Flexible Exercise Device

Abstract

A flexible exercise device includes a resilient portion connected between a handle and an excitation mass. The resilient member is tuned such that the spring rate of the resilient portion, in combination with the excitation mass, cooperate to provide a natural frequency that is below a user excitation frequency. The flexible exercise device provides a force feedback input into targeted muscle groups that influence a swing speed of a sports implement, such as a baseball bat.

What is claimed is: 
     
         1 . A flexible exercise device having a handle, a spring portion, and an excitation mass configured such that a natural frequency of at least the spring portion and the excitation mass is lower than a user excitation frequency. 
     
     
         2 . The flexible exercise device of  claim 1  wherein the natural frequency is about 2 hertz. 
     
     
         3 . The flexible exercise device of  claim 1  wherein the spring portion is a flexible rod having a length in a range of about 35 inches to about 40 inches and having a mass of about 4 ounces to about 6 ounces. 
     
     
         4 . The flexible exercise device of  claim 1  wherein the spring portion is configured as a polymer rod having a lightly damped frequency response. 
     
     
         5 . The flexible exercise device of  claim 4  wherein the spring portion is a fiberglass rod having a damping ratio in a range of about 0.011 to about 0.013. 
     
     
         6 . The flexible exercise device of  claim 4  wherein the spring portion is a parallel spring having a first resilient element and a second resilient element. 
     
     
         7 . The flexible exercise device of  claim 6  wherein the second resilient element is coaxially mounted relative to the first resilient element. 
     
     
         8 . The flexible exercise device of  claim 6  wherein the second resilient element is a polymer sleeve that is coaxially mounted to the first resilient element. 
     
     
         9 . The flexible exercise device of  claim 8  wherein the second resilient element has a durometer in a range of about 60 Shore A to about 80 Shore A. 
     
     
         10 . A flexible exercise device having a spring portion and an excitation mass configured to respond to a user excitation in a post-resonance frequency range such that a therapeutic effect is generated at the end of an oscillatory cycle. 
     
     
         11 . The flexible exercise device of  claim 10  wherein an isolation effect occurs in the middle of the oscillatory cycle. 
     
     
         12 . The flexible exercise device of  claim 12  wherein the spring portion and the excitation mass have a natural frequency of about 2 hertz and the excitation mass is in a range of about 4 ounces to about 6 ounces. 
     
     
         13 . The flexible exercise device of  claim 10  wherein the spring portion includes a first resilient element and a second resilient element coaxially disposed about the first resilient element. 
     
     
         14 . The flexible exercise device of  claim 10  wherein the excitation mass is configured to be moved along the spring portion to adjust a natural frequency of the spring portion and excitation mass to the post-resonance frequency range. 
     
     
         15 . The flexible exercise device of  claim 10  wherein the excitation mass moves relative to the spring portion during user excitation and includes a damping component. 
     
     
         16 . The flexible exercise device of  claim 10  wherein the spring portion is an e-glass fiberglass rod having a diameter in a range of about 0.25 inches to about 0.375 inches. 
     
     
         17 . A flexible exercise device having a spring portion and an excitation mass that cooperate to have a natural frequency above a use excitation frequency, the spring portion being formed from a polymer rod having a length in a range of about 35 inches to about 40 inches and a diameter of about 0.25 inches. 
     
     
         18 . The flexible exercise device of  claim 17  wherein the natural frequency is in a range of about 1.7 hertz to about 2.3 hertz and a damping ratio in a range of about 0.006 to about 0.017. 
     
     
         19 . The flexible exercise device of  claim 17  the spring portion includes a first resilient element and a second resilient element, the first resilient element being the polymer rod formed from a fiberglass material and the second resilient element being a polymer sleeve coaxially disposed over the first resilient element, the coaxial sleeve having a durometer in a range of about 60 to 80 Shore A. 
     
     
         20 . The flexible exercise device of  claim 19  wherein the first and second resilient elements cooperate with the excitation mass to produce a cantilevered first natural frequency of about 2.0 hertz and the excitation mass is about 5.5 ounces.