gears, universal joints, torque-transmitting couplings, or custom-milled joints configured to maintain torque transmission between non-parallel axes.

illustrates an alternative embodiment of the mount systemin which the tool is configured to be mounted to a door.

In this embodiment, a primary mount pieceis secured to a door via one or more door hooks, which are thin, flat elements that wrap around the top, bottom, or side edges of the door to hold the mount in place. The design permits stable attachment without the need for permanent hardware or modification of the door.

To accommodate users of different heights or to enable various exercise positions, the system may further include an adjustable-length connecting strapor other height-adjustment mechanism. This allows the mount to be vertically repositioned relative to the door surface to align the rotational axis of the tool with the intended joint of the user.