Circular Air Resitance 

Spin Strong is the first handheld and portable trainer to use circular air resistance. This is similar to how a jump rope works. A jump rope obviously creates the air resistance by swinging the rope in large circles very fast. However, Spin Strong generates air resistance using compact handle attached fin cords. These fin cords consist of short cords with freely rotating plastic triple fin modules attached.

The symmetrical layout of the three fins around the fin module are the key to their ability to create air resistance. As the fin modules attached to the cords are spun through the air, the air hits the symmetrical fins with balanced amounts of force on the fin modules (on each side of the cord). So, the fin modules steadily move through the air and generate continuous air resistance, as shown in the graphic below.

Air resistance opposes forward movement

Air resistance opposes an objects forward motion. In the case of circular movement, it’s constantly changing direction, but it’s the same principal. Air resistance provides continuous and directly opposing force to an arm’s “forward”movement along the path of the circle, or around the circle, as shown in the graphic below. 

Weights like dumb bells do not provide this kind of direct opposition. They are always exerting a downward force. An arm has to move a dumb bell around while holding it up in the air.

Complex and interrelated arm/shoulder movements

Spin Strong Rotary Training combines air resistance and circular arm motion. This is very complex movement. It includes muscles and joints from the hand, up the arm to the shoulder, and down into the core. All major joints are included.


The Spin Strong Training Musclle Diagram

The wrist joint is a circular joint and has full range of 360 degree movement. The elbow joint has 180 degree range of movement up and down, in terms of flexing and extending the arm, as well as almost 180 degree rotation of the lower arm. The shoulder joint, the most complex joint in the human body, is a circular joint also, and has a full range of 360 degree movement. The following picture shows the movement of these three joints.


Four arm movements in one

A circular movement of the arm or wrist is called circumduction. It equals four sequential movements of flexion (up), abduction (out), extension (down) and Adduction (in) as shown below.


Picture of an arm circle equals four sequential arm movements

Circular arm motion using the shoulder joint includes these four sequential movements. Circular wrist action includes four more arm movements. The arm is constantly flexing and rotating the lower arm using the elbow joint (which includes secondary joints). So each arm circle includes at least 10 sequential and interrelated arm movements. This is incredibly complicated. And it is happening close to two hundred times a minute.


Strengthens all major muscles of arms and shoulders

These movements engage and strengthen all the major muscles of the arms and shoulders. The hands are gripping the Spin Strong handles. Forearms are highly engaged in finger, hand and wrist movements. Biceps and triceps are engaged in elbow and shoulder movement. All the muscle of the shoulders are involved, as well as muscles of the upper body and the core.

This training builds fast twitch muscles for speed. Yet, it also increases the kind of strength that improves endurance. This exercise has been appreciated indirectly in that it is the arm action used in highly respected jump rope exercise. But now, it can be appreciated in its own right. The many different rotary exercises that can be done with Spin Strong show the true potential of this extensive and unique training for the upper body and especially the arms and shoulders.